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Diffstat (limited to 'gcc-4.2.1-5666.3/gcc/loop-unroll.c')
| -rw-r--r-- | gcc-4.2.1-5666.3/gcc/loop-unroll.c | 2225 |
1 files changed, 0 insertions, 2225 deletions
diff --git a/gcc-4.2.1-5666.3/gcc/loop-unroll.c b/gcc-4.2.1-5666.3/gcc/loop-unroll.c deleted file mode 100644 index 711b02161..000000000 --- a/gcc-4.2.1-5666.3/gcc/loop-unroll.c +++ /dev/null @@ -1,2225 +0,0 @@ -/* Loop unrolling and peeling. - Copyright (C) 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. */ - -#include "config.h" -#include "system.h" -#include "coretypes.h" -#include "tm.h" -#include "rtl.h" -#include "hard-reg-set.h" -#include "obstack.h" -#include "basic-block.h" -#include "cfgloop.h" -#include "cfglayout.h" -#include "params.h" -#include "output.h" -#include "expr.h" -#include "hashtab.h" -#include "recog.h" - -/* This pass performs loop unrolling and peeling. We only perform these - optimizations on innermost loops (with single exception) because - the impact on performance is greatest here, and we want to avoid - unnecessary code size growth. The gain is caused by greater sequentiality - of code, better code to optimize for further passes and in some cases - by fewer testings of exit conditions. The main problem is code growth, - that impacts performance negatively due to effect of caches. - - What we do: - - -- complete peeling of once-rolling loops; this is the above mentioned - exception, as this causes loop to be cancelled completely and - does not cause code growth - -- complete peeling of loops that roll (small) constant times. - -- simple peeling of first iterations of loops that do not roll much - (according to profile feedback) - -- unrolling of loops that roll constant times; this is almost always - win, as we get rid of exit condition tests. - -- unrolling of loops that roll number of times that we can compute - in runtime; we also get rid of exit condition tests here, but there - is the extra expense for calculating the number of iterations - -- simple unrolling of remaining loops; this is performed only if we - are asked to, as the gain is questionable in this case and often - it may even slow down the code - For more detailed descriptions of each of those, see comments at - appropriate function below. - - There is a lot of parameters (defined and described in params.def) that - control how much we unroll/peel. - - ??? A great problem is that we don't have a good way how to determine - how many times we should unroll the loop; the experiments I have made - showed that this choice may affect performance in order of several %. - */ - -/* Information about induction variables to split. */ - -struct iv_to_split -{ - rtx insn; /* The insn in that the induction variable occurs. */ - rtx base_var; /* The variable on that the values in the further - iterations are based. */ - rtx step; /* Step of the induction variable. */ - unsigned n_loc; - unsigned loc[3]; /* Location where the definition of the induction - variable occurs in the insn. For example if - N_LOC is 2, the expression is located at - XEXP (XEXP (single_set, loc[0]), loc[1]). */ -}; - -/* Information about accumulators to expand. */ - -struct var_to_expand -{ - rtx insn; /* The insn in that the variable expansion occurs. */ - rtx reg; /* The accumulator which is expanded. */ - VEC(rtx,heap) *var_expansions; /* The copies of the accumulator which is expanded. */ - enum rtx_code op; /* The type of the accumulation - addition, subtraction - or multiplication. */ - int expansion_count; /* Count the number of expansions generated so far. */ - int reuse_expansion; /* The expansion we intend to reuse to expand - the accumulator. If REUSE_EXPANSION is 0 reuse - the original accumulator. Else use - var_expansions[REUSE_EXPANSION - 1]. */ -}; - -/* Information about optimization applied in - the unrolled loop. */ - -struct opt_info -{ - htab_t insns_to_split; /* A hashtable of insns to split. */ - htab_t insns_with_var_to_expand; /* A hashtable of insns with accumulators - to expand. */ - unsigned first_new_block; /* The first basic block that was - duplicated. */ - basic_block loop_exit; /* The loop exit basic block. */ - basic_block loop_preheader; /* The loop preheader basic block. */ -}; - -static void decide_unrolling_and_peeling (struct loops *, int); -static void peel_loops_completely (struct loops *, int); -static void decide_peel_simple (struct loop *, int); -static void decide_peel_once_rolling (struct loop *, int); -static void decide_peel_completely (struct loop *, int); -static void decide_unroll_stupid (struct loop *, int); -static void decide_unroll_constant_iterations (struct loop *, int); -static void decide_unroll_runtime_iterations (struct loop *, int); -static void peel_loop_simple (struct loops *, struct loop *); -static void peel_loop_completely (struct loops *, struct loop *); -static void unroll_loop_stupid (struct loops *, struct loop *); -static void unroll_loop_constant_iterations (struct loops *, struct loop *); -static void unroll_loop_runtime_iterations (struct loops *, struct loop *); -static struct opt_info *analyze_insns_in_loop (struct loop *); -static void opt_info_start_duplication (struct opt_info *); -static void apply_opt_in_copies (struct opt_info *, unsigned, bool, bool); -static void free_opt_info (struct opt_info *); -static struct var_to_expand *analyze_insn_to_expand_var (struct loop*, rtx); -static bool referenced_in_one_insn_in_loop_p (struct loop *, rtx); -static struct iv_to_split *analyze_iv_to_split_insn (rtx); -static void expand_var_during_unrolling (struct var_to_expand *, rtx); -static int insert_var_expansion_initialization (void **, void *); -static int combine_var_copies_in_loop_exit (void **, void *); -static int release_var_copies (void **, void *); -static rtx get_expansion (struct var_to_expand *); - -/* Unroll and/or peel (depending on FLAGS) LOOPS. */ -void -unroll_and_peel_loops (struct loops *loops, int flags) -{ - struct loop *loop, *next; - bool check; - - /* First perform complete loop peeling (it is almost surely a win, - and affects parameters for further decision a lot). */ - peel_loops_completely (loops, flags); - - /* Now decide rest of unrolling and peeling. */ - decide_unrolling_and_peeling (loops, flags); - - loop = loops->tree_root; - while (loop->inner) - loop = loop->inner; - - /* Scan the loops, inner ones first. */ - while (loop != loops->tree_root) - { - if (loop->next) - { - next = loop->next; - while (next->inner) - next = next->inner; - } - else - next = loop->outer; - - check = true; - /* And perform the appropriate transformations. */ - switch (loop->lpt_decision.decision) - { - case LPT_PEEL_COMPLETELY: - /* Already done. */ - gcc_unreachable (); - case LPT_PEEL_SIMPLE: - peel_loop_simple (loops, loop); - break; - case LPT_UNROLL_CONSTANT: - unroll_loop_constant_iterations (loops, loop); - break; - case LPT_UNROLL_RUNTIME: - unroll_loop_runtime_iterations (loops, loop); - break; - case LPT_UNROLL_STUPID: - unroll_loop_stupid (loops, loop); - break; - case LPT_NONE: - check = false; - break; - default: - gcc_unreachable (); - } - if (check) - { -#ifdef ENABLE_CHECKING - verify_dominators (CDI_DOMINATORS); - verify_loop_structure (loops); -#endif - } - loop = next; - } - - iv_analysis_done (); -} - -/* Check whether exit of the LOOP is at the end of loop body. */ - -static bool -loop_exit_at_end_p (struct loop *loop) -{ - struct niter_desc *desc = get_simple_loop_desc (loop); - rtx insn; - - if (desc->in_edge->dest != loop->latch) - return false; - - /* Check that the latch is empty. */ - FOR_BB_INSNS (loop->latch, insn) - { - if (INSN_P (insn)) - return false; - } - - return true; -} - -/* Check whether to peel LOOPS (depending on FLAGS) completely and do so. */ -static void -peel_loops_completely (struct loops *loops, int flags) -{ - struct loop *loop; - unsigned i; - - /* Scan the loops, the inner ones first. */ - for (i = loops->num - 1; i > 0; i--) - { - loop = loops->parray[i]; - if (!loop) - continue; - - loop->lpt_decision.decision = LPT_NONE; - - if (dump_file) - fprintf (dump_file, - "\n;; *** Considering loop %d for complete peeling ***\n", - loop->num); - - loop->ninsns = num_loop_insns (loop); - - decide_peel_once_rolling (loop, flags); - if (loop->lpt_decision.decision == LPT_NONE) - decide_peel_completely (loop, flags); - - if (loop->lpt_decision.decision == LPT_PEEL_COMPLETELY) - { - peel_loop_completely (loops, loop); -#ifdef ENABLE_CHECKING - verify_dominators (CDI_DOMINATORS); - verify_loop_structure (loops); -#endif - } - } -} - -/* Decide whether unroll or peel LOOPS (depending on FLAGS) and how much. */ -static void -decide_unrolling_and_peeling (struct loops *loops, int flags) -{ - struct loop *loop = loops->tree_root, *next; - - while (loop->inner) - loop = loop->inner; - - /* Scan the loops, inner ones first. */ - while (loop != loops->tree_root) - { - if (loop->next) - { - next = loop->next; - while (next->inner) - next = next->inner; - } - else - next = loop->outer; - - loop->lpt_decision.decision = LPT_NONE; - - if (dump_file) - fprintf (dump_file, "\n;; *** Considering loop %d ***\n", loop->num); - - /* Do not peel cold areas. */ - if (!maybe_hot_bb_p (loop->header)) - { - if (dump_file) - fprintf (dump_file, ";; Not considering loop, cold area\n"); - loop = next; - continue; - } - - /* Can the loop be manipulated? */ - if (!can_duplicate_loop_p (loop)) - { - if (dump_file) - fprintf (dump_file, - ";; Not considering loop, cannot duplicate\n"); - loop = next; - continue; - } - - /* Skip non-innermost loops. */ - if (loop->inner) - { - if (dump_file) - fprintf (dump_file, ";; Not considering loop, is not innermost\n"); - loop = next; - continue; - } - - loop->ninsns = num_loop_insns (loop); - loop->av_ninsns = average_num_loop_insns (loop); - - /* Try transformations one by one in decreasing order of - priority. */ - - decide_unroll_constant_iterations (loop, flags); - if (loop->lpt_decision.decision == LPT_NONE) - decide_unroll_runtime_iterations (loop, flags); - if (loop->lpt_decision.decision == LPT_NONE) - decide_unroll_stupid (loop, flags); - if (loop->lpt_decision.decision == LPT_NONE) - decide_peel_simple (loop, flags); - - loop = next; - } -} - -/* Decide whether the LOOP is once rolling and suitable for complete - peeling. */ -static void -decide_peel_once_rolling (struct loop *loop, int flags ATTRIBUTE_UNUSED) -{ - struct niter_desc *desc; - - if (dump_file) - fprintf (dump_file, "\n;; Considering peeling once rolling loop\n"); - - /* Is the loop small enough? */ - if ((unsigned) PARAM_VALUE (PARAM_MAX_ONCE_PEELED_INSNS) < loop->ninsns) - { - if (dump_file) - fprintf (dump_file, ";; Not considering loop, is too big\n"); - return; - } - - /* Check for simple loops. */ - desc = get_simple_loop_desc (loop); - - /* Check number of iterations. */ - if (!desc->simple_p - || desc->assumptions - || desc->infinite - || !desc->const_iter - || desc->niter != 0) - { - if (dump_file) - fprintf (dump_file, - ";; Unable to prove that the loop rolls exactly once\n"); - return; - } - - /* Success. */ - if (dump_file) - fprintf (dump_file, ";; Decided to peel exactly once rolling loop\n"); - loop->lpt_decision.decision = LPT_PEEL_COMPLETELY; -} - -/* Decide whether the LOOP is suitable for complete peeling. */ -static void -decide_peel_completely (struct loop *loop, int flags ATTRIBUTE_UNUSED) -{ - unsigned npeel; - struct niter_desc *desc; - - if (dump_file) - fprintf (dump_file, "\n;; Considering peeling completely\n"); - - /* Skip non-innermost loops. */ - if (loop->inner) - { - if (dump_file) - fprintf (dump_file, ";; Not considering loop, is not innermost\n"); - return; - } - - /* Do not peel cold areas. */ - if (!maybe_hot_bb_p (loop->header)) - { - if (dump_file) - fprintf (dump_file, ";; Not considering loop, cold area\n"); - return; - } - - /* Can the loop be manipulated? */ - if (!can_duplicate_loop_p (loop)) - { - if (dump_file) - fprintf (dump_file, - ";; Not considering loop, cannot duplicate\n"); - return; - } - - /* npeel = number of iterations to peel. */ - npeel = PARAM_VALUE (PARAM_MAX_COMPLETELY_PEELED_INSNS) / loop->ninsns; - if (npeel > (unsigned) PARAM_VALUE (PARAM_MAX_COMPLETELY_PEEL_TIMES)) - npeel = PARAM_VALUE (PARAM_MAX_COMPLETELY_PEEL_TIMES); - - /* Is the loop small enough? */ - if (!npeel) - { - if (dump_file) - fprintf (dump_file, ";; Not considering loop, is too big\n"); - return; - } - - /* Check for simple loops. */ - desc = get_simple_loop_desc (loop); - - /* Check number of iterations. */ - if (!desc->simple_p - || desc->assumptions - || !desc->const_iter - || desc->infinite) - { - if (dump_file) - fprintf (dump_file, - ";; Unable to prove that the loop iterates constant times\n"); - return; - } - - if (desc->niter > npeel - 1) - { - if (dump_file) - { - fprintf (dump_file, - ";; Not peeling loop completely, rolls too much ("); - fprintf (dump_file, HOST_WIDEST_INT_PRINT_DEC, desc->niter); - fprintf (dump_file, " iterations > %d [maximum peelings])\n", npeel); - } - return; - } - - /* Success. */ - if (dump_file) - fprintf (dump_file, ";; Decided to peel loop completely\n"); - loop->lpt_decision.decision = LPT_PEEL_COMPLETELY; -} - -/* Peel all iterations of LOOP, remove exit edges and cancel the loop - completely. The transformation done: - - for (i = 0; i < 4; i++) - body; - - ==> - - i = 0; - body; i++; - body; i++; - body; i++; - body; i++; - */ -static void -peel_loop_completely (struct loops *loops, struct loop *loop) -{ - sbitmap wont_exit; - unsigned HOST_WIDE_INT npeel; - unsigned n_remove_edges, i; - edge *remove_edges, ein; - struct niter_desc *desc = get_simple_loop_desc (loop); - struct opt_info *opt_info = NULL; - - npeel = desc->niter; - - if (npeel) - { - bool ok; - - wont_exit = sbitmap_alloc (npeel + 1); - sbitmap_ones (wont_exit); - RESET_BIT (wont_exit, 0); - if (desc->noloop_assumptions) - RESET_BIT (wont_exit, 1); - - remove_edges = XCNEWVEC (edge, npeel); - n_remove_edges = 0; - - if (flag_split_ivs_in_unroller) - opt_info = analyze_insns_in_loop (loop); - - opt_info_start_duplication (opt_info); - ok = duplicate_loop_to_header_edge (loop, loop_preheader_edge (loop), - loops, npeel, - wont_exit, desc->out_edge, - remove_edges, &n_remove_edges, - DLTHE_FLAG_UPDATE_FREQ - | DLTHE_FLAG_COMPLETTE_PEEL - | (opt_info - ? DLTHE_RECORD_COPY_NUMBER : 0)); - gcc_assert (ok); - - free (wont_exit); - - if (opt_info) - { - apply_opt_in_copies (opt_info, npeel, false, true); - free_opt_info (opt_info); - } - - /* Remove the exit edges. */ - for (i = 0; i < n_remove_edges; i++) - remove_path (loops, remove_edges[i]); - free (remove_edges); - } - - ein = desc->in_edge; - free_simple_loop_desc (loop); - - /* Now remove the unreachable part of the last iteration and cancel - the loop. */ - remove_path (loops, ein); - - if (dump_file) - fprintf (dump_file, ";; Peeled loop completely, %d times\n", (int) npeel); -} - -/* Decide whether to unroll LOOP iterating constant number of times - and how much. */ - -static void -decide_unroll_constant_iterations (struct loop *loop, int flags) -{ - unsigned nunroll, nunroll_by_av, best_copies, best_unroll = 0, n_copies, i; - struct niter_desc *desc; - - if (!(flags & UAP_UNROLL)) - { - /* We were not asked to, just return back silently. */ - return; - } - - if (dump_file) - fprintf (dump_file, - "\n;; Considering unrolling loop with constant " - "number of iterations\n"); - - /* nunroll = total number of copies of the original loop body in - unrolled loop (i.e. if it is 2, we have to duplicate loop body once. */ - nunroll = PARAM_VALUE (PARAM_MAX_UNROLLED_INSNS) / loop->ninsns; - nunroll_by_av - = PARAM_VALUE (PARAM_MAX_AVERAGE_UNROLLED_INSNS) / loop->av_ninsns; - if (nunroll > nunroll_by_av) - nunroll = nunroll_by_av; - if (nunroll > (unsigned) PARAM_VALUE (PARAM_MAX_UNROLL_TIMES)) - nunroll = PARAM_VALUE (PARAM_MAX_UNROLL_TIMES); - - /* Skip big loops. */ - if (nunroll <= 1) - { - if (dump_file) - fprintf (dump_file, ";; Not considering loop, is too big\n"); - return; - } - - /* Check for simple loops. */ - desc = get_simple_loop_desc (loop); - - /* Check number of iterations. */ - if (!desc->simple_p || !desc->const_iter || desc->assumptions) - { - if (dump_file) - fprintf (dump_file, - ";; Unable to prove that the loop iterates constant times\n"); - return; - } - - /* Check whether the loop rolls enough to consider. */ - if (desc->niter < 2 * nunroll) - { - if (dump_file) - fprintf (dump_file, ";; Not unrolling loop, doesn't roll\n"); - return; - } - - /* Success; now compute number of iterations to unroll. We alter - nunroll so that as few as possible copies of loop body are - necessary, while still not decreasing the number of unrollings - too much (at most by 1). */ - best_copies = 2 * nunroll + 10; - - i = 2 * nunroll + 2; - if (i - 1 >= desc->niter) - i = desc->niter - 2; - - for (; i >= nunroll - 1; i--) - { - unsigned exit_mod = desc->niter % (i + 1); - - if (!loop_exit_at_end_p (loop)) - n_copies = exit_mod + i + 1; - else if (exit_mod != (unsigned) i - || desc->noloop_assumptions != NULL_RTX) - n_copies = exit_mod + i + 2; - else - n_copies = i + 1; - - if (n_copies < best_copies) - { - best_copies = n_copies; - best_unroll = i; - } - } - - if (dump_file) - fprintf (dump_file, ";; max_unroll %d (%d copies, initial %d).\n", - best_unroll + 1, best_copies, nunroll); - - loop->lpt_decision.decision = LPT_UNROLL_CONSTANT; - loop->lpt_decision.times = best_unroll; - - if (dump_file) - fprintf (dump_file, - ";; Decided to unroll the constant times rolling loop, %d times.\n", - loop->lpt_decision.times); -} - -/* Unroll LOOP with constant number of iterations LOOP->LPT_DECISION.TIMES + 1 - times. The transformation does this: - - for (i = 0; i < 102; i++) - body; - - ==> - - i = 0; - body; i++; - body; i++; - while (i < 102) - { - body; i++; - body; i++; - body; i++; - body; i++; - } - */ -static void -unroll_loop_constant_iterations (struct loops *loops, struct loop *loop) -{ - unsigned HOST_WIDE_INT niter; - unsigned exit_mod; - sbitmap wont_exit; - unsigned n_remove_edges, i; - edge *remove_edges; - unsigned max_unroll = loop->lpt_decision.times; - struct niter_desc *desc = get_simple_loop_desc (loop); - bool exit_at_end = loop_exit_at_end_p (loop); - struct opt_info *opt_info = NULL; - bool ok; - - niter = desc->niter; - - /* Should not get here (such loop should be peeled instead). */ - gcc_assert (niter > max_unroll + 1); - - exit_mod = niter % (max_unroll + 1); - - wont_exit = sbitmap_alloc (max_unroll + 1); - sbitmap_ones (wont_exit); - - remove_edges = XCNEWVEC (edge, max_unroll + exit_mod + 1); - n_remove_edges = 0; - if (flag_split_ivs_in_unroller - || flag_variable_expansion_in_unroller) - opt_info = analyze_insns_in_loop (loop); - - if (!exit_at_end) - { - /* The exit is not at the end of the loop; leave exit test - in the first copy, so that the loops that start with test - of exit condition have continuous body after unrolling. */ - - if (dump_file) - fprintf (dump_file, ";; Condition on beginning of loop.\n"); - - /* Peel exit_mod iterations. */ - RESET_BIT (wont_exit, 0); - if (desc->noloop_assumptions) - RESET_BIT (wont_exit, 1); - - if (exit_mod) - { - opt_info_start_duplication (opt_info); - ok = duplicate_loop_to_header_edge (loop, loop_preheader_edge (loop), - loops, exit_mod, - wont_exit, desc->out_edge, - remove_edges, &n_remove_edges, - DLTHE_FLAG_UPDATE_FREQ - | (opt_info && exit_mod > 1 - ? DLTHE_RECORD_COPY_NUMBER - : 0)); - gcc_assert (ok); - - if (opt_info && exit_mod > 1) - apply_opt_in_copies (opt_info, exit_mod, false, false); - - desc->noloop_assumptions = NULL_RTX; - desc->niter -= exit_mod; - desc->niter_max -= exit_mod; - } - - SET_BIT (wont_exit, 1); - } - else - { - /* Leave exit test in last copy, for the same reason as above if - the loop tests the condition at the end of loop body. */ - - if (dump_file) - fprintf (dump_file, ";; Condition on end of loop.\n"); - - /* We know that niter >= max_unroll + 2; so we do not need to care of - case when we would exit before reaching the loop. So just peel - exit_mod + 1 iterations. */ - if (exit_mod != max_unroll - || desc->noloop_assumptions) - { - RESET_BIT (wont_exit, 0); - if (desc->noloop_assumptions) - RESET_BIT (wont_exit, 1); - - opt_info_start_duplication (opt_info); - ok = duplicate_loop_to_header_edge (loop, loop_preheader_edge (loop), - loops, exit_mod + 1, - wont_exit, desc->out_edge, - remove_edges, &n_remove_edges, - DLTHE_FLAG_UPDATE_FREQ - | (opt_info && exit_mod > 0 - ? DLTHE_RECORD_COPY_NUMBER - : 0)); - gcc_assert (ok); - - if (opt_info && exit_mod > 0) - apply_opt_in_copies (opt_info, exit_mod + 1, false, false); - - desc->niter -= exit_mod + 1; - desc->niter_max -= exit_mod + 1; - desc->noloop_assumptions = NULL_RTX; - - SET_BIT (wont_exit, 0); - SET_BIT (wont_exit, 1); - } - - RESET_BIT (wont_exit, max_unroll); - } - - /* Now unroll the loop. */ - - opt_info_start_duplication (opt_info); - ok = duplicate_loop_to_header_edge (loop, loop_latch_edge (loop), - loops, max_unroll, - wont_exit, desc->out_edge, - remove_edges, &n_remove_edges, - DLTHE_FLAG_UPDATE_FREQ - | (opt_info - ? DLTHE_RECORD_COPY_NUMBER - : 0)); - gcc_assert (ok); - - if (opt_info) - { - apply_opt_in_copies (opt_info, max_unroll, true, true); - free_opt_info (opt_info); - } - - free (wont_exit); - - if (exit_at_end) - { - basic_block exit_block = get_bb_copy (desc->in_edge->src); - /* Find a new in and out edge; they are in the last copy we have made. */ - - if (EDGE_SUCC (exit_block, 0)->dest == desc->out_edge->dest) - { - desc->out_edge = EDGE_SUCC (exit_block, 0); - desc->in_edge = EDGE_SUCC (exit_block, 1); - } - else - { - desc->out_edge = EDGE_SUCC (exit_block, 1); - desc->in_edge = EDGE_SUCC (exit_block, 0); - } - } - - desc->niter /= max_unroll + 1; - desc->niter_max /= max_unroll + 1; - desc->niter_expr = GEN_INT (desc->niter); - - /* Remove the edges. */ - for (i = 0; i < n_remove_edges; i++) - remove_path (loops, remove_edges[i]); - free (remove_edges); - - if (dump_file) - fprintf (dump_file, - ";; Unrolled loop %d times, constant # of iterations %i insns\n", - max_unroll, num_loop_insns (loop)); -} - -/* Decide whether to unroll LOOP iterating runtime computable number of times - and how much. */ -static void -decide_unroll_runtime_iterations (struct loop *loop, int flags) -{ - unsigned nunroll, nunroll_by_av, i; - struct niter_desc *desc; - - if (!(flags & UAP_UNROLL)) - { - /* We were not asked to, just return back silently. */ - return; - } - - if (dump_file) - fprintf (dump_file, - "\n;; Considering unrolling loop with runtime " - "computable number of iterations\n"); - - /* nunroll = total number of copies of the original loop body in - unrolled loop (i.e. if it is 2, we have to duplicate loop body once. */ - nunroll = PARAM_VALUE (PARAM_MAX_UNROLLED_INSNS) / loop->ninsns; - nunroll_by_av = PARAM_VALUE (PARAM_MAX_AVERAGE_UNROLLED_INSNS) / loop->av_ninsns; - if (nunroll > nunroll_by_av) - nunroll = nunroll_by_av; - if (nunroll > (unsigned) PARAM_VALUE (PARAM_MAX_UNROLL_TIMES)) - nunroll = PARAM_VALUE (PARAM_MAX_UNROLL_TIMES); - - /* Skip big loops. */ - if (nunroll <= 1) - { - if (dump_file) - fprintf (dump_file, ";; Not considering loop, is too big\n"); - return; - } - - /* Check for simple loops. */ - desc = get_simple_loop_desc (loop); - - /* Check simpleness. */ - if (!desc->simple_p || desc->assumptions) - { - if (dump_file) - fprintf (dump_file, - ";; Unable to prove that the number of iterations " - "can be counted in runtime\n"); - return; - } - - if (desc->const_iter) - { - if (dump_file) - fprintf (dump_file, ";; Loop iterates constant times\n"); - return; - } - - /* If we have profile feedback, check whether the loop rolls. */ - if (loop->header->count && expected_loop_iterations (loop) < 2 * nunroll) - { - if (dump_file) - fprintf (dump_file, ";; Not unrolling loop, doesn't roll\n"); - return; - } - - /* Success; now force nunroll to be power of 2, as we are unable to - cope with overflows in computation of number of iterations. */ - for (i = 1; 2 * i <= nunroll; i *= 2) - continue; - - loop->lpt_decision.decision = LPT_UNROLL_RUNTIME; - loop->lpt_decision.times = i - 1; - - if (dump_file) - fprintf (dump_file, - ";; Decided to unroll the runtime computable " - "times rolling loop, %d times.\n", - loop->lpt_decision.times); -} - -/* Unroll LOOP for that we are able to count number of iterations in runtime - LOOP->LPT_DECISION.TIMES + 1 times. The transformation does this (with some - extra care for case n < 0): - - for (i = 0; i < n; i++) - body; - - ==> - - i = 0; - mod = n % 4; - - switch (mod) - { - case 3: - body; i++; - case 2: - body; i++; - case 1: - body; i++; - case 0: ; - } - - while (i < n) - { - body; i++; - body; i++; - body; i++; - body; i++; - } - */ -static void -unroll_loop_runtime_iterations (struct loops *loops, struct loop *loop) -{ - rtx old_niter, niter, init_code, branch_code, tmp; - unsigned i, j, p; - basic_block preheader, *body, *dom_bbs, swtch, ezc_swtch; - unsigned n_dom_bbs; - sbitmap wont_exit; - int may_exit_copy; - unsigned n_peel, n_remove_edges; - edge *remove_edges, e; - bool extra_zero_check, last_may_exit; - unsigned max_unroll = loop->lpt_decision.times; - struct niter_desc *desc = get_simple_loop_desc (loop); - bool exit_at_end = loop_exit_at_end_p (loop); - struct opt_info *opt_info = NULL; - bool ok; - - if (flag_split_ivs_in_unroller - || flag_variable_expansion_in_unroller) - opt_info = analyze_insns_in_loop (loop); - - /* Remember blocks whose dominators will have to be updated. */ - dom_bbs = XCNEWVEC (basic_block, n_basic_blocks); - n_dom_bbs = 0; - - body = get_loop_body (loop); - for (i = 0; i < loop->num_nodes; i++) - { - unsigned nldom; - basic_block *ldom; - - nldom = get_dominated_by (CDI_DOMINATORS, body[i], &ldom); - for (j = 0; j < nldom; j++) - if (!flow_bb_inside_loop_p (loop, ldom[j])) - dom_bbs[n_dom_bbs++] = ldom[j]; - - free (ldom); - } - free (body); - - if (!exit_at_end) - { - /* Leave exit in first copy (for explanation why see comment in - unroll_loop_constant_iterations). */ - may_exit_copy = 0; - n_peel = max_unroll - 1; - extra_zero_check = true; - last_may_exit = false; - } - else - { - /* Leave exit in last copy (for explanation why see comment in - unroll_loop_constant_iterations). */ - may_exit_copy = max_unroll; - n_peel = max_unroll; - extra_zero_check = false; - last_may_exit = true; - } - - /* Get expression for number of iterations. */ - start_sequence (); - old_niter = niter = gen_reg_rtx (desc->mode); - tmp = force_operand (copy_rtx (desc->niter_expr), niter); - if (tmp != niter) - emit_move_insn (niter, tmp); - - /* Count modulo by ANDing it with max_unroll; we use the fact that - the number of unrollings is a power of two, and thus this is correct - even if there is overflow in the computation. */ - niter = expand_simple_binop (desc->mode, AND, - niter, - GEN_INT (max_unroll), - NULL_RTX, 0, OPTAB_LIB_WIDEN); - - init_code = get_insns (); - end_sequence (); - - /* Precondition the loop. */ - loop_split_edge_with (loop_preheader_edge (loop), init_code); - - remove_edges = XCNEWVEC (edge, max_unroll + n_peel + 1); - n_remove_edges = 0; - - wont_exit = sbitmap_alloc (max_unroll + 2); - - /* Peel the first copy of loop body (almost always we must leave exit test - here; the only exception is when we have extra zero check and the number - of iterations is reliable. Also record the place of (possible) extra - zero check. */ - sbitmap_zero (wont_exit); - if (extra_zero_check - && !desc->noloop_assumptions) - SET_BIT (wont_exit, 1); - ezc_swtch = loop_preheader_edge (loop)->src; - ok = duplicate_loop_to_header_edge (loop, loop_preheader_edge (loop), - loops, 1, - wont_exit, desc->out_edge, - remove_edges, &n_remove_edges, - DLTHE_FLAG_UPDATE_FREQ); - gcc_assert (ok); - - /* Record the place where switch will be built for preconditioning. */ - swtch = loop_split_edge_with (loop_preheader_edge (loop), - NULL_RTX); - - for (i = 0; i < n_peel; i++) - { - /* Peel the copy. */ - sbitmap_zero (wont_exit); - if (i != n_peel - 1 || !last_may_exit) - SET_BIT (wont_exit, 1); - ok = duplicate_loop_to_header_edge (loop, loop_preheader_edge (loop), - loops, 1, - wont_exit, desc->out_edge, - remove_edges, &n_remove_edges, - DLTHE_FLAG_UPDATE_FREQ); - gcc_assert (ok); - - /* Create item for switch. */ - j = n_peel - i - (extra_zero_check ? 0 : 1); - p = REG_BR_PROB_BASE / (i + 2); - - preheader = loop_split_edge_with (loop_preheader_edge (loop), NULL_RTX); - branch_code = compare_and_jump_seq (copy_rtx (niter), GEN_INT (j), EQ, - block_label (preheader), p, - NULL_RTX); - - swtch = loop_split_edge_with (single_pred_edge (swtch), branch_code); - set_immediate_dominator (CDI_DOMINATORS, preheader, swtch); - single_pred_edge (swtch)->probability = REG_BR_PROB_BASE - p; - e = make_edge (swtch, preheader, - single_succ_edge (swtch)->flags & EDGE_IRREDUCIBLE_LOOP); - e->probability = p; - } - - if (extra_zero_check) - { - /* Add branch for zero iterations. */ - p = REG_BR_PROB_BASE / (max_unroll + 1); - swtch = ezc_swtch; - preheader = loop_split_edge_with (loop_preheader_edge (loop), NULL_RTX); - branch_code = compare_and_jump_seq (copy_rtx (niter), const0_rtx, EQ, - block_label (preheader), p, - NULL_RTX); - - swtch = loop_split_edge_with (single_succ_edge (swtch), branch_code); - set_immediate_dominator (CDI_DOMINATORS, preheader, swtch); - single_succ_edge (swtch)->probability = REG_BR_PROB_BASE - p; - e = make_edge (swtch, preheader, - single_succ_edge (swtch)->flags & EDGE_IRREDUCIBLE_LOOP); - e->probability = p; - } - - /* Recount dominators for outer blocks. */ - iterate_fix_dominators (CDI_DOMINATORS, dom_bbs, n_dom_bbs); - - /* And unroll loop. */ - - sbitmap_ones (wont_exit); - RESET_BIT (wont_exit, may_exit_copy); - opt_info_start_duplication (opt_info); - - ok = duplicate_loop_to_header_edge (loop, loop_latch_edge (loop), - loops, max_unroll, - wont_exit, desc->out_edge, - remove_edges, &n_remove_edges, - DLTHE_FLAG_UPDATE_FREQ - | (opt_info - ? DLTHE_RECORD_COPY_NUMBER - : 0)); - gcc_assert (ok); - - if (opt_info) - { - apply_opt_in_copies (opt_info, max_unroll, true, true); - free_opt_info (opt_info); - } - - free (wont_exit); - - if (exit_at_end) - { - basic_block exit_block = get_bb_copy (desc->in_edge->src); - /* Find a new in and out edge; they are in the last copy we have - made. */ - - if (EDGE_SUCC (exit_block, 0)->dest == desc->out_edge->dest) - { - desc->out_edge = EDGE_SUCC (exit_block, 0); - desc->in_edge = EDGE_SUCC (exit_block, 1); - } - else - { - desc->out_edge = EDGE_SUCC (exit_block, 1); - desc->in_edge = EDGE_SUCC (exit_block, 0); - } - } - - /* Remove the edges. */ - for (i = 0; i < n_remove_edges; i++) - remove_path (loops, remove_edges[i]); - free (remove_edges); - - /* We must be careful when updating the number of iterations due to - preconditioning and the fact that the value must be valid at entry - of the loop. After passing through the above code, we see that - the correct new number of iterations is this: */ - gcc_assert (!desc->const_iter); - desc->niter_expr = - simplify_gen_binary (UDIV, desc->mode, old_niter, - GEN_INT (max_unroll + 1)); - desc->niter_max /= max_unroll + 1; - if (exit_at_end) - { - desc->niter_expr = - simplify_gen_binary (MINUS, desc->mode, desc->niter_expr, const1_rtx); - desc->noloop_assumptions = NULL_RTX; - desc->niter_max--; - } - - if (dump_file) - fprintf (dump_file, - ";; Unrolled loop %d times, counting # of iterations " - "in runtime, %i insns\n", - max_unroll, num_loop_insns (loop)); - - if (dom_bbs) - free (dom_bbs); -} - -/* Decide whether to simply peel LOOP and how much. */ -static void -decide_peel_simple (struct loop *loop, int flags) -{ - unsigned npeel; - struct niter_desc *desc; - - if (!(flags & UAP_PEEL)) - { - /* We were not asked to, just return back silently. */ - return; - } - - if (dump_file) - fprintf (dump_file, "\n;; Considering simply peeling loop\n"); - - /* npeel = number of iterations to peel. */ - npeel = PARAM_VALUE (PARAM_MAX_PEELED_INSNS) / loop->ninsns; - if (npeel > (unsigned) PARAM_VALUE (PARAM_MAX_PEEL_TIMES)) - npeel = PARAM_VALUE (PARAM_MAX_PEEL_TIMES); - - /* Skip big loops. */ - if (!npeel) - { - if (dump_file) - fprintf (dump_file, ";; Not considering loop, is too big\n"); - return; - } - - /* Check for simple loops. */ - desc = get_simple_loop_desc (loop); - - /* Check number of iterations. */ - if (desc->simple_p && !desc->assumptions && desc->const_iter) - { - if (dump_file) - fprintf (dump_file, ";; Loop iterates constant times\n"); - return; - } - - /* Do not simply peel loops with branches inside -- it increases number - of mispredicts. */ - if (num_loop_branches (loop) > 1) - { - if (dump_file) - fprintf (dump_file, ";; Not peeling, contains branches\n"); - return; - } - - if (loop->header->count) - { - unsigned niter = expected_loop_iterations (loop); - if (niter + 1 > npeel) - { - if (dump_file) - { - fprintf (dump_file, ";; Not peeling loop, rolls too much ("); - fprintf (dump_file, HOST_WIDEST_INT_PRINT_DEC, - (HOST_WIDEST_INT) (niter + 1)); - fprintf (dump_file, " iterations > %d [maximum peelings])\n", - npeel); - } - return; - } - npeel = niter + 1; - } - else - { - /* For now we have no good heuristics to decide whether loop peeling - will be effective, so disable it. */ - if (dump_file) - fprintf (dump_file, - ";; Not peeling loop, no evidence it will be profitable\n"); - return; - } - - /* Success. */ - loop->lpt_decision.decision = LPT_PEEL_SIMPLE; - loop->lpt_decision.times = npeel; - - if (dump_file) - fprintf (dump_file, ";; Decided to simply peel the loop, %d times.\n", - loop->lpt_decision.times); -} - -/* Peel a LOOP LOOP->LPT_DECISION.TIMES times. The transformation: - while (cond) - body; - - ==> - - if (!cond) goto end; - body; - if (!cond) goto end; - body; - while (cond) - body; - end: ; - */ -static void -peel_loop_simple (struct loops *loops, struct loop *loop) -{ - sbitmap wont_exit; - unsigned npeel = loop->lpt_decision.times; - struct niter_desc *desc = get_simple_loop_desc (loop); - struct opt_info *opt_info = NULL; - bool ok; - - if (flag_split_ivs_in_unroller && npeel > 1) - opt_info = analyze_insns_in_loop (loop); - - wont_exit = sbitmap_alloc (npeel + 1); - sbitmap_zero (wont_exit); - - opt_info_start_duplication (opt_info); - - ok = duplicate_loop_to_header_edge (loop, loop_preheader_edge (loop), - loops, npeel, wont_exit, - NULL, NULL, - NULL, DLTHE_FLAG_UPDATE_FREQ - | (opt_info - ? DLTHE_RECORD_COPY_NUMBER - : 0)); - gcc_assert (ok); - - free (wont_exit); - - if (opt_info) - { - apply_opt_in_copies (opt_info, npeel, false, false); - free_opt_info (opt_info); - } - - if (desc->simple_p) - { - if (desc->const_iter) - { - desc->niter -= npeel; - desc->niter_expr = GEN_INT (desc->niter); - desc->noloop_assumptions = NULL_RTX; - } - else - { - /* We cannot just update niter_expr, as its value might be clobbered - inside loop. We could handle this by counting the number into - temporary just like we do in runtime unrolling, but it does not - seem worthwhile. */ - free_simple_loop_desc (loop); - } - } - if (dump_file) - fprintf (dump_file, ";; Peeling loop %d times\n", npeel); -} - -/* Decide whether to unroll LOOP stupidly and how much. */ -static void -decide_unroll_stupid (struct loop *loop, int flags) -{ - unsigned nunroll, nunroll_by_av, i; - struct niter_desc *desc; - - if (!(flags & UAP_UNROLL_ALL)) - { - /* We were not asked to, just return back silently. */ - return; - } - - if (dump_file) - fprintf (dump_file, "\n;; Considering unrolling loop stupidly\n"); - - /* nunroll = total number of copies of the original loop body in - unrolled loop (i.e. if it is 2, we have to duplicate loop body once. */ - nunroll = PARAM_VALUE (PARAM_MAX_UNROLLED_INSNS) / loop->ninsns; - nunroll_by_av - = PARAM_VALUE (PARAM_MAX_AVERAGE_UNROLLED_INSNS) / loop->av_ninsns; - if (nunroll > nunroll_by_av) - nunroll = nunroll_by_av; - if (nunroll > (unsigned) PARAM_VALUE (PARAM_MAX_UNROLL_TIMES)) - nunroll = PARAM_VALUE (PARAM_MAX_UNROLL_TIMES); - - /* Skip big loops. */ - if (nunroll <= 1) - { - if (dump_file) - fprintf (dump_file, ";; Not considering loop, is too big\n"); - return; - } - - /* Check for simple loops. */ - desc = get_simple_loop_desc (loop); - - /* Check simpleness. */ - if (desc->simple_p && !desc->assumptions) - { - if (dump_file) - fprintf (dump_file, ";; The loop is simple\n"); - return; - } - - /* Do not unroll loops with branches inside -- it increases number - of mispredicts. */ - if (num_loop_branches (loop) > 1) - { - if (dump_file) - fprintf (dump_file, ";; Not unrolling, contains branches\n"); - return; - } - - /* If we have profile feedback, check whether the loop rolls. */ - if (loop->header->count - && expected_loop_iterations (loop) < 2 * nunroll) - { - if (dump_file) - fprintf (dump_file, ";; Not unrolling loop, doesn't roll\n"); - return; - } - - /* Success. Now force nunroll to be power of 2, as it seems that this - improves results (partially because of better alignments, partially - because of some dark magic). */ - for (i = 1; 2 * i <= nunroll; i *= 2) - continue; - - loop->lpt_decision.decision = LPT_UNROLL_STUPID; - loop->lpt_decision.times = i - 1; - - if (dump_file) - fprintf (dump_file, - ";; Decided to unroll the loop stupidly, %d times.\n", - loop->lpt_decision.times); -} - -/* Unroll a LOOP LOOP->LPT_DECISION.TIMES times. The transformation: - while (cond) - body; - - ==> - - while (cond) - { - body; - if (!cond) break; - body; - if (!cond) break; - body; - if (!cond) break; - body; - } - */ -static void -unroll_loop_stupid (struct loops *loops, struct loop *loop) -{ - sbitmap wont_exit; - unsigned nunroll = loop->lpt_decision.times; - struct niter_desc *desc = get_simple_loop_desc (loop); - struct opt_info *opt_info = NULL; - bool ok; - - if (flag_split_ivs_in_unroller - || flag_variable_expansion_in_unroller) - opt_info = analyze_insns_in_loop (loop); - - - wont_exit = sbitmap_alloc (nunroll + 1); - sbitmap_zero (wont_exit); - opt_info_start_duplication (opt_info); - - ok = duplicate_loop_to_header_edge (loop, loop_latch_edge (loop), - loops, nunroll, wont_exit, - NULL, NULL, NULL, - DLTHE_FLAG_UPDATE_FREQ - | (opt_info - ? DLTHE_RECORD_COPY_NUMBER - : 0)); - gcc_assert (ok); - - if (opt_info) - { - apply_opt_in_copies (opt_info, nunroll, true, true); - free_opt_info (opt_info); - } - - free (wont_exit); - - if (desc->simple_p) - { - /* We indeed may get here provided that there are nontrivial assumptions - for a loop to be really simple. We could update the counts, but the - problem is that we are unable to decide which exit will be taken - (not really true in case the number of iterations is constant, - but noone will do anything with this information, so we do not - worry about it). */ - desc->simple_p = false; - } - - if (dump_file) - fprintf (dump_file, ";; Unrolled loop %d times, %i insns\n", - nunroll, num_loop_insns (loop)); -} - -/* A hash function for information about insns to split. */ - -static hashval_t -si_info_hash (const void *ivts) -{ - return (hashval_t) INSN_UID (((struct iv_to_split *) ivts)->insn); -} - -/* An equality functions for information about insns to split. */ - -static int -si_info_eq (const void *ivts1, const void *ivts2) -{ - const struct iv_to_split *i1 = ivts1; - const struct iv_to_split *i2 = ivts2; - - return i1->insn == i2->insn; -} - -/* Return a hash for VES, which is really a "var_to_expand *". */ - -static hashval_t -ve_info_hash (const void *ves) -{ - return (hashval_t) INSN_UID (((struct var_to_expand *) ves)->insn); -} - -/* Return true if IVTS1 and IVTS2 (which are really both of type - "var_to_expand *") refer to the same instruction. */ - -static int -ve_info_eq (const void *ivts1, const void *ivts2) -{ - const struct var_to_expand *i1 = ivts1; - const struct var_to_expand *i2 = ivts2; - - return i1->insn == i2->insn; -} - -/* Returns true if REG is referenced in one insn in LOOP. */ - -bool -referenced_in_one_insn_in_loop_p (struct loop *loop, rtx reg) -{ - basic_block *body, bb; - unsigned i; - int count_ref = 0; - rtx insn; - - body = get_loop_body (loop); - for (i = 0; i < loop->num_nodes; i++) - { - bb = body[i]; - - FOR_BB_INSNS (bb, insn) - { - if (rtx_referenced_p (reg, insn)) - count_ref++; - } - } - return (count_ref == 1); -} - -/* Determine whether INSN contains an accumulator - which can be expanded into separate copies, - one for each copy of the LOOP body. - - for (i = 0 ; i < n; i++) - sum += a[i]; - - ==> - - sum += a[i] - .... - i = i+1; - sum1 += a[i] - .... - i = i+1 - sum2 += a[i]; - .... - - Return NULL if INSN contains no opportunity for expansion of accumulator. - Otherwise, allocate a VAR_TO_EXPAND structure, fill it with the relevant - information and return a pointer to it. -*/ - -static struct var_to_expand * -analyze_insn_to_expand_var (struct loop *loop, rtx insn) -{ - rtx set, dest, src, op1; - struct var_to_expand *ves; - enum machine_mode mode1, mode2; - - set = single_set (insn); - if (!set) - return NULL; - - dest = SET_DEST (set); - src = SET_SRC (set); - - if (GET_CODE (src) != PLUS - && GET_CODE (src) != MINUS - && GET_CODE (src) != MULT) - return NULL; - - /* Hmm, this is a bit paradoxical. We know that INSN is a valid insn - in MD. But if there is no optab to generate the insn, we can not - perform the variable expansion. This can happen if an MD provides - an insn but not a named pattern to generate it, for example to avoid - producing code that needs additional mode switches like for x87/mmx. - - So we check have_insn_for which looks for an optab for the operation - in SRC. If it doesn't exist, we can't perform the expansion even - though INSN is valid. */ - if (!have_insn_for (GET_CODE (src), GET_MODE (src))) - return NULL; - - if (!XEXP (src, 0)) - return NULL; - - op1 = XEXP (src, 0); - - if (!REG_P (dest) - && !(GET_CODE (dest) == SUBREG - && REG_P (SUBREG_REG (dest)))) - return NULL; - - if (!rtx_equal_p (dest, op1)) - return NULL; - - if (!referenced_in_one_insn_in_loop_p (loop, dest)) - return NULL; - - if (rtx_referenced_p (dest, XEXP (src, 1))) - return NULL; - - mode1 = GET_MODE (dest); - mode2 = GET_MODE (XEXP (src, 1)); - if ((FLOAT_MODE_P (mode1) - || FLOAT_MODE_P (mode2)) - && !flag_unsafe_math_optimizations) - return NULL; - - /* Record the accumulator to expand. */ - ves = XNEW (struct var_to_expand); - ves->insn = insn; - ves->var_expansions = VEC_alloc (rtx, heap, 1); - ves->reg = copy_rtx (dest); - ves->op = GET_CODE (src); - ves->expansion_count = 0; - ves->reuse_expansion = 0; - return ves; -} - -/* Determine whether there is an induction variable in INSN that - we would like to split during unrolling. - - I.e. replace - - i = i + 1; - ... - i = i + 1; - ... - i = i + 1; - ... - - type chains by - - i0 = i + 1 - ... - i = i0 + 1 - ... - i = i0 + 2 - ... - - Return NULL if INSN contains no interesting IVs. Otherwise, allocate - an IV_TO_SPLIT structure, fill it with the relevant information and return a - pointer to it. */ - -static struct iv_to_split * -analyze_iv_to_split_insn (rtx insn) -{ - rtx set, dest; - struct rtx_iv iv; - struct iv_to_split *ivts; - bool ok; - - /* For now we just split the basic induction variables. Later this may be - extended for example by selecting also addresses of memory references. */ - set = single_set (insn); - if (!set) - return NULL; - - dest = SET_DEST (set); - if (!REG_P (dest)) - return NULL; - - if (!biv_p (insn, dest)) - return NULL; - - ok = iv_analyze_result (insn, dest, &iv); - - /* This used to be an assert under the assumption that if biv_p returns - true that iv_analyze_result must also return true. However, that - assumption is not strictly correct as evidenced by pr25569. - - Returning NULL when iv_analyze_result returns false is safe and - avoids the problems in pr25569 until the iv_analyze_* routines - can be fixed, which is apparently hard and time consuming - according to their author. */ - if (! ok) - return NULL; - - if (iv.step == const0_rtx - || iv.mode != iv.extend_mode) - return NULL; - - /* Record the insn to split. */ - ivts = XNEW (struct iv_to_split); - ivts->insn = insn; - ivts->base_var = NULL_RTX; - ivts->step = iv.step; - ivts->n_loc = 1; - ivts->loc[0] = 1; - - return ivts; -} - -/* Determines which of insns in LOOP can be optimized. - Return a OPT_INFO struct with the relevant hash tables filled - with all insns to be optimized. The FIRST_NEW_BLOCK field - is undefined for the return value. */ - -static struct opt_info * -analyze_insns_in_loop (struct loop *loop) -{ - basic_block *body, bb; - unsigned i, num_edges = 0; - struct opt_info *opt_info = XCNEW (struct opt_info); - rtx insn; - struct iv_to_split *ivts = NULL; - struct var_to_expand *ves = NULL; - PTR *slot1; - PTR *slot2; - edge *edges = get_loop_exit_edges (loop, &num_edges); - bool can_apply = false; - - iv_analysis_loop_init (loop); - - body = get_loop_body (loop); - - if (flag_split_ivs_in_unroller) - opt_info->insns_to_split = htab_create (5 * loop->num_nodes, - si_info_hash, si_info_eq, free); - - /* Record the loop exit bb and loop preheader before the unrolling. */ - if (!loop_preheader_edge (loop)->src) - { - loop_split_edge_with (loop_preheader_edge (loop), NULL_RTX); - opt_info->loop_preheader = loop_split_edge_with (loop_preheader_edge (loop), NULL_RTX); - } - else - opt_info->loop_preheader = loop_preheader_edge (loop)->src; - - if (num_edges == 1 - && !(edges[0]->flags & EDGE_COMPLEX)) - { - opt_info->loop_exit = loop_split_edge_with (edges[0], NULL_RTX); - can_apply = true; - } - - if (flag_variable_expansion_in_unroller - && can_apply) - opt_info->insns_with_var_to_expand = htab_create (5 * loop->num_nodes, - ve_info_hash, ve_info_eq, free); - - for (i = 0; i < loop->num_nodes; i++) - { - bb = body[i]; - if (!dominated_by_p (CDI_DOMINATORS, loop->latch, bb)) - continue; - - FOR_BB_INSNS (bb, insn) - { - if (!INSN_P (insn)) - continue; - - if (opt_info->insns_to_split) - ivts = analyze_iv_to_split_insn (insn); - - if (ivts) - { - slot1 = htab_find_slot (opt_info->insns_to_split, ivts, INSERT); - *slot1 = ivts; - continue; - } - - if (opt_info->insns_with_var_to_expand) - ves = analyze_insn_to_expand_var (loop, insn); - - if (ves) - { - slot2 = htab_find_slot (opt_info->insns_with_var_to_expand, ves, INSERT); - *slot2 = ves; - } - } - } - - free (edges); - free (body); - return opt_info; -} - -/* Called just before loop duplication. Records start of duplicated area - to OPT_INFO. */ - -static void -opt_info_start_duplication (struct opt_info *opt_info) -{ - if (opt_info) - opt_info->first_new_block = last_basic_block; -} - -/* Determine the number of iterations between initialization of the base - variable and the current copy (N_COPY). N_COPIES is the total number - of newly created copies. UNROLLING is true if we are unrolling - (not peeling) the loop. */ - -static unsigned -determine_split_iv_delta (unsigned n_copy, unsigned n_copies, bool unrolling) -{ - if (unrolling) - { - /* If we are unrolling, initialization is done in the original loop - body (number 0). */ - return n_copy; - } - else - { - /* If we are peeling, the copy in that the initialization occurs has - number 1. The original loop (number 0) is the last. */ - if (n_copy) - return n_copy - 1; - else - return n_copies; - } -} - -/* Locate in EXPR the expression corresponding to the location recorded - in IVTS, and return a pointer to the RTX for this location. */ - -static rtx * -get_ivts_expr (rtx expr, struct iv_to_split *ivts) -{ - unsigned i; - rtx *ret = &expr; - - for (i = 0; i < ivts->n_loc; i++) - ret = &XEXP (*ret, ivts->loc[i]); - - return ret; -} - -/* Allocate basic variable for the induction variable chain. Callback for - htab_traverse. */ - -static int -allocate_basic_variable (void **slot, void *data ATTRIBUTE_UNUSED) -{ - struct iv_to_split *ivts = *slot; - rtx expr = *get_ivts_expr (single_set (ivts->insn), ivts); - - ivts->base_var = gen_reg_rtx (GET_MODE (expr)); - - return 1; -} - -/* Insert initialization of basic variable of IVTS before INSN, taking - the initial value from INSN. */ - -static void -insert_base_initialization (struct iv_to_split *ivts, rtx insn) -{ - rtx expr = copy_rtx (*get_ivts_expr (single_set (insn), ivts)); - rtx seq; - - start_sequence (); - expr = force_operand (expr, ivts->base_var); - if (expr != ivts->base_var) - emit_move_insn (ivts->base_var, expr); - seq = get_insns (); - end_sequence (); - - emit_insn_before (seq, insn); -} - -/* Replace the use of induction variable described in IVTS in INSN - by base variable + DELTA * step. */ - -static void -split_iv (struct iv_to_split *ivts, rtx insn, unsigned delta) -{ - rtx expr, *loc, seq, incr, var; - enum machine_mode mode = GET_MODE (ivts->base_var); - rtx src, dest, set; - - /* Construct base + DELTA * step. */ - if (!delta) - expr = ivts->base_var; - else - { - incr = simplify_gen_binary (MULT, mode, - ivts->step, gen_int_mode (delta, mode)); - expr = simplify_gen_binary (PLUS, GET_MODE (ivts->base_var), - ivts->base_var, incr); - } - - /* Figure out where to do the replacement. */ - loc = get_ivts_expr (single_set (insn), ivts); - - /* If we can make the replacement right away, we're done. */ - if (validate_change (insn, loc, expr, 0)) - return; - - /* Otherwise, force EXPR into a register and try again. */ - start_sequence (); - var = gen_reg_rtx (mode); - expr = force_operand (expr, var); - if (expr != var) - emit_move_insn (var, expr); - seq = get_insns (); - end_sequence (); - emit_insn_before (seq, insn); - - if (validate_change (insn, loc, var, 0)) - return; - - /* The last chance. Try recreating the assignment in insn - completely from scratch. */ - set = single_set (insn); - gcc_assert (set); - - start_sequence (); - *loc = var; - src = copy_rtx (SET_SRC (set)); - dest = copy_rtx (SET_DEST (set)); - src = force_operand (src, dest); - if (src != dest) - emit_move_insn (dest, src); - seq = get_insns (); - end_sequence (); - - emit_insn_before (seq, insn); - delete_insn (insn); -} - - -/* Return one expansion of the accumulator recorded in struct VE. */ - -static rtx -get_expansion (struct var_to_expand *ve) -{ - rtx reg; - - if (ve->reuse_expansion == 0) - reg = ve->reg; - else - reg = VEC_index (rtx, ve->var_expansions, ve->reuse_expansion - 1); - - if (VEC_length (rtx, ve->var_expansions) == (unsigned) ve->reuse_expansion) - ve->reuse_expansion = 0; - else - ve->reuse_expansion++; - - return reg; -} - - -/* Given INSN replace the uses of the accumulator recorded in VE - with a new register. */ - -static void -expand_var_during_unrolling (struct var_to_expand *ve, rtx insn) -{ - rtx new_reg, set; - bool really_new_expansion = false; - - set = single_set (insn); - gcc_assert (set); - - /* Generate a new register only if the expansion limit has not been - reached. Else reuse an already existing expansion. */ - if (PARAM_VALUE (PARAM_MAX_VARIABLE_EXPANSIONS) > ve->expansion_count) - { - really_new_expansion = true; - new_reg = gen_reg_rtx (GET_MODE (ve->reg)); - } - else - new_reg = get_expansion (ve); - - validate_change (insn, &SET_DEST (set), new_reg, 1); - validate_change (insn, &XEXP (SET_SRC (set), 0), new_reg, 1); - - if (apply_change_group ()) - if (really_new_expansion) - { - VEC_safe_push (rtx, heap, ve->var_expansions, new_reg); - ve->expansion_count++; - } -} - -/* Initialize the variable expansions in loop preheader. - Callbacks for htab_traverse. PLACE_P is the loop-preheader - basic block where the initialization of the expansions - should take place. */ - -static int -insert_var_expansion_initialization (void **slot, void *place_p) -{ - struct var_to_expand *ve = *slot; - basic_block place = (basic_block)place_p; - rtx seq, var, zero_init, insn; - unsigned i; - - if (VEC_length (rtx, ve->var_expansions) == 0) - return 1; - - start_sequence (); - if (ve->op == PLUS || ve->op == MINUS) - for (i = 0; VEC_iterate (rtx, ve->var_expansions, i, var); i++) - { - zero_init = CONST0_RTX (GET_MODE (var)); - emit_move_insn (var, zero_init); - } - else if (ve->op == MULT) - for (i = 0; VEC_iterate (rtx, ve->var_expansions, i, var); i++) - { - zero_init = CONST1_RTX (GET_MODE (var)); - emit_move_insn (var, zero_init); - } - - seq = get_insns (); - end_sequence (); - - insn = BB_HEAD (place); - while (!NOTE_INSN_BASIC_BLOCK_P (insn)) - insn = NEXT_INSN (insn); - - emit_insn_after (seq, insn); - /* Continue traversing the hash table. */ - return 1; -} - -/* Combine the variable expansions at the loop exit. - Callbacks for htab_traverse. PLACE_P is the loop exit - basic block where the summation of the expansions should - take place. */ - -static int -combine_var_copies_in_loop_exit (void **slot, void *place_p) -{ - struct var_to_expand *ve = *slot; - basic_block place = (basic_block)place_p; - rtx sum = ve->reg; - rtx expr, seq, var, insn; - unsigned i; - - if (VEC_length (rtx, ve->var_expansions) == 0) - return 1; - - start_sequence (); - if (ve->op == PLUS || ve->op == MINUS) - for (i = 0; VEC_iterate (rtx, ve->var_expansions, i, var); i++) - { - sum = simplify_gen_binary (PLUS, GET_MODE (ve->reg), - var, sum); - } - else if (ve->op == MULT) - for (i = 0; VEC_iterate (rtx, ve->var_expansions, i, var); i++) - { - sum = simplify_gen_binary (MULT, GET_MODE (ve->reg), - var, sum); - } - - expr = force_operand (sum, ve->reg); - if (expr != ve->reg) - emit_move_insn (ve->reg, expr); - seq = get_insns (); - end_sequence (); - - insn = BB_HEAD (place); - while (!NOTE_INSN_BASIC_BLOCK_P (insn)) - insn = NEXT_INSN (insn); - - emit_insn_after (seq, insn); - - /* Continue traversing the hash table. */ - return 1; -} - -/* Apply loop optimizations in loop copies using the - data which gathered during the unrolling. Structure - OPT_INFO record that data. - - UNROLLING is true if we unrolled (not peeled) the loop. - REWRITE_ORIGINAL_BODY is true if we should also rewrite the original body of - the loop (as it should happen in complete unrolling, but not in ordinary - peeling of the loop). */ - -static void -apply_opt_in_copies (struct opt_info *opt_info, - unsigned n_copies, bool unrolling, - bool rewrite_original_loop) -{ - unsigned i, delta; - basic_block bb, orig_bb; - rtx insn, orig_insn, next; - struct iv_to_split ivts_templ, *ivts; - struct var_to_expand ve_templ, *ves; - - /* Sanity check -- we need to put initialization in the original loop - body. */ - gcc_assert (!unrolling || rewrite_original_loop); - - /* Allocate the basic variables (i0). */ - if (opt_info->insns_to_split) - htab_traverse (opt_info->insns_to_split, allocate_basic_variable, NULL); - - for (i = opt_info->first_new_block; i < (unsigned) last_basic_block; i++) - { - bb = BASIC_BLOCK (i); - orig_bb = get_bb_original (bb); - - /* bb->aux holds position in copy sequence initialized by - duplicate_loop_to_header_edge. */ - delta = determine_split_iv_delta ((size_t)bb->aux, n_copies, - unrolling); - bb->aux = 0; - orig_insn = BB_HEAD (orig_bb); - for (insn = BB_HEAD (bb); insn != NEXT_INSN (BB_END (bb)); insn = next) - { - next = NEXT_INSN (insn); - if (!INSN_P (insn)) - continue; - - while (!INSN_P (orig_insn)) - orig_insn = NEXT_INSN (orig_insn); - - ivts_templ.insn = orig_insn; - ve_templ.insn = orig_insn; - - /* Apply splitting iv optimization. */ - if (opt_info->insns_to_split) - { - ivts = htab_find (opt_info->insns_to_split, &ivts_templ); - - if (ivts) - { - gcc_assert (GET_CODE (PATTERN (insn)) - == GET_CODE (PATTERN (orig_insn))); - - if (!delta) - insert_base_initialization (ivts, insn); - split_iv (ivts, insn, delta); - } - } - /* Apply variable expansion optimization. */ - if (unrolling && opt_info->insns_with_var_to_expand) - { - ves = htab_find (opt_info->insns_with_var_to_expand, &ve_templ); - if (ves) - { - gcc_assert (GET_CODE (PATTERN (insn)) - == GET_CODE (PATTERN (orig_insn))); - expand_var_during_unrolling (ves, insn); - } - } - orig_insn = NEXT_INSN (orig_insn); - } - } - - if (!rewrite_original_loop) - return; - - /* Initialize the variable expansions in the loop preheader - and take care of combining them at the loop exit. */ - if (opt_info->insns_with_var_to_expand) - { - htab_traverse (opt_info->insns_with_var_to_expand, - insert_var_expansion_initialization, - opt_info->loop_preheader); - htab_traverse (opt_info->insns_with_var_to_expand, - combine_var_copies_in_loop_exit, - opt_info->loop_exit); - } - - /* Rewrite also the original loop body. Find them as originals of the blocks - in the last copied iteration, i.e. those that have - get_bb_copy (get_bb_original (bb)) == bb. */ - for (i = opt_info->first_new_block; i < (unsigned) last_basic_block; i++) - { - bb = BASIC_BLOCK (i); - orig_bb = get_bb_original (bb); - if (get_bb_copy (orig_bb) != bb) - continue; - - delta = determine_split_iv_delta (0, n_copies, unrolling); - for (orig_insn = BB_HEAD (orig_bb); - orig_insn != NEXT_INSN (BB_END (bb)); - orig_insn = next) - { - next = NEXT_INSN (orig_insn); - - if (!INSN_P (orig_insn)) - continue; - - ivts_templ.insn = orig_insn; - if (opt_info->insns_to_split) - { - ivts = htab_find (opt_info->insns_to_split, &ivts_templ); - if (ivts) - { - if (!delta) - insert_base_initialization (ivts, orig_insn); - split_iv (ivts, orig_insn, delta); - continue; - } - } - - } - } -} - -/* Release the data structures used for the variable expansion - optimization. Callbacks for htab_traverse. */ - -static int -release_var_copies (void **slot, void *data ATTRIBUTE_UNUSED) -{ - struct var_to_expand *ve = *slot; - - VEC_free (rtx, heap, ve->var_expansions); - - /* Continue traversing the hash table. */ - return 1; -} - -/* Release OPT_INFO. */ - -static void -free_opt_info (struct opt_info *opt_info) -{ - if (opt_info->insns_to_split) - htab_delete (opt_info->insns_to_split); - if (opt_info->insns_with_var_to_expand) - { - htab_traverse (opt_info->insns_with_var_to_expand, - release_var_copies, NULL); - htab_delete (opt_info->insns_with_var_to_expand); - } - free (opt_info); -} |