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authorBen Cheng <bccheng@google.com>2014-03-25 22:37:19 -0700
committerBen Cheng <bccheng@google.com>2014-03-25 22:37:19 -0700
commit1bc5aee63eb72b341f506ad058502cd0361f0d10 (patch)
treec607e8252f3405424ff15bc2d00aa38dadbb2518 /gcc-4.9/gcc/ifcvt.c
parent283a0bf58fcf333c58a2a92c3ebbc41fb9eb1fdb (diff)
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Initial checkin of GCC 4.9.0 from trunk (r208799).
Change-Id: I48a3c08bb98542aa215912a75f03c0890e497dba
Diffstat (limited to 'gcc-4.9/gcc/ifcvt.c')
-rw-r--r--gcc-4.9/gcc/ifcvt.c4686
1 files changed, 4686 insertions, 0 deletions
diff --git a/gcc-4.9/gcc/ifcvt.c b/gcc-4.9/gcc/ifcvt.c
new file mode 100644
index 000000000..0d1adce95
--- /dev/null
+++ b/gcc-4.9/gcc/ifcvt.c
@@ -0,0 +1,4686 @@
+/* If-conversion support.
+ Copyright (C) 2000-2014 Free Software Foundation, Inc.
+
+ This file is part of GCC.
+
+ GCC is free software; you can redistribute it and/or modify it
+ under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3, or (at your option)
+ any later version.
+
+ GCC is distributed in the hope that it will be useful, but WITHOUT
+ ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
+ License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with GCC; see the file COPYING3. If not see
+ <http://www.gnu.org/licenses/>. */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
+
+#include "rtl.h"
+#include "regs.h"
+#include "function.h"
+#include "flags.h"
+#include "insn-config.h"
+#include "recog.h"
+#include "except.h"
+#include "hard-reg-set.h"
+#include "basic-block.h"
+#include "expr.h"
+#include "output.h"
+#include "optabs.h"
+#include "diagnostic-core.h"
+#include "tm_p.h"
+#include "cfgloop.h"
+#include "target.h"
+#include "tree-pass.h"
+#include "df.h"
+#include "vec.h"
+#include "pointer-set.h"
+#include "dbgcnt.h"
+
+#ifndef HAVE_conditional_move
+#define HAVE_conditional_move 0
+#endif
+#ifndef HAVE_incscc
+#define HAVE_incscc 0
+#endif
+#ifndef HAVE_decscc
+#define HAVE_decscc 0
+#endif
+#ifndef HAVE_trap
+#define HAVE_trap 0
+#endif
+
+#ifndef MAX_CONDITIONAL_EXECUTE
+#define MAX_CONDITIONAL_EXECUTE \
+ (BRANCH_COST (optimize_function_for_speed_p (cfun), false) \
+ + 1)
+#endif
+
+#define IFCVT_MULTIPLE_DUMPS 1
+
+#define NULL_BLOCK ((basic_block) NULL)
+
+/* True if after combine pass. */
+static bool ifcvt_after_combine;
+
+/* # of IF-THEN or IF-THEN-ELSE blocks we looked at */
+static int num_possible_if_blocks;
+
+/* # of IF-THEN or IF-THEN-ELSE blocks were converted to conditional
+ execution. */
+static int num_updated_if_blocks;
+
+/* # of changes made. */
+static int num_true_changes;
+
+/* Whether conditional execution changes were made. */
+static int cond_exec_changed_p;
+
+/* Forward references. */
+static int count_bb_insns (const_basic_block);
+static bool cheap_bb_rtx_cost_p (const_basic_block, int, int);
+static rtx first_active_insn (basic_block);
+static rtx last_active_insn (basic_block, int);
+static rtx find_active_insn_before (basic_block, rtx);
+static rtx find_active_insn_after (basic_block, rtx);
+static basic_block block_fallthru (basic_block);
+static int cond_exec_process_insns (ce_if_block *, rtx, rtx, rtx, int, int);
+static rtx cond_exec_get_condition (rtx);
+static rtx noce_get_condition (rtx, rtx *, bool);
+static int noce_operand_ok (const_rtx);
+static void merge_if_block (ce_if_block *);
+static int find_cond_trap (basic_block, edge, edge);
+static basic_block find_if_header (basic_block, int);
+static int block_jumps_and_fallthru_p (basic_block, basic_block);
+static int noce_find_if_block (basic_block, edge, edge, int);
+static int cond_exec_find_if_block (ce_if_block *);
+static int find_if_case_1 (basic_block, edge, edge);
+static int find_if_case_2 (basic_block, edge, edge);
+static int dead_or_predicable (basic_block, basic_block, basic_block,
+ edge, int);
+static void noce_emit_move_insn (rtx, rtx);
+static rtx block_has_only_trap (basic_block);
+
+/* Count the number of non-jump active insns in BB. */
+
+static int
+count_bb_insns (const_basic_block bb)
+{
+ int count = 0;
+ rtx insn = BB_HEAD (bb);
+
+ while (1)
+ {
+ if (active_insn_p (insn) && !JUMP_P (insn))
+ count++;
+
+ if (insn == BB_END (bb))
+ break;
+ insn = NEXT_INSN (insn);
+ }
+
+ return count;
+}
+
+/* Determine whether the total insn_rtx_cost on non-jump insns in
+ basic block BB is less than MAX_COST. This function returns
+ false if the cost of any instruction could not be estimated.
+
+ The cost of the non-jump insns in BB is scaled by REG_BR_PROB_BASE
+ as those insns are being speculated. MAX_COST is scaled with SCALE
+ plus a small fudge factor. */
+
+static bool
+cheap_bb_rtx_cost_p (const_basic_block bb, int scale, int max_cost)
+{
+ int count = 0;
+ rtx insn = BB_HEAD (bb);
+ bool speed = optimize_bb_for_speed_p (bb);
+
+ /* Set scale to REG_BR_PROB_BASE to void the identical scaling
+ applied to insn_rtx_cost when optimizing for size. Only do
+ this after combine because if-conversion might interfere with
+ passes before combine.
+
+ Use optimize_function_for_speed_p instead of the pre-defined
+ variable speed to make sure it is set to same value for all
+ basic blocks in one if-conversion transformation. */
+ if (!optimize_function_for_speed_p (cfun) && ifcvt_after_combine)
+ scale = REG_BR_PROB_BASE;
+ /* Our branch probability/scaling factors are just estimates and don't
+ account for cases where we can get speculation for free and other
+ secondary benefits. So we fudge the scale factor to make speculating
+ appear a little more profitable when optimizing for performance. */
+ else
+ scale += REG_BR_PROB_BASE / 8;
+
+
+ max_cost *= scale;
+
+ while (1)
+ {
+ if (NONJUMP_INSN_P (insn))
+ {
+ int cost = insn_rtx_cost (PATTERN (insn), speed) * REG_BR_PROB_BASE;
+ if (cost == 0)
+ return false;
+
+ /* If this instruction is the load or set of a "stack" register,
+ such as a floating point register on x87, then the cost of
+ speculatively executing this insn may need to include
+ the additional cost of popping its result off of the
+ register stack. Unfortunately, correctly recognizing and
+ accounting for this additional overhead is tricky, so for
+ now we simply prohibit such speculative execution. */
+#ifdef STACK_REGS
+ {
+ rtx set = single_set (insn);
+ if (set && STACK_REG_P (SET_DEST (set)))
+ return false;
+ }
+#endif
+
+ count += cost;
+ if (count >= max_cost)
+ return false;
+ }
+ else if (CALL_P (insn))
+ return false;
+
+ if (insn == BB_END (bb))
+ break;
+ insn = NEXT_INSN (insn);
+ }
+
+ return true;
+}
+
+/* Return the first non-jump active insn in the basic block. */
+
+static rtx
+first_active_insn (basic_block bb)
+{
+ rtx insn = BB_HEAD (bb);
+
+ if (LABEL_P (insn))
+ {
+ if (insn == BB_END (bb))
+ return NULL_RTX;
+ insn = NEXT_INSN (insn);
+ }
+
+ while (NOTE_P (insn) || DEBUG_INSN_P (insn))
+ {
+ if (insn == BB_END (bb))
+ return NULL_RTX;
+ insn = NEXT_INSN (insn);
+ }
+
+ if (JUMP_P (insn))
+ return NULL_RTX;
+
+ return insn;
+}
+
+/* Return the last non-jump active (non-jump) insn in the basic block. */
+
+static rtx
+last_active_insn (basic_block bb, int skip_use_p)
+{
+ rtx insn = BB_END (bb);
+ rtx head = BB_HEAD (bb);
+
+ while (NOTE_P (insn)
+ || JUMP_P (insn)
+ || DEBUG_INSN_P (insn)
+ || (skip_use_p
+ && NONJUMP_INSN_P (insn)
+ && GET_CODE (PATTERN (insn)) == USE))
+ {
+ if (insn == head)
+ return NULL_RTX;
+ insn = PREV_INSN (insn);
+ }
+
+ if (LABEL_P (insn))
+ return NULL_RTX;
+
+ return insn;
+}
+
+/* Return the active insn before INSN inside basic block CURR_BB. */
+
+static rtx
+find_active_insn_before (basic_block curr_bb, rtx insn)
+{
+ if (!insn || insn == BB_HEAD (curr_bb))
+ return NULL_RTX;
+
+ while ((insn = PREV_INSN (insn)) != NULL_RTX)
+ {
+ if (NONJUMP_INSN_P (insn) || JUMP_P (insn) || CALL_P (insn))
+ break;
+
+ /* No other active insn all the way to the start of the basic block. */
+ if (insn == BB_HEAD (curr_bb))
+ return NULL_RTX;
+ }
+
+ return insn;
+}
+
+/* Return the active insn after INSN inside basic block CURR_BB. */
+
+static rtx
+find_active_insn_after (basic_block curr_bb, rtx insn)
+{
+ if (!insn || insn == BB_END (curr_bb))
+ return NULL_RTX;
+
+ while ((insn = NEXT_INSN (insn)) != NULL_RTX)
+ {
+ if (NONJUMP_INSN_P (insn) || JUMP_P (insn) || CALL_P (insn))
+ break;
+
+ /* No other active insn all the way to the end of the basic block. */
+ if (insn == BB_END (curr_bb))
+ return NULL_RTX;
+ }
+
+ return insn;
+}
+
+/* Return the basic block reached by falling though the basic block BB. */
+
+static basic_block
+block_fallthru (basic_block bb)
+{
+ edge e = find_fallthru_edge (bb->succs);
+
+ return (e) ? e->dest : NULL_BLOCK;
+}
+
+/* Go through a bunch of insns, converting them to conditional
+ execution format if possible. Return TRUE if all of the non-note
+ insns were processed. */
+
+static int
+cond_exec_process_insns (ce_if_block *ce_info ATTRIBUTE_UNUSED,
+ /* if block information */rtx start,
+ /* first insn to look at */rtx end,
+ /* last insn to look at */rtx test,
+ /* conditional execution test */int prob_val,
+ /* probability of branch taken. */int mod_ok)
+{
+ int must_be_last = FALSE;
+ rtx insn;
+ rtx xtest;
+ rtx pattern;
+
+ if (!start || !end)
+ return FALSE;
+
+ for (insn = start; ; insn = NEXT_INSN (insn))
+ {
+ /* dwarf2out can't cope with conditional prologues. */
+ if (NOTE_P (insn) && NOTE_KIND (insn) == NOTE_INSN_PROLOGUE_END)
+ return FALSE;
+
+ if (NOTE_P (insn) || DEBUG_INSN_P (insn))
+ goto insn_done;
+
+ gcc_assert (NONJUMP_INSN_P (insn) || CALL_P (insn));
+
+ /* dwarf2out can't cope with conditional unwind info. */
+ if (RTX_FRAME_RELATED_P (insn))
+ return FALSE;
+
+ /* Remove USE insns that get in the way. */
+ if (reload_completed && GET_CODE (PATTERN (insn)) == USE)
+ {
+ /* ??? Ug. Actually unlinking the thing is problematic,
+ given what we'd have to coordinate with our callers. */
+ SET_INSN_DELETED (insn);
+ goto insn_done;
+ }
+
+ /* Last insn wasn't last? */
+ if (must_be_last)
+ return FALSE;
+
+ if (modified_in_p (test, insn))
+ {
+ if (!mod_ok)
+ return FALSE;
+ must_be_last = TRUE;
+ }
+
+ /* Now build the conditional form of the instruction. */
+ pattern = PATTERN (insn);
+ xtest = copy_rtx (test);
+
+ /* If this is already a COND_EXEC, rewrite the test to be an AND of the
+ two conditions. */
+ if (GET_CODE (pattern) == COND_EXEC)
+ {
+ if (GET_MODE (xtest) != GET_MODE (COND_EXEC_TEST (pattern)))
+ return FALSE;
+
+ xtest = gen_rtx_AND (GET_MODE (xtest), xtest,
+ COND_EXEC_TEST (pattern));
+ pattern = COND_EXEC_CODE (pattern);
+ }
+
+ pattern = gen_rtx_COND_EXEC (VOIDmode, xtest, pattern);
+
+ /* If the machine needs to modify the insn being conditionally executed,
+ say for example to force a constant integer operand into a temp
+ register, do so here. */
+#ifdef IFCVT_MODIFY_INSN
+ IFCVT_MODIFY_INSN (ce_info, pattern, insn);
+ if (! pattern)
+ return FALSE;
+#endif
+
+ validate_change (insn, &PATTERN (insn), pattern, 1);
+
+ if (CALL_P (insn) && prob_val >= 0)
+ validate_change (insn, &REG_NOTES (insn),
+ gen_rtx_INT_LIST ((enum machine_mode) REG_BR_PROB,
+ prob_val, REG_NOTES (insn)), 1);
+
+ insn_done:
+ if (insn == end)
+ break;
+ }
+
+ return TRUE;
+}
+
+/* Return the condition for a jump. Do not do any special processing. */
+
+static rtx
+cond_exec_get_condition (rtx jump)
+{
+ rtx test_if, cond;
+
+ if (any_condjump_p (jump))
+ test_if = SET_SRC (pc_set (jump));
+ else
+ return NULL_RTX;
+ cond = XEXP (test_if, 0);
+
+ /* If this branches to JUMP_LABEL when the condition is false,
+ reverse the condition. */
+ if (GET_CODE (XEXP (test_if, 2)) == LABEL_REF
+ && XEXP (XEXP (test_if, 2), 0) == JUMP_LABEL (jump))
+ {
+ enum rtx_code rev = reversed_comparison_code (cond, jump);
+ if (rev == UNKNOWN)
+ return NULL_RTX;
+
+ cond = gen_rtx_fmt_ee (rev, GET_MODE (cond), XEXP (cond, 0),
+ XEXP (cond, 1));
+ }
+
+ return cond;
+}
+
+/* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it
+ to conditional execution. Return TRUE if we were successful at
+ converting the block. */
+
+static int
+cond_exec_process_if_block (ce_if_block * ce_info,
+ /* if block information */int do_multiple_p)
+{
+ basic_block test_bb = ce_info->test_bb; /* last test block */
+ basic_block then_bb = ce_info->then_bb; /* THEN */
+ basic_block else_bb = ce_info->else_bb; /* ELSE or NULL */
+ rtx test_expr; /* expression in IF_THEN_ELSE that is tested */
+ rtx then_start; /* first insn in THEN block */
+ rtx then_end; /* last insn + 1 in THEN block */
+ rtx else_start = NULL_RTX; /* first insn in ELSE block or NULL */
+ rtx else_end = NULL_RTX; /* last insn + 1 in ELSE block */
+ int max; /* max # of insns to convert. */
+ int then_mod_ok; /* whether conditional mods are ok in THEN */
+ rtx true_expr; /* test for else block insns */
+ rtx false_expr; /* test for then block insns */
+ int true_prob_val; /* probability of else block */
+ int false_prob_val; /* probability of then block */
+ rtx then_last_head = NULL_RTX; /* Last match at the head of THEN */
+ rtx else_last_head = NULL_RTX; /* Last match at the head of ELSE */
+ rtx then_first_tail = NULL_RTX; /* First match at the tail of THEN */
+ rtx else_first_tail = NULL_RTX; /* First match at the tail of ELSE */
+ int then_n_insns, else_n_insns, n_insns;
+ enum rtx_code false_code;
+ rtx note;
+
+ /* If test is comprised of && or || elements, and we've failed at handling
+ all of them together, just use the last test if it is the special case of
+ && elements without an ELSE block. */
+ if (!do_multiple_p && ce_info->num_multiple_test_blocks)
+ {
+ if (else_bb || ! ce_info->and_and_p)
+ return FALSE;
+
+ ce_info->test_bb = test_bb = ce_info->last_test_bb;
+ ce_info->num_multiple_test_blocks = 0;
+ ce_info->num_and_and_blocks = 0;
+ ce_info->num_or_or_blocks = 0;
+ }
+
+ /* Find the conditional jump to the ELSE or JOIN part, and isolate
+ the test. */
+ test_expr = cond_exec_get_condition (BB_END (test_bb));
+ if (! test_expr)
+ return FALSE;
+
+ /* If the conditional jump is more than just a conditional jump,
+ then we can not do conditional execution conversion on this block. */
+ if (! onlyjump_p (BB_END (test_bb)))
+ return FALSE;
+
+ /* Collect the bounds of where we're to search, skipping any labels, jumps
+ and notes at the beginning and end of the block. Then count the total
+ number of insns and see if it is small enough to convert. */
+ then_start = first_active_insn (then_bb);
+ then_end = last_active_insn (then_bb, TRUE);
+ then_n_insns = ce_info->num_then_insns = count_bb_insns (then_bb);
+ n_insns = then_n_insns;
+ max = MAX_CONDITIONAL_EXECUTE;
+
+ if (else_bb)
+ {
+ int n_matching;
+
+ max *= 2;
+ else_start = first_active_insn (else_bb);
+ else_end = last_active_insn (else_bb, TRUE);
+ else_n_insns = ce_info->num_else_insns = count_bb_insns (else_bb);
+ n_insns += else_n_insns;
+
+ /* Look for matching sequences at the head and tail of the two blocks,
+ and limit the range of insns to be converted if possible. */
+ n_matching = flow_find_cross_jump (then_bb, else_bb,
+ &then_first_tail, &else_first_tail,
+ NULL);
+ if (then_first_tail == BB_HEAD (then_bb))
+ then_start = then_end = NULL_RTX;
+ if (else_first_tail == BB_HEAD (else_bb))
+ else_start = else_end = NULL_RTX;
+
+ if (n_matching > 0)
+ {
+ if (then_end)
+ then_end = find_active_insn_before (then_bb, then_first_tail);
+ if (else_end)
+ else_end = find_active_insn_before (else_bb, else_first_tail);
+ n_insns -= 2 * n_matching;
+ }
+
+ if (then_start
+ && else_start
+ && then_n_insns > n_matching
+ && else_n_insns > n_matching)
+ {
+ int longest_match = MIN (then_n_insns - n_matching,
+ else_n_insns - n_matching);
+ n_matching
+ = flow_find_head_matching_sequence (then_bb, else_bb,
+ &then_last_head,
+ &else_last_head,
+ longest_match);
+
+ if (n_matching > 0)
+ {
+ rtx insn;
+
+ /* We won't pass the insns in the head sequence to
+ cond_exec_process_insns, so we need to test them here
+ to make sure that they don't clobber the condition. */
+ for (insn = BB_HEAD (then_bb);
+ insn != NEXT_INSN (then_last_head);
+ insn = NEXT_INSN (insn))
+ if (!LABEL_P (insn) && !NOTE_P (insn)
+ && !DEBUG_INSN_P (insn)
+ && modified_in_p (test_expr, insn))
+ return FALSE;
+ }
+
+ if (then_last_head == then_end)
+ then_start = then_end = NULL_RTX;
+ if (else_last_head == else_end)
+ else_start = else_end = NULL_RTX;
+
+ if (n_matching > 0)
+ {
+ if (then_start)
+ then_start = find_active_insn_after (then_bb, then_last_head);
+ if (else_start)
+ else_start = find_active_insn_after (else_bb, else_last_head);
+ n_insns -= 2 * n_matching;
+ }
+ }
+ }
+
+ if (n_insns > max)
+ return FALSE;
+
+ /* Map test_expr/test_jump into the appropriate MD tests to use on
+ the conditionally executed code. */
+
+ true_expr = test_expr;
+
+ false_code = reversed_comparison_code (true_expr, BB_END (test_bb));
+ if (false_code != UNKNOWN)
+ false_expr = gen_rtx_fmt_ee (false_code, GET_MODE (true_expr),
+ XEXP (true_expr, 0), XEXP (true_expr, 1));
+ else
+ false_expr = NULL_RTX;
+
+#ifdef IFCVT_MODIFY_TESTS
+ /* If the machine description needs to modify the tests, such as setting a
+ conditional execution register from a comparison, it can do so here. */
+ IFCVT_MODIFY_TESTS (ce_info, true_expr, false_expr);
+
+ /* See if the conversion failed. */
+ if (!true_expr || !false_expr)
+ goto fail;
+#endif
+
+ note = find_reg_note (BB_END (test_bb), REG_BR_PROB, NULL_RTX);
+ if (note)
+ {
+ true_prob_val = XINT (note, 0);
+ false_prob_val = REG_BR_PROB_BASE - true_prob_val;
+ }
+ else
+ {
+ true_prob_val = -1;
+ false_prob_val = -1;
+ }
+
+ /* If we have && or || tests, do them here. These tests are in the adjacent
+ blocks after the first block containing the test. */
+ if (ce_info->num_multiple_test_blocks > 0)
+ {
+ basic_block bb = test_bb;
+ basic_block last_test_bb = ce_info->last_test_bb;
+
+ if (! false_expr)
+ goto fail;
+
+ do
+ {
+ rtx start, end;
+ rtx t, f;
+ enum rtx_code f_code;
+
+ bb = block_fallthru (bb);
+ start = first_active_insn (bb);
+ end = last_active_insn (bb, TRUE);
+ if (start
+ && ! cond_exec_process_insns (ce_info, start, end, false_expr,
+ false_prob_val, FALSE))
+ goto fail;
+
+ /* If the conditional jump is more than just a conditional jump, then
+ we can not do conditional execution conversion on this block. */
+ if (! onlyjump_p (BB_END (bb)))
+ goto fail;
+
+ /* Find the conditional jump and isolate the test. */
+ t = cond_exec_get_condition (BB_END (bb));
+ if (! t)
+ goto fail;
+
+ f_code = reversed_comparison_code (t, BB_END (bb));
+ if (f_code == UNKNOWN)
+ goto fail;
+
+ f = gen_rtx_fmt_ee (f_code, GET_MODE (t), XEXP (t, 0), XEXP (t, 1));
+ if (ce_info->and_and_p)
+ {
+ t = gen_rtx_AND (GET_MODE (t), true_expr, t);
+ f = gen_rtx_IOR (GET_MODE (t), false_expr, f);
+ }
+ else
+ {
+ t = gen_rtx_IOR (GET_MODE (t), true_expr, t);
+ f = gen_rtx_AND (GET_MODE (t), false_expr, f);
+ }
+
+ /* If the machine description needs to modify the tests, such as
+ setting a conditional execution register from a comparison, it can
+ do so here. */
+#ifdef IFCVT_MODIFY_MULTIPLE_TESTS
+ IFCVT_MODIFY_MULTIPLE_TESTS (ce_info, bb, t, f);
+
+ /* See if the conversion failed. */
+ if (!t || !f)
+ goto fail;
+#endif
+
+ true_expr = t;
+ false_expr = f;
+ }
+ while (bb != last_test_bb);
+ }
+
+ /* For IF-THEN-ELSE blocks, we don't allow modifications of the test
+ on then THEN block. */
+ then_mod_ok = (else_bb == NULL_BLOCK);
+
+ /* Go through the THEN and ELSE blocks converting the insns if possible
+ to conditional execution. */
+
+ if (then_end
+ && (! false_expr
+ || ! cond_exec_process_insns (ce_info, then_start, then_end,
+ false_expr, false_prob_val,
+ then_mod_ok)))
+ goto fail;
+
+ if (else_bb && else_end
+ && ! cond_exec_process_insns (ce_info, else_start, else_end,
+ true_expr, true_prob_val, TRUE))
+ goto fail;
+
+ /* If we cannot apply the changes, fail. Do not go through the normal fail
+ processing, since apply_change_group will call cancel_changes. */
+ if (! apply_change_group ())
+ {
+#ifdef IFCVT_MODIFY_CANCEL
+ /* Cancel any machine dependent changes. */
+ IFCVT_MODIFY_CANCEL (ce_info);
+#endif
+ return FALSE;
+ }
+
+#ifdef IFCVT_MODIFY_FINAL
+ /* Do any machine dependent final modifications. */
+ IFCVT_MODIFY_FINAL (ce_info);
+#endif
+
+ /* Conversion succeeded. */
+ if (dump_file)
+ fprintf (dump_file, "%d insn%s converted to conditional execution.\n",
+ n_insns, (n_insns == 1) ? " was" : "s were");
+
+ /* Merge the blocks! If we had matching sequences, make sure to delete one
+ copy at the appropriate location first: delete the copy in the THEN branch
+ for a tail sequence so that the remaining one is executed last for both
+ branches, and delete the copy in the ELSE branch for a head sequence so
+ that the remaining one is executed first for both branches. */
+ if (then_first_tail)
+ {
+ rtx from = then_first_tail;
+ if (!INSN_P (from))
+ from = find_active_insn_after (then_bb, from);
+ delete_insn_chain (from, BB_END (then_bb), false);
+ }
+ if (else_last_head)
+ delete_insn_chain (first_active_insn (else_bb), else_last_head, false);
+
+ merge_if_block (ce_info);
+ cond_exec_changed_p = TRUE;
+ return TRUE;
+
+ fail:
+#ifdef IFCVT_MODIFY_CANCEL
+ /* Cancel any machine dependent changes. */
+ IFCVT_MODIFY_CANCEL (ce_info);
+#endif
+
+ cancel_changes (0);
+ return FALSE;
+}
+
+/* Used by noce_process_if_block to communicate with its subroutines.
+
+ The subroutines know that A and B may be evaluated freely. They
+ know that X is a register. They should insert new instructions
+ before cond_earliest. */
+
+struct noce_if_info
+{
+ /* The basic blocks that make up the IF-THEN-{ELSE-,}JOIN block. */
+ basic_block test_bb, then_bb, else_bb, join_bb;
+
+ /* The jump that ends TEST_BB. */
+ rtx jump;
+
+ /* The jump condition. */
+ rtx cond;
+
+ /* New insns should be inserted before this one. */
+ rtx cond_earliest;
+
+ /* Insns in the THEN and ELSE block. There is always just this
+ one insns in those blocks. The insns are single_set insns.
+ If there was no ELSE block, INSN_B is the last insn before
+ COND_EARLIEST, or NULL_RTX. In the former case, the insn
+ operands are still valid, as if INSN_B was moved down below
+ the jump. */
+ rtx insn_a, insn_b;
+
+ /* The SET_SRC of INSN_A and INSN_B. */
+ rtx a, b;
+
+ /* The SET_DEST of INSN_A. */
+ rtx x;
+
+ /* True if this if block is not canonical. In the canonical form of
+ if blocks, the THEN_BB is the block reached via the fallthru edge
+ from TEST_BB. For the noce transformations, we allow the symmetric
+ form as well. */
+ bool then_else_reversed;
+
+ /* Estimated cost of the particular branch instruction. */
+ int branch_cost;
+};
+
+static rtx noce_emit_store_flag (struct noce_if_info *, rtx, int, int);
+static int noce_try_move (struct noce_if_info *);
+static int noce_try_store_flag (struct noce_if_info *);
+static int noce_try_addcc (struct noce_if_info *);
+static int noce_try_store_flag_constants (struct noce_if_info *);
+static int noce_try_store_flag_mask (struct noce_if_info *);
+static rtx noce_emit_cmove (struct noce_if_info *, rtx, enum rtx_code, rtx,
+ rtx, rtx, rtx);
+static int noce_try_cmove (struct noce_if_info *);
+static int noce_try_cmove_arith (struct noce_if_info *);
+static rtx noce_get_alt_condition (struct noce_if_info *, rtx, rtx *);
+static int noce_try_minmax (struct noce_if_info *);
+static int noce_try_abs (struct noce_if_info *);
+static int noce_try_sign_mask (struct noce_if_info *);
+
+/* Helper function for noce_try_store_flag*. */
+
+static rtx
+noce_emit_store_flag (struct noce_if_info *if_info, rtx x, int reversep,
+ int normalize)
+{
+ rtx cond = if_info->cond;
+ int cond_complex;
+ enum rtx_code code;
+
+ cond_complex = (! general_operand (XEXP (cond, 0), VOIDmode)
+ || ! general_operand (XEXP (cond, 1), VOIDmode));
+
+ /* If earliest == jump, or when the condition is complex, try to
+ build the store_flag insn directly. */
+
+ if (cond_complex)
+ {
+ rtx set = pc_set (if_info->jump);
+ cond = XEXP (SET_SRC (set), 0);
+ if (GET_CODE (XEXP (SET_SRC (set), 2)) == LABEL_REF
+ && XEXP (XEXP (SET_SRC (set), 2), 0) == JUMP_LABEL (if_info->jump))
+ reversep = !reversep;
+ if (if_info->then_else_reversed)
+ reversep = !reversep;
+ }
+
+ if (reversep)
+ code = reversed_comparison_code (cond, if_info->jump);
+ else
+ code = GET_CODE (cond);
+
+ if ((if_info->cond_earliest == if_info->jump || cond_complex)
+ && (normalize == 0 || STORE_FLAG_VALUE == normalize))
+ {
+ rtx tmp;
+
+ tmp = gen_rtx_fmt_ee (code, GET_MODE (x), XEXP (cond, 0),
+ XEXP (cond, 1));
+ tmp = gen_rtx_SET (VOIDmode, x, tmp);
+
+ start_sequence ();
+ tmp = emit_insn (tmp);
+
+ if (recog_memoized (tmp) >= 0)
+ {
+ tmp = get_insns ();
+ end_sequence ();
+ emit_insn (tmp);
+
+ if_info->cond_earliest = if_info->jump;
+
+ return x;
+ }
+
+ end_sequence ();
+ }
+
+ /* Don't even try if the comparison operands or the mode of X are weird. */
+ if (cond_complex || !SCALAR_INT_MODE_P (GET_MODE (x)))
+ return NULL_RTX;
+
+ return emit_store_flag (x, code, XEXP (cond, 0),
+ XEXP (cond, 1), VOIDmode,
+ (code == LTU || code == LEU
+ || code == GEU || code == GTU), normalize);
+}
+
+/* Emit instruction to move an rtx, possibly into STRICT_LOW_PART.
+ X is the destination/target and Y is the value to copy. */
+
+static void
+noce_emit_move_insn (rtx x, rtx y)
+{
+ enum machine_mode outmode;
+ rtx outer, inner;
+ int bitpos;
+
+ if (GET_CODE (x) != STRICT_LOW_PART)
+ {
+ rtx seq, insn, target;
+ optab ot;
+
+ start_sequence ();
+ /* Check that the SET_SRC is reasonable before calling emit_move_insn,
+ otherwise construct a suitable SET pattern ourselves. */
+ insn = (OBJECT_P (y) || CONSTANT_P (y) || GET_CODE (y) == SUBREG)
+ ? emit_move_insn (x, y)
+ : emit_insn (gen_rtx_SET (VOIDmode, x, y));
+ seq = get_insns ();
+ end_sequence ();
+
+ if (recog_memoized (insn) <= 0)
+ {
+ if (GET_CODE (x) == ZERO_EXTRACT)
+ {
+ rtx op = XEXP (x, 0);
+ unsigned HOST_WIDE_INT size = INTVAL (XEXP (x, 1));
+ unsigned HOST_WIDE_INT start = INTVAL (XEXP (x, 2));
+
+ /* store_bit_field expects START to be relative to
+ BYTES_BIG_ENDIAN and adjusts this value for machines with
+ BITS_BIG_ENDIAN != BYTES_BIG_ENDIAN. In order to be able to
+ invoke store_bit_field again it is necessary to have the START
+ value from the first call. */
+ if (BITS_BIG_ENDIAN != BYTES_BIG_ENDIAN)
+ {
+ if (MEM_P (op))
+ start = BITS_PER_UNIT - start - size;
+ else
+ {
+ gcc_assert (REG_P (op));
+ start = BITS_PER_WORD - start - size;
+ }
+ }
+
+ gcc_assert (start < (MEM_P (op) ? BITS_PER_UNIT : BITS_PER_WORD));
+ store_bit_field (op, size, start, 0, 0, GET_MODE (x), y);
+ return;
+ }
+
+ switch (GET_RTX_CLASS (GET_CODE (y)))
+ {
+ case RTX_UNARY:
+ ot = code_to_optab (GET_CODE (y));
+ if (ot)
+ {
+ start_sequence ();
+ target = expand_unop (GET_MODE (y), ot, XEXP (y, 0), x, 0);
+ if (target != NULL_RTX)
+ {
+ if (target != x)
+ emit_move_insn (x, target);
+ seq = get_insns ();
+ }
+ end_sequence ();
+ }
+ break;
+
+ case RTX_BIN_ARITH:
+ case RTX_COMM_ARITH:
+ ot = code_to_optab (GET_CODE (y));
+ if (ot)
+ {
+ start_sequence ();
+ target = expand_binop (GET_MODE (y), ot,
+ XEXP (y, 0), XEXP (y, 1),
+ x, 0, OPTAB_DIRECT);
+ if (target != NULL_RTX)
+ {
+ if (target != x)
+ emit_move_insn (x, target);
+ seq = get_insns ();
+ }
+ end_sequence ();
+ }
+ break;
+
+ default:
+ break;
+ }
+ }
+
+ emit_insn (seq);
+ return;
+ }
+
+ outer = XEXP (x, 0);
+ inner = XEXP (outer, 0);
+ outmode = GET_MODE (outer);
+ bitpos = SUBREG_BYTE (outer) * BITS_PER_UNIT;
+ store_bit_field (inner, GET_MODE_BITSIZE (outmode), bitpos,
+ 0, 0, outmode, y);
+}
+
+/* Return sequence of instructions generated by if conversion. This
+ function calls end_sequence() to end the current stream, ensures
+ that are instructions are unshared, recognizable non-jump insns.
+ On failure, this function returns a NULL_RTX. */
+
+static rtx
+end_ifcvt_sequence (struct noce_if_info *if_info)
+{
+ rtx insn;
+ rtx seq = get_insns ();
+
+ set_used_flags (if_info->x);
+ set_used_flags (if_info->cond);
+ set_used_flags (if_info->a);
+ set_used_flags (if_info->b);
+ unshare_all_rtl_in_chain (seq);
+ end_sequence ();
+
+ /* Make sure that all of the instructions emitted are recognizable,
+ and that we haven't introduced a new jump instruction.
+ As an exercise for the reader, build a general mechanism that
+ allows proper placement of required clobbers. */
+ for (insn = seq; insn; insn = NEXT_INSN (insn))
+ if (JUMP_P (insn)
+ || recog_memoized (insn) == -1)
+ return NULL_RTX;
+
+ return seq;
+}
+
+/* Convert "if (a != b) x = a; else x = b" into "x = a" and
+ "if (a == b) x = a; else x = b" into "x = b". */
+
+static int
+noce_try_move (struct noce_if_info *if_info)
+{
+ rtx cond = if_info->cond;
+ enum rtx_code code = GET_CODE (cond);
+ rtx y, seq;
+
+ if (code != NE && code != EQ)
+ return FALSE;
+
+ /* This optimization isn't valid if either A or B could be a NaN
+ or a signed zero. */
+ if (HONOR_NANS (GET_MODE (if_info->x))
+ || HONOR_SIGNED_ZEROS (GET_MODE (if_info->x)))
+ return FALSE;
+
+ /* Check whether the operands of the comparison are A and in
+ either order. */
+ if ((rtx_equal_p (if_info->a, XEXP (cond, 0))
+ && rtx_equal_p (if_info->b, XEXP (cond, 1)))
+ || (rtx_equal_p (if_info->a, XEXP (cond, 1))
+ && rtx_equal_p (if_info->b, XEXP (cond, 0))))
+ {
+ y = (code == EQ) ? if_info->a : if_info->b;
+
+ /* Avoid generating the move if the source is the destination. */
+ if (! rtx_equal_p (if_info->x, y))
+ {
+ start_sequence ();
+ noce_emit_move_insn (if_info->x, y);
+ seq = end_ifcvt_sequence (if_info);
+ if (!seq)
+ return FALSE;
+
+ emit_insn_before_setloc (seq, if_info->jump,
+ INSN_LOCATION (if_info->insn_a));
+ }
+ return TRUE;
+ }
+ return FALSE;
+}
+
+/* Convert "if (test) x = 1; else x = 0".
+
+ Only try 0 and STORE_FLAG_VALUE here. Other combinations will be
+ tried in noce_try_store_flag_constants after noce_try_cmove has had
+ a go at the conversion. */
+
+static int
+noce_try_store_flag (struct noce_if_info *if_info)
+{
+ int reversep;
+ rtx target, seq;
+
+ if (CONST_INT_P (if_info->b)
+ && INTVAL (if_info->b) == STORE_FLAG_VALUE
+ && if_info->a == const0_rtx)
+ reversep = 0;
+ else if (if_info->b == const0_rtx
+ && CONST_INT_P (if_info->a)
+ && INTVAL (if_info->a) == STORE_FLAG_VALUE
+ && (reversed_comparison_code (if_info->cond, if_info->jump)
+ != UNKNOWN))
+ reversep = 1;
+ else
+ return FALSE;
+
+ start_sequence ();
+
+ target = noce_emit_store_flag (if_info, if_info->x, reversep, 0);
+ if (target)
+ {
+ if (target != if_info->x)
+ noce_emit_move_insn (if_info->x, target);
+
+ seq = end_ifcvt_sequence (if_info);
+ if (! seq)
+ return FALSE;
+
+ emit_insn_before_setloc (seq, if_info->jump,
+ INSN_LOCATION (if_info->insn_a));
+ return TRUE;
+ }
+ else
+ {
+ end_sequence ();
+ return FALSE;
+ }
+}
+
+/* Convert "if (test) x = a; else x = b", for A and B constant. */
+
+static int
+noce_try_store_flag_constants (struct noce_if_info *if_info)
+{
+ rtx target, seq;
+ int reversep;
+ HOST_WIDE_INT itrue, ifalse, diff, tmp;
+ int normalize, can_reverse;
+ enum machine_mode mode;
+
+ if (CONST_INT_P (if_info->a)
+ && CONST_INT_P (if_info->b))
+ {
+ mode = GET_MODE (if_info->x);
+ ifalse = INTVAL (if_info->a);
+ itrue = INTVAL (if_info->b);
+
+ diff = (unsigned HOST_WIDE_INT) itrue - ifalse;
+ /* Make sure we can represent the difference between the two values. */
+ if ((diff > 0)
+ != ((ifalse < 0) != (itrue < 0) ? ifalse < 0 : ifalse < itrue))
+ return FALSE;
+
+ diff = trunc_int_for_mode (diff, mode);
+
+ can_reverse = (reversed_comparison_code (if_info->cond, if_info->jump)
+ != UNKNOWN);
+
+ reversep = 0;
+ if (diff == STORE_FLAG_VALUE || diff == -STORE_FLAG_VALUE)
+ normalize = 0;
+ else if (ifalse == 0 && exact_log2 (itrue) >= 0
+ && (STORE_FLAG_VALUE == 1
+ || if_info->branch_cost >= 2))
+ normalize = 1;
+ else if (itrue == 0 && exact_log2 (ifalse) >= 0 && can_reverse
+ && (STORE_FLAG_VALUE == 1 || if_info->branch_cost >= 2))
+ normalize = 1, reversep = 1;
+ else if (itrue == -1
+ && (STORE_FLAG_VALUE == -1
+ || if_info->branch_cost >= 2))
+ normalize = -1;
+ else if (ifalse == -1 && can_reverse
+ && (STORE_FLAG_VALUE == -1 || if_info->branch_cost >= 2))
+ normalize = -1, reversep = 1;
+ else if ((if_info->branch_cost >= 2 && STORE_FLAG_VALUE == -1)
+ || if_info->branch_cost >= 3)
+ normalize = -1;
+ else
+ return FALSE;
+
+ if (reversep)
+ {
+ tmp = itrue; itrue = ifalse; ifalse = tmp;
+ diff = trunc_int_for_mode (-(unsigned HOST_WIDE_INT) diff, mode);
+ }
+
+ start_sequence ();
+ target = noce_emit_store_flag (if_info, if_info->x, reversep, normalize);
+ if (! target)
+ {
+ end_sequence ();
+ return FALSE;
+ }
+
+ /* if (test) x = 3; else x = 4;
+ => x = 3 + (test == 0); */
+ if (diff == STORE_FLAG_VALUE || diff == -STORE_FLAG_VALUE)
+ {
+ target = expand_simple_binop (mode,
+ (diff == STORE_FLAG_VALUE
+ ? PLUS : MINUS),
+ gen_int_mode (ifalse, mode), target,
+ if_info->x, 0, OPTAB_WIDEN);
+ }
+
+ /* if (test) x = 8; else x = 0;
+ => x = (test != 0) << 3; */
+ else if (ifalse == 0 && (tmp = exact_log2 (itrue)) >= 0)
+ {
+ target = expand_simple_binop (mode, ASHIFT,
+ target, GEN_INT (tmp), if_info->x, 0,
+ OPTAB_WIDEN);
+ }
+
+ /* if (test) x = -1; else x = b;
+ => x = -(test != 0) | b; */
+ else if (itrue == -1)
+ {
+ target = expand_simple_binop (mode, IOR,
+ target, gen_int_mode (ifalse, mode),
+ if_info->x, 0, OPTAB_WIDEN);
+ }
+
+ /* if (test) x = a; else x = b;
+ => x = (-(test != 0) & (b - a)) + a; */
+ else
+ {
+ target = expand_simple_binop (mode, AND,
+ target, gen_int_mode (diff, mode),
+ if_info->x, 0, OPTAB_WIDEN);
+ if (target)
+ target = expand_simple_binop (mode, PLUS,
+ target, gen_int_mode (ifalse, mode),
+ if_info->x, 0, OPTAB_WIDEN);
+ }
+
+ if (! target)
+ {
+ end_sequence ();
+ return FALSE;
+ }
+
+ if (target != if_info->x)
+ noce_emit_move_insn (if_info->x, target);
+
+ seq = end_ifcvt_sequence (if_info);
+ if (!seq)
+ return FALSE;
+
+ emit_insn_before_setloc (seq, if_info->jump,
+ INSN_LOCATION (if_info->insn_a));
+ return TRUE;
+ }
+
+ return FALSE;
+}
+
+/* Convert "if (test) foo++" into "foo += (test != 0)", and
+ similarly for "foo--". */
+
+static int
+noce_try_addcc (struct noce_if_info *if_info)
+{
+ rtx target, seq;
+ int subtract, normalize;
+
+ if (GET_CODE (if_info->a) == PLUS
+ && rtx_equal_p (XEXP (if_info->a, 0), if_info->b)
+ && (reversed_comparison_code (if_info->cond, if_info->jump)
+ != UNKNOWN))
+ {
+ rtx cond = if_info->cond;
+ enum rtx_code code = reversed_comparison_code (cond, if_info->jump);
+
+ /* First try to use addcc pattern. */
+ if (general_operand (XEXP (cond, 0), VOIDmode)
+ && general_operand (XEXP (cond, 1), VOIDmode))
+ {
+ start_sequence ();
+ target = emit_conditional_add (if_info->x, code,
+ XEXP (cond, 0),
+ XEXP (cond, 1),
+ VOIDmode,
+ if_info->b,
+ XEXP (if_info->a, 1),
+ GET_MODE (if_info->x),
+ (code == LTU || code == GEU
+ || code == LEU || code == GTU));
+ if (target)
+ {
+ if (target != if_info->x)
+ noce_emit_move_insn (if_info->x, target);
+
+ seq = end_ifcvt_sequence (if_info);
+ if (!seq)
+ return FALSE;
+
+ emit_insn_before_setloc (seq, if_info->jump,
+ INSN_LOCATION (if_info->insn_a));
+ return TRUE;
+ }
+ end_sequence ();
+ }
+
+ /* If that fails, construct conditional increment or decrement using
+ setcc. */
+ if (if_info->branch_cost >= 2
+ && (XEXP (if_info->a, 1) == const1_rtx
+ || XEXP (if_info->a, 1) == constm1_rtx))
+ {
+ start_sequence ();
+ if (STORE_FLAG_VALUE == INTVAL (XEXP (if_info->a, 1)))
+ subtract = 0, normalize = 0;
+ else if (-STORE_FLAG_VALUE == INTVAL (XEXP (if_info->a, 1)))
+ subtract = 1, normalize = 0;
+ else
+ subtract = 0, normalize = INTVAL (XEXP (if_info->a, 1));
+
+
+ target = noce_emit_store_flag (if_info,
+ gen_reg_rtx (GET_MODE (if_info->x)),
+ 1, normalize);
+
+ if (target)
+ target = expand_simple_binop (GET_MODE (if_info->x),
+ subtract ? MINUS : PLUS,
+ if_info->b, target, if_info->x,
+ 0, OPTAB_WIDEN);
+ if (target)
+ {
+ if (target != if_info->x)
+ noce_emit_move_insn (if_info->x, target);
+
+ seq = end_ifcvt_sequence (if_info);
+ if (!seq)
+ return FALSE;
+
+ emit_insn_before_setloc (seq, if_info->jump,
+ INSN_LOCATION (if_info->insn_a));
+ return TRUE;
+ }
+ end_sequence ();
+ }
+ }
+
+ return FALSE;
+}
+
+/* Convert "if (test) x = 0;" to "x &= -(test == 0);" */
+
+static int
+noce_try_store_flag_mask (struct noce_if_info *if_info)
+{
+ rtx target, seq;
+ int reversep;
+
+ reversep = 0;
+ if ((if_info->branch_cost >= 2
+ || STORE_FLAG_VALUE == -1)
+ && ((if_info->a == const0_rtx
+ && rtx_equal_p (if_info->b, if_info->x))
+ || ((reversep = (reversed_comparison_code (if_info->cond,
+ if_info->jump)
+ != UNKNOWN))
+ && if_info->b == const0_rtx
+ && rtx_equal_p (if_info->a, if_info->x))))
+ {
+ start_sequence ();
+ target = noce_emit_store_flag (if_info,
+ gen_reg_rtx (GET_MODE (if_info->x)),
+ reversep, -1);
+ if (target)
+ target = expand_simple_binop (GET_MODE (if_info->x), AND,
+ if_info->x,
+ target, if_info->x, 0,
+ OPTAB_WIDEN);
+
+ if (target)
+ {
+ if (target != if_info->x)
+ noce_emit_move_insn (if_info->x, target);
+
+ seq = end_ifcvt_sequence (if_info);
+ if (!seq)
+ return FALSE;
+
+ emit_insn_before_setloc (seq, if_info->jump,
+ INSN_LOCATION (if_info->insn_a));
+ return TRUE;
+ }
+
+ end_sequence ();
+ }
+
+ return FALSE;
+}
+
+/* Helper function for noce_try_cmove and noce_try_cmove_arith. */
+
+static rtx
+noce_emit_cmove (struct noce_if_info *if_info, rtx x, enum rtx_code code,
+ rtx cmp_a, rtx cmp_b, rtx vfalse, rtx vtrue)
+{
+ rtx target ATTRIBUTE_UNUSED;
+ int unsignedp ATTRIBUTE_UNUSED;
+
+ /* If earliest == jump, try to build the cmove insn directly.
+ This is helpful when combine has created some complex condition
+ (like for alpha's cmovlbs) that we can't hope to regenerate
+ through the normal interface. */
+
+ if (if_info->cond_earliest == if_info->jump)
+ {
+ rtx tmp;
+
+ tmp = gen_rtx_fmt_ee (code, GET_MODE (if_info->cond), cmp_a, cmp_b);
+ tmp = gen_rtx_IF_THEN_ELSE (GET_MODE (x), tmp, vtrue, vfalse);
+ tmp = gen_rtx_SET (VOIDmode, x, tmp);
+
+ start_sequence ();
+ tmp = emit_insn (tmp);
+
+ if (recog_memoized (tmp) >= 0)
+ {
+ tmp = get_insns ();
+ end_sequence ();
+ emit_insn (tmp);
+
+ return x;
+ }
+
+ end_sequence ();
+ }
+
+ /* Don't even try if the comparison operands are weird. */
+ if (! general_operand (cmp_a, GET_MODE (cmp_a))
+ || ! general_operand (cmp_b, GET_MODE (cmp_b)))
+ return NULL_RTX;
+
+#if HAVE_conditional_move
+ unsignedp = (code == LTU || code == GEU
+ || code == LEU || code == GTU);
+
+ target = emit_conditional_move (x, code, cmp_a, cmp_b, VOIDmode,
+ vtrue, vfalse, GET_MODE (x),
+ unsignedp);
+ if (target)
+ return target;
+
+ /* We might be faced with a situation like:
+
+ x = (reg:M TARGET)
+ vtrue = (subreg:M (reg:N VTRUE) BYTE)
+ vfalse = (subreg:M (reg:N VFALSE) BYTE)
+
+ We can't do a conditional move in mode M, but it's possible that we
+ could do a conditional move in mode N instead and take a subreg of
+ the result.
+
+ If we can't create new pseudos, though, don't bother. */
+ if (reload_completed)
+ return NULL_RTX;
+
+ if (GET_CODE (vtrue) == SUBREG && GET_CODE (vfalse) == SUBREG)
+ {
+ rtx reg_vtrue = SUBREG_REG (vtrue);
+ rtx reg_vfalse = SUBREG_REG (vfalse);
+ unsigned int byte_vtrue = SUBREG_BYTE (vtrue);
+ unsigned int byte_vfalse = SUBREG_BYTE (vfalse);
+ rtx promoted_target;
+
+ if (GET_MODE (reg_vtrue) != GET_MODE (reg_vfalse)
+ || byte_vtrue != byte_vfalse
+ || (SUBREG_PROMOTED_VAR_P (vtrue)
+ != SUBREG_PROMOTED_VAR_P (vfalse))
+ || (SUBREG_PROMOTED_UNSIGNED_P (vtrue)
+ != SUBREG_PROMOTED_UNSIGNED_P (vfalse)))
+ return NULL_RTX;
+
+ promoted_target = gen_reg_rtx (GET_MODE (reg_vtrue));
+
+ target = emit_conditional_move (promoted_target, code, cmp_a, cmp_b,
+ VOIDmode, reg_vtrue, reg_vfalse,
+ GET_MODE (reg_vtrue), unsignedp);
+ /* Nope, couldn't do it in that mode either. */
+ if (!target)
+ return NULL_RTX;
+
+ target = gen_rtx_SUBREG (GET_MODE (vtrue), promoted_target, byte_vtrue);
+ SUBREG_PROMOTED_VAR_P (target) = SUBREG_PROMOTED_VAR_P (vtrue);
+ SUBREG_PROMOTED_UNSIGNED_SET (target, SUBREG_PROMOTED_UNSIGNED_P (vtrue));
+ emit_move_insn (x, target);
+ return x;
+ }
+ else
+ return NULL_RTX;
+#else
+ /* We'll never get here, as noce_process_if_block doesn't call the
+ functions involved. Ifdef code, however, should be discouraged
+ because it leads to typos in the code not selected. However,
+ emit_conditional_move won't exist either. */
+ return NULL_RTX;
+#endif
+}
+
+/* Try only simple constants and registers here. More complex cases
+ are handled in noce_try_cmove_arith after noce_try_store_flag_arith
+ has had a go at it. */
+
+static int
+noce_try_cmove (struct noce_if_info *if_info)
+{
+ enum rtx_code code;
+ rtx target, seq;
+
+ if ((CONSTANT_P (if_info->a) || register_operand (if_info->a, VOIDmode))
+ && (CONSTANT_P (if_info->b) || register_operand (if_info->b, VOIDmode)))
+ {
+ start_sequence ();
+
+ code = GET_CODE (if_info->cond);
+ target = noce_emit_cmove (if_info, if_info->x, code,
+ XEXP (if_info->cond, 0),
+ XEXP (if_info->cond, 1),
+ if_info->a, if_info->b);
+
+ if (target)
+ {
+ if (target != if_info->x)
+ noce_emit_move_insn (if_info->x, target);
+
+ seq = end_ifcvt_sequence (if_info);
+ if (!seq)
+ return FALSE;
+
+ emit_insn_before_setloc (seq, if_info->jump,
+ INSN_LOCATION (if_info->insn_a));
+ return TRUE;
+ }
+ else
+ {
+ end_sequence ();
+ return FALSE;
+ }
+ }
+
+ return FALSE;
+}
+
+/* Try more complex cases involving conditional_move. */
+
+static int
+noce_try_cmove_arith (struct noce_if_info *if_info)
+{
+ rtx a = if_info->a;
+ rtx b = if_info->b;
+ rtx x = if_info->x;
+ rtx orig_a, orig_b;
+ rtx insn_a, insn_b;
+ rtx tmp, target;
+ int is_mem = 0;
+ int insn_cost;
+ enum rtx_code code;
+
+ /* A conditional move from two memory sources is equivalent to a
+ conditional on their addresses followed by a load. Don't do this
+ early because it'll screw alias analysis. Note that we've
+ already checked for no side effects. */
+ /* ??? FIXME: Magic number 5. */
+ if (cse_not_expected
+ && MEM_P (a) && MEM_P (b)
+ && MEM_ADDR_SPACE (a) == MEM_ADDR_SPACE (b)
+ && if_info->branch_cost >= 5)
+ {
+ enum machine_mode address_mode = get_address_mode (a);
+
+ a = XEXP (a, 0);
+ b = XEXP (b, 0);
+ x = gen_reg_rtx (address_mode);
+ is_mem = 1;
+ }
+
+ /* ??? We could handle this if we knew that a load from A or B could
+ not trap or fault. This is also true if we've already loaded
+ from the address along the path from ENTRY. */
+ else if (may_trap_or_fault_p (a) || may_trap_or_fault_p (b))
+ return FALSE;
+
+ /* if (test) x = a + b; else x = c - d;
+ => y = a + b;
+ x = c - d;
+ if (test)
+ x = y;
+ */
+
+ code = GET_CODE (if_info->cond);
+ insn_a = if_info->insn_a;
+ insn_b = if_info->insn_b;
+
+ /* Total insn_rtx_cost should be smaller than branch cost. Exit
+ if insn_rtx_cost can't be estimated. */
+ if (insn_a)
+ {
+ insn_cost
+ = insn_rtx_cost (PATTERN (insn_a),
+ optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn_a)));
+ if (insn_cost == 0 || insn_cost > COSTS_N_INSNS (if_info->branch_cost))
+ return FALSE;
+ }
+ else
+ insn_cost = 0;
+
+ if (insn_b)
+ {
+ insn_cost
+ += insn_rtx_cost (PATTERN (insn_b),
+ optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn_b)));
+ if (insn_cost == 0 || insn_cost > COSTS_N_INSNS (if_info->branch_cost))
+ return FALSE;
+ }
+
+ /* Possibly rearrange operands to make things come out more natural. */
+ if (reversed_comparison_code (if_info->cond, if_info->jump) != UNKNOWN)
+ {
+ int reversep = 0;
+ if (rtx_equal_p (b, x))
+ reversep = 1;
+ else if (general_operand (b, GET_MODE (b)))
+ reversep = 1;
+
+ if (reversep)
+ {
+ code = reversed_comparison_code (if_info->cond, if_info->jump);
+ tmp = a, a = b, b = tmp;
+ tmp = insn_a, insn_a = insn_b, insn_b = tmp;
+ }
+ }
+
+ start_sequence ();
+
+ orig_a = a;
+ orig_b = b;
+
+ /* If either operand is complex, load it into a register first.
+ The best way to do this is to copy the original insn. In this
+ way we preserve any clobbers etc that the insn may have had.
+ This is of course not possible in the IS_MEM case. */
+ if (! general_operand (a, GET_MODE (a)))
+ {
+ rtx set;
+
+ if (is_mem)
+ {
+ tmp = gen_reg_rtx (GET_MODE (a));
+ tmp = emit_insn (gen_rtx_SET (VOIDmode, tmp, a));
+ }
+ else if (! insn_a)
+ goto end_seq_and_fail;
+ else
+ {
+ a = gen_reg_rtx (GET_MODE (a));
+ tmp = copy_rtx (insn_a);
+ set = single_set (tmp);
+ SET_DEST (set) = a;
+ tmp = emit_insn (PATTERN (tmp));
+ }
+ if (recog_memoized (tmp) < 0)
+ goto end_seq_and_fail;
+ }
+ if (! general_operand (b, GET_MODE (b)))
+ {
+ rtx set, last;
+
+ if (is_mem)
+ {
+ tmp = gen_reg_rtx (GET_MODE (b));
+ tmp = gen_rtx_SET (VOIDmode, tmp, b);
+ }
+ else if (! insn_b)
+ goto end_seq_and_fail;
+ else
+ {
+ b = gen_reg_rtx (GET_MODE (b));
+ tmp = copy_rtx (insn_b);
+ set = single_set (tmp);
+ SET_DEST (set) = b;
+ tmp = PATTERN (tmp);
+ }
+
+ /* If insn to set up A clobbers any registers B depends on, try to
+ swap insn that sets up A with the one that sets up B. If even
+ that doesn't help, punt. */
+ last = get_last_insn ();
+ if (last && modified_in_p (orig_b, last))
+ {
+ tmp = emit_insn_before (tmp, get_insns ());
+ if (modified_in_p (orig_a, tmp))
+ goto end_seq_and_fail;
+ }
+ else
+ tmp = emit_insn (tmp);
+
+ if (recog_memoized (tmp) < 0)
+ goto end_seq_and_fail;
+ }
+
+ target = noce_emit_cmove (if_info, x, code, XEXP (if_info->cond, 0),
+ XEXP (if_info->cond, 1), a, b);
+
+ if (! target)
+ goto end_seq_and_fail;
+
+ /* If we're handling a memory for above, emit the load now. */
+ if (is_mem)
+ {
+ tmp = gen_rtx_MEM (GET_MODE (if_info->x), target);
+
+ /* Copy over flags as appropriate. */
+ if (MEM_VOLATILE_P (if_info->a) || MEM_VOLATILE_P (if_info->b))
+ MEM_VOLATILE_P (tmp) = 1;
+ if (MEM_ALIAS_SET (if_info->a) == MEM_ALIAS_SET (if_info->b))
+ set_mem_alias_set (tmp, MEM_ALIAS_SET (if_info->a));
+ set_mem_align (tmp,
+ MIN (MEM_ALIGN (if_info->a), MEM_ALIGN (if_info->b)));
+
+ gcc_assert (MEM_ADDR_SPACE (if_info->a) == MEM_ADDR_SPACE (if_info->b));
+ set_mem_addr_space (tmp, MEM_ADDR_SPACE (if_info->a));
+
+ noce_emit_move_insn (if_info->x, tmp);
+ }
+ else if (target != x)
+ noce_emit_move_insn (x, target);
+
+ tmp = end_ifcvt_sequence (if_info);
+ if (!tmp)
+ return FALSE;
+
+ emit_insn_before_setloc (tmp, if_info->jump, INSN_LOCATION (if_info->insn_a));
+ return TRUE;
+
+ end_seq_and_fail:
+ end_sequence ();
+ return FALSE;
+}
+
+/* For most cases, the simplified condition we found is the best
+ choice, but this is not the case for the min/max/abs transforms.
+ For these we wish to know that it is A or B in the condition. */
+
+static rtx
+noce_get_alt_condition (struct noce_if_info *if_info, rtx target,
+ rtx *earliest)
+{
+ rtx cond, set, insn;
+ int reverse;
+
+ /* If target is already mentioned in the known condition, return it. */
+ if (reg_mentioned_p (target, if_info->cond))
+ {
+ *earliest = if_info->cond_earliest;
+ return if_info->cond;
+ }
+
+ set = pc_set (if_info->jump);
+ cond = XEXP (SET_SRC (set), 0);
+ reverse
+ = GET_CODE (XEXP (SET_SRC (set), 2)) == LABEL_REF
+ && XEXP (XEXP (SET_SRC (set), 2), 0) == JUMP_LABEL (if_info->jump);
+ if (if_info->then_else_reversed)
+ reverse = !reverse;
+
+ /* If we're looking for a constant, try to make the conditional
+ have that constant in it. There are two reasons why it may
+ not have the constant we want:
+
+ 1. GCC may have needed to put the constant in a register, because
+ the target can't compare directly against that constant. For
+ this case, we look for a SET immediately before the comparison
+ that puts a constant in that register.
+
+ 2. GCC may have canonicalized the conditional, for example
+ replacing "if x < 4" with "if x <= 3". We can undo that (or
+ make equivalent types of changes) to get the constants we need
+ if they're off by one in the right direction. */
+
+ if (CONST_INT_P (target))
+ {
+ enum rtx_code code = GET_CODE (if_info->cond);
+ rtx op_a = XEXP (if_info->cond, 0);
+ rtx op_b = XEXP (if_info->cond, 1);
+ rtx prev_insn;
+
+ /* First, look to see if we put a constant in a register. */
+ prev_insn = prev_nonnote_insn (if_info->cond_earliest);
+ if (prev_insn
+ && BLOCK_FOR_INSN (prev_insn)
+ == BLOCK_FOR_INSN (if_info->cond_earliest)
+ && INSN_P (prev_insn)
+ && GET_CODE (PATTERN (prev_insn)) == SET)
+ {
+ rtx src = find_reg_equal_equiv_note (prev_insn);
+ if (!src)
+ src = SET_SRC (PATTERN (prev_insn));
+ if (CONST_INT_P (src))
+ {
+ if (rtx_equal_p (op_a, SET_DEST (PATTERN (prev_insn))))
+ op_a = src;
+ else if (rtx_equal_p (op_b, SET_DEST (PATTERN (prev_insn))))
+ op_b = src;
+
+ if (CONST_INT_P (op_a))
+ {
+ rtx tmp = op_a;
+ op_a = op_b;
+ op_b = tmp;
+ code = swap_condition (code);
+ }
+ }
+ }
+
+ /* Now, look to see if we can get the right constant by
+ adjusting the conditional. */
+ if (CONST_INT_P (op_b))
+ {
+ HOST_WIDE_INT desired_val = INTVAL (target);
+ HOST_WIDE_INT actual_val = INTVAL (op_b);
+
+ switch (code)
+ {
+ case LT:
+ if (actual_val == desired_val + 1)
+ {
+ code = LE;
+ op_b = GEN_INT (desired_val);
+ }
+ break;
+ case LE:
+ if (actual_val == desired_val - 1)
+ {
+ code = LT;
+ op_b = GEN_INT (desired_val);
+ }
+ break;
+ case GT:
+ if (actual_val == desired_val - 1)
+ {
+ code = GE;
+ op_b = GEN_INT (desired_val);
+ }
+ break;
+ case GE:
+ if (actual_val == desired_val + 1)
+ {
+ code = GT;
+ op_b = GEN_INT (desired_val);
+ }
+ break;
+ default:
+ break;
+ }
+ }
+
+ /* If we made any changes, generate a new conditional that is
+ equivalent to what we started with, but has the right
+ constants in it. */
+ if (code != GET_CODE (if_info->cond)
+ || op_a != XEXP (if_info->cond, 0)
+ || op_b != XEXP (if_info->cond, 1))
+ {
+ cond = gen_rtx_fmt_ee (code, GET_MODE (cond), op_a, op_b);
+ *earliest = if_info->cond_earliest;
+ return cond;
+ }
+ }
+
+ cond = canonicalize_condition (if_info->jump, cond, reverse,
+ earliest, target, false, true);
+ if (! cond || ! reg_mentioned_p (target, cond))
+ return NULL;
+
+ /* We almost certainly searched back to a different place.
+ Need to re-verify correct lifetimes. */
+
+ /* X may not be mentioned in the range (cond_earliest, jump]. */
+ for (insn = if_info->jump; insn != *earliest; insn = PREV_INSN (insn))
+ if (INSN_P (insn) && reg_overlap_mentioned_p (if_info->x, PATTERN (insn)))
+ return NULL;
+
+ /* A and B may not be modified in the range [cond_earliest, jump). */
+ for (insn = *earliest; insn != if_info->jump; insn = NEXT_INSN (insn))
+ if (INSN_P (insn)
+ && (modified_in_p (if_info->a, insn)
+ || modified_in_p (if_info->b, insn)))
+ return NULL;
+
+ return cond;
+}
+
+/* Convert "if (a < b) x = a; else x = b;" to "x = min(a, b);", etc. */
+
+static int
+noce_try_minmax (struct noce_if_info *if_info)
+{
+ rtx cond, earliest, target, seq;
+ enum rtx_code code, op;
+ int unsignedp;
+
+ /* ??? Reject modes with NaNs or signed zeros since we don't know how
+ they will be resolved with an SMIN/SMAX. It wouldn't be too hard
+ to get the target to tell us... */
+ if (HONOR_SIGNED_ZEROS (GET_MODE (if_info->x))
+ || HONOR_NANS (GET_MODE (if_info->x)))
+ return FALSE;
+
+ cond = noce_get_alt_condition (if_info, if_info->a, &earliest);
+ if (!cond)
+ return FALSE;
+
+ /* Verify the condition is of the form we expect, and canonicalize
+ the comparison code. */
+ code = GET_CODE (cond);
+ if (rtx_equal_p (XEXP (cond, 0), if_info->a))
+ {
+ if (! rtx_equal_p (XEXP (cond, 1), if_info->b))
+ return FALSE;
+ }
+ else if (rtx_equal_p (XEXP (cond, 1), if_info->a))
+ {
+ if (! rtx_equal_p (XEXP (cond, 0), if_info->b))
+ return FALSE;
+ code = swap_condition (code);
+ }
+ else
+ return FALSE;
+
+ /* Determine what sort of operation this is. Note that the code is for
+ a taken branch, so the code->operation mapping appears backwards. */
+ switch (code)
+ {
+ case LT:
+ case LE:
+ case UNLT:
+ case UNLE:
+ op = SMAX;
+ unsignedp = 0;
+ break;
+ case GT:
+ case GE:
+ case UNGT:
+ case UNGE:
+ op = SMIN;
+ unsignedp = 0;
+ break;
+ case LTU:
+ case LEU:
+ op = UMAX;
+ unsignedp = 1;
+ break;
+ case GTU:
+ case GEU:
+ op = UMIN;
+ unsignedp = 1;
+ break;
+ default:
+ return FALSE;
+ }
+
+ start_sequence ();
+
+ target = expand_simple_binop (GET_MODE (if_info->x), op,
+ if_info->a, if_info->b,
+ if_info->x, unsignedp, OPTAB_WIDEN);
+ if (! target)
+ {
+ end_sequence ();
+ return FALSE;
+ }
+ if (target != if_info->x)
+ noce_emit_move_insn (if_info->x, target);
+
+ seq = end_ifcvt_sequence (if_info);
+ if (!seq)
+ return FALSE;
+
+ emit_insn_before_setloc (seq, if_info->jump, INSN_LOCATION (if_info->insn_a));
+ if_info->cond = cond;
+ if_info->cond_earliest = earliest;
+
+ return TRUE;
+}
+
+/* Convert "if (a < 0) x = -a; else x = a;" to "x = abs(a);",
+ "if (a < 0) x = ~a; else x = a;" to "x = one_cmpl_abs(a);",
+ etc. */
+
+static int
+noce_try_abs (struct noce_if_info *if_info)
+{
+ rtx cond, earliest, target, seq, a, b, c;
+ int negate;
+ bool one_cmpl = false;
+
+ /* Reject modes with signed zeros. */
+ if (HONOR_SIGNED_ZEROS (GET_MODE (if_info->x)))
+ return FALSE;
+
+ /* Recognize A and B as constituting an ABS or NABS. The canonical
+ form is a branch around the negation, taken when the object is the
+ first operand of a comparison against 0 that evaluates to true. */
+ a = if_info->a;
+ b = if_info->b;
+ if (GET_CODE (a) == NEG && rtx_equal_p (XEXP (a, 0), b))
+ negate = 0;
+ else if (GET_CODE (b) == NEG && rtx_equal_p (XEXP (b, 0), a))
+ {
+ c = a; a = b; b = c;
+ negate = 1;
+ }
+ else if (GET_CODE (a) == NOT && rtx_equal_p (XEXP (a, 0), b))
+ {
+ negate = 0;
+ one_cmpl = true;
+ }
+ else if (GET_CODE (b) == NOT && rtx_equal_p (XEXP (b, 0), a))
+ {
+ c = a; a = b; b = c;
+ negate = 1;
+ one_cmpl = true;
+ }
+ else
+ return FALSE;
+
+ cond = noce_get_alt_condition (if_info, b, &earliest);
+ if (!cond)
+ return FALSE;
+
+ /* Verify the condition is of the form we expect. */
+ if (rtx_equal_p (XEXP (cond, 0), b))
+ c = XEXP (cond, 1);
+ else if (rtx_equal_p (XEXP (cond, 1), b))
+ {
+ c = XEXP (cond, 0);
+ negate = !negate;
+ }
+ else
+ return FALSE;
+
+ /* Verify that C is zero. Search one step backward for a
+ REG_EQUAL note or a simple source if necessary. */
+ if (REG_P (c))
+ {
+ rtx set, insn = prev_nonnote_insn (earliest);
+ if (insn
+ && BLOCK_FOR_INSN (insn) == BLOCK_FOR_INSN (earliest)
+ && (set = single_set (insn))
+ && rtx_equal_p (SET_DEST (set), c))
+ {
+ rtx note = find_reg_equal_equiv_note (insn);
+ if (note)
+ c = XEXP (note, 0);
+ else
+ c = SET_SRC (set);
+ }
+ else
+ return FALSE;
+ }
+ if (MEM_P (c)
+ && GET_CODE (XEXP (c, 0)) == SYMBOL_REF
+ && CONSTANT_POOL_ADDRESS_P (XEXP (c, 0)))
+ c = get_pool_constant (XEXP (c, 0));
+
+ /* Work around funny ideas get_condition has wrt canonicalization.
+ Note that these rtx constants are known to be CONST_INT, and
+ therefore imply integer comparisons. */
+ if (c == constm1_rtx && GET_CODE (cond) == GT)
+ ;
+ else if (c == const1_rtx && GET_CODE (cond) == LT)
+ ;
+ else if (c != CONST0_RTX (GET_MODE (b)))
+ return FALSE;
+
+ /* Determine what sort of operation this is. */
+ switch (GET_CODE (cond))
+ {
+ case LT:
+ case LE:
+ case UNLT:
+ case UNLE:
+ negate = !negate;
+ break;
+ case GT:
+ case GE:
+ case UNGT:
+ case UNGE:
+ break;
+ default:
+ return FALSE;
+ }
+
+ start_sequence ();
+ if (one_cmpl)
+ target = expand_one_cmpl_abs_nojump (GET_MODE (if_info->x), b,
+ if_info->x);
+ else
+ target = expand_abs_nojump (GET_MODE (if_info->x), b, if_info->x, 1);
+
+ /* ??? It's a quandary whether cmove would be better here, especially
+ for integers. Perhaps combine will clean things up. */
+ if (target && negate)
+ {
+ if (one_cmpl)
+ target = expand_simple_unop (GET_MODE (target), NOT, target,
+ if_info->x, 0);
+ else
+ target = expand_simple_unop (GET_MODE (target), NEG, target,
+ if_info->x, 0);
+ }
+
+ if (! target)
+ {
+ end_sequence ();
+ return FALSE;
+ }
+
+ if (target != if_info->x)
+ noce_emit_move_insn (if_info->x, target);
+
+ seq = end_ifcvt_sequence (if_info);
+ if (!seq)
+ return FALSE;
+
+ emit_insn_before_setloc (seq, if_info->jump, INSN_LOCATION (if_info->insn_a));
+ if_info->cond = cond;
+ if_info->cond_earliest = earliest;
+
+ return TRUE;
+}
+
+/* Convert "if (m < 0) x = b; else x = 0;" to "x = (m >> C) & b;". */
+
+static int
+noce_try_sign_mask (struct noce_if_info *if_info)
+{
+ rtx cond, t, m, c, seq;
+ enum machine_mode mode;
+ enum rtx_code code;
+ bool t_unconditional;
+
+ cond = if_info->cond;
+ code = GET_CODE (cond);
+ m = XEXP (cond, 0);
+ c = XEXP (cond, 1);
+
+ t = NULL_RTX;
+ if (if_info->a == const0_rtx)
+ {
+ if ((code == LT && c == const0_rtx)
+ || (code == LE && c == constm1_rtx))
+ t = if_info->b;
+ }
+ else if (if_info->b == const0_rtx)
+ {
+ if ((code == GE && c == const0_rtx)
+ || (code == GT && c == constm1_rtx))
+ t = if_info->a;
+ }
+
+ if (! t || side_effects_p (t))
+ return FALSE;
+
+ /* We currently don't handle different modes. */
+ mode = GET_MODE (t);
+ if (GET_MODE (m) != mode)
+ return FALSE;
+
+ /* This is only profitable if T is unconditionally executed/evaluated in the
+ original insn sequence or T is cheap. The former happens if B is the
+ non-zero (T) value and if INSN_B was taken from TEST_BB, or there was no
+ INSN_B which can happen for e.g. conditional stores to memory. For the
+ cost computation use the block TEST_BB where the evaluation will end up
+ after the transformation. */
+ t_unconditional =
+ (t == if_info->b
+ && (if_info->insn_b == NULL_RTX
+ || BLOCK_FOR_INSN (if_info->insn_b) == if_info->test_bb));
+ if (!(t_unconditional
+ || (set_src_cost (t, optimize_bb_for_speed_p (if_info->test_bb))
+ < COSTS_N_INSNS (2))))
+ return FALSE;
+
+ start_sequence ();
+ /* Use emit_store_flag to generate "m < 0 ? -1 : 0" instead of expanding
+ "(signed) m >> 31" directly. This benefits targets with specialized
+ insns to obtain the signmask, but still uses ashr_optab otherwise. */
+ m = emit_store_flag (gen_reg_rtx (mode), LT, m, const0_rtx, mode, 0, -1);
+ t = m ? expand_binop (mode, and_optab, m, t, NULL_RTX, 0, OPTAB_DIRECT)
+ : NULL_RTX;
+
+ if (!t)
+ {
+ end_sequence ();
+ return FALSE;
+ }
+
+ noce_emit_move_insn (if_info->x, t);
+
+ seq = end_ifcvt_sequence (if_info);
+ if (!seq)
+ return FALSE;
+
+ emit_insn_before_setloc (seq, if_info->jump, INSN_LOCATION (if_info->insn_a));
+ return TRUE;
+}
+
+
+/* Optimize away "if (x & C) x |= C" and similar bit manipulation
+ transformations. */
+
+static int
+noce_try_bitop (struct noce_if_info *if_info)
+{
+ rtx cond, x, a, result, seq;
+ enum machine_mode mode;
+ enum rtx_code code;
+ int bitnum;
+
+ x = if_info->x;
+ cond = if_info->cond;
+ code = GET_CODE (cond);
+
+ /* Check for no else condition. */
+ if (! rtx_equal_p (x, if_info->b))
+ return FALSE;
+
+ /* Check for a suitable condition. */
+ if (code != NE && code != EQ)
+ return FALSE;
+ if (XEXP (cond, 1) != const0_rtx)
+ return FALSE;
+ cond = XEXP (cond, 0);
+
+ /* ??? We could also handle AND here. */
+ if (GET_CODE (cond) == ZERO_EXTRACT)
+ {
+ if (XEXP (cond, 1) != const1_rtx
+ || !CONST_INT_P (XEXP (cond, 2))
+ || ! rtx_equal_p (x, XEXP (cond, 0)))
+ return FALSE;
+ bitnum = INTVAL (XEXP (cond, 2));
+ mode = GET_MODE (x);
+ if (BITS_BIG_ENDIAN)
+ bitnum = GET_MODE_BITSIZE (mode) - 1 - bitnum;
+ if (bitnum < 0 || bitnum >= HOST_BITS_PER_WIDE_INT)
+ return FALSE;
+ }
+ else
+ return FALSE;
+
+ a = if_info->a;
+ if (GET_CODE (a) == IOR || GET_CODE (a) == XOR)
+ {
+ /* Check for "if (X & C) x = x op C". */
+ if (! rtx_equal_p (x, XEXP (a, 0))
+ || !CONST_INT_P (XEXP (a, 1))
+ || (INTVAL (XEXP (a, 1)) & GET_MODE_MASK (mode))
+ != (unsigned HOST_WIDE_INT) 1 << bitnum)
+ return FALSE;
+
+ /* if ((x & C) == 0) x |= C; is transformed to x |= C. */
+ /* if ((x & C) != 0) x |= C; is transformed to nothing. */
+ if (GET_CODE (a) == IOR)
+ result = (code == NE) ? a : NULL_RTX;
+ else if (code == NE)
+ {
+ /* if ((x & C) == 0) x ^= C; is transformed to x |= C. */
+ result = gen_int_mode ((HOST_WIDE_INT) 1 << bitnum, mode);
+ result = simplify_gen_binary (IOR, mode, x, result);
+ }
+ else
+ {
+ /* if ((x & C) != 0) x ^= C; is transformed to x &= ~C. */
+ result = gen_int_mode (~((HOST_WIDE_INT) 1 << bitnum), mode);
+ result = simplify_gen_binary (AND, mode, x, result);
+ }
+ }
+ else if (GET_CODE (a) == AND)
+ {
+ /* Check for "if (X & C) x &= ~C". */
+ if (! rtx_equal_p (x, XEXP (a, 0))
+ || !CONST_INT_P (XEXP (a, 1))
+ || (INTVAL (XEXP (a, 1)) & GET_MODE_MASK (mode))
+ != (~((HOST_WIDE_INT) 1 << bitnum) & GET_MODE_MASK (mode)))
+ return FALSE;
+
+ /* if ((x & C) == 0) x &= ~C; is transformed to nothing. */
+ /* if ((x & C) != 0) x &= ~C; is transformed to x &= ~C. */
+ result = (code == EQ) ? a : NULL_RTX;
+ }
+ else
+ return FALSE;
+
+ if (result)
+ {
+ start_sequence ();
+ noce_emit_move_insn (x, result);
+ seq = end_ifcvt_sequence (if_info);
+ if (!seq)
+ return FALSE;
+
+ emit_insn_before_setloc (seq, if_info->jump,
+ INSN_LOCATION (if_info->insn_a));
+ }
+ return TRUE;
+}
+
+
+/* Similar to get_condition, only the resulting condition must be
+ valid at JUMP, instead of at EARLIEST.
+
+ If THEN_ELSE_REVERSED is true, the fallthrough does not go to the
+ THEN block of the caller, and we have to reverse the condition. */
+
+static rtx
+noce_get_condition (rtx jump, rtx *earliest, bool then_else_reversed)
+{
+ rtx cond, set, tmp;
+ bool reverse;
+
+ if (! any_condjump_p (jump))
+ return NULL_RTX;
+
+ set = pc_set (jump);
+
+ /* If this branches to JUMP_LABEL when the condition is false,
+ reverse the condition. */
+ reverse = (GET_CODE (XEXP (SET_SRC (set), 2)) == LABEL_REF
+ && XEXP (XEXP (SET_SRC (set), 2), 0) == JUMP_LABEL (jump));
+
+ /* We may have to reverse because the caller's if block is not canonical,
+ i.e. the THEN block isn't the fallthrough block for the TEST block
+ (see find_if_header). */
+ if (then_else_reversed)
+ reverse = !reverse;
+
+ /* If the condition variable is a register and is MODE_INT, accept it. */
+
+ cond = XEXP (SET_SRC (set), 0);
+ tmp = XEXP (cond, 0);
+ if (REG_P (tmp) && GET_MODE_CLASS (GET_MODE (tmp)) == MODE_INT
+ && (GET_MODE (tmp) != BImode
+ || !targetm.small_register_classes_for_mode_p (BImode)))
+ {
+ *earliest = jump;
+
+ if (reverse)
+ cond = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond)),
+ GET_MODE (cond), tmp, XEXP (cond, 1));
+ return cond;
+ }
+
+ /* Otherwise, fall back on canonicalize_condition to do the dirty
+ work of manipulating MODE_CC values and COMPARE rtx codes. */
+ tmp = canonicalize_condition (jump, cond, reverse, earliest,
+ NULL_RTX, false, true);
+
+ /* We don't handle side-effects in the condition, like handling
+ REG_INC notes and making sure no duplicate conditions are emitted. */
+ if (tmp != NULL_RTX && side_effects_p (tmp))
+ return NULL_RTX;
+
+ return tmp;
+}
+
+/* Return true if OP is ok for if-then-else processing. */
+
+static int
+noce_operand_ok (const_rtx op)
+{
+ if (side_effects_p (op))
+ return FALSE;
+
+ /* We special-case memories, so handle any of them with
+ no address side effects. */
+ if (MEM_P (op))
+ return ! side_effects_p (XEXP (op, 0));
+
+ return ! may_trap_p (op);
+}
+
+/* Return true if a write into MEM may trap or fault. */
+
+static bool
+noce_mem_write_may_trap_or_fault_p (const_rtx mem)
+{
+ rtx addr;
+
+ if (MEM_READONLY_P (mem))
+ return true;
+
+ if (may_trap_or_fault_p (mem))
+ return true;
+
+ addr = XEXP (mem, 0);
+
+ /* Call target hook to avoid the effects of -fpic etc.... */
+ addr = targetm.delegitimize_address (addr);
+
+ while (addr)
+ switch (GET_CODE (addr))
+ {
+ case CONST:
+ case PRE_DEC:
+ case PRE_INC:
+ case POST_DEC:
+ case POST_INC:
+ case POST_MODIFY:
+ addr = XEXP (addr, 0);
+ break;
+ case LO_SUM:
+ case PRE_MODIFY:
+ addr = XEXP (addr, 1);
+ break;
+ case PLUS:
+ if (CONST_INT_P (XEXP (addr, 1)))
+ addr = XEXP (addr, 0);
+ else
+ return false;
+ break;
+ case LABEL_REF:
+ return true;
+ case SYMBOL_REF:
+ if (SYMBOL_REF_DECL (addr)
+ && decl_readonly_section (SYMBOL_REF_DECL (addr), 0))
+ return true;
+ return false;
+ default:
+ return false;
+ }
+
+ return false;
+}
+
+/* Return whether we can use store speculation for MEM. TOP_BB is the
+ basic block above the conditional block where we are considering
+ doing the speculative store. We look for whether MEM is set
+ unconditionally later in the function. */
+
+static bool
+noce_can_store_speculate_p (basic_block top_bb, const_rtx mem)
+{
+ basic_block dominator;
+
+ for (dominator = get_immediate_dominator (CDI_POST_DOMINATORS, top_bb);
+ dominator != NULL;
+ dominator = get_immediate_dominator (CDI_POST_DOMINATORS, dominator))
+ {
+ rtx insn;
+
+ FOR_BB_INSNS (dominator, insn)
+ {
+ /* If we see something that might be a memory barrier, we
+ have to stop looking. Even if the MEM is set later in
+ the function, we still don't want to set it
+ unconditionally before the barrier. */
+ if (INSN_P (insn)
+ && (volatile_insn_p (PATTERN (insn))
+ || (CALL_P (insn) && (!RTL_CONST_CALL_P (insn)))))
+ return false;
+
+ if (memory_must_be_modified_in_insn_p (mem, insn))
+ return true;
+ if (modified_in_p (XEXP (mem, 0), insn))
+ return false;
+
+ }
+ }
+
+ return false;
+}
+
+/* Given a simple IF-THEN-JOIN or IF-THEN-ELSE-JOIN block, attempt to convert
+ it without using conditional execution. Return TRUE if we were successful
+ at converting the block. */
+
+static int
+noce_process_if_block (struct noce_if_info *if_info)
+{
+ basic_block test_bb = if_info->test_bb; /* test block */
+ basic_block then_bb = if_info->then_bb; /* THEN */
+ basic_block else_bb = if_info->else_bb; /* ELSE or NULL */
+ basic_block join_bb = if_info->join_bb; /* JOIN */
+ rtx jump = if_info->jump;
+ rtx cond = if_info->cond;
+ rtx insn_a, insn_b;
+ rtx set_a, set_b;
+ rtx orig_x, x, a, b;
+
+ /* We're looking for patterns of the form
+
+ (1) if (...) x = a; else x = b;
+ (2) x = b; if (...) x = a;
+ (3) if (...) x = a; // as if with an initial x = x.
+
+ The later patterns require jumps to be more expensive.
+
+ ??? For future expansion, look for multiple X in such patterns. */
+
+ /* Look for one of the potential sets. */
+ insn_a = first_active_insn (then_bb);
+ if (! insn_a
+ || insn_a != last_active_insn (then_bb, FALSE)
+ || (set_a = single_set (insn_a)) == NULL_RTX)
+ return FALSE;
+
+ x = SET_DEST (set_a);
+ a = SET_SRC (set_a);
+
+ /* Look for the other potential set. Make sure we've got equivalent
+ destinations. */
+ /* ??? This is overconservative. Storing to two different mems is
+ as easy as conditionally computing the address. Storing to a
+ single mem merely requires a scratch memory to use as one of the
+ destination addresses; often the memory immediately below the
+ stack pointer is available for this. */
+ set_b = NULL_RTX;
+ if (else_bb)
+ {
+ insn_b = first_active_insn (else_bb);
+ if (! insn_b
+ || insn_b != last_active_insn (else_bb, FALSE)
+ || (set_b = single_set (insn_b)) == NULL_RTX
+ || ! rtx_equal_p (x, SET_DEST (set_b)))
+ return FALSE;
+ }
+ else
+ {
+ insn_b = prev_nonnote_nondebug_insn (if_info->cond_earliest);
+ /* We're going to be moving the evaluation of B down from above
+ COND_EARLIEST to JUMP. Make sure the relevant data is still
+ intact. */
+ if (! insn_b
+ || BLOCK_FOR_INSN (insn_b) != BLOCK_FOR_INSN (if_info->cond_earliest)
+ || !NONJUMP_INSN_P (insn_b)
+ || (set_b = single_set (insn_b)) == NULL_RTX
+ || ! rtx_equal_p (x, SET_DEST (set_b))
+ || ! noce_operand_ok (SET_SRC (set_b))
+ || reg_overlap_mentioned_p (x, SET_SRC (set_b))
+ || modified_between_p (SET_SRC (set_b), insn_b, jump)
+ /* Avoid extending the lifetime of hard registers on small
+ register class machines. */
+ || (REG_P (SET_SRC (set_b))
+ && HARD_REGISTER_P (SET_SRC (set_b))
+ && targetm.small_register_classes_for_mode_p
+ (GET_MODE (SET_SRC (set_b))))
+ /* Likewise with X. In particular this can happen when
+ noce_get_condition looks farther back in the instruction
+ stream than one might expect. */
+ || reg_overlap_mentioned_p (x, cond)
+ || reg_overlap_mentioned_p (x, a)
+ || modified_between_p (x, insn_b, jump))
+ insn_b = set_b = NULL_RTX;
+ }
+
+ /* If x has side effects then only the if-then-else form is safe to
+ convert. But even in that case we would need to restore any notes
+ (such as REG_INC) at then end. That can be tricky if
+ noce_emit_move_insn expands to more than one insn, so disable the
+ optimization entirely for now if there are side effects. */
+ if (side_effects_p (x))
+ return FALSE;
+
+ b = (set_b ? SET_SRC (set_b) : x);
+
+ /* Only operate on register destinations, and even then avoid extending
+ the lifetime of hard registers on small register class machines. */
+ orig_x = x;
+ if (!REG_P (x)
+ || (HARD_REGISTER_P (x)
+ && targetm.small_register_classes_for_mode_p (GET_MODE (x))))
+ {
+ if (GET_MODE (x) == BLKmode)
+ return FALSE;
+
+ if (GET_CODE (x) == ZERO_EXTRACT
+ && (!CONST_INT_P (XEXP (x, 1))
+ || !CONST_INT_P (XEXP (x, 2))))
+ return FALSE;
+
+ x = gen_reg_rtx (GET_MODE (GET_CODE (x) == STRICT_LOW_PART
+ ? XEXP (x, 0) : x));
+ }
+
+ /* Don't operate on sources that may trap or are volatile. */
+ if (! noce_operand_ok (a) || ! noce_operand_ok (b))
+ return FALSE;
+
+ retry:
+ /* Set up the info block for our subroutines. */
+ if_info->insn_a = insn_a;
+ if_info->insn_b = insn_b;
+ if_info->x = x;
+ if_info->a = a;
+ if_info->b = b;
+
+ /* Try optimizations in some approximation of a useful order. */
+ /* ??? Should first look to see if X is live incoming at all. If it
+ isn't, we don't need anything but an unconditional set. */
+
+ /* Look and see if A and B are really the same. Avoid creating silly
+ cmove constructs that no one will fix up later. */
+ if (rtx_equal_p (a, b))
+ {
+ /* If we have an INSN_B, we don't have to create any new rtl. Just
+ move the instruction that we already have. If we don't have an
+ INSN_B, that means that A == X, and we've got a noop move. In
+ that case don't do anything and let the code below delete INSN_A. */
+ if (insn_b && else_bb)
+ {
+ rtx note;
+
+ if (else_bb && insn_b == BB_END (else_bb))
+ BB_END (else_bb) = PREV_INSN (insn_b);
+ reorder_insns (insn_b, insn_b, PREV_INSN (jump));
+
+ /* If there was a REG_EQUAL note, delete it since it may have been
+ true due to this insn being after a jump. */
+ if ((note = find_reg_note (insn_b, REG_EQUAL, NULL_RTX)) != 0)
+ remove_note (insn_b, note);
+
+ insn_b = NULL_RTX;
+ }
+ /* If we have "x = b; if (...) x = a;", and x has side-effects, then
+ x must be executed twice. */
+ else if (insn_b && side_effects_p (orig_x))
+ return FALSE;
+
+ x = orig_x;
+ goto success;
+ }
+
+ if (!set_b && MEM_P (orig_x))
+ {
+ /* Disallow the "if (...) x = a;" form (implicit "else x = x;")
+ for optimizations if writing to x may trap or fault,
+ i.e. it's a memory other than a static var or a stack slot,
+ is misaligned on strict aligned machines or is read-only. If
+ x is a read-only memory, then the program is valid only if we
+ avoid the store into it. If there are stores on both the
+ THEN and ELSE arms, then we can go ahead with the conversion;
+ either the program is broken, or the condition is always
+ false such that the other memory is selected. */
+ if (noce_mem_write_may_trap_or_fault_p (orig_x))
+ return FALSE;
+
+ /* Avoid store speculation: given "if (...) x = a" where x is a
+ MEM, we only want to do the store if x is always set
+ somewhere in the function. This avoids cases like
+ if (pthread_mutex_trylock(mutex))
+ ++global_variable;
+ where we only want global_variable to be changed if the mutex
+ is held. FIXME: This should ideally be expressed directly in
+ RTL somehow. */
+ if (!noce_can_store_speculate_p (test_bb, orig_x))
+ return FALSE;
+ }
+
+ if (noce_try_move (if_info))
+ goto success;
+ if (noce_try_store_flag (if_info))
+ goto success;
+ if (noce_try_bitop (if_info))
+ goto success;
+ if (noce_try_minmax (if_info))
+ goto success;
+ if (noce_try_abs (if_info))
+ goto success;
+ if (HAVE_conditional_move
+ && noce_try_cmove (if_info))
+ goto success;
+ if (! targetm.have_conditional_execution ())
+ {
+ if (noce_try_store_flag_constants (if_info))
+ goto success;
+ if (noce_try_addcc (if_info))
+ goto success;
+ if (noce_try_store_flag_mask (if_info))
+ goto success;
+ if (HAVE_conditional_move
+ && noce_try_cmove_arith (if_info))
+ goto success;
+ if (noce_try_sign_mask (if_info))
+ goto success;
+ }
+
+ if (!else_bb && set_b)
+ {
+ insn_b = set_b = NULL_RTX;
+ b = orig_x;
+ goto retry;
+ }
+
+ return FALSE;
+
+ success:
+
+ /* If we used a temporary, fix it up now. */
+ if (orig_x != x)
+ {
+ rtx seq;
+
+ start_sequence ();
+ noce_emit_move_insn (orig_x, x);
+ seq = get_insns ();
+ set_used_flags (orig_x);
+ unshare_all_rtl_in_chain (seq);
+ end_sequence ();
+
+ emit_insn_before_setloc (seq, BB_END (test_bb), INSN_LOCATION (insn_a));
+ }
+
+ /* The original THEN and ELSE blocks may now be removed. The test block
+ must now jump to the join block. If the test block and the join block
+ can be merged, do so. */
+ if (else_bb)
+ {
+ delete_basic_block (else_bb);
+ num_true_changes++;
+ }
+ else
+ remove_edge (find_edge (test_bb, join_bb));
+
+ remove_edge (find_edge (then_bb, join_bb));
+ redirect_edge_and_branch_force (single_succ_edge (test_bb), join_bb);
+ delete_basic_block (then_bb);
+ num_true_changes++;
+
+ if (can_merge_blocks_p (test_bb, join_bb))
+ {
+ merge_blocks (test_bb, join_bb);
+ num_true_changes++;
+ }
+
+ num_updated_if_blocks++;
+ return TRUE;
+}
+
+/* Check whether a block is suitable for conditional move conversion.
+ Every insn must be a simple set of a register to a constant or a
+ register. For each assignment, store the value in the pointer map
+ VALS, keyed indexed by register pointer, then store the register
+ pointer in REGS. COND is the condition we will test. */
+
+static int
+check_cond_move_block (basic_block bb,
+ struct pointer_map_t *vals,
+ vec<rtx> *regs,
+ rtx cond)
+{
+ rtx insn;
+
+ /* We can only handle simple jumps at the end of the basic block.
+ It is almost impossible to update the CFG otherwise. */
+ insn = BB_END (bb);
+ if (JUMP_P (insn) && !onlyjump_p (insn))
+ return FALSE;
+
+ FOR_BB_INSNS (bb, insn)
+ {
+ rtx set, dest, src;
+ void **slot;
+
+ if (!NONDEBUG_INSN_P (insn) || JUMP_P (insn))
+ continue;
+ set = single_set (insn);
+ if (!set)
+ return FALSE;
+
+ dest = SET_DEST (set);
+ src = SET_SRC (set);
+ if (!REG_P (dest)
+ || (HARD_REGISTER_P (dest)
+ && targetm.small_register_classes_for_mode_p (GET_MODE (dest))))
+ return FALSE;
+
+ if (!CONSTANT_P (src) && !register_operand (src, VOIDmode))
+ return FALSE;
+
+ if (side_effects_p (src) || side_effects_p (dest))
+ return FALSE;
+
+ if (may_trap_p (src) || may_trap_p (dest))
+ return FALSE;
+
+ /* Don't try to handle this if the source register was
+ modified earlier in the block. */
+ if ((REG_P (src)
+ && pointer_map_contains (vals, src))
+ || (GET_CODE (src) == SUBREG && REG_P (SUBREG_REG (src))
+ && pointer_map_contains (vals, SUBREG_REG (src))))
+ return FALSE;
+
+ /* Don't try to handle this if the destination register was
+ modified earlier in the block. */
+ if (pointer_map_contains (vals, dest))
+ return FALSE;
+
+ /* Don't try to handle this if the condition uses the
+ destination register. */
+ if (reg_overlap_mentioned_p (dest, cond))
+ return FALSE;
+
+ /* Don't try to handle this if the source register is modified
+ later in the block. */
+ if (!CONSTANT_P (src)
+ && modified_between_p (src, insn, NEXT_INSN (BB_END (bb))))
+ return FALSE;
+
+ slot = pointer_map_insert (vals, (void *) dest);
+ *slot = (void *) src;
+
+ regs->safe_push (dest);
+ }
+
+ return TRUE;
+}
+
+/* Given a basic block BB suitable for conditional move conversion,
+ a condition COND, and pointer maps THEN_VALS and ELSE_VALS containing
+ the register values depending on COND, emit the insns in the block as
+ conditional moves. If ELSE_BLOCK is true, THEN_BB was already
+ processed. The caller has started a sequence for the conversion.
+ Return true if successful, false if something goes wrong. */
+
+static bool
+cond_move_convert_if_block (struct noce_if_info *if_infop,
+ basic_block bb, rtx cond,
+ struct pointer_map_t *then_vals,
+ struct pointer_map_t *else_vals,
+ bool else_block_p)
+{
+ enum rtx_code code;
+ rtx insn, cond_arg0, cond_arg1;
+
+ code = GET_CODE (cond);
+ cond_arg0 = XEXP (cond, 0);
+ cond_arg1 = XEXP (cond, 1);
+
+ FOR_BB_INSNS (bb, insn)
+ {
+ rtx set, target, dest, t, e;
+ void **then_slot, **else_slot;
+
+ /* ??? Maybe emit conditional debug insn? */
+ if (!NONDEBUG_INSN_P (insn) || JUMP_P (insn))
+ continue;
+ set = single_set (insn);
+ gcc_assert (set && REG_P (SET_DEST (set)));
+
+ dest = SET_DEST (set);
+
+ then_slot = pointer_map_contains (then_vals, dest);
+ else_slot = pointer_map_contains (else_vals, dest);
+ t = then_slot ? (rtx) *then_slot : NULL_RTX;
+ e = else_slot ? (rtx) *else_slot : NULL_RTX;
+
+ if (else_block_p)
+ {
+ /* If this register was set in the then block, we already
+ handled this case there. */
+ if (t)
+ continue;
+ t = dest;
+ gcc_assert (e);
+ }
+ else
+ {
+ gcc_assert (t);
+ if (!e)
+ e = dest;
+ }
+
+ target = noce_emit_cmove (if_infop, dest, code, cond_arg0, cond_arg1,
+ t, e);
+ if (!target)
+ return false;
+
+ if (target != dest)
+ noce_emit_move_insn (dest, target);
+ }
+
+ return true;
+}
+
+/* Given a simple IF-THEN-JOIN or IF-THEN-ELSE-JOIN block, attempt to convert
+ it using only conditional moves. Return TRUE if we were successful at
+ converting the block. */
+
+static int
+cond_move_process_if_block (struct noce_if_info *if_info)
+{
+ basic_block test_bb = if_info->test_bb;
+ basic_block then_bb = if_info->then_bb;
+ basic_block else_bb = if_info->else_bb;
+ basic_block join_bb = if_info->join_bb;
+ rtx jump = if_info->jump;
+ rtx cond = if_info->cond;
+ rtx seq, loc_insn;
+ rtx reg;
+ int c;
+ struct pointer_map_t *then_vals;
+ struct pointer_map_t *else_vals;
+ vec<rtx> then_regs = vNULL;
+ vec<rtx> else_regs = vNULL;
+ unsigned int i;
+ int success_p = FALSE;
+
+ /* Build a mapping for each block to the value used for each
+ register. */
+ then_vals = pointer_map_create ();
+ else_vals = pointer_map_create ();
+
+ /* Make sure the blocks are suitable. */
+ if (!check_cond_move_block (then_bb, then_vals, &then_regs, cond)
+ || (else_bb
+ && !check_cond_move_block (else_bb, else_vals, &else_regs, cond)))
+ goto done;
+
+ /* Make sure the blocks can be used together. If the same register
+ is set in both blocks, and is not set to a constant in both
+ cases, then both blocks must set it to the same register. We
+ have already verified that if it is set to a register, that the
+ source register does not change after the assignment. Also count
+ the number of registers set in only one of the blocks. */
+ c = 0;
+ FOR_EACH_VEC_ELT (then_regs, i, reg)
+ {
+ void **then_slot = pointer_map_contains (then_vals, reg);
+ void **else_slot = pointer_map_contains (else_vals, reg);
+
+ gcc_checking_assert (then_slot);
+ if (!else_slot)
+ ++c;
+ else
+ {
+ rtx then_val = (rtx) *then_slot;
+ rtx else_val = (rtx) *else_slot;
+ if (!CONSTANT_P (then_val) && !CONSTANT_P (else_val)
+ && !rtx_equal_p (then_val, else_val))
+ goto done;
+ }
+ }
+
+ /* Finish off c for MAX_CONDITIONAL_EXECUTE. */
+ FOR_EACH_VEC_ELT (else_regs, i, reg)
+ {
+ gcc_checking_assert (pointer_map_contains (else_vals, reg));
+ if (!pointer_map_contains (then_vals, reg))
+ ++c;
+ }
+
+ /* Make sure it is reasonable to convert this block. What matters
+ is the number of assignments currently made in only one of the
+ branches, since if we convert we are going to always execute
+ them. */
+ if (c > MAX_CONDITIONAL_EXECUTE)
+ goto done;
+
+ /* Try to emit the conditional moves. First do the then block,
+ then do anything left in the else blocks. */
+ start_sequence ();
+ if (!cond_move_convert_if_block (if_info, then_bb, cond,
+ then_vals, else_vals, false)
+ || (else_bb
+ && !cond_move_convert_if_block (if_info, else_bb, cond,
+ then_vals, else_vals, true)))
+ {
+ end_sequence ();
+ goto done;
+ }
+ seq = end_ifcvt_sequence (if_info);
+ if (!seq)
+ goto done;
+
+ loc_insn = first_active_insn (then_bb);
+ if (!loc_insn)
+ {
+ loc_insn = first_active_insn (else_bb);
+ gcc_assert (loc_insn);
+ }
+ emit_insn_before_setloc (seq, jump, INSN_LOCATION (loc_insn));
+
+ if (else_bb)
+ {
+ delete_basic_block (else_bb);
+ num_true_changes++;
+ }
+ else
+ remove_edge (find_edge (test_bb, join_bb));
+
+ remove_edge (find_edge (then_bb, join_bb));
+ redirect_edge_and_branch_force (single_succ_edge (test_bb), join_bb);
+ delete_basic_block (then_bb);
+ num_true_changes++;
+
+ if (can_merge_blocks_p (test_bb, join_bb))
+ {
+ merge_blocks (test_bb, join_bb);
+ num_true_changes++;
+ }
+
+ num_updated_if_blocks++;
+
+ success_p = TRUE;
+
+done:
+ pointer_map_destroy (then_vals);
+ pointer_map_destroy (else_vals);
+ then_regs.release ();
+ else_regs.release ();
+ return success_p;
+}
+
+
+/* Determine if a given basic block heads a simple IF-THEN-JOIN or an
+ IF-THEN-ELSE-JOIN block.
+
+ If so, we'll try to convert the insns to not require the branch,
+ using only transformations that do not require conditional execution.
+
+ Return TRUE if we were successful at converting the block. */
+
+static int
+noce_find_if_block (basic_block test_bb, edge then_edge, edge else_edge,
+ int pass)
+{
+ basic_block then_bb, else_bb, join_bb;
+ bool then_else_reversed = false;
+ rtx jump, cond;
+ rtx cond_earliest;
+ struct noce_if_info if_info;
+
+ /* We only ever should get here before reload. */
+ gcc_assert (!reload_completed);
+
+ /* Recognize an IF-THEN-ELSE-JOIN block. */
+ if (single_pred_p (then_edge->dest)
+ && single_succ_p (then_edge->dest)
+ && single_pred_p (else_edge->dest)
+ && single_succ_p (else_edge->dest)
+ && single_succ (then_edge->dest) == single_succ (else_edge->dest))
+ {
+ then_bb = then_edge->dest;
+ else_bb = else_edge->dest;
+ join_bb = single_succ (then_bb);
+ }
+ /* Recognize an IF-THEN-JOIN block. */
+ else if (single_pred_p (then_edge->dest)
+ && single_succ_p (then_edge->dest)
+ && single_succ (then_edge->dest) == else_edge->dest)
+ {
+ then_bb = then_edge->dest;
+ else_bb = NULL_BLOCK;
+ join_bb = else_edge->dest;
+ }
+ /* Recognize an IF-ELSE-JOIN block. We can have those because the order
+ of basic blocks in cfglayout mode does not matter, so the fallthrough
+ edge can go to any basic block (and not just to bb->next_bb, like in
+ cfgrtl mode). */
+ else if (single_pred_p (else_edge->dest)
+ && single_succ_p (else_edge->dest)
+ && single_succ (else_edge->dest) == then_edge->dest)
+ {
+ /* The noce transformations do not apply to IF-ELSE-JOIN blocks.
+ To make this work, we have to invert the THEN and ELSE blocks
+ and reverse the jump condition. */
+ then_bb = else_edge->dest;
+ else_bb = NULL_BLOCK;
+ join_bb = single_succ (then_bb);
+ then_else_reversed = true;
+ }
+ else
+ /* Not a form we can handle. */
+ return FALSE;
+
+ /* The edges of the THEN and ELSE blocks cannot have complex edges. */
+ if (single_succ_edge (then_bb)->flags & EDGE_COMPLEX)
+ return FALSE;
+ if (else_bb
+ && single_succ_edge (else_bb)->flags & EDGE_COMPLEX)
+ return FALSE;
+
+ num_possible_if_blocks++;
+
+ if (dump_file)
+ {
+ fprintf (dump_file,
+ "\nIF-THEN%s-JOIN block found, pass %d, test %d, then %d",
+ (else_bb) ? "-ELSE" : "",
+ pass, test_bb->index, then_bb->index);
+
+ if (else_bb)
+ fprintf (dump_file, ", else %d", else_bb->index);
+
+ fprintf (dump_file, ", join %d\n", join_bb->index);
+ }
+
+ /* If the conditional jump is more than just a conditional
+ jump, then we can not do if-conversion on this block. */
+ jump = BB_END (test_bb);
+ if (! onlyjump_p (jump))
+ return FALSE;
+
+ /* If this is not a standard conditional jump, we can't parse it. */
+ cond = noce_get_condition (jump, &cond_earliest, then_else_reversed);
+ if (!cond)
+ return FALSE;
+
+ /* We must be comparing objects whose modes imply the size. */
+ if (GET_MODE (XEXP (cond, 0)) == BLKmode)
+ return FALSE;
+
+ /* Initialize an IF_INFO struct to pass around. */
+ memset (&if_info, 0, sizeof if_info);
+ if_info.test_bb = test_bb;
+ if_info.then_bb = then_bb;
+ if_info.else_bb = else_bb;
+ if_info.join_bb = join_bb;
+ if_info.cond = cond;
+ if_info.cond_earliest = cond_earliest;
+ if_info.jump = jump;
+ if_info.then_else_reversed = then_else_reversed;
+ if_info.branch_cost = BRANCH_COST (optimize_bb_for_speed_p (test_bb),
+ predictable_edge_p (then_edge));
+
+ /* Do the real work. */
+
+ if (noce_process_if_block (&if_info))
+ return TRUE;
+
+ if (HAVE_conditional_move
+ && cond_move_process_if_block (&if_info))
+ return TRUE;
+
+ return FALSE;
+}
+
+
+/* Merge the blocks and mark for local life update. */
+
+static void
+merge_if_block (struct ce_if_block * ce_info)
+{
+ basic_block test_bb = ce_info->test_bb; /* last test block */
+ basic_block then_bb = ce_info->then_bb; /* THEN */
+ basic_block else_bb = ce_info->else_bb; /* ELSE or NULL */
+ basic_block join_bb = ce_info->join_bb; /* join block */
+ basic_block combo_bb;
+
+ /* All block merging is done into the lower block numbers. */
+
+ combo_bb = test_bb;
+ df_set_bb_dirty (test_bb);
+
+ /* Merge any basic blocks to handle && and || subtests. Each of
+ the blocks are on the fallthru path from the predecessor block. */
+ if (ce_info->num_multiple_test_blocks > 0)
+ {
+ basic_block bb = test_bb;
+ basic_block last_test_bb = ce_info->last_test_bb;
+ basic_block fallthru = block_fallthru (bb);
+
+ do
+ {
+ bb = fallthru;
+ fallthru = block_fallthru (bb);
+ merge_blocks (combo_bb, bb);
+ num_true_changes++;
+ }
+ while (bb != last_test_bb);
+ }
+
+ /* Merge TEST block into THEN block. Normally the THEN block won't have a
+ label, but it might if there were || tests. That label's count should be
+ zero, and it normally should be removed. */
+
+ if (then_bb)
+ {
+ /* If THEN_BB has no successors, then there's a BARRIER after it.
+ If COMBO_BB has more than one successor (THEN_BB), then that BARRIER
+ is no longer needed, and in fact it is incorrect to leave it in
+ the insn stream. */
+ if (EDGE_COUNT (then_bb->succs) == 0
+ && EDGE_COUNT (combo_bb->succs) > 1)
+ {
+ rtx end = NEXT_INSN (BB_END (then_bb));
+ while (end && NOTE_P (end) && !NOTE_INSN_BASIC_BLOCK_P (end))
+ end = NEXT_INSN (end);
+
+ if (end && BARRIER_P (end))
+ delete_insn (end);
+ }
+ merge_blocks (combo_bb, then_bb);
+ num_true_changes++;
+ }
+
+ /* The ELSE block, if it existed, had a label. That label count
+ will almost always be zero, but odd things can happen when labels
+ get their addresses taken. */
+ if (else_bb)
+ {
+ /* If ELSE_BB has no successors, then there's a BARRIER after it.
+ If COMBO_BB has more than one successor (ELSE_BB), then that BARRIER
+ is no longer needed, and in fact it is incorrect to leave it in
+ the insn stream. */
+ if (EDGE_COUNT (else_bb->succs) == 0
+ && EDGE_COUNT (combo_bb->succs) > 1)
+ {
+ rtx end = NEXT_INSN (BB_END (else_bb));
+ while (end && NOTE_P (end) && !NOTE_INSN_BASIC_BLOCK_P (end))
+ end = NEXT_INSN (end);
+
+ if (end && BARRIER_P (end))
+ delete_insn (end);
+ }
+ merge_blocks (combo_bb, else_bb);
+ num_true_changes++;
+ }
+
+ /* If there was no join block reported, that means it was not adjacent
+ to the others, and so we cannot merge them. */
+
+ if (! join_bb)
+ {
+ rtx last = BB_END (combo_bb);
+
+ /* The outgoing edge for the current COMBO block should already
+ be correct. Verify this. */
+ if (EDGE_COUNT (combo_bb->succs) == 0)
+ gcc_assert (find_reg_note (last, REG_NORETURN, NULL)
+ || (NONJUMP_INSN_P (last)
+ && GET_CODE (PATTERN (last)) == TRAP_IF
+ && (TRAP_CONDITION (PATTERN (last))
+ == const_true_rtx)));
+
+ else
+ /* There should still be something at the end of the THEN or ELSE
+ blocks taking us to our final destination. */
+ gcc_assert (JUMP_P (last)
+ || (EDGE_SUCC (combo_bb, 0)->dest
+ == EXIT_BLOCK_PTR_FOR_FN (cfun)
+ && CALL_P (last)
+ && SIBLING_CALL_P (last))
+ || ((EDGE_SUCC (combo_bb, 0)->flags & EDGE_EH)
+ && can_throw_internal (last)));
+ }
+
+ /* The JOIN block may have had quite a number of other predecessors too.
+ Since we've already merged the TEST, THEN and ELSE blocks, we should
+ have only one remaining edge from our if-then-else diamond. If there
+ is more than one remaining edge, it must come from elsewhere. There
+ may be zero incoming edges if the THEN block didn't actually join
+ back up (as with a call to a non-return function). */
+ else if (EDGE_COUNT (join_bb->preds) < 2
+ && join_bb != EXIT_BLOCK_PTR_FOR_FN (cfun))
+ {
+ /* We can merge the JOIN cleanly and update the dataflow try
+ again on this pass.*/
+ merge_blocks (combo_bb, join_bb);
+ num_true_changes++;
+ }
+ else
+ {
+ /* We cannot merge the JOIN. */
+
+ /* The outgoing edge for the current COMBO block should already
+ be correct. Verify this. */
+ gcc_assert (single_succ_p (combo_bb)
+ && single_succ (combo_bb) == join_bb);
+
+ /* Remove the jump and cruft from the end of the COMBO block. */
+ if (join_bb != EXIT_BLOCK_PTR_FOR_FN (cfun))
+ tidy_fallthru_edge (single_succ_edge (combo_bb));
+ }
+
+ num_updated_if_blocks++;
+}
+
+/* Find a block ending in a simple IF condition and try to transform it
+ in some way. When converting a multi-block condition, put the new code
+ in the first such block and delete the rest. Return a pointer to this
+ first block if some transformation was done. Return NULL otherwise. */
+
+static basic_block
+find_if_header (basic_block test_bb, int pass)
+{
+ ce_if_block ce_info;
+ edge then_edge;
+ edge else_edge;
+
+ /* The kind of block we're looking for has exactly two successors. */
+ if (EDGE_COUNT (test_bb->succs) != 2)
+ return NULL;
+
+ then_edge = EDGE_SUCC (test_bb, 0);
+ else_edge = EDGE_SUCC (test_bb, 1);
+
+ if (df_get_bb_dirty (then_edge->dest))
+ return NULL;
+ if (df_get_bb_dirty (else_edge->dest))
+ return NULL;
+
+ /* Neither edge should be abnormal. */
+ if ((then_edge->flags & EDGE_COMPLEX)
+ || (else_edge->flags & EDGE_COMPLEX))
+ return NULL;
+
+ /* Nor exit the loop. */
+ if ((then_edge->flags & EDGE_LOOP_EXIT)
+ || (else_edge->flags & EDGE_LOOP_EXIT))
+ return NULL;
+
+ /* The THEN edge is canonically the one that falls through. */
+ if (then_edge->flags & EDGE_FALLTHRU)
+ ;
+ else if (else_edge->flags & EDGE_FALLTHRU)
+ {
+ edge e = else_edge;
+ else_edge = then_edge;
+ then_edge = e;
+ }
+ else
+ /* Otherwise this must be a multiway branch of some sort. */
+ return NULL;
+
+ memset (&ce_info, 0, sizeof (ce_info));
+ ce_info.test_bb = test_bb;
+ ce_info.then_bb = then_edge->dest;
+ ce_info.else_bb = else_edge->dest;
+ ce_info.pass = pass;
+
+#ifdef IFCVT_MACHDEP_INIT
+ IFCVT_MACHDEP_INIT (&ce_info);
+#endif
+
+ if (!reload_completed
+ && noce_find_if_block (test_bb, then_edge, else_edge, pass))
+ goto success;
+
+ if (reload_completed
+ && targetm.have_conditional_execution ()
+ && cond_exec_find_if_block (&ce_info))
+ goto success;
+
+ if (HAVE_trap
+ && optab_handler (ctrap_optab, word_mode) != CODE_FOR_nothing
+ && find_cond_trap (test_bb, then_edge, else_edge))
+ goto success;
+
+ if (dom_info_state (CDI_POST_DOMINATORS) >= DOM_NO_FAST_QUERY
+ && (reload_completed || !targetm.have_conditional_execution ()))
+ {
+ if (find_if_case_1 (test_bb, then_edge, else_edge))
+ goto success;
+ if (find_if_case_2 (test_bb, then_edge, else_edge))
+ goto success;
+ }
+
+ return NULL;
+
+ success:
+ if (dump_file)
+ fprintf (dump_file, "Conversion succeeded on pass %d.\n", pass);
+ /* Set this so we continue looking. */
+ cond_exec_changed_p = TRUE;
+ return ce_info.test_bb;
+}
+
+/* Return true if a block has two edges, one of which falls through to the next
+ block, and the other jumps to a specific block, so that we can tell if the
+ block is part of an && test or an || test. Returns either -1 or the number
+ of non-note, non-jump, non-USE/CLOBBER insns in the block. */
+
+static int
+block_jumps_and_fallthru_p (basic_block cur_bb, basic_block target_bb)
+{
+ edge cur_edge;
+ int fallthru_p = FALSE;
+ int jump_p = FALSE;
+ rtx insn;
+ rtx end;
+ int n_insns = 0;
+ edge_iterator ei;
+
+ if (!cur_bb || !target_bb)
+ return -1;
+
+ /* If no edges, obviously it doesn't jump or fallthru. */
+ if (EDGE_COUNT (cur_bb->succs) == 0)
+ return FALSE;
+
+ FOR_EACH_EDGE (cur_edge, ei, cur_bb->succs)
+ {
+ if (cur_edge->flags & EDGE_COMPLEX)
+ /* Anything complex isn't what we want. */
+ return -1;
+
+ else if (cur_edge->flags & EDGE_FALLTHRU)
+ fallthru_p = TRUE;
+
+ else if (cur_edge->dest == target_bb)
+ jump_p = TRUE;
+
+ else
+ return -1;
+ }
+
+ if ((jump_p & fallthru_p) == 0)
+ return -1;
+
+ /* Don't allow calls in the block, since this is used to group && and ||
+ together for conditional execution support. ??? we should support
+ conditional execution support across calls for IA-64 some day, but
+ for now it makes the code simpler. */
+ end = BB_END (cur_bb);
+ insn = BB_HEAD (cur_bb);
+
+ while (insn != NULL_RTX)
+ {
+ if (CALL_P (insn))
+ return -1;
+
+ if (INSN_P (insn)
+ && !JUMP_P (insn)
+ && !DEBUG_INSN_P (insn)
+ && GET_CODE (PATTERN (insn)) != USE
+ && GET_CODE (PATTERN (insn)) != CLOBBER)
+ n_insns++;
+
+ if (insn == end)
+ break;
+
+ insn = NEXT_INSN (insn);
+ }
+
+ return n_insns;
+}
+
+/* Determine if a given basic block heads a simple IF-THEN or IF-THEN-ELSE
+ block. If so, we'll try to convert the insns to not require the branch.
+ Return TRUE if we were successful at converting the block. */
+
+static int
+cond_exec_find_if_block (struct ce_if_block * ce_info)
+{
+ basic_block test_bb = ce_info->test_bb;
+ basic_block then_bb = ce_info->then_bb;
+ basic_block else_bb = ce_info->else_bb;
+ basic_block join_bb = NULL_BLOCK;
+ edge cur_edge;
+ basic_block next;
+ edge_iterator ei;
+
+ ce_info->last_test_bb = test_bb;
+
+ /* We only ever should get here after reload,
+ and if we have conditional execution. */
+ gcc_assert (reload_completed && targetm.have_conditional_execution ());
+
+ /* Discover if any fall through predecessors of the current test basic block
+ were && tests (which jump to the else block) or || tests (which jump to
+ the then block). */
+ if (single_pred_p (test_bb)
+ && single_pred_edge (test_bb)->flags == EDGE_FALLTHRU)
+ {
+ basic_block bb = single_pred (test_bb);
+ basic_block target_bb;
+ int max_insns = MAX_CONDITIONAL_EXECUTE;
+ int n_insns;
+
+ /* Determine if the preceding block is an && or || block. */
+ if ((n_insns = block_jumps_and_fallthru_p (bb, else_bb)) >= 0)
+ {
+ ce_info->and_and_p = TRUE;
+ target_bb = else_bb;
+ }
+ else if ((n_insns = block_jumps_and_fallthru_p (bb, then_bb)) >= 0)
+ {
+ ce_info->and_and_p = FALSE;
+ target_bb = then_bb;
+ }
+ else
+ target_bb = NULL_BLOCK;
+
+ if (target_bb && n_insns <= max_insns)
+ {
+ int total_insns = 0;
+ int blocks = 0;
+
+ ce_info->last_test_bb = test_bb;
+
+ /* Found at least one && or || block, look for more. */
+ do
+ {
+ ce_info->test_bb = test_bb = bb;
+ total_insns += n_insns;
+ blocks++;
+
+ if (!single_pred_p (bb))
+ break;
+
+ bb = single_pred (bb);
+ n_insns = block_jumps_and_fallthru_p (bb, target_bb);
+ }
+ while (n_insns >= 0 && (total_insns + n_insns) <= max_insns);
+
+ ce_info->num_multiple_test_blocks = blocks;
+ ce_info->num_multiple_test_insns = total_insns;
+
+ if (ce_info->and_and_p)
+ ce_info->num_and_and_blocks = blocks;
+ else
+ ce_info->num_or_or_blocks = blocks;
+ }
+ }
+
+ /* The THEN block of an IF-THEN combo must have exactly one predecessor,
+ other than any || blocks which jump to the THEN block. */
+ if ((EDGE_COUNT (then_bb->preds) - ce_info->num_or_or_blocks) != 1)
+ return FALSE;
+
+ /* The edges of the THEN and ELSE blocks cannot have complex edges. */
+ FOR_EACH_EDGE (cur_edge, ei, then_bb->preds)
+ {
+ if (cur_edge->flags & EDGE_COMPLEX)
+ return FALSE;
+ }
+
+ FOR_EACH_EDGE (cur_edge, ei, else_bb->preds)
+ {
+ if (cur_edge->flags & EDGE_COMPLEX)
+ return FALSE;
+ }
+
+ /* The THEN block of an IF-THEN combo must have zero or one successors. */
+ if (EDGE_COUNT (then_bb->succs) > 0
+ && (!single_succ_p (then_bb)
+ || (single_succ_edge (then_bb)->flags & EDGE_COMPLEX)
+ || (epilogue_completed
+ && tablejump_p (BB_END (then_bb), NULL, NULL))))
+ return FALSE;
+
+ /* If the THEN block has no successors, conditional execution can still
+ make a conditional call. Don't do this unless the ELSE block has
+ only one incoming edge -- the CFG manipulation is too ugly otherwise.
+ Check for the last insn of the THEN block being an indirect jump, which
+ is listed as not having any successors, but confuses the rest of the CE
+ code processing. ??? we should fix this in the future. */
+ if (EDGE_COUNT (then_bb->succs) == 0)
+ {
+ if (single_pred_p (else_bb) && else_bb != EXIT_BLOCK_PTR_FOR_FN (cfun))
+ {
+ rtx last_insn = BB_END (then_bb);
+
+ while (last_insn
+ && NOTE_P (last_insn)
+ && last_insn != BB_HEAD (then_bb))
+ last_insn = PREV_INSN (last_insn);
+
+ if (last_insn
+ && JUMP_P (last_insn)
+ && ! simplejump_p (last_insn))
+ return FALSE;
+
+ join_bb = else_bb;
+ else_bb = NULL_BLOCK;
+ }
+ else
+ return FALSE;
+ }
+
+ /* If the THEN block's successor is the other edge out of the TEST block,
+ then we have an IF-THEN combo without an ELSE. */
+ else if (single_succ (then_bb) == else_bb)
+ {
+ join_bb = else_bb;
+ else_bb = NULL_BLOCK;
+ }
+
+ /* If the THEN and ELSE block meet in a subsequent block, and the ELSE
+ has exactly one predecessor and one successor, and the outgoing edge
+ is not complex, then we have an IF-THEN-ELSE combo. */
+ else if (single_succ_p (else_bb)
+ && single_succ (then_bb) == single_succ (else_bb)
+ && single_pred_p (else_bb)
+ && !(single_succ_edge (else_bb)->flags & EDGE_COMPLEX)
+ && !(epilogue_completed
+ && tablejump_p (BB_END (else_bb), NULL, NULL)))
+ join_bb = single_succ (else_bb);
+
+ /* Otherwise it is not an IF-THEN or IF-THEN-ELSE combination. */
+ else
+ return FALSE;
+
+ num_possible_if_blocks++;
+
+ if (dump_file)
+ {
+ fprintf (dump_file,
+ "\nIF-THEN%s block found, pass %d, start block %d "
+ "[insn %d], then %d [%d]",
+ (else_bb) ? "-ELSE" : "",
+ ce_info->pass,
+ test_bb->index,
+ BB_HEAD (test_bb) ? (int)INSN_UID (BB_HEAD (test_bb)) : -1,
+ then_bb->index,
+ BB_HEAD (then_bb) ? (int)INSN_UID (BB_HEAD (then_bb)) : -1);
+
+ if (else_bb)
+ fprintf (dump_file, ", else %d [%d]",
+ else_bb->index,
+ BB_HEAD (else_bb) ? (int)INSN_UID (BB_HEAD (else_bb)) : -1);
+
+ fprintf (dump_file, ", join %d [%d]",
+ join_bb->index,
+ BB_HEAD (join_bb) ? (int)INSN_UID (BB_HEAD (join_bb)) : -1);
+
+ if (ce_info->num_multiple_test_blocks > 0)
+ fprintf (dump_file, ", %d %s block%s last test %d [%d]",
+ ce_info->num_multiple_test_blocks,
+ (ce_info->and_and_p) ? "&&" : "||",
+ (ce_info->num_multiple_test_blocks == 1) ? "" : "s",
+ ce_info->last_test_bb->index,
+ ((BB_HEAD (ce_info->last_test_bb))
+ ? (int)INSN_UID (BB_HEAD (ce_info->last_test_bb))
+ : -1));
+
+ fputc ('\n', dump_file);
+ }
+
+ /* Make sure IF, THEN, and ELSE, blocks are adjacent. Actually, we get the
+ first condition for free, since we've already asserted that there's a
+ fallthru edge from IF to THEN. Likewise for the && and || blocks, since
+ we checked the FALLTHRU flag, those are already adjacent to the last IF
+ block. */
+ /* ??? As an enhancement, move the ELSE block. Have to deal with
+ BLOCK notes, if by no other means than backing out the merge if they
+ exist. Sticky enough I don't want to think about it now. */
+ next = then_bb;
+ if (else_bb && (next = next->next_bb) != else_bb)
+ return FALSE;
+ if ((next = next->next_bb) != join_bb
+ && join_bb != EXIT_BLOCK_PTR_FOR_FN (cfun))
+ {
+ if (else_bb)
+ join_bb = NULL;
+ else
+ return FALSE;
+ }
+
+ /* Do the real work. */
+
+ ce_info->else_bb = else_bb;
+ ce_info->join_bb = join_bb;
+
+ /* If we have && and || tests, try to first handle combining the && and ||
+ tests into the conditional code, and if that fails, go back and handle
+ it without the && and ||, which at present handles the && case if there
+ was no ELSE block. */
+ if (cond_exec_process_if_block (ce_info, TRUE))
+ return TRUE;
+
+ if (ce_info->num_multiple_test_blocks)
+ {
+ cancel_changes (0);
+
+ if (cond_exec_process_if_block (ce_info, FALSE))
+ return TRUE;
+ }
+
+ return FALSE;
+}
+
+/* Convert a branch over a trap, or a branch
+ to a trap, into a conditional trap. */
+
+static int
+find_cond_trap (basic_block test_bb, edge then_edge, edge else_edge)
+{
+ basic_block then_bb = then_edge->dest;
+ basic_block else_bb = else_edge->dest;
+ basic_block other_bb, trap_bb;
+ rtx trap, jump, cond, cond_earliest, seq;
+ enum rtx_code code;
+
+ /* Locate the block with the trap instruction. */
+ /* ??? While we look for no successors, we really ought to allow
+ EH successors. Need to fix merge_if_block for that to work. */
+ if ((trap = block_has_only_trap (then_bb)) != NULL)
+ trap_bb = then_bb, other_bb = else_bb;
+ else if ((trap = block_has_only_trap (else_bb)) != NULL)
+ trap_bb = else_bb, other_bb = then_bb;
+ else
+ return FALSE;
+
+ if (dump_file)
+ {
+ fprintf (dump_file, "\nTRAP-IF block found, start %d, trap %d\n",
+ test_bb->index, trap_bb->index);
+ }
+
+ /* If this is not a standard conditional jump, we can't parse it. */
+ jump = BB_END (test_bb);
+ cond = noce_get_condition (jump, &cond_earliest, false);
+ if (! cond)
+ return FALSE;
+
+ /* If the conditional jump is more than just a conditional jump, then
+ we can not do if-conversion on this block. */
+ if (! onlyjump_p (jump))
+ return FALSE;
+
+ /* We must be comparing objects whose modes imply the size. */
+ if (GET_MODE (XEXP (cond, 0)) == BLKmode)
+ return FALSE;
+
+ /* Reverse the comparison code, if necessary. */
+ code = GET_CODE (cond);
+ if (then_bb == trap_bb)
+ {
+ code = reversed_comparison_code (cond, jump);
+ if (code == UNKNOWN)
+ return FALSE;
+ }
+
+ /* Attempt to generate the conditional trap. */
+ seq = gen_cond_trap (code, copy_rtx (XEXP (cond, 0)),
+ copy_rtx (XEXP (cond, 1)),
+ TRAP_CODE (PATTERN (trap)));
+ if (seq == NULL)
+ return FALSE;
+
+ /* Emit the new insns before cond_earliest. */
+ emit_insn_before_setloc (seq, cond_earliest, INSN_LOCATION (trap));
+
+ /* Delete the trap block if possible. */
+ remove_edge (trap_bb == then_bb ? then_edge : else_edge);
+ df_set_bb_dirty (test_bb);
+ df_set_bb_dirty (then_bb);
+ df_set_bb_dirty (else_bb);
+
+ if (EDGE_COUNT (trap_bb->preds) == 0)
+ {
+ delete_basic_block (trap_bb);
+ num_true_changes++;
+ }
+
+ /* Wire together the blocks again. */
+ if (current_ir_type () == IR_RTL_CFGLAYOUT)
+ single_succ_edge (test_bb)->flags |= EDGE_FALLTHRU;
+ else if (trap_bb == then_bb)
+ {
+ rtx lab, newjump;
+
+ lab = JUMP_LABEL (jump);
+ newjump = emit_jump_insn_after (gen_jump (lab), jump);
+ LABEL_NUSES (lab) += 1;
+ JUMP_LABEL (newjump) = lab;
+ emit_barrier_after (newjump);
+ }
+ delete_insn (jump);
+
+ if (can_merge_blocks_p (test_bb, other_bb))
+ {
+ merge_blocks (test_bb, other_bb);
+ num_true_changes++;
+ }
+
+ num_updated_if_blocks++;
+ return TRUE;
+}
+
+/* Subroutine of find_cond_trap: if BB contains only a trap insn,
+ return it. */
+
+static rtx
+block_has_only_trap (basic_block bb)
+{
+ rtx trap;
+
+ /* We're not the exit block. */
+ if (bb == EXIT_BLOCK_PTR_FOR_FN (cfun))
+ return NULL_RTX;
+
+ /* The block must have no successors. */
+ if (EDGE_COUNT (bb->succs) > 0)
+ return NULL_RTX;
+
+ /* The only instruction in the THEN block must be the trap. */
+ trap = first_active_insn (bb);
+ if (! (trap == BB_END (bb)
+ && GET_CODE (PATTERN (trap)) == TRAP_IF
+ && TRAP_CONDITION (PATTERN (trap)) == const_true_rtx))
+ return NULL_RTX;
+
+ return trap;
+}
+
+/* Look for IF-THEN-ELSE cases in which one of THEN or ELSE is
+ transformable, but not necessarily the other. There need be no
+ JOIN block.
+
+ Return TRUE if we were successful at converting the block.
+
+ Cases we'd like to look at:
+
+ (1)
+ if (test) goto over; // x not live
+ x = a;
+ goto label;
+ over:
+
+ becomes
+
+ x = a;
+ if (! test) goto label;
+
+ (2)
+ if (test) goto E; // x not live
+ x = big();
+ goto L;
+ E:
+ x = b;
+ goto M;
+
+ becomes
+
+ x = b;
+ if (test) goto M;
+ x = big();
+ goto L;
+
+ (3) // This one's really only interesting for targets that can do
+ // multiway branching, e.g. IA-64 BBB bundles. For other targets
+ // it results in multiple branches on a cache line, which often
+ // does not sit well with predictors.
+
+ if (test1) goto E; // predicted not taken
+ x = a;
+ if (test2) goto F;
+ ...
+ E:
+ x = b;
+ J:
+
+ becomes
+
+ x = a;
+ if (test1) goto E;
+ if (test2) goto F;
+
+ Notes:
+
+ (A) Don't do (2) if the branch is predicted against the block we're
+ eliminating. Do it anyway if we can eliminate a branch; this requires
+ that the sole successor of the eliminated block postdominate the other
+ side of the if.
+
+ (B) With CE, on (3) we can steal from both sides of the if, creating
+
+ if (test1) x = a;
+ if (!test1) x = b;
+ if (test1) goto J;
+ if (test2) goto F;
+ ...
+ J:
+
+ Again, this is most useful if J postdominates.
+
+ (C) CE substitutes for helpful life information.
+
+ (D) These heuristics need a lot of work. */
+
+/* Tests for case 1 above. */
+
+static int
+find_if_case_1 (basic_block test_bb, edge then_edge, edge else_edge)
+{
+ basic_block then_bb = then_edge->dest;
+ basic_block else_bb = else_edge->dest;
+ basic_block new_bb;
+ int then_bb_index, then_prob;
+ rtx else_target = NULL_RTX;
+
+ /* If we are partitioning hot/cold basic blocks, we don't want to
+ mess up unconditional or indirect jumps that cross between hot
+ and cold sections.
+
+ Basic block partitioning may result in some jumps that appear to
+ be optimizable (or blocks that appear to be mergeable), but which really
+ must be left untouched (they are required to make it safely across
+ partition boundaries). See the comments at the top of
+ bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
+
+ if ((BB_END (then_bb)
+ && find_reg_note (BB_END (then_bb), REG_CROSSING_JUMP, NULL_RTX))
+ || (BB_END (test_bb)
+ && find_reg_note (BB_END (test_bb), REG_CROSSING_JUMP, NULL_RTX))
+ || (BB_END (else_bb)
+ && find_reg_note (BB_END (else_bb), REG_CROSSING_JUMP,
+ NULL_RTX)))
+ return FALSE;
+
+ /* THEN has one successor. */
+ if (!single_succ_p (then_bb))
+ return FALSE;
+
+ /* THEN does not fall through, but is not strange either. */
+ if (single_succ_edge (then_bb)->flags & (EDGE_COMPLEX | EDGE_FALLTHRU))
+ return FALSE;
+
+ /* THEN has one predecessor. */
+ if (!single_pred_p (then_bb))
+ return FALSE;
+
+ /* THEN must do something. */
+ if (forwarder_block_p (then_bb))
+ return FALSE;
+
+ num_possible_if_blocks++;
+ if (dump_file)
+ fprintf (dump_file,
+ "\nIF-CASE-1 found, start %d, then %d\n",
+ test_bb->index, then_bb->index);
+
+ if (then_edge->probability)
+ then_prob = REG_BR_PROB_BASE - then_edge->probability;
+ else
+ then_prob = REG_BR_PROB_BASE / 2;
+
+ /* We're speculating from the THEN path, we want to make sure the cost
+ of speculation is within reason. */
+ if (! cheap_bb_rtx_cost_p (then_bb, then_prob,
+ COSTS_N_INSNS (BRANCH_COST (optimize_bb_for_speed_p (then_edge->src),
+ predictable_edge_p (then_edge)))))
+ return FALSE;
+
+ if (else_bb == EXIT_BLOCK_PTR_FOR_FN (cfun))
+ {
+ rtx jump = BB_END (else_edge->src);
+ gcc_assert (JUMP_P (jump));
+ else_target = JUMP_LABEL (jump);
+ }
+
+ /* Registers set are dead, or are predicable. */
+ if (! dead_or_predicable (test_bb, then_bb, else_bb,
+ single_succ_edge (then_bb), 1))
+ return FALSE;
+
+ /* Conversion went ok, including moving the insns and fixing up the
+ jump. Adjust the CFG to match. */
+
+ /* We can avoid creating a new basic block if then_bb is immediately
+ followed by else_bb, i.e. deleting then_bb allows test_bb to fall
+ through to else_bb. */
+
+ if (then_bb->next_bb == else_bb
+ && then_bb->prev_bb == test_bb
+ && else_bb != EXIT_BLOCK_PTR_FOR_FN (cfun))
+ {
+ redirect_edge_succ (FALLTHRU_EDGE (test_bb), else_bb);
+ new_bb = 0;
+ }
+ else if (else_bb == EXIT_BLOCK_PTR_FOR_FN (cfun))
+ new_bb = force_nonfallthru_and_redirect (FALLTHRU_EDGE (test_bb),
+ else_bb, else_target);
+ else
+ new_bb = redirect_edge_and_branch_force (FALLTHRU_EDGE (test_bb),
+ else_bb);
+
+ df_set_bb_dirty (test_bb);
+ df_set_bb_dirty (else_bb);
+
+ then_bb_index = then_bb->index;
+ delete_basic_block (then_bb);
+
+ /* Make rest of code believe that the newly created block is the THEN_BB
+ block we removed. */
+ if (new_bb)
+ {
+ df_bb_replace (then_bb_index, new_bb);
+ /* This should have been done above via force_nonfallthru_and_redirect
+ (possibly called from redirect_edge_and_branch_force). */
+ gcc_checking_assert (BB_PARTITION (new_bb) == BB_PARTITION (test_bb));
+ }
+
+ num_true_changes++;
+ num_updated_if_blocks++;
+
+ return TRUE;
+}
+
+/* Test for case 2 above. */
+
+static int
+find_if_case_2 (basic_block test_bb, edge then_edge, edge else_edge)
+{
+ basic_block then_bb = then_edge->dest;
+ basic_block else_bb = else_edge->dest;
+ edge else_succ;
+ int then_prob, else_prob;
+
+ /* We do not want to speculate (empty) loop latches. */
+ if (current_loops
+ && else_bb->loop_father->latch == else_bb)
+ return FALSE;
+
+ /* If we are partitioning hot/cold basic blocks, we don't want to
+ mess up unconditional or indirect jumps that cross between hot
+ and cold sections.
+
+ Basic block partitioning may result in some jumps that appear to
+ be optimizable (or blocks that appear to be mergeable), but which really
+ must be left untouched (they are required to make it safely across
+ partition boundaries). See the comments at the top of
+ bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
+
+ if ((BB_END (then_bb)
+ && find_reg_note (BB_END (then_bb), REG_CROSSING_JUMP, NULL_RTX))
+ || (BB_END (test_bb)
+ && find_reg_note (BB_END (test_bb), REG_CROSSING_JUMP, NULL_RTX))
+ || (BB_END (else_bb)
+ && find_reg_note (BB_END (else_bb), REG_CROSSING_JUMP,
+ NULL_RTX)))
+ return FALSE;
+
+ /* ELSE has one successor. */
+ if (!single_succ_p (else_bb))
+ return FALSE;
+ else
+ else_succ = single_succ_edge (else_bb);
+
+ /* ELSE outgoing edge is not complex. */
+ if (else_succ->flags & EDGE_COMPLEX)
+ return FALSE;
+
+ /* ELSE has one predecessor. */
+ if (!single_pred_p (else_bb))
+ return FALSE;
+
+ /* THEN is not EXIT. */
+ if (then_bb->index < NUM_FIXED_BLOCKS)
+ return FALSE;
+
+ if (else_edge->probability)
+ {
+ else_prob = else_edge->probability;
+ then_prob = REG_BR_PROB_BASE - else_prob;
+ }
+ else
+ {
+ else_prob = REG_BR_PROB_BASE / 2;
+ then_prob = REG_BR_PROB_BASE / 2;
+ }
+
+ /* ELSE is predicted or SUCC(ELSE) postdominates THEN. */
+ if (else_prob > then_prob)
+ ;
+ else if (else_succ->dest->index < NUM_FIXED_BLOCKS
+ || dominated_by_p (CDI_POST_DOMINATORS, then_bb,
+ else_succ->dest))
+ ;
+ else
+ return FALSE;
+
+ num_possible_if_blocks++;
+ if (dump_file)
+ fprintf (dump_file,
+ "\nIF-CASE-2 found, start %d, else %d\n",
+ test_bb->index, else_bb->index);
+
+ /* We're speculating from the ELSE path, we want to make sure the cost
+ of speculation is within reason. */
+ if (! cheap_bb_rtx_cost_p (else_bb, else_prob,
+ COSTS_N_INSNS (BRANCH_COST (optimize_bb_for_speed_p (else_edge->src),
+ predictable_edge_p (else_edge)))))
+ return FALSE;
+
+ /* Registers set are dead, or are predicable. */
+ if (! dead_or_predicable (test_bb, else_bb, then_bb, else_succ, 0))
+ return FALSE;
+
+ /* Conversion went ok, including moving the insns and fixing up the
+ jump. Adjust the CFG to match. */
+
+ df_set_bb_dirty (test_bb);
+ df_set_bb_dirty (then_bb);
+ delete_basic_block (else_bb);
+
+ num_true_changes++;
+ num_updated_if_blocks++;
+
+ /* ??? We may now fallthru from one of THEN's successors into a join
+ block. Rerun cleanup_cfg? Examine things manually? Wait? */
+
+ return TRUE;
+}
+
+/* Used by the code above to perform the actual rtl transformations.
+ Return TRUE if successful.
+
+ TEST_BB is the block containing the conditional branch. MERGE_BB
+ is the block containing the code to manipulate. DEST_EDGE is an
+ edge representing a jump to the join block; after the conversion,
+ TEST_BB should be branching to its destination.
+ REVERSEP is true if the sense of the branch should be reversed. */
+
+static int
+dead_or_predicable (basic_block test_bb, basic_block merge_bb,
+ basic_block other_bb, edge dest_edge, int reversep)
+{
+ basic_block new_dest = dest_edge->dest;
+ rtx head, end, jump, earliest = NULL_RTX, old_dest;
+ bitmap merge_set = NULL;
+ /* Number of pending changes. */
+ int n_validated_changes = 0;
+ rtx new_dest_label = NULL_RTX;
+
+ jump = BB_END (test_bb);
+
+ /* Find the extent of the real code in the merge block. */
+ head = BB_HEAD (merge_bb);
+ end = BB_END (merge_bb);
+
+ while (DEBUG_INSN_P (end) && end != head)
+ end = PREV_INSN (end);
+
+ /* If merge_bb ends with a tablejump, predicating/moving insn's
+ into test_bb and then deleting merge_bb will result in the jumptable
+ that follows merge_bb being removed along with merge_bb and then we
+ get an unresolved reference to the jumptable. */
+ if (tablejump_p (end, NULL, NULL))
+ return FALSE;
+
+ if (LABEL_P (head))
+ head = NEXT_INSN (head);
+ while (DEBUG_INSN_P (head) && head != end)
+ head = NEXT_INSN (head);
+ if (NOTE_P (head))
+ {
+ if (head == end)
+ {
+ head = end = NULL_RTX;
+ goto no_body;
+ }
+ head = NEXT_INSN (head);
+ while (DEBUG_INSN_P (head) && head != end)
+ head = NEXT_INSN (head);
+ }
+
+ if (JUMP_P (end))
+ {
+ if (head == end)
+ {
+ head = end = NULL_RTX;
+ goto no_body;
+ }
+ end = PREV_INSN (end);
+ while (DEBUG_INSN_P (end) && end != head)
+ end = PREV_INSN (end);
+ }
+
+ /* Don't move frame-related insn across the conditional branch. This
+ can lead to one of the paths of the branch having wrong unwind info. */
+ if (epilogue_completed)
+ {
+ rtx insn = head;
+ while (1)
+ {
+ if (INSN_P (insn) && RTX_FRAME_RELATED_P (insn))
+ return FALSE;
+ if (insn == end)
+ break;
+ insn = NEXT_INSN (insn);
+ }
+ }
+
+ /* Disable handling dead code by conditional execution if the machine needs
+ to do anything funny with the tests, etc. */
+#ifndef IFCVT_MODIFY_TESTS
+ if (targetm.have_conditional_execution ())
+ {
+ /* In the conditional execution case, we have things easy. We know
+ the condition is reversible. We don't have to check life info
+ because we're going to conditionally execute the code anyway.
+ All that's left is making sure the insns involved can actually
+ be predicated. */
+
+ rtx cond;
+
+ cond = cond_exec_get_condition (jump);
+ if (! cond)
+ return FALSE;
+
+ rtx note = find_reg_note (jump, REG_BR_PROB, NULL_RTX);
+ int prob_val = (note ? XINT (note, 0) : -1);
+
+ if (reversep)
+ {
+ enum rtx_code rev = reversed_comparison_code (cond, jump);
+ if (rev == UNKNOWN)
+ return FALSE;
+ cond = gen_rtx_fmt_ee (rev, GET_MODE (cond), XEXP (cond, 0),
+ XEXP (cond, 1));
+ if (prob_val >= 0)
+ prob_val = REG_BR_PROB_BASE - prob_val;
+ }
+
+ if (cond_exec_process_insns (NULL, head, end, cond, prob_val, 0)
+ && verify_changes (0))
+ n_validated_changes = num_validated_changes ();
+ else
+ cancel_changes (0);
+
+ earliest = jump;
+ }
+#endif
+
+ /* If we allocated new pseudos (e.g. in the conditional move
+ expander called from noce_emit_cmove), we must resize the
+ array first. */
+ if (max_regno < max_reg_num ())
+ max_regno = max_reg_num ();
+
+ /* Try the NCE path if the CE path did not result in any changes. */
+ if (n_validated_changes == 0)
+ {
+ rtx cond, insn;
+ regset live;
+ bool success;
+
+ /* In the non-conditional execution case, we have to verify that there
+ are no trapping operations, no calls, no references to memory, and
+ that any registers modified are dead at the branch site. */
+
+ if (!any_condjump_p (jump))
+ return FALSE;
+
+ /* Find the extent of the conditional. */
+ cond = noce_get_condition (jump, &earliest, false);
+ if (!cond)
+ return FALSE;
+
+ live = BITMAP_ALLOC (&reg_obstack);
+ simulate_backwards_to_point (merge_bb, live, end);
+ success = can_move_insns_across (head, end, earliest, jump,
+ merge_bb, live,
+ df_get_live_in (other_bb), NULL);
+ BITMAP_FREE (live);
+ if (!success)
+ return FALSE;
+
+ /* Collect the set of registers set in MERGE_BB. */
+ merge_set = BITMAP_ALLOC (&reg_obstack);
+
+ FOR_BB_INSNS (merge_bb, insn)
+ if (NONDEBUG_INSN_P (insn))
+ df_simulate_find_defs (insn, merge_set);
+
+#ifdef HAVE_simple_return
+ /* If shrink-wrapping, disable this optimization when test_bb is
+ the first basic block and merge_bb exits. The idea is to not
+ move code setting up a return register as that may clobber a
+ register used to pass function parameters, which then must be
+ saved in caller-saved regs. A caller-saved reg requires the
+ prologue, killing a shrink-wrap opportunity. */
+ if ((flag_shrink_wrap && HAVE_simple_return && !epilogue_completed)
+ && ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb == test_bb
+ && single_succ_p (new_dest)
+ && single_succ (new_dest) == EXIT_BLOCK_PTR_FOR_FN (cfun)
+ && bitmap_intersect_p (df_get_live_in (new_dest), merge_set))
+ {
+ regset return_regs;
+ unsigned int i;
+
+ return_regs = BITMAP_ALLOC (&reg_obstack);
+
+ /* Start off with the intersection of regs used to pass
+ params and regs used to return values. */
+ for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+ if (FUNCTION_ARG_REGNO_P (i)
+ && targetm.calls.function_value_regno_p (i))
+ bitmap_set_bit (return_regs, INCOMING_REGNO (i));
+
+ bitmap_and_into (return_regs,
+ df_get_live_out (ENTRY_BLOCK_PTR_FOR_FN (cfun)));
+ bitmap_and_into (return_regs,
+ df_get_live_in (EXIT_BLOCK_PTR_FOR_FN (cfun)));
+ if (!bitmap_empty_p (return_regs))
+ {
+ FOR_BB_INSNS_REVERSE (new_dest, insn)
+ if (NONDEBUG_INSN_P (insn))
+ {
+ df_ref *def_rec;
+ unsigned int uid = INSN_UID (insn);
+
+ /* If this insn sets any reg in return_regs.. */
+ for (def_rec = DF_INSN_UID_DEFS (uid); *def_rec; def_rec++)
+ {
+ df_ref def = *def_rec;
+ unsigned r = DF_REF_REGNO (def);
+
+ if (bitmap_bit_p (return_regs, r))
+ break;
+ }
+ /* ..then add all reg uses to the set of regs
+ we're interested in. */
+ if (*def_rec)
+ df_simulate_uses (insn, return_regs);
+ }
+ if (bitmap_intersect_p (merge_set, return_regs))
+ {
+ BITMAP_FREE (return_regs);
+ BITMAP_FREE (merge_set);
+ return FALSE;
+ }
+ }
+ BITMAP_FREE (return_regs);
+ }
+#endif
+ }
+
+ no_body:
+ /* We don't want to use normal invert_jump or redirect_jump because
+ we don't want to delete_insn called. Also, we want to do our own
+ change group management. */
+
+ old_dest = JUMP_LABEL (jump);
+ if (other_bb != new_dest)
+ {
+ if (JUMP_P (BB_END (dest_edge->src)))
+ new_dest_label = JUMP_LABEL (BB_END (dest_edge->src));
+ else if (new_dest == EXIT_BLOCK_PTR_FOR_FN (cfun))
+ new_dest_label = ret_rtx;
+ else
+ new_dest_label = block_label (new_dest);
+
+ if (reversep
+ ? ! invert_jump_1 (jump, new_dest_label)
+ : ! redirect_jump_1 (jump, new_dest_label))
+ goto cancel;
+ }
+
+ if (verify_changes (n_validated_changes))
+ confirm_change_group ();
+ else
+ goto cancel;
+
+ if (other_bb != new_dest)
+ {
+ redirect_jump_2 (jump, old_dest, new_dest_label, 0, reversep);
+
+ redirect_edge_succ (BRANCH_EDGE (test_bb), new_dest);
+ if (reversep)
+ {
+ gcov_type count, probability;
+ count = BRANCH_EDGE (test_bb)->count;
+ BRANCH_EDGE (test_bb)->count = FALLTHRU_EDGE (test_bb)->count;
+ FALLTHRU_EDGE (test_bb)->count = count;
+ probability = BRANCH_EDGE (test_bb)->probability;
+ BRANCH_EDGE (test_bb)->probability
+ = FALLTHRU_EDGE (test_bb)->probability;
+ FALLTHRU_EDGE (test_bb)->probability = probability;
+ update_br_prob_note (test_bb);
+ }
+ }
+
+ /* Move the insns out of MERGE_BB to before the branch. */
+ if (head != NULL)
+ {
+ rtx insn;
+
+ if (end == BB_END (merge_bb))
+ BB_END (merge_bb) = PREV_INSN (head);
+
+ /* PR 21767: when moving insns above a conditional branch, the REG_EQUAL
+ notes being moved might become invalid. */
+ insn = head;
+ do
+ {
+ rtx note, set;
+
+ if (! INSN_P (insn))
+ continue;
+ note = find_reg_note (insn, REG_EQUAL, NULL_RTX);
+ if (! note)
+ continue;
+ set = single_set (insn);
+ if (!set || !function_invariant_p (SET_SRC (set))
+ || !function_invariant_p (XEXP (note, 0)))
+ remove_note (insn, note);
+ } while (insn != end && (insn = NEXT_INSN (insn)));
+
+ /* PR46315: when moving insns above a conditional branch, the REG_EQUAL
+ notes referring to the registers being set might become invalid. */
+ if (merge_set)
+ {
+ unsigned i;
+ bitmap_iterator bi;
+
+ EXECUTE_IF_SET_IN_BITMAP (merge_set, 0, i, bi)
+ remove_reg_equal_equiv_notes_for_regno (i);
+
+ BITMAP_FREE (merge_set);
+ }
+
+ reorder_insns (head, end, PREV_INSN (earliest));
+ }
+
+ /* Remove the jump and edge if we can. */
+ if (other_bb == new_dest)
+ {
+ delete_insn (jump);
+ remove_edge (BRANCH_EDGE (test_bb));
+ /* ??? Can't merge blocks here, as then_bb is still in use.
+ At minimum, the merge will get done just before bb-reorder. */
+ }
+
+ return TRUE;
+
+ cancel:
+ cancel_changes (0);
+
+ if (merge_set)
+ BITMAP_FREE (merge_set);
+
+ return FALSE;
+}
+
+/* Main entry point for all if-conversion. AFTER_COMBINE is true if
+ we are after combine pass. */
+
+static void
+if_convert (bool after_combine)
+{
+ basic_block bb;
+ int pass;
+
+ if (optimize == 1)
+ {
+ df_live_add_problem ();
+ df_live_set_all_dirty ();
+ }
+
+ /* Record whether we are after combine pass. */
+ ifcvt_after_combine = after_combine;
+ num_possible_if_blocks = 0;
+ num_updated_if_blocks = 0;
+ num_true_changes = 0;
+
+ loop_optimizer_init (AVOID_CFG_MODIFICATIONS);
+ mark_loop_exit_edges ();
+ loop_optimizer_finalize ();
+ free_dominance_info (CDI_DOMINATORS);
+
+ /* Compute postdominators. */
+ calculate_dominance_info (CDI_POST_DOMINATORS);
+
+ df_set_flags (DF_LR_RUN_DCE);
+
+ /* Go through each of the basic blocks looking for things to convert. If we
+ have conditional execution, we make multiple passes to allow us to handle
+ IF-THEN{-ELSE} blocks within other IF-THEN{-ELSE} blocks. */
+ pass = 0;
+ do
+ {
+ df_analyze ();
+ /* Only need to do dce on the first pass. */
+ df_clear_flags (DF_LR_RUN_DCE);
+ cond_exec_changed_p = FALSE;
+ pass++;
+
+#ifdef IFCVT_MULTIPLE_DUMPS
+ if (dump_file && pass > 1)
+ fprintf (dump_file, "\n\n========== Pass %d ==========\n", pass);
+#endif
+
+ FOR_EACH_BB_FN (bb, cfun)
+ {
+ basic_block new_bb;
+ while (!df_get_bb_dirty (bb)
+ && (new_bb = find_if_header (bb, pass)) != NULL)
+ bb = new_bb;
+ }
+
+#ifdef IFCVT_MULTIPLE_DUMPS
+ if (dump_file && cond_exec_changed_p)
+ print_rtl_with_bb (dump_file, get_insns (), dump_flags);
+#endif
+ }
+ while (cond_exec_changed_p);
+
+#ifdef IFCVT_MULTIPLE_DUMPS
+ if (dump_file)
+ fprintf (dump_file, "\n\n========== no more changes\n");
+#endif
+
+ free_dominance_info (CDI_POST_DOMINATORS);
+
+ if (dump_file)
+ fflush (dump_file);
+
+ clear_aux_for_blocks ();
+
+ /* If we allocated new pseudos, we must resize the array for sched1. */
+ if (max_regno < max_reg_num ())
+ max_regno = max_reg_num ();
+
+ /* Write the final stats. */
+ if (dump_file && num_possible_if_blocks > 0)
+ {
+ fprintf (dump_file,
+ "\n%d possible IF blocks searched.\n",
+ num_possible_if_blocks);
+ fprintf (dump_file,
+ "%d IF blocks converted.\n",
+ num_updated_if_blocks);
+ fprintf (dump_file,
+ "%d true changes made.\n\n\n",
+ num_true_changes);
+ }
+
+ if (optimize == 1)
+ df_remove_problem (df_live);
+
+#ifdef ENABLE_CHECKING
+ verify_flow_info ();
+#endif
+}
+
+static bool
+gate_handle_if_conversion (void)
+{
+ return (optimize > 0)
+ && dbg_cnt (if_conversion);
+}
+
+/* If-conversion and CFG cleanup. */
+static unsigned int
+rest_of_handle_if_conversion (void)
+{
+ if (flag_if_conversion)
+ {
+ if (dump_file)
+ {
+ dump_reg_info (dump_file);
+ dump_flow_info (dump_file, dump_flags);
+ }
+ cleanup_cfg (CLEANUP_EXPENSIVE);
+ if_convert (false);
+ }
+
+ cleanup_cfg (0);
+ return 0;
+}
+
+namespace {
+
+const pass_data pass_data_rtl_ifcvt =
+{
+ RTL_PASS, /* type */
+ "ce1", /* name */
+ OPTGROUP_NONE, /* optinfo_flags */
+ true, /* has_gate */
+ true, /* has_execute */
+ TV_IFCVT, /* tv_id */
+ 0, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ ( TODO_df_finish | TODO_verify_rtl_sharing | 0 ), /* todo_flags_finish */
+};
+
+class pass_rtl_ifcvt : public rtl_opt_pass
+{
+public:
+ pass_rtl_ifcvt (gcc::context *ctxt)
+ : rtl_opt_pass (pass_data_rtl_ifcvt, ctxt)
+ {}
+
+ /* opt_pass methods: */
+ bool gate () { return gate_handle_if_conversion (); }
+ unsigned int execute () { return rest_of_handle_if_conversion (); }
+
+}; // class pass_rtl_ifcvt
+
+} // anon namespace
+
+rtl_opt_pass *
+make_pass_rtl_ifcvt (gcc::context *ctxt)
+{
+ return new pass_rtl_ifcvt (ctxt);
+}
+
+static bool
+gate_handle_if_after_combine (void)
+{
+ return optimize > 0 && flag_if_conversion
+ && dbg_cnt (if_after_combine);
+}
+
+
+/* Rerun if-conversion, as combine may have simplified things enough
+ to now meet sequence length restrictions. */
+static unsigned int
+rest_of_handle_if_after_combine (void)
+{
+ if_convert (true);
+ return 0;
+}
+
+namespace {
+
+const pass_data pass_data_if_after_combine =
+{
+ RTL_PASS, /* type */
+ "ce2", /* name */
+ OPTGROUP_NONE, /* optinfo_flags */
+ true, /* has_gate */
+ true, /* has_execute */
+ TV_IFCVT, /* tv_id */
+ 0, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ ( TODO_df_finish | TODO_verify_rtl_sharing ), /* todo_flags_finish */
+};
+
+class pass_if_after_combine : public rtl_opt_pass
+{
+public:
+ pass_if_after_combine (gcc::context *ctxt)
+ : rtl_opt_pass (pass_data_if_after_combine, ctxt)
+ {}
+
+ /* opt_pass methods: */
+ bool gate () { return gate_handle_if_after_combine (); }
+ unsigned int execute () { return rest_of_handle_if_after_combine (); }
+
+}; // class pass_if_after_combine
+
+} // anon namespace
+
+rtl_opt_pass *
+make_pass_if_after_combine (gcc::context *ctxt)
+{
+ return new pass_if_after_combine (ctxt);
+}
+
+
+static bool
+gate_handle_if_after_reload (void)
+{
+ return optimize > 0 && flag_if_conversion2
+ && dbg_cnt (if_after_reload);
+}
+
+static unsigned int
+rest_of_handle_if_after_reload (void)
+{
+ if_convert (true);
+ return 0;
+}
+
+
+namespace {
+
+const pass_data pass_data_if_after_reload =
+{
+ RTL_PASS, /* type */
+ "ce3", /* name */
+ OPTGROUP_NONE, /* optinfo_flags */
+ true, /* has_gate */
+ true, /* has_execute */
+ TV_IFCVT2, /* tv_id */
+ 0, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ ( TODO_df_finish | TODO_verify_rtl_sharing ), /* todo_flags_finish */
+};
+
+class pass_if_after_reload : public rtl_opt_pass
+{
+public:
+ pass_if_after_reload (gcc::context *ctxt)
+ : rtl_opt_pass (pass_data_if_after_reload, ctxt)
+ {}
+
+ /* opt_pass methods: */
+ bool gate () { return gate_handle_if_after_reload (); }
+ unsigned int execute () { return rest_of_handle_if_after_reload (); }
+
+}; // class pass_if_after_reload
+
+} // anon namespace
+
+rtl_opt_pass *
+make_pass_if_after_reload (gcc::context *ctxt)
+{
+ return new pass_if_after_reload (ctxt);
+}