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-/* Register to Stack convert for GNU compiler.
- Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
- 2000, 2001, 2002, 2003, 2004, 2005 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 2, 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 COPYING. If not, write to the Free
- Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
- 02110-1301, USA. */
-
-/* This pass converts stack-like registers from the "flat register
- file" model that gcc uses, to a stack convention that the 387 uses.
-
- * The form of the input:
-
- On input, the function consists of insn that have had their
- registers fully allocated to a set of "virtual" registers. Note that
- the word "virtual" is used differently here than elsewhere in gcc: for
- each virtual stack reg, there is a hard reg, but the mapping between
- them is not known until this pass is run. On output, hard register
- numbers have been substituted, and various pop and exchange insns have
- been emitted. The hard register numbers and the virtual register
- numbers completely overlap - before this pass, all stack register
- numbers are virtual, and afterward they are all hard.
-
- The virtual registers can be manipulated normally by gcc, and their
- semantics are the same as for normal registers. After the hard
- register numbers are substituted, the semantics of an insn containing
- stack-like regs are not the same as for an insn with normal regs: for
- instance, it is not safe to delete an insn that appears to be a no-op
- move. In general, no insn containing hard regs should be changed
- after this pass is done.
-
- * The form of the output:
-
- After this pass, hard register numbers represent the distance from
- the current top of stack to the desired register. A reference to
- FIRST_STACK_REG references the top of stack, FIRST_STACK_REG + 1,
- represents the register just below that, and so forth. Also, REG_DEAD
- notes indicate whether or not a stack register should be popped.
-
- A "swap" insn looks like a parallel of two patterns, where each
- pattern is a SET: one sets A to B, the other B to A.
-
- A "push" or "load" insn is a SET whose SET_DEST is FIRST_STACK_REG
- and whose SET_DEST is REG or MEM. Any other SET_DEST, such as PLUS,
- will replace the existing stack top, not push a new value.
-
- A store insn is a SET whose SET_DEST is FIRST_STACK_REG, and whose
- SET_SRC is REG or MEM.
-
- The case where the SET_SRC and SET_DEST are both FIRST_STACK_REG
- appears ambiguous. As a special case, the presence of a REG_DEAD note
- for FIRST_STACK_REG differentiates between a load insn and a pop.
-
- If a REG_DEAD is present, the insn represents a "pop" that discards
- the top of the register stack. If there is no REG_DEAD note, then the
- insn represents a "dup" or a push of the current top of stack onto the
- stack.
-
- * Methodology:
-
- Existing REG_DEAD and REG_UNUSED notes for stack registers are
- deleted and recreated from scratch. REG_DEAD is never created for a
- SET_DEST, only REG_UNUSED.
-
- * asm_operands:
-
- There are several rules on the usage of stack-like regs in
- asm_operands insns. These rules apply only to the operands that are
- stack-like regs:
-
- 1. Given a set of input regs that die in an asm_operands, it is
- necessary to know which are implicitly popped by the asm, and
- which must be explicitly popped by gcc.
-
- An input reg that is implicitly popped by the asm must be
- explicitly clobbered, unless it is constrained to match an
- output operand.
-
- 2. For any input reg that is implicitly popped by an asm, it is
- necessary to know how to adjust the stack to compensate for the pop.
- If any non-popped input is closer to the top of the reg-stack than
- the implicitly popped reg, it would not be possible to know what the
- stack looked like - it's not clear how the rest of the stack "slides
- up".
-
- All implicitly popped input regs must be closer to the top of
- the reg-stack than any input that is not implicitly popped.
-
- 3. It is possible that if an input dies in an insn, reload might
- use the input reg for an output reload. Consider this example:
-
- asm ("foo" : "=t" (a) : "f" (b));
-
- This asm says that input B is not popped by the asm, and that
- the asm pushes a result onto the reg-stack, i.e., the stack is one
- deeper after the asm than it was before. But, it is possible that
- reload will think that it can use the same reg for both the input and
- the output, if input B dies in this insn.
-
- If any input operand uses the "f" constraint, all output reg
- constraints must use the "&" earlyclobber.
-
- The asm above would be written as
-
- asm ("foo" : "=&t" (a) : "f" (b));
-
- 4. Some operands need to be in particular places on the stack. All
- output operands fall in this category - there is no other way to
- know which regs the outputs appear in unless the user indicates
- this in the constraints.
-
- Output operands must specifically indicate which reg an output
- appears in after an asm. "=f" is not allowed: the operand
- constraints must select a class with a single reg.
-
- 5. Output operands may not be "inserted" between existing stack regs.
- Since no 387 opcode uses a read/write operand, all output operands
- are dead before the asm_operands, and are pushed by the asm_operands.
- It makes no sense to push anywhere but the top of the reg-stack.
-
- Output operands must start at the top of the reg-stack: output
- operands may not "skip" a reg.
-
- 6. Some asm statements may need extra stack space for internal
- calculations. This can be guaranteed by clobbering stack registers
- unrelated to the inputs and outputs.
-
- Here are a couple of reasonable asms to want to write. This asm
- takes one input, which is internally popped, and produces two outputs.
-
- asm ("fsincos" : "=t" (cos), "=u" (sin) : "0" (inp));
-
- This asm takes two inputs, which are popped by the fyl2xp1 opcode,
- and replaces them with one output. The user must code the "st(1)"
- clobber for reg-stack.c to know that fyl2xp1 pops both inputs.
-
- asm ("fyl2xp1" : "=t" (result) : "0" (x), "u" (y) : "st(1)");
-
-*/
-
-#include "config.h"
-#include "system.h"
-#include "coretypes.h"
-#include "tm.h"
-#include "tree.h"
-#include "rtl.h"
-#include "tm_p.h"
-#include "function.h"
-#include "insn-config.h"
-#include "regs.h"
-#include "hard-reg-set.h"
-#include "flags.h"
-#include "toplev.h"
-#include "recog.h"
-#include "output.h"
-#include "basic-block.h"
-#include "varray.h"
-#include "reload.h"
-#include "ggc.h"
-#include "timevar.h"
-#include "tree-pass.h"
-#include "target.h"
-#include "vecprim.h"
-
-#ifdef STACK_REGS
-
-/* We use this array to cache info about insns, because otherwise we
- spend too much time in stack_regs_mentioned_p.
-
- Indexed by insn UIDs. A value of zero is uninitialized, one indicates
- the insn uses stack registers, two indicates the insn does not use
- stack registers. */
-static VEC(char,heap) *stack_regs_mentioned_data;
-
-#define REG_STACK_SIZE (LAST_STACK_REG - FIRST_STACK_REG + 1)
-
-int regstack_completed = 0;
-
-/* This is the basic stack record. TOP is an index into REG[] such
- that REG[TOP] is the top of stack. If TOP is -1 the stack is empty.
-
- If TOP is -2, REG[] is not yet initialized. Stack initialization
- consists of placing each live reg in array `reg' and setting `top'
- appropriately.
-
- REG_SET indicates which registers are live. */
-
-typedef struct stack_def
-{
- int top; /* index to top stack element */
- HARD_REG_SET reg_set; /* set of live registers */
- unsigned char reg[REG_STACK_SIZE];/* register - stack mapping */
-} *stack;
-
-/* This is used to carry information about basic blocks. It is
- attached to the AUX field of the standard CFG block. */
-
-typedef struct block_info_def
-{
- struct stack_def stack_in; /* Input stack configuration. */
- struct stack_def stack_out; /* Output stack configuration. */
- HARD_REG_SET out_reg_set; /* Stack regs live on output. */
- int done; /* True if block already converted. */
- int predecessors; /* Number of predecessors that need
- to be visited. */
-} *block_info;
-
-#define BLOCK_INFO(B) ((block_info) (B)->aux)
-
-/* Passed to change_stack to indicate where to emit insns. */
-enum emit_where
-{
- EMIT_AFTER,
- EMIT_BEFORE
-};
-
-/* The block we're currently working on. */
-static basic_block current_block;
-
-/* In the current_block, whether we're processing the first register
- stack or call instruction, i.e. the regstack is currently the
- same as BLOCK_INFO(current_block)->stack_in. */
-static bool starting_stack_p;
-
-/* This is the register file for all register after conversion. */
-static rtx
- FP_mode_reg[LAST_STACK_REG+1-FIRST_STACK_REG][(int) MAX_MACHINE_MODE];
-
-#define FP_MODE_REG(regno,mode) \
- (FP_mode_reg[(regno)-FIRST_STACK_REG][(int) (mode)])
-
-/* Used to initialize uninitialized registers. */
-static rtx not_a_num;
-
-/* Forward declarations */
-
-static int stack_regs_mentioned_p (rtx pat);
-static void pop_stack (stack, int);
-static rtx *get_true_reg (rtx *);
-
-static int check_asm_stack_operands (rtx);
-static int get_asm_operand_n_inputs (rtx);
-static rtx stack_result (tree);
-static void replace_reg (rtx *, int);
-static void remove_regno_note (rtx, enum reg_note, unsigned int);
-static int get_hard_regnum (stack, rtx);
-static rtx emit_pop_insn (rtx, stack, rtx, enum emit_where);
-static void swap_to_top(rtx, stack, rtx, rtx);
-static bool move_for_stack_reg (rtx, stack, rtx);
-static bool move_nan_for_stack_reg (rtx, stack, rtx);
-static int swap_rtx_condition_1 (rtx);
-static int swap_rtx_condition (rtx);
-static void compare_for_stack_reg (rtx, stack, rtx);
-static bool subst_stack_regs_pat (rtx, stack, rtx);
-static void subst_asm_stack_regs (rtx, stack);
-static bool subst_stack_regs (rtx, stack);
-static void change_stack (rtx, stack, stack, enum emit_where);
-static void print_stack (FILE *, stack);
-static rtx next_flags_user (rtx);
-
-/* Return nonzero if any stack register is mentioned somewhere within PAT. */
-
-static int
-stack_regs_mentioned_p (rtx pat)
-{
- const char *fmt;
- int i;
-
- if (STACK_REG_P (pat))
- return 1;
-
- fmt = GET_RTX_FORMAT (GET_CODE (pat));
- for (i = GET_RTX_LENGTH (GET_CODE (pat)) - 1; i >= 0; i--)
- {
- if (fmt[i] == 'E')
- {
- int j;
-
- for (j = XVECLEN (pat, i) - 1; j >= 0; j--)
- if (stack_regs_mentioned_p (XVECEXP (pat, i, j)))
- return 1;
- }
- else if (fmt[i] == 'e' && stack_regs_mentioned_p (XEXP (pat, i)))
- return 1;
- }
-
- return 0;
-}
-
-/* Return nonzero if INSN mentions stacked registers, else return zero. */
-
-int
-stack_regs_mentioned (rtx insn)
-{
- unsigned int uid, max;
- int test;
-
- if (! INSN_P (insn) || !stack_regs_mentioned_data)
- return 0;
-
- uid = INSN_UID (insn);
- max = VEC_length (char, stack_regs_mentioned_data);
- if (uid >= max)
- {
- char *p;
- unsigned int old_max = max;
-
- /* Allocate some extra size to avoid too many reallocs, but
- do not grow too quickly. */
- max = uid + uid / 20 + 1;
- VEC_safe_grow (char, heap, stack_regs_mentioned_data, max);
- p = VEC_address (char, stack_regs_mentioned_data);
- memset (&p[old_max], 0,
- sizeof (char) * (max - old_max));
- }
-
- test = VEC_index (char, stack_regs_mentioned_data, uid);
- if (test == 0)
- {
- /* This insn has yet to be examined. Do so now. */
- test = stack_regs_mentioned_p (PATTERN (insn)) ? 1 : 2;
- VEC_replace (char, stack_regs_mentioned_data, uid, test);
- }
-
- return test == 1;
-}
-
-static rtx ix86_flags_rtx;
-
-static rtx
-next_flags_user (rtx insn)
-{
- /* Search forward looking for the first use of this value.
- Stop at block boundaries. */
-
- while (insn != BB_END (current_block))
- {
- insn = NEXT_INSN (insn);
-
- if (INSN_P (insn) && reg_mentioned_p (ix86_flags_rtx, PATTERN (insn)))
- return insn;
-
- if (CALL_P (insn))
- return NULL_RTX;
- }
- return NULL_RTX;
-}
-
-/* Reorganize the stack into ascending numbers, before this insn. */
-
-static void
-straighten_stack (rtx insn, stack regstack)
-{
- struct stack_def temp_stack;
- int top;
-
- /* If there is only a single register on the stack, then the stack is
- already in increasing order and no reorganization is needed.
-
- Similarly if the stack is empty. */
- if (regstack->top <= 0)
- return;
-
- COPY_HARD_REG_SET (temp_stack.reg_set, regstack->reg_set);
-
- for (top = temp_stack.top = regstack->top; top >= 0; top--)
- temp_stack.reg[top] = FIRST_STACK_REG + temp_stack.top - top;
-
- change_stack (insn, regstack, &temp_stack, EMIT_BEFORE);
-}
-
-/* Pop a register from the stack. */
-
-static void
-pop_stack (stack regstack, int regno)
-{
- int top = regstack->top;
-
- CLEAR_HARD_REG_BIT (regstack->reg_set, regno);
- regstack->top--;
- /* If regno was not at the top of stack then adjust stack. */
- if (regstack->reg [top] != regno)
- {
- int i;
- for (i = regstack->top; i >= 0; i--)
- if (regstack->reg [i] == regno)
- {
- int j;
- for (j = i; j < top; j++)
- regstack->reg [j] = regstack->reg [j + 1];
- break;
- }
- }
-}
-
-/* Return a pointer to the REG expression within PAT. If PAT is not a
- REG, possible enclosed by a conversion rtx, return the inner part of
- PAT that stopped the search. */
-
-static rtx *
-get_true_reg (rtx *pat)
-{
- for (;;)
- switch (GET_CODE (*pat))
- {
- case SUBREG:
- /* Eliminate FP subregister accesses in favor of the
- actual FP register in use. */
- {
- rtx subreg;
- if (FP_REG_P (subreg = SUBREG_REG (*pat)))
- {
- int regno_off = subreg_regno_offset (REGNO (subreg),
- GET_MODE (subreg),
- SUBREG_BYTE (*pat),
- GET_MODE (*pat));
- *pat = FP_MODE_REG (REGNO (subreg) + regno_off,
- GET_MODE (subreg));
- default:
- return pat;
- }
- }
- case FLOAT:
- case FIX:
- case FLOAT_EXTEND:
- pat = & XEXP (*pat, 0);
- break;
-
- case FLOAT_TRUNCATE:
- if (!flag_unsafe_math_optimizations)
- return pat;
- pat = & XEXP (*pat, 0);
- break;
- }
-}
-
-/* Set if we find any malformed asms in a block. */
-static bool any_malformed_asm;
-
-/* There are many rules that an asm statement for stack-like regs must
- follow. Those rules are explained at the top of this file: the rule
- numbers below refer to that explanation. */
-
-static int
-check_asm_stack_operands (rtx insn)
-{
- int i;
- int n_clobbers;
- int malformed_asm = 0;
- rtx body = PATTERN (insn);
-
- char reg_used_as_output[FIRST_PSEUDO_REGISTER];
- char implicitly_dies[FIRST_PSEUDO_REGISTER];
- int alt;
-
- rtx *clobber_reg = 0;
- int n_inputs, n_outputs;
-
- /* Find out what the constraints require. If no constraint
- alternative matches, this asm is malformed. */
- extract_insn (insn);
- constrain_operands (1);
- alt = which_alternative;
-
- preprocess_constraints ();
-
- n_inputs = get_asm_operand_n_inputs (body);
- n_outputs = recog_data.n_operands - n_inputs;
-
- if (alt < 0)
- {
- malformed_asm = 1;
- /* Avoid further trouble with this insn. */
- PATTERN (insn) = gen_rtx_USE (VOIDmode, const0_rtx);
- return 0;
- }
-
- /* Strip SUBREGs here to make the following code simpler. */
- for (i = 0; i < recog_data.n_operands; i++)
- if (GET_CODE (recog_data.operand[i]) == SUBREG
- && REG_P (SUBREG_REG (recog_data.operand[i])))
- recog_data.operand[i] = SUBREG_REG (recog_data.operand[i]);
-
- /* Set up CLOBBER_REG. */
-
- n_clobbers = 0;
-
- if (GET_CODE (body) == PARALLEL)
- {
- clobber_reg = alloca (XVECLEN (body, 0) * sizeof (rtx));
-
- for (i = 0; i < XVECLEN (body, 0); i++)
- if (GET_CODE (XVECEXP (body, 0, i)) == CLOBBER)
- {
- rtx clobber = XVECEXP (body, 0, i);
- rtx reg = XEXP (clobber, 0);
-
- if (GET_CODE (reg) == SUBREG && REG_P (SUBREG_REG (reg)))
- reg = SUBREG_REG (reg);
-
- if (STACK_REG_P (reg))
- {
- clobber_reg[n_clobbers] = reg;
- n_clobbers++;
- }
- }
- }
-
- /* Enforce rule #4: Output operands must specifically indicate which
- reg an output appears in after an asm. "=f" is not allowed: the
- operand constraints must select a class with a single reg.
-
- Also enforce rule #5: Output operands must start at the top of
- the reg-stack: output operands may not "skip" a reg. */
-
- memset (reg_used_as_output, 0, sizeof (reg_used_as_output));
- for (i = 0; i < n_outputs; i++)
- if (STACK_REG_P (recog_data.operand[i]))
- {
- if (reg_class_size[(int) recog_op_alt[i][alt].cl] != 1)
- {
- error_for_asm (insn, "output constraint %d must specify a single register", i);
- malformed_asm = 1;
- }
- else
- {
- int j;
-
- for (j = 0; j < n_clobbers; j++)
- if (REGNO (recog_data.operand[i]) == REGNO (clobber_reg[j]))
- {
- error_for_asm (insn, "output constraint %d cannot be specified together with \"%s\" clobber",
- i, reg_names [REGNO (clobber_reg[j])]);
- malformed_asm = 1;
- break;
- }
- if (j == n_clobbers)
- reg_used_as_output[REGNO (recog_data.operand[i])] = 1;
- }
- }
-
-
- /* Search for first non-popped reg. */
- for (i = FIRST_STACK_REG; i < LAST_STACK_REG + 1; i++)
- if (! reg_used_as_output[i])
- break;
-
- /* If there are any other popped regs, that's an error. */
- for (; i < LAST_STACK_REG + 1; i++)
- if (reg_used_as_output[i])
- break;
-
- if (i != LAST_STACK_REG + 1)
- {
- error_for_asm (insn, "output regs must be grouped at top of stack");
- malformed_asm = 1;
- }
-
- /* Enforce rule #2: All implicitly popped input regs must be closer
- to the top of the reg-stack than any input that is not implicitly
- popped. */
-
- memset (implicitly_dies, 0, sizeof (implicitly_dies));
- for (i = n_outputs; i < n_outputs + n_inputs; i++)
- if (STACK_REG_P (recog_data.operand[i]))
- {
- /* An input reg is implicitly popped if it is tied to an
- output, or if there is a CLOBBER for it. */
- int j;
-
- for (j = 0; j < n_clobbers; j++)
- if (operands_match_p (clobber_reg[j], recog_data.operand[i]))
- break;
-
- if (j < n_clobbers || recog_op_alt[i][alt].matches >= 0)
- implicitly_dies[REGNO (recog_data.operand[i])] = 1;
- }
-
- /* Search for first non-popped reg. */
- for (i = FIRST_STACK_REG; i < LAST_STACK_REG + 1; i++)
- if (! implicitly_dies[i])
- break;
-
- /* If there are any other popped regs, that's an error. */
- for (; i < LAST_STACK_REG + 1; i++)
- if (implicitly_dies[i])
- break;
-
- if (i != LAST_STACK_REG + 1)
- {
- error_for_asm (insn,
- "implicitly popped regs must be grouped at top of stack");
- malformed_asm = 1;
- }
-
- /* Enforce rule #3: If any input operand uses the "f" constraint, all
- output constraints must use the "&" earlyclobber.
-
- ??? Detect this more deterministically by having constrain_asm_operands
- record any earlyclobber. */
-
- for (i = n_outputs; i < n_outputs + n_inputs; i++)
- if (recog_op_alt[i][alt].matches == -1)
- {
- int j;
-
- for (j = 0; j < n_outputs; j++)
- if (operands_match_p (recog_data.operand[j], recog_data.operand[i]))
- {
- error_for_asm (insn,
- "output operand %d must use %<&%> constraint", j);
- malformed_asm = 1;
- }
- }
-
- if (malformed_asm)
- {
- /* Avoid further trouble with this insn. */
- PATTERN (insn) = gen_rtx_USE (VOIDmode, const0_rtx);
- any_malformed_asm = true;
- return 0;
- }
-
- return 1;
-}
-
-/* Calculate the number of inputs and outputs in BODY, an
- asm_operands. N_OPERANDS is the total number of operands, and
- N_INPUTS and N_OUTPUTS are pointers to ints into which the results are
- placed. */
-
-static int
-get_asm_operand_n_inputs (rtx body)
-{
- switch (GET_CODE (body))
- {
- case SET:
- gcc_assert (GET_CODE (SET_SRC (body)) == ASM_OPERANDS);
- return ASM_OPERANDS_INPUT_LENGTH (SET_SRC (body));
-
- case ASM_OPERANDS:
- return ASM_OPERANDS_INPUT_LENGTH (body);
-
- case PARALLEL:
- return get_asm_operand_n_inputs (XVECEXP (body, 0, 0));
-
- default:
- gcc_unreachable ();
- }
-}
-
-/* If current function returns its result in an fp stack register,
- return the REG. Otherwise, return 0. */
-
-static rtx
-stack_result (tree decl)
-{
- rtx result;
-
- /* If the value is supposed to be returned in memory, then clearly
- it is not returned in a stack register. */
- if (aggregate_value_p (DECL_RESULT (decl), decl))
- return 0;
-
- result = DECL_RTL_IF_SET (DECL_RESULT (decl));
- if (result != 0)
- result = targetm.calls.function_value (TREE_TYPE (DECL_RESULT (decl)),
- decl, true);
-
- return result != 0 && STACK_REG_P (result) ? result : 0;
-}
-
-
-/*
- * This section deals with stack register substitution, and forms the second
- * pass over the RTL.
- */
-
-/* Replace REG, which is a pointer to a stack reg RTX, with an RTX for
- the desired hard REGNO. */
-
-static void
-replace_reg (rtx *reg, int regno)
-{
- gcc_assert (regno >= FIRST_STACK_REG);
- gcc_assert (regno <= LAST_STACK_REG);
- gcc_assert (STACK_REG_P (*reg));
-
- gcc_assert (SCALAR_FLOAT_MODE_P (GET_MODE (*reg))
- || GET_MODE_CLASS (GET_MODE (*reg)) == MODE_COMPLEX_FLOAT);
-
- *reg = FP_MODE_REG (regno, GET_MODE (*reg));
-}
-
-/* Remove a note of type NOTE, which must be found, for register
- number REGNO from INSN. Remove only one such note. */
-
-static void
-remove_regno_note (rtx insn, enum reg_note note, unsigned int regno)
-{
- rtx *note_link, this;
-
- note_link = &REG_NOTES (insn);
- for (this = *note_link; this; this = XEXP (this, 1))
- if (REG_NOTE_KIND (this) == note
- && REG_P (XEXP (this, 0)) && REGNO (XEXP (this, 0)) == regno)
- {
- *note_link = XEXP (this, 1);
- return;
- }
- else
- note_link = &XEXP (this, 1);
-
- gcc_unreachable ();
-}
-
-/* Find the hard register number of virtual register REG in REGSTACK.
- The hard register number is relative to the top of the stack. -1 is
- returned if the register is not found. */
-
-static int
-get_hard_regnum (stack regstack, rtx reg)
-{
- int i;
-
- gcc_assert (STACK_REG_P (reg));
-
- for (i = regstack->top; i >= 0; i--)
- if (regstack->reg[i] == REGNO (reg))
- break;
-
- return i >= 0 ? (FIRST_STACK_REG + regstack->top - i) : -1;
-}
-
-/* Emit an insn to pop virtual register REG before or after INSN.
- REGSTACK is the stack state after INSN and is updated to reflect this
- pop. WHEN is either emit_insn_before or emit_insn_after. A pop insn
- is represented as a SET whose destination is the register to be popped
- and source is the top of stack. A death note for the top of stack
- cases the movdf pattern to pop. */
-
-static rtx
-emit_pop_insn (rtx insn, stack regstack, rtx reg, enum emit_where where)
-{
- rtx pop_insn, pop_rtx;
- int hard_regno;
-
- /* For complex types take care to pop both halves. These may survive in
- CLOBBER and USE expressions. */
- if (COMPLEX_MODE_P (GET_MODE (reg)))
- {
- rtx reg1 = FP_MODE_REG (REGNO (reg), DFmode);
- rtx reg2 = FP_MODE_REG (REGNO (reg) + 1, DFmode);
-
- pop_insn = NULL_RTX;
- if (get_hard_regnum (regstack, reg1) >= 0)
- pop_insn = emit_pop_insn (insn, regstack, reg1, where);
- if (get_hard_regnum (regstack, reg2) >= 0)
- pop_insn = emit_pop_insn (insn, regstack, reg2, where);
- gcc_assert (pop_insn);
- return pop_insn;
- }
-
- hard_regno = get_hard_regnum (regstack, reg);
-
- gcc_assert (hard_regno >= FIRST_STACK_REG);
-
- pop_rtx = gen_rtx_SET (VOIDmode, FP_MODE_REG (hard_regno, DFmode),
- FP_MODE_REG (FIRST_STACK_REG, DFmode));
-
- if (where == EMIT_AFTER)
- pop_insn = emit_insn_after (pop_rtx, insn);
- else
- pop_insn = emit_insn_before (pop_rtx, insn);
-
- REG_NOTES (pop_insn)
- = gen_rtx_EXPR_LIST (REG_DEAD, FP_MODE_REG (FIRST_STACK_REG, DFmode),
- REG_NOTES (pop_insn));
-
- regstack->reg[regstack->top - (hard_regno - FIRST_STACK_REG)]
- = regstack->reg[regstack->top];
- regstack->top -= 1;
- CLEAR_HARD_REG_BIT (regstack->reg_set, REGNO (reg));
-
- return pop_insn;
-}
-
-/* Emit an insn before or after INSN to swap virtual register REG with
- the top of stack. REGSTACK is the stack state before the swap, and
- is updated to reflect the swap. A swap insn is represented as a
- PARALLEL of two patterns: each pattern moves one reg to the other.
-
- If REG is already at the top of the stack, no insn is emitted. */
-
-static void
-emit_swap_insn (rtx insn, stack regstack, rtx reg)
-{
- int hard_regno;
- rtx swap_rtx;
- int tmp, other_reg; /* swap regno temps */
- rtx i1; /* the stack-reg insn prior to INSN */
- rtx i1set = NULL_RTX; /* the SET rtx within I1 */
-
- hard_regno = get_hard_regnum (regstack, reg);
-
- if (hard_regno == FIRST_STACK_REG)
- return;
- if (hard_regno == -1)
- {
- /* Something failed if the register wasn't on the stack. If we had
- malformed asms, we zapped the instruction itself, but that didn't
- produce the same pattern of register sets as before. To prevent
- further failure, adjust REGSTACK to include REG at TOP. */
- gcc_assert (any_malformed_asm);
- regstack->reg[++regstack->top] = REGNO (reg);
- return;
- }
- gcc_assert (hard_regno >= FIRST_STACK_REG);
-
- other_reg = regstack->top - (hard_regno - FIRST_STACK_REG);
-
- tmp = regstack->reg[other_reg];
- regstack->reg[other_reg] = regstack->reg[regstack->top];
- regstack->reg[regstack->top] = tmp;
-
- /* Find the previous insn involving stack regs, but don't pass a
- block boundary. */
- i1 = NULL;
- if (current_block && insn != BB_HEAD (current_block))
- {
- rtx tmp = PREV_INSN (insn);
- rtx limit = PREV_INSN (BB_HEAD (current_block));
- while (tmp != limit)
- {
- if (LABEL_P (tmp)
- || CALL_P (tmp)
- || NOTE_INSN_BASIC_BLOCK_P (tmp)
- || (NONJUMP_INSN_P (tmp)
- && stack_regs_mentioned (tmp)))
- {
- i1 = tmp;
- break;
- }
- tmp = PREV_INSN (tmp);
- }
- }
-
- if (i1 != NULL_RTX
- && (i1set = single_set (i1)) != NULL_RTX)
- {
- rtx i1src = *get_true_reg (&SET_SRC (i1set));
- rtx i1dest = *get_true_reg (&SET_DEST (i1set));
-
- /* If the previous register stack push was from the reg we are to
- swap with, omit the swap. */
-
- if (REG_P (i1dest) && REGNO (i1dest) == FIRST_STACK_REG
- && REG_P (i1src)
- && REGNO (i1src) == (unsigned) hard_regno - 1
- && find_regno_note (i1, REG_DEAD, FIRST_STACK_REG) == NULL_RTX)
- return;
-
- /* If the previous insn wrote to the reg we are to swap with,
- omit the swap. */
-
- if (REG_P (i1dest) && REGNO (i1dest) == (unsigned) hard_regno
- && REG_P (i1src) && REGNO (i1src) == FIRST_STACK_REG
- && find_regno_note (i1, REG_DEAD, FIRST_STACK_REG) == NULL_RTX)
- return;
- }
-
- /* Avoid emitting the swap if this is the first register stack insn
- of the current_block. Instead update the current_block's stack_in
- and let compensate edges take care of this for us. */
- if (current_block && starting_stack_p)
- {
- BLOCK_INFO (current_block)->stack_in = *regstack;
- starting_stack_p = false;
- return;
- }
-
- swap_rtx = gen_swapxf (FP_MODE_REG (hard_regno, XFmode),
- FP_MODE_REG (FIRST_STACK_REG, XFmode));
-
- if (i1)
- emit_insn_after (swap_rtx, i1);
- else if (current_block)
- emit_insn_before (swap_rtx, BB_HEAD (current_block));
- else
- emit_insn_before (swap_rtx, insn);
-}
-
-/* Emit an insns before INSN to swap virtual register SRC1 with
- the top of stack and virtual register SRC2 with second stack
- slot. REGSTACK is the stack state before the swaps, and
- is updated to reflect the swaps. A swap insn is represented as a
- PARALLEL of two patterns: each pattern moves one reg to the other.
-
- If SRC1 and/or SRC2 are already at the right place, no swap insn
- is emitted. */
-
-static void
-swap_to_top (rtx insn, stack regstack, rtx src1, rtx src2)
-{
- struct stack_def temp_stack;
- int regno, j, k, temp;
-
- temp_stack = *regstack;
-
- /* Place operand 1 at the top of stack. */
- regno = get_hard_regnum (&temp_stack, src1);
- gcc_assert (regno >= 0);
- if (regno != FIRST_STACK_REG)
- {
- k = temp_stack.top - (regno - FIRST_STACK_REG);
- j = temp_stack.top;
-
- temp = temp_stack.reg[k];
- temp_stack.reg[k] = temp_stack.reg[j];
- temp_stack.reg[j] = temp;
- }
-
- /* Place operand 2 next on the stack. */
- regno = get_hard_regnum (&temp_stack, src2);
- gcc_assert (regno >= 0);
- if (regno != FIRST_STACK_REG + 1)
- {
- k = temp_stack.top - (regno - FIRST_STACK_REG);
- j = temp_stack.top - 1;
-
- temp = temp_stack.reg[k];
- temp_stack.reg[k] = temp_stack.reg[j];
- temp_stack.reg[j] = temp;
- }
-
- change_stack (insn, regstack, &temp_stack, EMIT_BEFORE);
-}
-
-/* Handle a move to or from a stack register in PAT, which is in INSN.
- REGSTACK is the current stack. Return whether a control flow insn
- was deleted in the process. */
-
-static bool
-move_for_stack_reg (rtx insn, stack regstack, rtx pat)
-{
- rtx *psrc = get_true_reg (&SET_SRC (pat));
- rtx *pdest = get_true_reg (&SET_DEST (pat));
- rtx src, dest;
- rtx note;
- bool control_flow_insn_deleted = false;
-
- src = *psrc; dest = *pdest;
-
- if (STACK_REG_P (src) && STACK_REG_P (dest))
- {
- /* Write from one stack reg to another. If SRC dies here, then
- just change the register mapping and delete the insn. */
-
- note = find_regno_note (insn, REG_DEAD, REGNO (src));
- if (note)
- {
- int i;
-
- /* If this is a no-op move, there must not be a REG_DEAD note. */
- gcc_assert (REGNO (src) != REGNO (dest));
-
- for (i = regstack->top; i >= 0; i--)
- if (regstack->reg[i] == REGNO (src))
- break;
-
- /* The destination must be dead, or life analysis is borked. */
- gcc_assert (get_hard_regnum (regstack, dest) < FIRST_STACK_REG);
-
- /* If the source is not live, this is yet another case of
- uninitialized variables. Load up a NaN instead. */
- if (i < 0)
- return move_nan_for_stack_reg (insn, regstack, dest);
-
- /* It is possible that the dest is unused after this insn.
- If so, just pop the src. */
-
- if (find_regno_note (insn, REG_UNUSED, REGNO (dest)))
- emit_pop_insn (insn, regstack, src, EMIT_AFTER);
- else
- {
- regstack->reg[i] = REGNO (dest);
- SET_HARD_REG_BIT (regstack->reg_set, REGNO (dest));
- CLEAR_HARD_REG_BIT (regstack->reg_set, REGNO (src));
- }
-
- control_flow_insn_deleted |= control_flow_insn_p (insn);
- delete_insn (insn);
- return control_flow_insn_deleted;
- }
-
- /* The source reg does not die. */
-
- /* If this appears to be a no-op move, delete it, or else it
- will confuse the machine description output patterns. But if
- it is REG_UNUSED, we must pop the reg now, as per-insn processing
- for REG_UNUSED will not work for deleted insns. */
-
- if (REGNO (src) == REGNO (dest))
- {
- if (find_regno_note (insn, REG_UNUSED, REGNO (dest)))
- emit_pop_insn (insn, regstack, dest, EMIT_AFTER);
-
- control_flow_insn_deleted |= control_flow_insn_p (insn);
- delete_insn (insn);
- return control_flow_insn_deleted;
- }
-
- /* The destination ought to be dead. */
- gcc_assert (get_hard_regnum (regstack, dest) < FIRST_STACK_REG);
-
- replace_reg (psrc, get_hard_regnum (regstack, src));
-
- regstack->reg[++regstack->top] = REGNO (dest);
- SET_HARD_REG_BIT (regstack->reg_set, REGNO (dest));
- replace_reg (pdest, FIRST_STACK_REG);
- }
- else if (STACK_REG_P (src))
- {
- /* Save from a stack reg to MEM, or possibly integer reg. Since
- only top of stack may be saved, emit an exchange first if
- needs be. */
-
- emit_swap_insn (insn, regstack, src);
-
- note = find_regno_note (insn, REG_DEAD, REGNO (src));
- if (note)
- {
- replace_reg (&XEXP (note, 0), FIRST_STACK_REG);
- regstack->top--;
- CLEAR_HARD_REG_BIT (regstack->reg_set, REGNO (src));
- }
- else if ((GET_MODE (src) == XFmode)
- && regstack->top < REG_STACK_SIZE - 1)
- {
- /* A 387 cannot write an XFmode value to a MEM without
- clobbering the source reg. The output code can handle
- this by reading back the value from the MEM.
- But it is more efficient to use a temp register if one is
- available. Push the source value here if the register
- stack is not full, and then write the value to memory via
- a pop. */
- rtx push_rtx;
- rtx top_stack_reg = FP_MODE_REG (FIRST_STACK_REG, GET_MODE (src));
-
- push_rtx = gen_movxf (top_stack_reg, top_stack_reg);
- emit_insn_before (push_rtx, insn);
- REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_DEAD, top_stack_reg,
- REG_NOTES (insn));
- }
-
- replace_reg (psrc, FIRST_STACK_REG);
- }
- else
- {
- gcc_assert (STACK_REG_P (dest));
-
- /* Load from MEM, or possibly integer REG or constant, into the
- stack regs. The actual target is always the top of the
- stack. The stack mapping is changed to reflect that DEST is
- now at top of stack. */
-
- /* The destination ought to be dead. */
- gcc_assert (get_hard_regnum (regstack, dest) < FIRST_STACK_REG);
-
- gcc_assert (regstack->top < REG_STACK_SIZE);
-
- regstack->reg[++regstack->top] = REGNO (dest);
- SET_HARD_REG_BIT (regstack->reg_set, REGNO (dest));
- replace_reg (pdest, FIRST_STACK_REG);
- }
-
- return control_flow_insn_deleted;
-}
-
-/* A helper function which replaces INSN with a pattern that loads up
- a NaN into DEST, then invokes move_for_stack_reg. */
-
-static bool
-move_nan_for_stack_reg (rtx insn, stack regstack, rtx dest)
-{
- rtx pat;
-
- dest = FP_MODE_REG (REGNO (dest), SFmode);
- pat = gen_rtx_SET (VOIDmode, dest, not_a_num);
- PATTERN (insn) = pat;
- INSN_CODE (insn) = -1;
-
- return move_for_stack_reg (insn, regstack, pat);
-}
-
-/* Swap the condition on a branch, if there is one. Return true if we
- found a condition to swap. False if the condition was not used as
- such. */
-
-static int
-swap_rtx_condition_1 (rtx pat)
-{
- const char *fmt;
- int i, r = 0;
-
- if (COMPARISON_P (pat))
- {
- PUT_CODE (pat, swap_condition (GET_CODE (pat)));
- r = 1;
- }
- else
- {
- fmt = GET_RTX_FORMAT (GET_CODE (pat));
- for (i = GET_RTX_LENGTH (GET_CODE (pat)) - 1; i >= 0; i--)
- {
- if (fmt[i] == 'E')
- {
- int j;
-
- for (j = XVECLEN (pat, i) - 1; j >= 0; j--)
- r |= swap_rtx_condition_1 (XVECEXP (pat, i, j));
- }
- else if (fmt[i] == 'e')
- r |= swap_rtx_condition_1 (XEXP (pat, i));
- }
- }
-
- return r;
-}
-
-static int
-swap_rtx_condition (rtx insn)
-{
- rtx pat = PATTERN (insn);
-
- /* We're looking for a single set to cc0 or an HImode temporary. */
-
- if (GET_CODE (pat) == SET
- && REG_P (SET_DEST (pat))
- && REGNO (SET_DEST (pat)) == FLAGS_REG)
- {
- insn = next_flags_user (insn);
- if (insn == NULL_RTX)
- return 0;
- pat = PATTERN (insn);
- }
-
- /* See if this is, or ends in, a fnstsw. If so, we're not doing anything
- with the cc value right now. We may be able to search for one
- though. */
-
- if (GET_CODE (pat) == SET
- && GET_CODE (SET_SRC (pat)) == UNSPEC
- && XINT (SET_SRC (pat), 1) == UNSPEC_FNSTSW)
- {
- rtx dest = SET_DEST (pat);
-
- /* Search forward looking for the first use of this value.
- Stop at block boundaries. */
- while (insn != BB_END (current_block))
- {
- insn = NEXT_INSN (insn);
- if (INSN_P (insn) && reg_mentioned_p (dest, insn))
- break;
- if (CALL_P (insn))
- return 0;
- }
-
- /* We haven't found it. */
- if (insn == BB_END (current_block))
- return 0;
-
- /* So we've found the insn using this value. If it is anything
- other than sahf or the value does not die (meaning we'd have
- to search further), then we must give up. */
- pat = PATTERN (insn);
- if (GET_CODE (pat) != SET
- || GET_CODE (SET_SRC (pat)) != UNSPEC
- || XINT (SET_SRC (pat), 1) != UNSPEC_SAHF
- || ! dead_or_set_p (insn, dest))
- return 0;
-
- /* Now we are prepared to handle this as a normal cc0 setter. */
- insn = next_flags_user (insn);
- if (insn == NULL_RTX)
- return 0;
- pat = PATTERN (insn);
- }
-
- if (swap_rtx_condition_1 (pat))
- {
- int fail = 0;
- INSN_CODE (insn) = -1;
- if (recog_memoized (insn) == -1)
- fail = 1;
- /* In case the flags don't die here, recurse to try fix
- following user too. */
- else if (! dead_or_set_p (insn, ix86_flags_rtx))
- {
- insn = next_flags_user (insn);
- if (!insn || !swap_rtx_condition (insn))
- fail = 1;
- }
- if (fail)
- {
- swap_rtx_condition_1 (pat);
- return 0;
- }
- return 1;
- }
- return 0;
-}
-
-/* Handle a comparison. Special care needs to be taken to avoid
- causing comparisons that a 387 cannot do correctly, such as EQ.
-
- Also, a pop insn may need to be emitted. The 387 does have an
- `fcompp' insn that can pop two regs, but it is sometimes too expensive
- to do this - a `fcomp' followed by a `fstpl %st(0)' may be easier to
- set up. */
-
-static void
-compare_for_stack_reg (rtx insn, stack regstack, rtx pat_src)
-{
- rtx *src1, *src2;
- rtx src1_note, src2_note;
-
- src1 = get_true_reg (&XEXP (pat_src, 0));
- src2 = get_true_reg (&XEXP (pat_src, 1));
-
- /* ??? If fxch turns out to be cheaper than fstp, give priority to
- registers that die in this insn - move those to stack top first. */
- if ((! STACK_REG_P (*src1)
- || (STACK_REG_P (*src2)
- && get_hard_regnum (regstack, *src2) == FIRST_STACK_REG))
- && swap_rtx_condition (insn))
- {
- rtx temp;
- temp = XEXP (pat_src, 0);
- XEXP (pat_src, 0) = XEXP (pat_src, 1);
- XEXP (pat_src, 1) = temp;
-
- src1 = get_true_reg (&XEXP (pat_src, 0));
- src2 = get_true_reg (&XEXP (pat_src, 1));
-
- INSN_CODE (insn) = -1;
- }
-
- /* We will fix any death note later. */
-
- src1_note = find_regno_note (insn, REG_DEAD, REGNO (*src1));
-
- if (STACK_REG_P (*src2))
- src2_note = find_regno_note (insn, REG_DEAD, REGNO (*src2));
- else
- src2_note = NULL_RTX;
-
- emit_swap_insn (insn, regstack, *src1);
-
- replace_reg (src1, FIRST_STACK_REG);
-
- if (STACK_REG_P (*src2))
- replace_reg (src2, get_hard_regnum (regstack, *src2));
-
- if (src1_note)
- {
- pop_stack (regstack, REGNO (XEXP (src1_note, 0)));
- replace_reg (&XEXP (src1_note, 0), FIRST_STACK_REG);
- }
-
- /* If the second operand dies, handle that. But if the operands are
- the same stack register, don't bother, because only one death is
- needed, and it was just handled. */
-
- if (src2_note
- && ! (STACK_REG_P (*src1) && STACK_REG_P (*src2)
- && REGNO (*src1) == REGNO (*src2)))
- {
- /* As a special case, two regs may die in this insn if src2 is
- next to top of stack and the top of stack also dies. Since
- we have already popped src1, "next to top of stack" is really
- at top (FIRST_STACK_REG) now. */
-
- if (get_hard_regnum (regstack, XEXP (src2_note, 0)) == FIRST_STACK_REG
- && src1_note)
- {
- pop_stack (regstack, REGNO (XEXP (src2_note, 0)));
- replace_reg (&XEXP (src2_note, 0), FIRST_STACK_REG + 1);
- }
- else
- {
- /* The 386 can only represent death of the first operand in
- the case handled above. In all other cases, emit a separate
- pop and remove the death note from here. */
-
- /* link_cc0_insns (insn); */
-
- remove_regno_note (insn, REG_DEAD, REGNO (XEXP (src2_note, 0)));
-
- emit_pop_insn (insn, regstack, XEXP (src2_note, 0),
- EMIT_AFTER);
- }
- }
-}
-
-/* Substitute new registers in PAT, which is part of INSN. REGSTACK
- is the current register layout. Return whether a control flow insn
- was deleted in the process. */
-
-static bool
-subst_stack_regs_pat (rtx insn, stack regstack, rtx pat)
-{
- rtx *dest, *src;
- bool control_flow_insn_deleted = false;
-
- switch (GET_CODE (pat))
- {
- case USE:
- /* Deaths in USE insns can happen in non optimizing compilation.
- Handle them by popping the dying register. */
- src = get_true_reg (&XEXP (pat, 0));
- if (STACK_REG_P (*src)
- && find_regno_note (insn, REG_DEAD, REGNO (*src)))
- {
- emit_pop_insn (insn, regstack, *src, EMIT_AFTER);
- return control_flow_insn_deleted;
- }
- /* ??? Uninitialized USE should not happen. */
- else
- gcc_assert (get_hard_regnum (regstack, *src) != -1);
- break;
-
- case CLOBBER:
- {
- rtx note;
-
- dest = get_true_reg (&XEXP (pat, 0));
- if (STACK_REG_P (*dest))
- {
- note = find_reg_note (insn, REG_DEAD, *dest);
-
- if (pat != PATTERN (insn))
- {
- /* The fix_truncdi_1 pattern wants to be able to allocate
- its own scratch register. It does this by clobbering
- an fp reg so that it is assured of an empty reg-stack
- register. If the register is live, kill it now.
- Remove the DEAD/UNUSED note so we don't try to kill it
- later too. */
-
- if (note)
- emit_pop_insn (insn, regstack, *dest, EMIT_BEFORE);
- else
- {
- note = find_reg_note (insn, REG_UNUSED, *dest);
- gcc_assert (note);
- }
- remove_note (insn, note);
- replace_reg (dest, FIRST_STACK_REG + 1);
- }
- else
- {
- /* A top-level clobber with no REG_DEAD, and no hard-regnum
- indicates an uninitialized value. Because reload removed
- all other clobbers, this must be due to a function
- returning without a value. Load up a NaN. */
-
- if (!note)
- {
- rtx t = *dest;
- if (COMPLEX_MODE_P (GET_MODE (t)))
- {
- rtx u = FP_MODE_REG (REGNO (t) + 1, SFmode);
- if (get_hard_regnum (regstack, u) == -1)
- {
- rtx pat2 = gen_rtx_CLOBBER (VOIDmode, u);
- rtx insn2 = emit_insn_before (pat2, insn);
- control_flow_insn_deleted
- |= move_nan_for_stack_reg (insn2, regstack, u);
- }
- }
- if (get_hard_regnum (regstack, t) == -1)
- control_flow_insn_deleted
- |= move_nan_for_stack_reg (insn, regstack, t);
- }
- }
- }
- break;
- }
-
- case SET:
- {
- rtx *src1 = (rtx *) 0, *src2;
- rtx src1_note, src2_note;
- rtx pat_src;
-
- dest = get_true_reg (&SET_DEST (pat));
- src = get_true_reg (&SET_SRC (pat));
- pat_src = SET_SRC (pat);
-
- /* See if this is a `movM' pattern, and handle elsewhere if so. */
- if (STACK_REG_P (*src)
- || (STACK_REG_P (*dest)
- && (REG_P (*src) || MEM_P (*src)
- || GET_CODE (*src) == CONST_DOUBLE)))
- {
- control_flow_insn_deleted |= move_for_stack_reg (insn, regstack, pat);
- break;
- }
-
- switch (GET_CODE (pat_src))
- {
- case COMPARE:
- compare_for_stack_reg (insn, regstack, pat_src);
- break;
-
- case CALL:
- {
- int count;
- for (count = hard_regno_nregs[REGNO (*dest)][GET_MODE (*dest)];
- --count >= 0;)
- {
- regstack->reg[++regstack->top] = REGNO (*dest) + count;
- SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest) + count);
- }
- }
- replace_reg (dest, FIRST_STACK_REG);
- break;
-
- case REG:
- /* This is a `tstM2' case. */
- gcc_assert (*dest == cc0_rtx);
- src1 = src;
-
- /* Fall through. */
-
- case FLOAT_TRUNCATE:
- case SQRT:
- case ABS:
- case NEG:
- /* These insns only operate on the top of the stack. DEST might
- be cc0_rtx if we're processing a tstM pattern. Also, it's
- possible that the tstM case results in a REG_DEAD note on the
- source. */
-
- if (src1 == 0)
- src1 = get_true_reg (&XEXP (pat_src, 0));
-
- emit_swap_insn (insn, regstack, *src1);
-
- src1_note = find_regno_note (insn, REG_DEAD, REGNO (*src1));
-
- if (STACK_REG_P (*dest))
- replace_reg (dest, FIRST_STACK_REG);
-
- if (src1_note)
- {
- replace_reg (&XEXP (src1_note, 0), FIRST_STACK_REG);
- regstack->top--;
- CLEAR_HARD_REG_BIT (regstack->reg_set, REGNO (*src1));
- }
-
- replace_reg (src1, FIRST_STACK_REG);
- break;
-
- case MINUS:
- case DIV:
- /* On i386, reversed forms of subM3 and divM3 exist for
- MODE_FLOAT, so the same code that works for addM3 and mulM3
- can be used. */
- case MULT:
- case PLUS:
- /* These insns can accept the top of stack as a destination
- from a stack reg or mem, or can use the top of stack as a
- source and some other stack register (possibly top of stack)
- as a destination. */
-
- src1 = get_true_reg (&XEXP (pat_src, 0));
- src2 = get_true_reg (&XEXP (pat_src, 1));
-
- /* We will fix any death note later. */
-
- if (STACK_REG_P (*src1))
- src1_note = find_regno_note (insn, REG_DEAD, REGNO (*src1));
- else
- src1_note = NULL_RTX;
- if (STACK_REG_P (*src2))
- src2_note = find_regno_note (insn, REG_DEAD, REGNO (*src2));
- else
- src2_note = NULL_RTX;
-
- /* If either operand is not a stack register, then the dest
- must be top of stack. */
-
- if (! STACK_REG_P (*src1) || ! STACK_REG_P (*src2))
- emit_swap_insn (insn, regstack, *dest);
- else
- {
- /* Both operands are REG. If neither operand is already
- at the top of stack, choose to make the one that is the dest
- the new top of stack. */
-
- int src1_hard_regnum, src2_hard_regnum;
-
- src1_hard_regnum = get_hard_regnum (regstack, *src1);
- src2_hard_regnum = get_hard_regnum (regstack, *src2);
- gcc_assert (src1_hard_regnum != -1);
- gcc_assert (src2_hard_regnum != -1);
-
- if (src1_hard_regnum != FIRST_STACK_REG
- && src2_hard_regnum != FIRST_STACK_REG)
- emit_swap_insn (insn, regstack, *dest);
- }
-
- if (STACK_REG_P (*src1))
- replace_reg (src1, get_hard_regnum (regstack, *src1));
- if (STACK_REG_P (*src2))
- replace_reg (src2, get_hard_regnum (regstack, *src2));
-
- if (src1_note)
- {
- rtx src1_reg = XEXP (src1_note, 0);
-
- /* If the register that dies is at the top of stack, then
- the destination is somewhere else - merely substitute it.
- But if the reg that dies is not at top of stack, then
- move the top of stack to the dead reg, as though we had
- done the insn and then a store-with-pop. */
-
- if (REGNO (src1_reg) == regstack->reg[regstack->top])
- {
- SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
- replace_reg (dest, get_hard_regnum (regstack, *dest));
- }
- else
- {
- int regno = get_hard_regnum (regstack, src1_reg);
-
- SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
- replace_reg (dest, regno);
-
- regstack->reg[regstack->top - (regno - FIRST_STACK_REG)]
- = regstack->reg[regstack->top];
- }
-
- CLEAR_HARD_REG_BIT (regstack->reg_set,
- REGNO (XEXP (src1_note, 0)));
- replace_reg (&XEXP (src1_note, 0), FIRST_STACK_REG);
- regstack->top--;
- }
- else if (src2_note)
- {
- rtx src2_reg = XEXP (src2_note, 0);
- if (REGNO (src2_reg) == regstack->reg[regstack->top])
- {
- SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
- replace_reg (dest, get_hard_regnum (regstack, *dest));
- }
- else
- {
- int regno = get_hard_regnum (regstack, src2_reg);
-
- SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
- replace_reg (dest, regno);
-
- regstack->reg[regstack->top - (regno - FIRST_STACK_REG)]
- = regstack->reg[regstack->top];
- }
-
- CLEAR_HARD_REG_BIT (regstack->reg_set,
- REGNO (XEXP (src2_note, 0)));
- replace_reg (&XEXP (src2_note, 0), FIRST_STACK_REG);
- regstack->top--;
- }
- else
- {
- SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
- replace_reg (dest, get_hard_regnum (regstack, *dest));
- }
-
- /* Keep operand 1 matching with destination. */
- if (COMMUTATIVE_ARITH_P (pat_src)
- && REG_P (*src1) && REG_P (*src2)
- && REGNO (*src1) != REGNO (*dest))
- {
- int tmp = REGNO (*src1);
- replace_reg (src1, REGNO (*src2));
- replace_reg (src2, tmp);
- }
- break;
-
- case UNSPEC:
- switch (XINT (pat_src, 1))
- {
- case UNSPEC_FIST:
-
- case UNSPEC_FIST_FLOOR:
- case UNSPEC_FIST_CEIL:
-
- /* These insns only operate on the top of the stack. */
-
- src1 = get_true_reg (&XVECEXP (pat_src, 0, 0));
- emit_swap_insn (insn, regstack, *src1);
-
- src1_note = find_regno_note (insn, REG_DEAD, REGNO (*src1));
-
- if (STACK_REG_P (*dest))
- replace_reg (dest, FIRST_STACK_REG);
-
- if (src1_note)
- {
- replace_reg (&XEXP (src1_note, 0), FIRST_STACK_REG);
- regstack->top--;
- CLEAR_HARD_REG_BIT (regstack->reg_set, REGNO (*src1));
- }
-
- replace_reg (src1, FIRST_STACK_REG);
- break;
-
- case UNSPEC_SIN:
- case UNSPEC_COS:
- case UNSPEC_FRNDINT:
- case UNSPEC_F2XM1:
-
- case UNSPEC_FRNDINT_FLOOR:
- case UNSPEC_FRNDINT_CEIL:
- case UNSPEC_FRNDINT_TRUNC:
- case UNSPEC_FRNDINT_MASK_PM:
-
- /* These insns only operate on the top of the stack. */
-
- src1 = get_true_reg (&XVECEXP (pat_src, 0, 0));
-
- emit_swap_insn (insn, regstack, *src1);
-
- /* Input should never die, it is
- replaced with output. */
- src1_note = find_regno_note (insn, REG_DEAD, REGNO (*src1));
- gcc_assert (!src1_note);
-
- if (STACK_REG_P (*dest))
- replace_reg (dest, FIRST_STACK_REG);
-
- replace_reg (src1, FIRST_STACK_REG);
- break;
-
- case UNSPEC_FPATAN:
- case UNSPEC_FYL2X:
- case UNSPEC_FYL2XP1:
- /* These insns operate on the top two stack slots. */
-
- src1 = get_true_reg (&XVECEXP (pat_src, 0, 0));
- src2 = get_true_reg (&XVECEXP (pat_src, 0, 1));
-
- src1_note = find_regno_note (insn, REG_DEAD, REGNO (*src1));
- src2_note = find_regno_note (insn, REG_DEAD, REGNO (*src2));
-
- swap_to_top (insn, regstack, *src1, *src2);
-
- replace_reg (src1, FIRST_STACK_REG);
- replace_reg (src2, FIRST_STACK_REG + 1);
-
- if (src1_note)
- replace_reg (&XEXP (src1_note, 0), FIRST_STACK_REG);
- if (src2_note)
- replace_reg (&XEXP (src2_note, 0), FIRST_STACK_REG + 1);
-
- /* Pop both input operands from the stack. */
- CLEAR_HARD_REG_BIT (regstack->reg_set,
- regstack->reg[regstack->top]);
- CLEAR_HARD_REG_BIT (regstack->reg_set,
- regstack->reg[regstack->top - 1]);
- regstack->top -= 2;
-
- /* Push the result back onto the stack. */
- regstack->reg[++regstack->top] = REGNO (*dest);
- SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
- replace_reg (dest, FIRST_STACK_REG);
- break;
-
- case UNSPEC_FSCALE_FRACT:
- case UNSPEC_FPREM_F:
- case UNSPEC_FPREM1_F:
- /* These insns operate on the top two stack slots.
- first part of double input, double output insn. */
-
- src1 = get_true_reg (&XVECEXP (pat_src, 0, 0));
- src2 = get_true_reg (&XVECEXP (pat_src, 0, 1));
-
- src1_note = find_regno_note (insn, REG_DEAD, REGNO (*src1));
- src2_note = find_regno_note (insn, REG_DEAD, REGNO (*src2));
-
- /* Inputs should never die, they are
- replaced with outputs. */
- gcc_assert (!src1_note);
- gcc_assert (!src2_note);
-
- swap_to_top (insn, regstack, *src1, *src2);
-
- /* Push the result back onto stack. Empty stack slot
- will be filled in second part of insn. */
- if (STACK_REG_P (*dest)) {
- regstack->reg[regstack->top] = REGNO (*dest);
- SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
- replace_reg (dest, FIRST_STACK_REG);
- }
-
- replace_reg (src1, FIRST_STACK_REG);
- replace_reg (src2, FIRST_STACK_REG + 1);
- break;
-
- case UNSPEC_FSCALE_EXP:
- case UNSPEC_FPREM_U:
- case UNSPEC_FPREM1_U:
- /* These insns operate on the top two stack slots./
- second part of double input, double output insn. */
-
- src1 = get_true_reg (&XVECEXP (pat_src, 0, 0));
- src2 = get_true_reg (&XVECEXP (pat_src, 0, 1));
-
- src1_note = find_regno_note (insn, REG_DEAD, REGNO (*src1));
- src2_note = find_regno_note (insn, REG_DEAD, REGNO (*src2));
-
- /* Inputs should never die, they are
- replaced with outputs. */
- gcc_assert (!src1_note);
- gcc_assert (!src2_note);
-
- swap_to_top (insn, regstack, *src1, *src2);
-
- /* Push the result back onto stack. Fill empty slot from
- first part of insn and fix top of stack pointer. */
- if (STACK_REG_P (*dest)) {
- regstack->reg[regstack->top - 1] = REGNO (*dest);
- SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
- replace_reg (dest, FIRST_STACK_REG + 1);
- }
-
- replace_reg (src1, FIRST_STACK_REG);
- replace_reg (src2, FIRST_STACK_REG + 1);
- break;
-
- case UNSPEC_SINCOS_COS:
- case UNSPEC_TAN_ONE:
- case UNSPEC_XTRACT_FRACT:
- /* These insns operate on the top two stack slots,
- first part of one input, double output insn. */
-
- src1 = get_true_reg (&XVECEXP (pat_src, 0, 0));
-
- emit_swap_insn (insn, regstack, *src1);
-
- /* Input should never die, it is
- replaced with output. */
- src1_note = find_regno_note (insn, REG_DEAD, REGNO (*src1));
- gcc_assert (!src1_note);
-
- /* Push the result back onto stack. Empty stack slot
- will be filled in second part of insn. */
- if (STACK_REG_P (*dest)) {
- regstack->reg[regstack->top + 1] = REGNO (*dest);
- SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
- replace_reg (dest, FIRST_STACK_REG);
- }
-
- replace_reg (src1, FIRST_STACK_REG);
- break;
-
- case UNSPEC_SINCOS_SIN:
- case UNSPEC_TAN_TAN:
- case UNSPEC_XTRACT_EXP:
- /* These insns operate on the top two stack slots,
- second part of one input, double output insn. */
-
- src1 = get_true_reg (&XVECEXP (pat_src, 0, 0));
-
- emit_swap_insn (insn, regstack, *src1);
-
- /* Input should never die, it is
- replaced with output. */
- src1_note = find_regno_note (insn, REG_DEAD, REGNO (*src1));
- gcc_assert (!src1_note);
-
- /* Push the result back onto stack. Fill empty slot from
- first part of insn and fix top of stack pointer. */
- if (STACK_REG_P (*dest)) {
- regstack->reg[regstack->top] = REGNO (*dest);
- SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
- replace_reg (dest, FIRST_STACK_REG + 1);
-
- regstack->top++;
- }
-
- replace_reg (src1, FIRST_STACK_REG);
- break;
-
- case UNSPEC_SAHF:
- /* (unspec [(unspec [(compare)] UNSPEC_FNSTSW)] UNSPEC_SAHF)
- The combination matches the PPRO fcomi instruction. */
-
- pat_src = XVECEXP (pat_src, 0, 0);
- gcc_assert (GET_CODE (pat_src) == UNSPEC);
- gcc_assert (XINT (pat_src, 1) == UNSPEC_FNSTSW);
- /* Fall through. */
-
- case UNSPEC_FNSTSW:
- /* Combined fcomp+fnstsw generated for doing well with
- CSE. When optimizing this would have been broken
- up before now. */
-
- pat_src = XVECEXP (pat_src, 0, 0);
- gcc_assert (GET_CODE (pat_src) == COMPARE);
-
- compare_for_stack_reg (insn, regstack, pat_src);
- break;
-
- default:
- gcc_unreachable ();
- }
- break;
-
- case IF_THEN_ELSE:
- /* This insn requires the top of stack to be the destination. */
-
- src1 = get_true_reg (&XEXP (pat_src, 1));
- src2 = get_true_reg (&XEXP (pat_src, 2));
-
- src1_note = find_regno_note (insn, REG_DEAD, REGNO (*src1));
- src2_note = find_regno_note (insn, REG_DEAD, REGNO (*src2));
-
- /* If the comparison operator is an FP comparison operator,
- it is handled correctly by compare_for_stack_reg () who
- will move the destination to the top of stack. But if the
- comparison operator is not an FP comparison operator, we
- have to handle it here. */
- if (get_hard_regnum (regstack, *dest) >= FIRST_STACK_REG
- && REGNO (*dest) != regstack->reg[regstack->top])
- {
- /* In case one of operands is the top of stack and the operands
- dies, it is safe to make it the destination operand by
- reversing the direction of cmove and avoid fxch. */
- if ((REGNO (*src1) == regstack->reg[regstack->top]
- && src1_note)
- || (REGNO (*src2) == regstack->reg[regstack->top]
- && src2_note))
- {
- int idx1 = (get_hard_regnum (regstack, *src1)
- - FIRST_STACK_REG);
- int idx2 = (get_hard_regnum (regstack, *src2)
- - FIRST_STACK_REG);
-
- /* Make reg-stack believe that the operands are already
- swapped on the stack */
- regstack->reg[regstack->top - idx1] = REGNO (*src2);
- regstack->reg[regstack->top - idx2] = REGNO (*src1);
-
- /* Reverse condition to compensate the operand swap.
- i386 do have comparison always reversible. */
- PUT_CODE (XEXP (pat_src, 0),
- reversed_comparison_code (XEXP (pat_src, 0), insn));
- }
- else
- emit_swap_insn (insn, regstack, *dest);
- }
-
- {
- rtx src_note [3];
- int i;
-
- src_note[0] = 0;
- src_note[1] = src1_note;
- src_note[2] = src2_note;
-
- if (STACK_REG_P (*src1))
- replace_reg (src1, get_hard_regnum (regstack, *src1));
- if (STACK_REG_P (*src2))
- replace_reg (src2, get_hard_regnum (regstack, *src2));
-
- for (i = 1; i <= 2; i++)
- if (src_note [i])
- {
- int regno = REGNO (XEXP (src_note[i], 0));
-
- /* If the register that dies is not at the top of
- stack, then move the top of stack to the dead reg.
- Top of stack should never die, as it is the
- destination. */
- gcc_assert (regno != regstack->reg[regstack->top]);
- remove_regno_note (insn, REG_DEAD, regno);
- emit_pop_insn (insn, regstack, XEXP (src_note[i], 0),
- EMIT_AFTER);
- }
- }
-
- /* Make dest the top of stack. Add dest to regstack if
- not present. */
- if (get_hard_regnum (regstack, *dest) < FIRST_STACK_REG)
- regstack->reg[++regstack->top] = REGNO (*dest);
- SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
- replace_reg (dest, FIRST_STACK_REG);
- break;
-
- default:
- gcc_unreachable ();
- }
- break;
- }
-
- default:
- break;
- }
-
- return control_flow_insn_deleted;
-}
-
-/* Substitute hard regnums for any stack regs in INSN, which has
- N_INPUTS inputs and N_OUTPUTS outputs. REGSTACK is the stack info
- before the insn, and is updated with changes made here.
-
- There are several requirements and assumptions about the use of
- stack-like regs in asm statements. These rules are enforced by
- record_asm_stack_regs; see comments there for details. Any
- asm_operands left in the RTL at this point may be assume to meet the
- requirements, since record_asm_stack_regs removes any problem asm. */
-
-static void
-subst_asm_stack_regs (rtx insn, stack regstack)
-{
- rtx body = PATTERN (insn);
- int alt;
-
- rtx *note_reg; /* Array of note contents */
- rtx **note_loc; /* Address of REG field of each note */
- enum reg_note *note_kind; /* The type of each note */
-
- rtx *clobber_reg = 0;
- rtx **clobber_loc = 0;
-
- struct stack_def temp_stack;
- int n_notes;
- int n_clobbers;
- rtx note;
- int i;
- int n_inputs, n_outputs;
-
- if (! check_asm_stack_operands (insn))
- return;
-
- /* Find out what the constraints required. If no constraint
- alternative matches, that is a compiler bug: we should have caught
- such an insn in check_asm_stack_operands. */
- extract_insn (insn);
- constrain_operands (1);
- alt = which_alternative;
-
- preprocess_constraints ();
-
- n_inputs = get_asm_operand_n_inputs (body);
- n_outputs = recog_data.n_operands - n_inputs;
-
- gcc_assert (alt >= 0);
-
- /* Strip SUBREGs here to make the following code simpler. */
- for (i = 0; i < recog_data.n_operands; i++)
- if (GET_CODE (recog_data.operand[i]) == SUBREG
- && REG_P (SUBREG_REG (recog_data.operand[i])))
- {
- recog_data.operand_loc[i] = & SUBREG_REG (recog_data.operand[i]);
- recog_data.operand[i] = SUBREG_REG (recog_data.operand[i]);
- }
-
- /* Set up NOTE_REG, NOTE_LOC and NOTE_KIND. */
-
- for (i = 0, note = REG_NOTES (insn); note; note = XEXP (note, 1))
- i++;
-
- note_reg = alloca (i * sizeof (rtx));
- note_loc = alloca (i * sizeof (rtx *));
- note_kind = alloca (i * sizeof (enum reg_note));
-
- n_notes = 0;
- for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
- {
- rtx reg = XEXP (note, 0);
- rtx *loc = & XEXP (note, 0);
-
- if (GET_CODE (reg) == SUBREG && REG_P (SUBREG_REG (reg)))
- {
- loc = & SUBREG_REG (reg);
- reg = SUBREG_REG (reg);
- }
-
- if (STACK_REG_P (reg)
- && (REG_NOTE_KIND (note) == REG_DEAD
- || REG_NOTE_KIND (note) == REG_UNUSED))
- {
- note_reg[n_notes] = reg;
- note_loc[n_notes] = loc;
- note_kind[n_notes] = REG_NOTE_KIND (note);
- n_notes++;
- }
- }
-
- /* Set up CLOBBER_REG and CLOBBER_LOC. */
-
- n_clobbers = 0;
-
- if (GET_CODE (body) == PARALLEL)
- {
- clobber_reg = alloca (XVECLEN (body, 0) * sizeof (rtx));
- clobber_loc = alloca (XVECLEN (body, 0) * sizeof (rtx *));
-
- for (i = 0; i < XVECLEN (body, 0); i++)
- if (GET_CODE (XVECEXP (body, 0, i)) == CLOBBER)
- {
- rtx clobber = XVECEXP (body, 0, i);
- rtx reg = XEXP (clobber, 0);
- rtx *loc = & XEXP (clobber, 0);
-
- if (GET_CODE (reg) == SUBREG && REG_P (SUBREG_REG (reg)))
- {
- loc = & SUBREG_REG (reg);
- reg = SUBREG_REG (reg);
- }
-
- if (STACK_REG_P (reg))
- {
- clobber_reg[n_clobbers] = reg;
- clobber_loc[n_clobbers] = loc;
- n_clobbers++;
- }
- }
- }
-
- temp_stack = *regstack;
-
- /* Put the input regs into the desired place in TEMP_STACK. */
-
- for (i = n_outputs; i < n_outputs + n_inputs; i++)
- if (STACK_REG_P (recog_data.operand[i])
- && reg_class_subset_p (recog_op_alt[i][alt].cl,
- FLOAT_REGS)
- && recog_op_alt[i][alt].cl != FLOAT_REGS)
- {
- /* If an operand needs to be in a particular reg in
- FLOAT_REGS, the constraint was either 't' or 'u'. Since
- these constraints are for single register classes, and
- reload guaranteed that operand[i] is already in that class,
- we can just use REGNO (recog_data.operand[i]) to know which
- actual reg this operand needs to be in. */
-
- int regno = get_hard_regnum (&temp_stack, recog_data.operand[i]);
-
- gcc_assert (regno >= 0);
-
- if ((unsigned int) regno != REGNO (recog_data.operand[i]))
- {
- /* recog_data.operand[i] is not in the right place. Find
- it and swap it with whatever is already in I's place.
- K is where recog_data.operand[i] is now. J is where it
- should be. */
- int j, k, temp;
-
- k = temp_stack.top - (regno - FIRST_STACK_REG);
- j = (temp_stack.top
- - (REGNO (recog_data.operand[i]) - FIRST_STACK_REG));
-
- temp = temp_stack.reg[k];
- temp_stack.reg[k] = temp_stack.reg[j];
- temp_stack.reg[j] = temp;
- }
- }
-
- /* Emit insns before INSN to make sure the reg-stack is in the right
- order. */
-
- change_stack (insn, regstack, &temp_stack, EMIT_BEFORE);
-
- /* Make the needed input register substitutions. Do death notes and
- clobbers too, because these are for inputs, not outputs. */
-
- for (i = n_outputs; i < n_outputs + n_inputs; i++)
- if (STACK_REG_P (recog_data.operand[i]))
- {
- int regnum = get_hard_regnum (regstack, recog_data.operand[i]);
-
- gcc_assert (regnum >= 0);
-
- replace_reg (recog_data.operand_loc[i], regnum);
- }
-
- for (i = 0; i < n_notes; i++)
- if (note_kind[i] == REG_DEAD)
- {
- int regnum = get_hard_regnum (regstack, note_reg[i]);
-
- gcc_assert (regnum >= 0);
-
- replace_reg (note_loc[i], regnum);
- }
-
- for (i = 0; i < n_clobbers; i++)
- {
- /* It's OK for a CLOBBER to reference a reg that is not live.
- Don't try to replace it in that case. */
- int regnum = get_hard_regnum (regstack, clobber_reg[i]);
-
- if (regnum >= 0)
- {
- /* Sigh - clobbers always have QImode. But replace_reg knows
- that these regs can't be MODE_INT and will assert. Just put
- the right reg there without calling replace_reg. */
-
- *clobber_loc[i] = FP_MODE_REG (regnum, DFmode);
- }
- }
-
- /* Now remove from REGSTACK any inputs that the asm implicitly popped. */
-
- for (i = n_outputs; i < n_outputs + n_inputs; i++)
- if (STACK_REG_P (recog_data.operand[i]))
- {
- /* An input reg is implicitly popped if it is tied to an
- output, or if there is a CLOBBER for it. */
- int j;
-
- for (j = 0; j < n_clobbers; j++)
- if (operands_match_p (clobber_reg[j], recog_data.operand[i]))
- break;
-
- if (j < n_clobbers || recog_op_alt[i][alt].matches >= 0)
- {
- /* recog_data.operand[i] might not be at the top of stack.
- But that's OK, because all we need to do is pop the
- right number of regs off of the top of the reg-stack.
- record_asm_stack_regs guaranteed that all implicitly
- popped regs were grouped at the top of the reg-stack. */
-
- CLEAR_HARD_REG_BIT (regstack->reg_set,
- regstack->reg[regstack->top]);
- regstack->top--;
- }
- }
-
- /* Now add to REGSTACK any outputs that the asm implicitly pushed.
- Note that there isn't any need to substitute register numbers.
- ??? Explain why this is true. */
-
- for (i = LAST_STACK_REG; i >= FIRST_STACK_REG; i--)
- {
- /* See if there is an output for this hard reg. */
- int j;
-
- for (j = 0; j < n_outputs; j++)
- if (STACK_REG_P (recog_data.operand[j])
- && REGNO (recog_data.operand[j]) == (unsigned) i)
- {
- regstack->reg[++regstack->top] = i;
- SET_HARD_REG_BIT (regstack->reg_set, i);
- break;
- }
- }
-
- /* Now emit a pop insn for any REG_UNUSED output, or any REG_DEAD
- input that the asm didn't implicitly pop. If the asm didn't
- implicitly pop an input reg, that reg will still be live.
-
- Note that we can't use find_regno_note here: the register numbers
- in the death notes have already been substituted. */
-
- for (i = 0; i < n_outputs; i++)
- if (STACK_REG_P (recog_data.operand[i]))
- {
- int j;
-
- for (j = 0; j < n_notes; j++)
- if (REGNO (recog_data.operand[i]) == REGNO (note_reg[j])
- && note_kind[j] == REG_UNUSED)
- {
- insn = emit_pop_insn (insn, regstack, recog_data.operand[i],
- EMIT_AFTER);
- break;
- }
- }
-
- for (i = n_outputs; i < n_outputs + n_inputs; i++)
- if (STACK_REG_P (recog_data.operand[i]))
- {
- int j;
-
- for (j = 0; j < n_notes; j++)
- if (REGNO (recog_data.operand[i]) == REGNO (note_reg[j])
- && note_kind[j] == REG_DEAD
- && TEST_HARD_REG_BIT (regstack->reg_set,
- REGNO (recog_data.operand[i])))
- {
- insn = emit_pop_insn (insn, regstack, recog_data.operand[i],
- EMIT_AFTER);
- break;
- }
- }
-}
-
-/* Substitute stack hard reg numbers for stack virtual registers in
- INSN. Non-stack register numbers are not changed. REGSTACK is the
- current stack content. Insns may be emitted as needed to arrange the
- stack for the 387 based on the contents of the insn. Return whether
- a control flow insn was deleted in the process. */
-
-static bool
-subst_stack_regs (rtx insn, stack regstack)
-{
- rtx *note_link, note;
- bool control_flow_insn_deleted = false;
- int i;
-
- if (CALL_P (insn))
- {
- int top = regstack->top;
-
- /* If there are any floating point parameters to be passed in
- registers for this call, make sure they are in the right
- order. */
-
- if (top >= 0)
- {
- straighten_stack (insn, regstack);
-
- /* Now mark the arguments as dead after the call. */
-
- while (regstack->top >= 0)
- {
- CLEAR_HARD_REG_BIT (regstack->reg_set, FIRST_STACK_REG + regstack->top);
- regstack->top--;
- }
- }
- }
-
- /* Do the actual substitution if any stack regs are mentioned.
- Since we only record whether entire insn mentions stack regs, and
- subst_stack_regs_pat only works for patterns that contain stack regs,
- we must check each pattern in a parallel here. A call_value_pop could
- fail otherwise. */
-
- if (stack_regs_mentioned (insn))
- {
- int n_operands = asm_noperands (PATTERN (insn));
- if (n_operands >= 0)
- {
- /* This insn is an `asm' with operands. Decode the operands,
- decide how many are inputs, and do register substitution.
- Any REG_UNUSED notes will be handled by subst_asm_stack_regs. */
-
- subst_asm_stack_regs (insn, regstack);
- return control_flow_insn_deleted;
- }
-
- if (GET_CODE (PATTERN (insn)) == PARALLEL)
- for (i = 0; i < XVECLEN (PATTERN (insn), 0); i++)
- {
- if (stack_regs_mentioned_p (XVECEXP (PATTERN (insn), 0, i)))
- {
- if (GET_CODE (XVECEXP (PATTERN (insn), 0, i)) == CLOBBER)
- XVECEXP (PATTERN (insn), 0, i)
- = shallow_copy_rtx (XVECEXP (PATTERN (insn), 0, i));
- control_flow_insn_deleted
- |= subst_stack_regs_pat (insn, regstack,
- XVECEXP (PATTERN (insn), 0, i));
- }
- }
- else
- control_flow_insn_deleted
- |= subst_stack_regs_pat (insn, regstack, PATTERN (insn));
- }
-
- /* subst_stack_regs_pat may have deleted a no-op insn. If so, any
- REG_UNUSED will already have been dealt with, so just return. */
-
- if (NOTE_P (insn) || INSN_DELETED_P (insn))
- return control_flow_insn_deleted;
-
- /* If this a noreturn call, we can't insert pop insns after it.
- Instead, reset the stack state to empty. */
- if (CALL_P (insn)
- && find_reg_note (insn, REG_NORETURN, NULL))
- {
- regstack->top = -1;
- CLEAR_HARD_REG_SET (regstack->reg_set);
- return control_flow_insn_deleted;
- }
-
- /* If there is a REG_UNUSED note on a stack register on this insn,
- the indicated reg must be popped. The REG_UNUSED note is removed,
- since the form of the newly emitted pop insn references the reg,
- making it no longer `unset'. */
-
- note_link = &REG_NOTES (insn);
- for (note = *note_link; note; note = XEXP (note, 1))
- if (REG_NOTE_KIND (note) == REG_UNUSED && STACK_REG_P (XEXP (note, 0)))
- {
- *note_link = XEXP (note, 1);
- insn = emit_pop_insn (insn, regstack, XEXP (note, 0), EMIT_AFTER);
- }
- else
- note_link = &XEXP (note, 1);
-
- return control_flow_insn_deleted;
-}
-
-/* Change the organization of the stack so that it fits a new basic
- block. Some registers might have to be popped, but there can never be
- a register live in the new block that is not now live.
-
- Insert any needed insns before or after INSN, as indicated by
- WHERE. OLD is the original stack layout, and NEW is the desired
- form. OLD is updated to reflect the code emitted, i.e., it will be
- the same as NEW upon return.
-
- This function will not preserve block_end[]. But that information
- is no longer needed once this has executed. */
-
-static void
-change_stack (rtx insn, stack old, stack new, enum emit_where where)
-{
- int reg;
- int update_end = 0;
-
- /* Stack adjustments for the first insn in a block update the
- current_block's stack_in instead of inserting insns directly.
- compensate_edges will add the necessary code later. */
- if (current_block
- && starting_stack_p
- && where == EMIT_BEFORE)
- {
- BLOCK_INFO (current_block)->stack_in = *new;
- starting_stack_p = false;
- *old = *new;
- return;
- }
-
- /* We will be inserting new insns "backwards". If we are to insert
- after INSN, find the next insn, and insert before it. */
-
- if (where == EMIT_AFTER)
- {
- if (current_block && BB_END (current_block) == insn)
- update_end = 1;
- insn = NEXT_INSN (insn);
- }
-
- /* Pop any registers that are not needed in the new block. */
-
- /* If the destination block's stack already has a specified layout
- and contains two or more registers, use a more intelligent algorithm
- to pop registers that minimizes the number number of fxchs below. */
- if (new->top > 0)
- {
- bool slots[REG_STACK_SIZE];
- int pops[REG_STACK_SIZE];
- int next, dest, topsrc;
-
- /* First pass to determine the free slots. */
- for (reg = 0; reg <= new->top; reg++)
- slots[reg] = TEST_HARD_REG_BIT (new->reg_set, old->reg[reg]);
-
- /* Second pass to allocate preferred slots. */
- topsrc = -1;
- for (reg = old->top; reg > new->top; reg--)
- if (TEST_HARD_REG_BIT (new->reg_set, old->reg[reg]))
- {
- dest = -1;
- for (next = 0; next <= new->top; next++)
- if (!slots[next] && new->reg[next] == old->reg[reg])
- {
- /* If this is a preference for the new top of stack, record
- the fact by remembering it's old->reg in topsrc. */
- if (next == new->top)
- topsrc = reg;
- slots[next] = true;
- dest = next;
- break;
- }
- pops[reg] = dest;
- }
- else
- pops[reg] = reg;
-
- /* Intentionally, avoid placing the top of stack in it's correct
- location, if we still need to permute the stack below and we
- can usefully place it somewhere else. This is the case if any
- slot is still unallocated, in which case we should place the
- top of stack there. */
- if (topsrc != -1)
- for (reg = 0; reg < new->top; reg++)
- if (!slots[reg])
- {
- pops[topsrc] = reg;
- slots[new->top] = false;
- slots[reg] = true;
- break;
- }
-
- /* Third pass allocates remaining slots and emits pop insns. */
- next = new->top;
- for (reg = old->top; reg > new->top; reg--)
- {
- dest = pops[reg];
- if (dest == -1)
- {
- /* Find next free slot. */
- while (slots[next])
- next--;
- dest = next--;
- }
- emit_pop_insn (insn, old, FP_MODE_REG (old->reg[dest], DFmode),
- EMIT_BEFORE);
- }
- }
- else
- {
- /* The following loop attempts to maximize the number of times we
- pop the top of the stack, as this permits the use of the faster
- ffreep instruction on platforms that support it. */
- int live, next;
-
- live = 0;
- for (reg = 0; reg <= old->top; reg++)
- if (TEST_HARD_REG_BIT (new->reg_set, old->reg[reg]))
- live++;
-
- next = live;
- while (old->top >= live)
- if (TEST_HARD_REG_BIT (new->reg_set, old->reg[old->top]))
- {
- while (TEST_HARD_REG_BIT (new->reg_set, old->reg[next]))
- next--;
- emit_pop_insn (insn, old, FP_MODE_REG (old->reg[next], DFmode),
- EMIT_BEFORE);
- }
- else
- emit_pop_insn (insn, old, FP_MODE_REG (old->reg[old->top], DFmode),
- EMIT_BEFORE);
- }
-
- if (new->top == -2)
- {
- /* If the new block has never been processed, then it can inherit
- the old stack order. */
-
- new->top = old->top;
- memcpy (new->reg, old->reg, sizeof (new->reg));
- }
- else
- {
- /* This block has been entered before, and we must match the
- previously selected stack order. */
-
- /* By now, the only difference should be the order of the stack,
- not their depth or liveliness. */
-
- GO_IF_HARD_REG_EQUAL (old->reg_set, new->reg_set, win);
- gcc_unreachable ();
- win:
- gcc_assert (old->top == new->top);
-
- /* If the stack is not empty (new->top != -1), loop here emitting
- swaps until the stack is correct.
-
- The worst case number of swaps emitted is N + 2, where N is the
- depth of the stack. In some cases, the reg at the top of
- stack may be correct, but swapped anyway in order to fix
- other regs. But since we never swap any other reg away from
- its correct slot, this algorithm will converge. */
-
- if (new->top != -1)
- do
- {
- /* Swap the reg at top of stack into the position it is
- supposed to be in, until the correct top of stack appears. */
-
- while (old->reg[old->top] != new->reg[new->top])
- {
- for (reg = new->top; reg >= 0; reg--)
- if (new->reg[reg] == old->reg[old->top])
- break;
-
- gcc_assert (reg != -1);
-
- emit_swap_insn (insn, old,
- FP_MODE_REG (old->reg[reg], DFmode));
- }
-
- /* See if any regs remain incorrect. If so, bring an
- incorrect reg to the top of stack, and let the while loop
- above fix it. */
-
- for (reg = new->top; reg >= 0; reg--)
- if (new->reg[reg] != old->reg[reg])
- {
- emit_swap_insn (insn, old,
- FP_MODE_REG (old->reg[reg], DFmode));
- break;
- }
- } while (reg >= 0);
-
- /* At this point there must be no differences. */
-
- for (reg = old->top; reg >= 0; reg--)
- gcc_assert (old->reg[reg] == new->reg[reg]);
- }
-
- if (update_end)
- BB_END (current_block) = PREV_INSN (insn);
-}
-
-/* Print stack configuration. */
-
-static void
-print_stack (FILE *file, stack s)
-{
- if (! file)
- return;
-
- if (s->top == -2)
- fprintf (file, "uninitialized\n");
- else if (s->top == -1)
- fprintf (file, "empty\n");
- else
- {
- int i;
- fputs ("[ ", file);
- for (i = 0; i <= s->top; ++i)
- fprintf (file, "%d ", s->reg[i]);
- fputs ("]\n", file);
- }
-}
-
-/* This function was doing life analysis. We now let the regular live
- code do it's job, so we only need to check some extra invariants
- that reg-stack expects. Primary among these being that all registers
- are initialized before use.
-
- The function returns true when code was emitted to CFG edges and
- commit_edge_insertions needs to be called. */
-
-static int
-convert_regs_entry (void)
-{
- int inserted = 0;
- edge e;
- edge_iterator ei;
-
- /* Load something into each stack register live at function entry.
- Such live registers can be caused by uninitialized variables or
- functions not returning values on all paths. In order to keep
- the push/pop code happy, and to not scrog the register stack, we
- must put something in these registers. Use a QNaN.
-
- Note that we are inserting converted code here. This code is
- never seen by the convert_regs pass. */
-
- FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
- {
- basic_block block = e->dest;
- block_info bi = BLOCK_INFO (block);
- int reg, top = -1;
-
- for (reg = LAST_STACK_REG; reg >= FIRST_STACK_REG; --reg)
- if (TEST_HARD_REG_BIT (bi->stack_in.reg_set, reg))
- {
- rtx init;
-
- bi->stack_in.reg[++top] = reg;
-
- init = gen_rtx_SET (VOIDmode,
- FP_MODE_REG (FIRST_STACK_REG, SFmode),
- not_a_num);
- insert_insn_on_edge (init, e);
- inserted = 1;
- }
-
- bi->stack_in.top = top;
- }
-
- return inserted;
-}
-
-/* Construct the desired stack for function exit. This will either
- be `empty', or the function return value at top-of-stack. */
-
-static void
-convert_regs_exit (void)
-{
- int value_reg_low, value_reg_high;
- stack output_stack;
- rtx retvalue;
-
- retvalue = stack_result (current_function_decl);
- value_reg_low = value_reg_high = -1;
- if (retvalue)
- {
- value_reg_low = REGNO (retvalue);
- value_reg_high = value_reg_low
- + hard_regno_nregs[value_reg_low][GET_MODE (retvalue)] - 1;
- }
-
- output_stack = &BLOCK_INFO (EXIT_BLOCK_PTR)->stack_in;
- if (value_reg_low == -1)
- output_stack->top = -1;
- else
- {
- int reg;
-
- output_stack->top = value_reg_high - value_reg_low;
- for (reg = value_reg_low; reg <= value_reg_high; ++reg)
- {
- output_stack->reg[value_reg_high - reg] = reg;
- SET_HARD_REG_BIT (output_stack->reg_set, reg);
- }
- }
-}
-
-/* Copy the stack info from the end of edge E's source block to the
- start of E's destination block. */
-
-static void
-propagate_stack (edge e)
-{
- stack src_stack = &BLOCK_INFO (e->src)->stack_out;
- stack dest_stack = &BLOCK_INFO (e->dest)->stack_in;
- int reg;
-
- /* Preserve the order of the original stack, but check whether
- any pops are needed. */
- dest_stack->top = -1;
- for (reg = 0; reg <= src_stack->top; ++reg)
- if (TEST_HARD_REG_BIT (dest_stack->reg_set, src_stack->reg[reg]))
- dest_stack->reg[++dest_stack->top] = src_stack->reg[reg];
-}
-
-
-/* Adjust the stack of edge E's source block on exit to match the stack
- of it's target block upon input. The stack layouts of both blocks
- should have been defined by now. */
-
-static bool
-compensate_edge (edge e)
-{
- basic_block source = e->src, target = e->dest;
- stack target_stack = &BLOCK_INFO (target)->stack_in;
- stack source_stack = &BLOCK_INFO (source)->stack_out;
- struct stack_def regstack;
- int reg;
-
- if (dump_file)
- fprintf (dump_file, "Edge %d->%d: ", source->index, target->index);
-
- gcc_assert (target_stack->top != -2);
-
- /* Check whether stacks are identical. */
- if (target_stack->top == source_stack->top)
- {
- for (reg = target_stack->top; reg >= 0; --reg)
- if (target_stack->reg[reg] != source_stack->reg[reg])
- break;
-
- if (reg == -1)
- {
- if (dump_file)
- fprintf (dump_file, "no changes needed\n");
- return false;
- }
- }
-
- if (dump_file)
- {
- fprintf (dump_file, "correcting stack to ");
- print_stack (dump_file, target_stack);
- }
-
- /* Abnormal calls may appear to have values live in st(0), but the
- abnormal return path will not have actually loaded the values. */
- if (e->flags & EDGE_ABNORMAL_CALL)
- {
- /* Assert that the lifetimes are as we expect -- one value
- live at st(0) on the end of the source block, and no
- values live at the beginning of the destination block.
- For complex return values, we may have st(1) live as well. */
- gcc_assert (source_stack->top == 0 || source_stack->top == 1);
- gcc_assert (target_stack->top == -1);
- return false;
- }
-
- /* Handle non-call EH edges specially. The normal return path have
- values in registers. These will be popped en masse by the unwind
- library. */
- if (e->flags & EDGE_EH)
- {
- gcc_assert (target_stack->top == -1);
- return false;
- }
-
- /* We don't support abnormal edges. Global takes care to
- avoid any live register across them, so we should never
- have to insert instructions on such edges. */
- gcc_assert (! (e->flags & EDGE_ABNORMAL));
-
- /* Make a copy of source_stack as change_stack is destructive. */
- regstack = *source_stack;
-
- /* It is better to output directly to the end of the block
- instead of to the edge, because emit_swap can do minimal
- insn scheduling. We can do this when there is only one
- edge out, and it is not abnormal. */
- if (EDGE_COUNT (source->succs) == 1)
- {
- current_block = source;
- change_stack (BB_END (source), &regstack, target_stack,
- (JUMP_P (BB_END (source)) ? EMIT_BEFORE : EMIT_AFTER));
- }
- else
- {
- rtx seq, after;
-
- current_block = NULL;
- start_sequence ();
-
- /* ??? change_stack needs some point to emit insns after. */
- after = emit_note (NOTE_INSN_DELETED);
-
- change_stack (after, &regstack, target_stack, EMIT_BEFORE);
-
- seq = get_insns ();
- end_sequence ();
-
- insert_insn_on_edge (seq, e);
- return true;
- }
- return false;
-}
-
-/* Traverse all non-entry edges in the CFG, and emit the necessary
- edge compensation code to change the stack from stack_out of the
- source block to the stack_in of the destination block. */
-
-static bool
-compensate_edges (void)
-{
- bool inserted = false;
- basic_block bb;
-
- starting_stack_p = false;
-
- FOR_EACH_BB (bb)
- if (bb != ENTRY_BLOCK_PTR)
- {
- edge e;
- edge_iterator ei;
-
- FOR_EACH_EDGE (e, ei, bb->succs)
- inserted |= compensate_edge (e);
- }
- return inserted;
-}
-
-/* Select the better of two edges E1 and E2 to use to determine the
- stack layout for their shared destination basic block. This is
- typically the more frequently executed. The edge E1 may be NULL
- (in which case E2 is returned), but E2 is always non-NULL. */
-
-static edge
-better_edge (edge e1, edge e2)
-{
- if (!e1)
- return e2;
-
- if (EDGE_FREQUENCY (e1) > EDGE_FREQUENCY (e2))
- return e1;
- if (EDGE_FREQUENCY (e1) < EDGE_FREQUENCY (e2))
- return e2;
-
- if (e1->count > e2->count)
- return e1;
- if (e1->count < e2->count)
- return e2;
-
- /* Prefer critical edges to minimize inserting compensation code on
- critical edges. */
-
- if (EDGE_CRITICAL_P (e1) != EDGE_CRITICAL_P (e2))
- return EDGE_CRITICAL_P (e1) ? e1 : e2;
-
- /* Avoid non-deterministic behavior. */
- return (e1->src->index < e2->src->index) ? e1 : e2;
-}
-
-/* Convert stack register references in one block. */
-
-static void
-convert_regs_1 (basic_block block)
-{
- struct stack_def regstack;
- block_info bi = BLOCK_INFO (block);
- int reg;
- rtx insn, next;
- bool control_flow_insn_deleted = false;
-
- any_malformed_asm = false;
-
- /* Choose an initial stack layout, if one hasn't already been chosen. */
- if (bi->stack_in.top == -2)
- {
- edge e, beste = NULL;
- edge_iterator ei;
-
- /* Select the best incoming edge (typically the most frequent) to
- use as a template for this basic block. */
- FOR_EACH_EDGE (e, ei, block->preds)
- if (BLOCK_INFO (e->src)->done)
- beste = better_edge (beste, e);
-
- if (beste)
- propagate_stack (beste);
- else
- {
- /* No predecessors. Create an arbitrary input stack. */
- bi->stack_in.top = -1;
- for (reg = LAST_STACK_REG; reg >= FIRST_STACK_REG; --reg)
- if (TEST_HARD_REG_BIT (bi->stack_in.reg_set, reg))
- bi->stack_in.reg[++bi->stack_in.top] = reg;
- }
- }
-
- if (dump_file)
- {
- fprintf (dump_file, "\nBasic block %d\nInput stack: ", block->index);
- print_stack (dump_file, &bi->stack_in);
- }
-
- /* Process all insns in this block. Keep track of NEXT so that we
- don't process insns emitted while substituting in INSN. */
- current_block = block;
- next = BB_HEAD (block);
- regstack = bi->stack_in;
- starting_stack_p = true;
-
- do
- {
- insn = next;
- next = NEXT_INSN (insn);
-
- /* Ensure we have not missed a block boundary. */
- gcc_assert (next);
- if (insn == BB_END (block))
- next = NULL;
-
- /* Don't bother processing unless there is a stack reg
- mentioned or if it's a CALL_INSN. */
- if (stack_regs_mentioned (insn)
- || CALL_P (insn))
- {
- if (dump_file)
- {
- fprintf (dump_file, " insn %d input stack: ",
- INSN_UID (insn));
- print_stack (dump_file, &regstack);
- }
- control_flow_insn_deleted |= subst_stack_regs (insn, &regstack);
- starting_stack_p = false;
- }
- }
- while (next);
-
- if (dump_file)
- {
- fprintf (dump_file, "Expected live registers [");
- for (reg = FIRST_STACK_REG; reg <= LAST_STACK_REG; ++reg)
- if (TEST_HARD_REG_BIT (bi->out_reg_set, reg))
- fprintf (dump_file, " %d", reg);
- fprintf (dump_file, " ]\nOutput stack: ");
- print_stack (dump_file, &regstack);
- }
-
- insn = BB_END (block);
- if (JUMP_P (insn))
- insn = PREV_INSN (insn);
-
- /* If the function is declared to return a value, but it returns one
- in only some cases, some registers might come live here. Emit
- necessary moves for them. */
-
- for (reg = FIRST_STACK_REG; reg <= LAST_STACK_REG; ++reg)
- {
- if (TEST_HARD_REG_BIT (bi->out_reg_set, reg)
- && ! TEST_HARD_REG_BIT (regstack.reg_set, reg))
- {
- rtx set;
-
- if (dump_file)
- fprintf (dump_file, "Emitting insn initializing reg %d\n", reg);
-
- set = gen_rtx_SET (VOIDmode, FP_MODE_REG (reg, SFmode), not_a_num);
- insn = emit_insn_after (set, insn);
- control_flow_insn_deleted |= subst_stack_regs (insn, &regstack);
- }
- }
-
- /* Amongst the insns possibly deleted during the substitution process above,
- might have been the only trapping insn in the block. We purge the now
- possibly dead EH edges here to avoid an ICE from fixup_abnormal_edges,
- called at the end of convert_regs. The order in which we process the
- blocks ensures that we never delete an already processed edge.
-
- Note that, at this point, the CFG may have been damaged by the emission
- of instructions after an abnormal call, which moves the basic block end
- (and is the reason why we call fixup_abnormal_edges later). So we must
- be sure that the trapping insn has been deleted before trying to purge
- dead edges, otherwise we risk purging valid edges.
-
- ??? We are normally supposed not to delete trapping insns, so we pretend
- that the insns deleted above don't actually trap. It would have been
- better to detect this earlier and avoid creating the EH edge in the first
- place, still, but we don't have enough information at that time. */
-
- if (control_flow_insn_deleted)
- purge_dead_edges (block);
-
- /* Something failed if the stack lives don't match. If we had malformed
- asms, we zapped the instruction itself, but that didn't produce the
- same pattern of register kills as before. */
- GO_IF_HARD_REG_EQUAL (regstack.reg_set, bi->out_reg_set, win);
- gcc_assert (any_malformed_asm);
- win:
- bi->stack_out = regstack;
- bi->done = true;
-}
-
-/* Convert registers in all blocks reachable from BLOCK. */
-
-static void
-convert_regs_2 (basic_block block)
-{
- basic_block *stack, *sp;
-
- /* We process the blocks in a top-down manner, in a way such that one block
- is only processed after all its predecessors. The number of predecessors
- of every block has already been computed. */
-
- stack = XNEWVEC (basic_block, n_basic_blocks);
- sp = stack;
-
- *sp++ = block;
-
- do
- {
- edge e;
- edge_iterator ei;
-
- block = *--sp;
-
- /* Processing BLOCK is achieved by convert_regs_1, which may purge
- some dead EH outgoing edge after the deletion of the trapping
- insn inside the block. Since the number of predecessors of
- BLOCK's successors was computed based on the initial edge set,
- we check the necessity to process some of these successors
- before such an edge deletion may happen. However, there is
- a pitfall: if BLOCK is the only predecessor of a successor and
- the edge between them happens to be deleted, the successor
- becomes unreachable and should not be processed. The problem
- is that there is no way to preventively detect this case so we
- stack the successor in all cases and hand over the task of
- fixing up the discrepancy to convert_regs_1. */
-
- FOR_EACH_EDGE (e, ei, block->succs)
- if (! (e->flags & EDGE_DFS_BACK))
- {
- BLOCK_INFO (e->dest)->predecessors--;
- if (!BLOCK_INFO (e->dest)->predecessors)
- *sp++ = e->dest;
- }
-
- convert_regs_1 (block);
- }
- while (sp != stack);
-
- free (stack);
-}
-
-/* Traverse all basic blocks in a function, converting the register
- references in each insn from the "flat" register file that gcc uses,
- to the stack-like registers the 387 uses. */
-
-static void
-convert_regs (void)
-{
- int inserted;
- basic_block b;
- edge e;
- edge_iterator ei;
-
- /* Initialize uninitialized registers on function entry. */
- inserted = convert_regs_entry ();
-
- /* Construct the desired stack for function exit. */
- convert_regs_exit ();
- BLOCK_INFO (EXIT_BLOCK_PTR)->done = 1;
-
- /* ??? Future: process inner loops first, and give them arbitrary
- initial stacks which emit_swap_insn can modify. This ought to
- prevent double fxch that often appears at the head of a loop. */
-
- /* Process all blocks reachable from all entry points. */
- FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
- convert_regs_2 (e->dest);
-
- /* ??? Process all unreachable blocks. Though there's no excuse
- for keeping these even when not optimizing. */
- FOR_EACH_BB (b)
- {
- block_info bi = BLOCK_INFO (b);
-
- if (! bi->done)
- convert_regs_2 (b);
- }
-
- inserted |= compensate_edges ();
-
- clear_aux_for_blocks ();
-
- fixup_abnormal_edges ();
- if (inserted)
- commit_edge_insertions ();
-
- if (dump_file)
- fputc ('\n', dump_file);
-}
-
-/* Convert register usage from "flat" register file usage to a "stack
- register file. FILE is the dump file, if used.
-
- Construct a CFG and run life analysis. Then convert each insn one
- by one. Run a last cleanup_cfg pass, if optimizing, to eliminate
- code duplication created when the converter inserts pop insns on
- the edges. */
-
-static bool
-reg_to_stack (void)
-{
- basic_block bb;
- int i;
- int max_uid;
-
- /* Clean up previous run. */
- if (stack_regs_mentioned_data != NULL)
- VEC_free (char, heap, stack_regs_mentioned_data);
-
- /* See if there is something to do. Flow analysis is quite
- expensive so we might save some compilation time. */
- for (i = FIRST_STACK_REG; i <= LAST_STACK_REG; i++)
- if (regs_ever_live[i])
- break;
- if (i > LAST_STACK_REG)
- return false;
-
- /* Ok, floating point instructions exist. If not optimizing,
- build the CFG and run life analysis.
- Also need to rebuild life when superblock scheduling is done
- as it don't update liveness yet. */
- if (!optimize
- || ((flag_sched2_use_superblocks || flag_sched2_use_traces)
- && flag_schedule_insns_after_reload))
- {
- count_or_remove_death_notes (NULL, 1);
- life_analysis (PROP_DEATH_NOTES);
- }
- mark_dfs_back_edges ();
-
- /* Set up block info for each basic block. */
- alloc_aux_for_blocks (sizeof (struct block_info_def));
- FOR_EACH_BB (bb)
- {
- block_info bi = BLOCK_INFO (bb);
- edge_iterator ei;
- edge e;
- int reg;
-
- FOR_EACH_EDGE (e, ei, bb->preds)
- if (!(e->flags & EDGE_DFS_BACK)
- && e->src != ENTRY_BLOCK_PTR)
- bi->predecessors++;
-
- /* Set current register status at last instruction `uninitialized'. */
- bi->stack_in.top = -2;
-
- /* Copy live_at_end and live_at_start into temporaries. */
- for (reg = FIRST_STACK_REG; reg <= LAST_STACK_REG; reg++)
- {
- if (REGNO_REG_SET_P (bb->il.rtl->global_live_at_end, reg))
- SET_HARD_REG_BIT (bi->out_reg_set, reg);
- if (REGNO_REG_SET_P (bb->il.rtl->global_live_at_start, reg))
- SET_HARD_REG_BIT (bi->stack_in.reg_set, reg);
- }
- }
-
- /* Create the replacement registers up front. */
- for (i = FIRST_STACK_REG; i <= LAST_STACK_REG; i++)
- {
- enum machine_mode mode;
- for (mode = GET_CLASS_NARROWEST_MODE (MODE_FLOAT);
- mode != VOIDmode;
- mode = GET_MODE_WIDER_MODE (mode))
- FP_MODE_REG (i, mode) = gen_rtx_REG (mode, i);
- for (mode = GET_CLASS_NARROWEST_MODE (MODE_COMPLEX_FLOAT);
- mode != VOIDmode;
- mode = GET_MODE_WIDER_MODE (mode))
- FP_MODE_REG (i, mode) = gen_rtx_REG (mode, i);
- }
-
- ix86_flags_rtx = gen_rtx_REG (CCmode, FLAGS_REG);
-
- /* A QNaN for initializing uninitialized variables.
-
- ??? We can't load from constant memory in PIC mode, because
- we're inserting these instructions before the prologue and
- the PIC register hasn't been set up. In that case, fall back
- on zero, which we can get from `ldz'. */
-
- if (flag_pic)
- not_a_num = CONST0_RTX (SFmode);
- else
- {
- not_a_num = gen_lowpart (SFmode, GEN_INT (0x7fc00000));
- not_a_num = force_const_mem (SFmode, not_a_num);
- }
-
- /* Allocate a cache for stack_regs_mentioned. */
- max_uid = get_max_uid ();
- stack_regs_mentioned_data = VEC_alloc (char, heap, max_uid + 1);
- memset (VEC_address (char, stack_regs_mentioned_data),
- 0, sizeof (char) * max_uid + 1);
-
- convert_regs ();
-
- free_aux_for_blocks ();
- return true;
-}
-#endif /* STACK_REGS */
-
-static bool
-gate_handle_stack_regs (void)
-{
-#ifdef STACK_REGS
- return 1;
-#else
- return 0;
-#endif
-}
-
-/* Convert register usage from flat register file usage to a stack
- register file. */
-static unsigned int
-rest_of_handle_stack_regs (void)
-{
-#ifdef STACK_REGS
- if (reg_to_stack () && optimize)
- {
- regstack_completed = 1;
- if (cleanup_cfg (CLEANUP_EXPENSIVE | CLEANUP_POST_REGSTACK
- | (flag_crossjumping ? CLEANUP_CROSSJUMP : 0))
- && (flag_reorder_blocks || flag_reorder_blocks_and_partition))
- {
- reorder_basic_blocks (0);
- cleanup_cfg (CLEANUP_EXPENSIVE | CLEANUP_POST_REGSTACK);
- }
- }
- else
- regstack_completed = 1;
-#endif
- return 0;
-}
-
-struct tree_opt_pass pass_stack_regs =
-{
- "stack", /* name */
- gate_handle_stack_regs, /* gate */
- rest_of_handle_stack_regs, /* execute */
- NULL, /* sub */
- NULL, /* next */
- 0, /* static_pass_number */
- TV_REG_STACK, /* tv_id */
- 0, /* properties_required */
- 0, /* properties_provided */
- 0, /* properties_destroyed */
- 0, /* todo_flags_start */
- TODO_dump_func |
- TODO_ggc_collect, /* todo_flags_finish */
- 'k' /* letter */
-};