| /* Loop unrolling. |
| Copyright (C) 2002-2017 Free Software Foundation, Inc. |
| |
| This file is part of GCC. |
| |
| GCC is free software; you can redistribute it and/or modify it under |
| the terms of the GNU General Public License as published by the Free |
| Software Foundation; either version 3, or (at your option) any later |
| version. |
| |
| GCC is distributed in the hope that it will be useful, but WITHOUT ANY |
| WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GCC; see the file COPYING3. If not see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include "config.h" |
| #include "system.h" |
| #include "coretypes.h" |
| #include "backend.h" |
| #include "target.h" |
| #include "rtl.h" |
| #include "tree.h" |
| #include "cfghooks.h" |
| #include "memmodel.h" |
| #include "optabs.h" |
| #include "emit-rtl.h" |
| #include "recog.h" |
| #include "profile.h" |
| #include "cfgrtl.h" |
| #include "cfgloop.h" |
| #include "params.h" |
| #include "dojump.h" |
| #include "expr.h" |
| #include "dumpfile.h" |
| |
| /* This pass performs loop unrolling. We only perform this |
| optimization 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: |
| |
| -- 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. |
| |
| ??? 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 *insn; /* The insn in that the induction variable occurs. */ |
| rtx orig_var; /* The variable (register) for the IV before split. */ |
| rtx base_var; /* The variable on that the values in the further |
| iterations are based. */ |
| rtx step; /* Step of the induction variable. */ |
| struct iv_to_split *next; /* Next entry in walking order. */ |
| }; |
| |
| /* Information about accumulators to expand. */ |
| |
| struct var_to_expand |
| { |
| rtx_insn *insn; /* The insn in that the variable expansion occurs. */ |
| rtx reg; /* The accumulator which is expanded. */ |
| vec<rtx> var_expansions; /* The copies of the accumulator which is expanded. */ |
| struct var_to_expand *next; /* Next entry in walking order. */ |
| 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]. */ |
| }; |
| |
| /* Hashtable helper for iv_to_split. */ |
| |
| struct iv_split_hasher : free_ptr_hash <iv_to_split> |
| { |
| static inline hashval_t hash (const iv_to_split *); |
| static inline bool equal (const iv_to_split *, const iv_to_split *); |
| }; |
| |
| |
| /* A hash function for information about insns to split. */ |
| |
| inline hashval_t |
| iv_split_hasher::hash (const iv_to_split *ivts) |
| { |
| return (hashval_t) INSN_UID (ivts->insn); |
| } |
| |
| /* An equality functions for information about insns to split. */ |
| |
| inline bool |
| iv_split_hasher::equal (const iv_to_split *i1, const iv_to_split *i2) |
| { |
| return i1->insn == i2->insn; |
| } |
| |
| /* Hashtable helper for iv_to_split. */ |
| |
| struct var_expand_hasher : free_ptr_hash <var_to_expand> |
| { |
| static inline hashval_t hash (const var_to_expand *); |
| static inline bool equal (const var_to_expand *, const var_to_expand *); |
| }; |
| |
| /* Return a hash for VES. */ |
| |
| inline hashval_t |
| var_expand_hasher::hash (const var_to_expand *ves) |
| { |
| return (hashval_t) INSN_UID (ves->insn); |
| } |
| |
| /* Return true if I1 and I2 refer to the same instruction. */ |
| |
| inline bool |
| var_expand_hasher::equal (const var_to_expand *i1, const var_to_expand *i2) |
| { |
| return i1->insn == i2->insn; |
| } |
| |
| /* Information about optimization applied in |
| the unrolled loop. */ |
| |
| struct opt_info |
| { |
| hash_table<iv_split_hasher> *insns_to_split; /* A hashtable of insns to |
| split. */ |
| struct iv_to_split *iv_to_split_head; /* The first iv to split. */ |
| struct iv_to_split **iv_to_split_tail; /* Pointer to the tail of the list. */ |
| hash_table<var_expand_hasher> *insns_with_var_to_expand; /* A hashtable of |
| insns with accumulators to expand. */ |
| struct var_to_expand *var_to_expand_head; /* The first var to expand. */ |
| struct var_to_expand **var_to_expand_tail; /* Pointer to the tail of the list. */ |
| 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_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 unroll_loop_stupid (struct loop *); |
| static void decide_unrolling (int); |
| static void unroll_loop_constant_iterations (struct loop *); |
| static void unroll_loop_runtime_iterations (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_insn *); |
| static bool referenced_in_one_insn_in_loop_p (struct loop *, rtx, int *); |
| static struct iv_to_split *analyze_iv_to_split_insn (rtx_insn *); |
| static void expand_var_during_unrolling (struct var_to_expand *, rtx_insn *); |
| static void insert_var_expansion_initialization (struct var_to_expand *, |
| basic_block); |
| static void combine_var_copies_in_loop_exit (struct var_to_expand *, |
| basic_block); |
| static rtx get_expansion (struct var_to_expand *); |
| |
| /* Emit a message summarizing the unroll that will be |
| performed for LOOP, along with the loop's location LOCUS, if |
| appropriate given the dump or -fopt-info settings. */ |
| |
| static void |
| report_unroll (struct loop *loop, location_t locus) |
| { |
| int report_flags = MSG_OPTIMIZED_LOCATIONS | TDF_RTL | TDF_DETAILS; |
| |
| if (loop->lpt_decision.decision == LPT_NONE) |
| return; |
| |
| if (!dump_enabled_p ()) |
| return; |
| |
| dump_printf_loc (report_flags, locus, |
| "loop unrolled %d times", |
| loop->lpt_decision.times); |
| if (profile_info) |
| dump_printf (report_flags, |
| " (header execution count %d)", |
| (int)loop->header->count); |
| |
| dump_printf (report_flags, "\n"); |
| } |
| |
| /* Decide whether unroll loops and how much. */ |
| static void |
| decide_unrolling (int flags) |
| { |
| struct loop *loop; |
| |
| /* Scan the loops, inner ones first. */ |
| FOR_EACH_LOOP (loop, LI_FROM_INNERMOST) |
| { |
| loop->lpt_decision.decision = LPT_NONE; |
| location_t locus = get_loop_location (loop); |
| |
| if (dump_enabled_p ()) |
| dump_printf_loc (TDF_RTL, locus, |
| ";; *** Considering loop %d at BB %d for " |
| "unrolling ***\n", |
| loop->num, loop->header->index); |
| |
| /* Do not peel cold areas. */ |
| if (optimize_loop_for_size_p (loop)) |
| { |
| if (dump_file) |
| fprintf (dump_file, ";; Not considering loop, cold area\n"); |
| continue; |
| } |
| |
| /* Can the loop be manipulated? */ |
| if (!can_duplicate_loop_p (loop)) |
| { |
| if (dump_file) |
| fprintf (dump_file, |
| ";; Not considering loop, cannot duplicate\n"); |
| continue; |
| } |
| |
| /* Skip non-innermost loops. */ |
| if (loop->inner) |
| { |
| if (dump_file) |
| fprintf (dump_file, ";; Not considering loop, is not innermost\n"); |
| 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); |
| |
| report_unroll (loop, locus); |
| } |
| } |
| |
| /* Unroll LOOPS. */ |
| void |
| unroll_loops (int flags) |
| { |
| struct loop *loop; |
| bool changed = false; |
| |
| /* Now decide rest of unrolling. */ |
| decide_unrolling (flags); |
| |
| /* Scan the loops, inner ones first. */ |
| FOR_EACH_LOOP (loop, LI_FROM_INNERMOST) |
| { |
| /* And perform the appropriate transformations. */ |
| switch (loop->lpt_decision.decision) |
| { |
| case LPT_UNROLL_CONSTANT: |
| unroll_loop_constant_iterations (loop); |
| changed = true; |
| break; |
| case LPT_UNROLL_RUNTIME: |
| unroll_loop_runtime_iterations (loop); |
| changed = true; |
| break; |
| case LPT_UNROLL_STUPID: |
| unroll_loop_stupid (loop); |
| changed = true; |
| break; |
| case LPT_NONE: |
| break; |
| default: |
| gcc_unreachable (); |
| } |
| } |
| |
| if (changed) |
| { |
| calculate_dominance_info (CDI_DOMINATORS); |
| fix_loop_structure (NULL); |
| } |
| |
| 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 *insn; |
| |
| /* We should never have conditional in latch block. */ |
| gcc_assert (desc->in_edge->dest != loop->header); |
| |
| 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) && active_insn_p (insn)) |
| return false; |
| } |
| |
| return true; |
| } |
| |
| /* 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; |
| widest_int iterations; |
| |
| 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); |
| |
| if (targetm.loop_unroll_adjust) |
| nunroll = targetm.loop_unroll_adjust (nunroll, loop); |
| |
| /* 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. |
| Consult also loop bounds and profile; in the case the loop has more |
| than one exit it may well loop less than determined maximal number |
| of iterations. */ |
| if (desc->niter < 2 * nunroll |
| || ((get_estimated_loop_iterations (loop, &iterations) |
| || get_likely_max_loop_iterations (loop, &iterations)) |
| && wi::ltu_p (iterations, 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; |
| } |
| } |
| |
| loop->lpt_decision.decision = LPT_UNROLL_CONSTANT; |
| loop->lpt_decision.times = best_unroll; |
| } |
| |
| /* Unroll LOOP with constant number of iterations LOOP->LPT_DECISION.TIMES times. |
| The transformation does this: |
| |
| for (i = 0; i < 102; i++) |
| body; |
| |
| ==> (LOOP->LPT_DECISION.TIMES == 3) |
| |
| i = 0; |
| body; i++; |
| body; i++; |
| while (i < 102) |
| { |
| body; i++; |
| body; i++; |
| body; i++; |
| body; i++; |
| } |
| */ |
| static void |
| unroll_loop_constant_iterations (struct loop *loop) |
| { |
| unsigned HOST_WIDE_INT niter; |
| unsigned exit_mod; |
| unsigned i; |
| edge e; |
| 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); |
| |
| auto_sbitmap wont_exit (max_unroll + 2); |
| bitmap_ones (wont_exit); |
| |
| auto_vec<edge> remove_edges; |
| 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 at beginning of loop.\n"); |
| |
| /* Peel exit_mod iterations. */ |
| bitmap_clear_bit (wont_exit, 0); |
| if (desc->noloop_assumptions) |
| bitmap_clear_bit (wont_exit, 1); |
| |
| if (exit_mod) |
| { |
| opt_info_start_duplication (opt_info); |
| ok = duplicate_loop_to_header_edge (loop, loop_preheader_edge (loop), |
| exit_mod, |
| wont_exit, desc->out_edge, |
| &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; |
| loop->nb_iterations_upper_bound -= exit_mod; |
| if (loop->any_estimate |
| && wi::leu_p (exit_mod, loop->nb_iterations_estimate)) |
| loop->nb_iterations_estimate -= exit_mod; |
| else |
| loop->any_estimate = false; |
| if (loop->any_likely_upper_bound |
| && wi::leu_p (exit_mod, loop->nb_iterations_likely_upper_bound)) |
| loop->nb_iterations_likely_upper_bound -= exit_mod; |
| else |
| loop->any_likely_upper_bound = false; |
| } |
| |
| bitmap_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 at 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) |
| { |
| bitmap_clear_bit (wont_exit, 0); |
| if (desc->noloop_assumptions) |
| bitmap_clear_bit (wont_exit, 1); |
| |
| opt_info_start_duplication (opt_info); |
| ok = duplicate_loop_to_header_edge (loop, loop_preheader_edge (loop), |
| exit_mod + 1, |
| wont_exit, desc->out_edge, |
| &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; |
| loop->nb_iterations_upper_bound -= exit_mod + 1; |
| if (loop->any_estimate |
| && wi::leu_p (exit_mod + 1, loop->nb_iterations_estimate)) |
| loop->nb_iterations_estimate -= exit_mod + 1; |
| else |
| loop->any_estimate = false; |
| if (loop->any_likely_upper_bound |
| && wi::leu_p (exit_mod + 1, loop->nb_iterations_likely_upper_bound)) |
| loop->nb_iterations_likely_upper_bound -= exit_mod + 1; |
| else |
| loop->any_likely_upper_bound = false; |
| desc->noloop_assumptions = NULL_RTX; |
| |
| bitmap_set_bit (wont_exit, 0); |
| bitmap_set_bit (wont_exit, 1); |
| } |
| |
| bitmap_clear_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), |
| max_unroll, |
| wont_exit, desc->out_edge, |
| &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); |
| } |
| |
| 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; |
| loop->nb_iterations_upper_bound |
| = wi::udiv_trunc (loop->nb_iterations_upper_bound, max_unroll + 1); |
| if (loop->any_estimate) |
| loop->nb_iterations_estimate |
| = wi::udiv_trunc (loop->nb_iterations_estimate, max_unroll + 1); |
| if (loop->any_likely_upper_bound) |
| loop->nb_iterations_likely_upper_bound |
| = wi::udiv_trunc (loop->nb_iterations_likely_upper_bound, max_unroll + 1); |
| desc->niter_expr = gen_int_mode (desc->niter, desc->mode); |
| |
| /* Remove the edges. */ |
| FOR_EACH_VEC_ELT (remove_edges, i, e) |
| remove_path (e); |
| |
| 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; |
| widest_int iterations; |
| |
| 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); |
| |
| if (targetm.loop_unroll_adjust) |
| nunroll = targetm.loop_unroll_adjust (nunroll, loop); |
| |
| /* 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; |
| } |
| |
| /* Check whether the loop rolls. */ |
| if ((get_estimated_loop_iterations (loop, &iterations) |
| || get_likely_max_loop_iterations (loop, &iterations)) |
| && wi::ltu_p (iterations, 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; |
| } |
| |
| /* Splits edge E and inserts the sequence of instructions INSNS on it, and |
| returns the newly created block. If INSNS is NULL_RTX, nothing is changed |
| and NULL is returned instead. */ |
| |
| basic_block |
| split_edge_and_insert (edge e, rtx_insn *insns) |
| { |
| basic_block bb; |
| |
| if (!insns) |
| return NULL; |
| bb = split_edge (e); |
| emit_insn_after (insns, BB_END (bb)); |
| |
| /* ??? We used to assume that INSNS can contain control flow insns, and |
| that we had to try to find sub basic blocks in BB to maintain a valid |
| CFG. For this purpose we used to set the BB_SUPERBLOCK flag on BB |
| and call break_superblocks when going out of cfglayout mode. But it |
| turns out that this never happens; and that if it does ever happen, |
| the verify_flow_info at the end of the RTL loop passes would fail. |
| |
| There are two reasons why we expected we could have control flow insns |
| in INSNS. The first is when a comparison has to be done in parts, and |
| the second is when the number of iterations is computed for loops with |
| the number of iterations known at runtime. In both cases, test cases |
| to get control flow in INSNS appear to be impossible to construct: |
| |
| * If do_compare_rtx_and_jump needs several branches to do comparison |
| in a mode that needs comparison by parts, we cannot analyze the |
| number of iterations of the loop, and we never get to unrolling it. |
| |
| * The code in expand_divmod that was suspected to cause creation of |
| branching code seems to be only accessed for signed division. The |
| divisions used by # of iterations analysis are always unsigned. |
| Problems might arise on architectures that emits branching code |
| for some operations that may appear in the unroller (especially |
| for division), but we have no such architectures. |
| |
| Considering all this, it was decided that we should for now assume |
| that INSNS can in theory contain control flow insns, but in practice |
| it never does. So we don't handle the theoretical case, and should |
| a real failure ever show up, we have a pretty good clue for how to |
| fix it. */ |
| |
| return bb; |
| } |
| |
| /* Prepare a sequence comparing OP0 with OP1 using COMP and jumping to LABEL if |
| true, with probability PROB. If CINSN is not NULL, it is the insn to copy |
| in order to create a jump. */ |
| |
| static rtx_insn * |
| compare_and_jump_seq (rtx op0, rtx op1, enum rtx_code comp, |
| rtx_code_label *label, int prob, rtx_insn *cinsn) |
| { |
| rtx_insn *seq; |
| rtx_jump_insn *jump; |
| rtx cond; |
| machine_mode mode; |
| |
| mode = GET_MODE (op0); |
| if (mode == VOIDmode) |
| mode = GET_MODE (op1); |
| |
| start_sequence (); |
| if (GET_MODE_CLASS (mode) == MODE_CC) |
| { |
| /* A hack -- there seems to be no easy generic way how to make a |
| conditional jump from a ccmode comparison. */ |
| gcc_assert (cinsn); |
| cond = XEXP (SET_SRC (pc_set (cinsn)), 0); |
| gcc_assert (GET_CODE (cond) == comp); |
| gcc_assert (rtx_equal_p (op0, XEXP (cond, 0))); |
| gcc_assert (rtx_equal_p (op1, XEXP (cond, 1))); |
| emit_jump_insn (copy_insn (PATTERN (cinsn))); |
| jump = as_a <rtx_jump_insn *> (get_last_insn ()); |
| JUMP_LABEL (jump) = JUMP_LABEL (cinsn); |
| LABEL_NUSES (JUMP_LABEL (jump))++; |
| redirect_jump (jump, label, 0); |
| } |
| else |
| { |
| gcc_assert (!cinsn); |
| |
| op0 = force_operand (op0, NULL_RTX); |
| op1 = force_operand (op1, NULL_RTX); |
| do_compare_rtx_and_jump (op0, op1, comp, 0, |
| mode, NULL_RTX, NULL, label, -1); |
| jump = as_a <rtx_jump_insn *> (get_last_insn ()); |
| jump->set_jump_target (label); |
| LABEL_NUSES (label)++; |
| } |
| add_int_reg_note (jump, REG_BR_PROB, prob); |
| |
| seq = get_insns (); |
| end_sequence (); |
| |
| return seq; |
| } |
| |
| /* Unroll LOOP for which we are able to count number of iterations in runtime |
| LOOP->LPT_DECISION.TIMES times. The transformation does this (with some |
| extra care for case n < 0): |
| |
| for (i = 0; i < n; i++) |
| body; |
| |
| ==> (LOOP->LPT_DECISION.TIMES == 3) |
| |
| 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 loop *loop) |
| { |
| rtx old_niter, niter, tmp; |
| rtx_insn *init_code, *branch_code; |
| unsigned i, j, p; |
| basic_block preheader, *body, swtch, ezc_swtch = NULL; |
| int may_exit_copy, iter_freq, new_freq; |
| gcov_type iter_count, new_count; |
| unsigned n_peel; |
| edge 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. */ |
| auto_vec<basic_block> dom_bbs; |
| |
| body = get_loop_body (loop); |
| for (i = 0; i < loop->num_nodes; i++) |
| { |
| vec<basic_block> ldom; |
| basic_block bb; |
| |
| ldom = get_dominated_by (CDI_DOMINATORS, body[i]); |
| FOR_EACH_VEC_ELT (ldom, j, bb) |
| if (!flow_bb_inside_loop_p (loop, bb)) |
| dom_bbs.safe_push (bb); |
| |
| ldom.release (); |
| } |
| 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); |
| |
| /* For loops that exit at end and whose number of iterations is reliable, |
| add one to niter to account for first pass through loop body before |
| reaching exit test. */ |
| if (exit_at_end && !desc->noloop_assumptions) |
| { |
| niter = expand_simple_binop (desc->mode, PLUS, |
| niter, const1_rtx, |
| NULL_RTX, 0, OPTAB_LIB_WIDEN); |
| old_niter = niter; |
| } |
| |
| /* 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_mode (max_unroll, desc->mode), |
| NULL_RTX, 0, OPTAB_LIB_WIDEN); |
| |
| init_code = get_insns (); |
| end_sequence (); |
| unshare_all_rtl_in_chain (init_code); |
| |
| /* Precondition the loop. */ |
| split_edge_and_insert (loop_preheader_edge (loop), init_code); |
| |
| auto_vec<edge> remove_edges; |
| |
| auto_sbitmap wont_exit (max_unroll + 2); |
| |
| if (extra_zero_check || desc->noloop_assumptions) |
| { |
| /* Peel the first copy of loop body. Leave the exit test if the number |
| of iterations is not reliable. Also record the place of the extra zero |
| check. */ |
| bitmap_clear (wont_exit); |
| if (!desc->noloop_assumptions) |
| bitmap_set_bit (wont_exit, 1); |
| ezc_swtch = loop_preheader_edge (loop)->src; |
| ok = duplicate_loop_to_header_edge (loop, loop_preheader_edge (loop), |
| 1, wont_exit, desc->out_edge, |
| &remove_edges, |
| DLTHE_FLAG_UPDATE_FREQ); |
| gcc_assert (ok); |
| } |
| |
| /* Record the place where switch will be built for preconditioning. */ |
| swtch = split_edge (loop_preheader_edge (loop)); |
| |
| /* Compute frequency/count increments for each switch block and initialize |
| innermost switch block. Switch blocks and peeled loop copies are built |
| from innermost outward. */ |
| iter_freq = new_freq = swtch->frequency / (max_unroll + 1); |
| iter_count = new_count = swtch->count / (max_unroll + 1); |
| swtch->frequency = new_freq; |
| swtch->count = new_count; |
| single_succ_edge (swtch)->count = new_count; |
| |
| for (i = 0; i < n_peel; i++) |
| { |
| /* Peel the copy. */ |
| bitmap_clear (wont_exit); |
| if (i != n_peel - 1 || !last_may_exit) |
| bitmap_set_bit (wont_exit, 1); |
| ok = duplicate_loop_to_header_edge (loop, loop_preheader_edge (loop), |
| 1, wont_exit, desc->out_edge, |
| &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 = split_edge (loop_preheader_edge (loop)); |
| /* Add in frequency/count of edge from switch block. */ |
| preheader->frequency += iter_freq; |
| preheader->count += iter_count; |
| single_succ_edge (preheader)->count = preheader->count; |
| branch_code = compare_and_jump_seq (copy_rtx (niter), |
| gen_int_mode (j, desc->mode), EQ, |
| block_label (preheader), p, |
| NULL); |
| |
| /* We rely on the fact that the compare and jump cannot be optimized out, |
| and hence the cfg we create is correct. */ |
| gcc_assert (branch_code != NULL_RTX); |
| |
| swtch = split_edge_and_insert (single_pred_edge (swtch), branch_code); |
| set_immediate_dominator (CDI_DOMINATORS, preheader, swtch); |
| single_succ_edge (swtch)->probability = REG_BR_PROB_BASE - p; |
| single_succ_edge (swtch)->count = new_count; |
| new_freq += iter_freq; |
| new_count += iter_count; |
| swtch->frequency = new_freq; |
| swtch->count = new_count; |
| e = make_edge (swtch, preheader, |
| single_succ_edge (swtch)->flags & EDGE_IRREDUCIBLE_LOOP); |
| e->count = iter_count; |
| e->probability = p; |
| } |
| |
| if (extra_zero_check) |
| { |
| /* Add branch for zero iterations. */ |
| p = REG_BR_PROB_BASE / (max_unroll + 1); |
| swtch = ezc_swtch; |
| preheader = split_edge (loop_preheader_edge (loop)); |
| /* Recompute frequency/count adjustments since initial peel copy may |
| have exited and reduced those values that were computed above. */ |
| iter_freq = swtch->frequency / (max_unroll + 1); |
| iter_count = swtch->count / (max_unroll + 1); |
| /* Add in frequency/count of edge from switch block. */ |
| preheader->frequency += iter_freq; |
| preheader->count += iter_count; |
| single_succ_edge (preheader)->count = preheader->count; |
| branch_code = compare_and_jump_seq (copy_rtx (niter), const0_rtx, EQ, |
| block_label (preheader), p, |
| NULL); |
| gcc_assert (branch_code != NULL_RTX); |
| |
| swtch = split_edge_and_insert (single_succ_edge (swtch), branch_code); |
| set_immediate_dominator (CDI_DOMINATORS, preheader, swtch); |
| single_succ_edge (swtch)->probability = REG_BR_PROB_BASE - p; |
| single_succ_edge (swtch)->count -= iter_count; |
| e = make_edge (swtch, preheader, |
| single_succ_edge (swtch)->flags & EDGE_IRREDUCIBLE_LOOP); |
| e->count = iter_count; |
| e->probability = p; |
| } |
| |
| /* Recount dominators for outer blocks. */ |
| iterate_fix_dominators (CDI_DOMINATORS, dom_bbs, false); |
| |
| /* And unroll loop. */ |
| |
| bitmap_ones (wont_exit); |
| bitmap_clear_bit (wont_exit, may_exit_copy); |
| opt_info_start_duplication (opt_info); |
| |
| ok = duplicate_loop_to_header_edge (loop, loop_latch_edge (loop), |
| max_unroll, |
| wont_exit, desc->out_edge, |
| &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); |
| } |
| |
| 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_EACH_VEC_ELT (remove_edges, i, e) |
| remove_path (e); |
| |
| /* 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_mode (max_unroll + 1, desc->mode)); |
| loop->nb_iterations_upper_bound |
| = wi::udiv_trunc (loop->nb_iterations_upper_bound, max_unroll + 1); |
| if (loop->any_estimate) |
| loop->nb_iterations_estimate |
| = wi::udiv_trunc (loop->nb_iterations_estimate, max_unroll + 1); |
| if (loop->any_likely_upper_bound) |
| loop->nb_iterations_likely_upper_bound |
| = wi::udiv_trunc (loop->nb_iterations_likely_upper_bound, 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; |
| --loop->nb_iterations_upper_bound; |
| if (loop->any_estimate |
| && loop->nb_iterations_estimate != 0) |
| --loop->nb_iterations_estimate; |
| else |
| loop->any_estimate = false; |
| if (loop->any_likely_upper_bound |
| && loop->nb_iterations_likely_upper_bound != 0) |
| --loop->nb_iterations_likely_upper_bound; |
| else |
| loop->any_likely_upper_bound = false; |
| } |
| |
| if (dump_file) |
| fprintf (dump_file, |
| ";; Unrolled loop %d times, counting # of iterations " |
| "in runtime, %i insns\n", |
| max_unroll, num_loop_insns (loop)); |
| } |
| |
| /* 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; |
| widest_int iterations; |
| |
| 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); |
| |
| if (targetm.loop_unroll_adjust) |
| nunroll = targetm.loop_unroll_adjust (nunroll, loop); |
| |
| /* 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. |
| TODO: this heuristic needs tunning; call inside the loop body |
| is also relatively good reason to not unroll. */ |
| if (num_loop_branches (loop) > 1) |
| { |
| if (dump_file) |
| fprintf (dump_file, ";; Not unrolling, contains branches\n"); |
| return; |
| } |
| |
| /* Check whether the loop rolls. */ |
| if ((get_estimated_loop_iterations (loop, &iterations) |
| || get_likely_max_loop_iterations (loop, &iterations)) |
| && wi::ltu_p (iterations, 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; |
| } |
| |
| /* Unroll a LOOP LOOP->LPT_DECISION.TIMES times. The transformation does this: |
| |
| while (cond) |
| body; |
| |
| ==> (LOOP->LPT_DECISION.TIMES == 3) |
| |
| while (cond) |
| { |
| body; |
| if (!cond) break; |
| body; |
| if (!cond) break; |
| body; |
| if (!cond) break; |
| body; |
| } |
| */ |
| static void |
| unroll_loop_stupid (struct loop *loop) |
| { |
| 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); |
| |
| auto_sbitmap wont_exit (nunroll + 1); |
| bitmap_clear (wont_exit); |
| opt_info_start_duplication (opt_info); |
| |
| ok = duplicate_loop_to_header_edge (loop, loop_latch_edge (loop), |
| nunroll, wont_exit, |
| 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); |
| } |
| |
| 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 no one 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)); |
| } |
| |
| /* Returns true if REG is referenced in one nondebug insn in LOOP. |
| Set *DEBUG_USES to the number of debug insns that reference the |
| variable. */ |
| |
| static bool |
| referenced_in_one_insn_in_loop_p (struct loop *loop, rtx reg, |
| int *debug_uses) |
| { |
| basic_block *body, bb; |
| unsigned i; |
| int count_ref = 0; |
| rtx_insn *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)) |
| continue; |
| else if (DEBUG_INSN_P (insn)) |
| ++*debug_uses; |
| else if (++count_ref > 1) |
| break; |
| } |
| free (body); |
| return (count_ref == 1); |
| } |
| |
| /* Reset the DEBUG_USES debug insns in LOOP that reference REG. */ |
| |
| static void |
| reset_debug_uses_in_loop (struct loop *loop, rtx reg, int debug_uses) |
| { |
| basic_block *body, bb; |
| unsigned i; |
| rtx_insn *insn; |
| |
| body = get_loop_body (loop); |
| for (i = 0; debug_uses && i < loop->num_nodes; i++) |
| { |
| bb = body[i]; |
| |
| FOR_BB_INSNS (bb, insn) |
| if (!DEBUG_INSN_P (insn) || !rtx_referenced_p (reg, insn)) |
| continue; |
| else |
| { |
| validate_change (insn, &INSN_VAR_LOCATION_LOC (insn), |
| gen_rtx_UNKNOWN_VAR_LOC (), 0); |
| if (!--debug_uses) |
| break; |
| } |
| } |
| free (body); |
| } |
| |
| /* 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 *insn) |
| { |
| rtx set, dest, src; |
| struct var_to_expand *ves; |
| unsigned accum_pos; |
| enum rtx_code code; |
| int debug_uses = 0; |
| |
| set = single_set (insn); |
| if (!set) |
| return NULL; |
| |
| dest = SET_DEST (set); |
| src = SET_SRC (set); |
| code = GET_CODE (src); |
| |
| if (code != PLUS && code != MINUS && code != MULT && code != FMA) |
| return NULL; |
| |
| if (FLOAT_MODE_P (GET_MODE (dest))) |
| { |
| if (!flag_associative_math) |
| return NULL; |
| /* In the case of FMA, we're also changing the rounding. */ |
| if (code == FMA && !flag_unsafe_math_optimizations) |
| 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 (code, GET_MODE (src))) |
| return NULL; |
| |
| if (!REG_P (dest) |
| && !(GET_CODE (dest) == SUBREG |
| && REG_P (SUBREG_REG (dest)))) |
| return NULL; |
| |
| /* Find the accumulator use within the operation. */ |
| if (code == FMA) |
| { |
| /* We only support accumulation via FMA in the ADD position. */ |
| if (!rtx_equal_p (dest, XEXP (src, 2))) |
| return NULL; |
| accum_pos = 2; |
| } |
| else if (rtx_equal_p (dest, XEXP (src, 0))) |
| accum_pos = 0; |
| else if (rtx_equal_p (dest, XEXP (src, 1))) |
| { |
| /* The method of expansion that we are using; which includes the |
| initialization of the expansions with zero and the summation of |
| the expansions at the end of the computation will yield wrong |
| results for (x = something - x) thus avoid using it in that case. */ |
| if (code == MINUS) |
| return NULL; |
| accum_pos = 1; |
| } |
| else |
| return NULL; |
| |
| /* It must not otherwise be used. */ |
| if (code == FMA) |
| { |
| if (rtx_referenced_p (dest, XEXP (src, 0)) |
| || rtx_referenced_p (dest, XEXP (src, 1))) |
| return NULL; |
| } |
| else if (rtx_referenced_p (dest, XEXP (src, 1 - accum_pos))) |
| return NULL; |
| |
| /* It must be used in exactly one insn. */ |
| if (!referenced_in_one_insn_in_loop_p (loop, dest, &debug_uses)) |
| return NULL; |
| |
| if (dump_file) |
| { |
| fprintf (dump_file, "\n;; Expanding Accumulator "); |
| print_rtl (dump_file, dest); |
| fprintf (dump_file, "\n"); |
| } |
| |
| if (debug_uses) |
| /* Instead of resetting the debug insns, we could replace each |
| debug use in the loop with the sum or product of all expanded |
| accumulators. Since we'll only know of all expansions at the |
| end, we'd have to keep track of which vars_to_expand a debug |
| insn in the loop references, take note of each copy of the |
| debug insn during unrolling, and when it's all done, compute |
| the sum or product of each variable and adjust the original |
| debug insn and each copy thereof. What a pain! */ |
| reset_debug_uses_in_loop (loop, dest, debug_uses); |
| |
| /* Record the accumulator to expand. */ |
| ves = XNEW (struct var_to_expand); |
| ves->insn = insn; |
| ves->reg = copy_rtx (dest); |
| ves->var_expansions.create (1); |
| ves->next = NULL; |
| 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 *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->orig_var = dest; |
| ivts->base_var = NULL_RTX; |
| ivts->step = iv.step; |
| ivts->next = NULL; |
| |
| 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; |
| struct opt_info *opt_info = XCNEW (struct opt_info); |
| rtx_insn *insn; |
| struct iv_to_split *ivts = NULL; |
| struct var_to_expand *ves = NULL; |
| iv_to_split **slot1; |
| var_to_expand **slot2; |
| vec<edge> edges = get_loop_exit_edges (loop); |
| edge exit; |
| 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 |
| = new hash_table<iv_split_hasher> (5 * loop->num_nodes); |
| opt_info->iv_to_split_head = NULL; |
| opt_info->iv_to_split_tail = &opt_info->iv_to_split_head; |
| } |
| |
| /* Record the loop exit bb and loop preheader before the unrolling. */ |
| opt_info->loop_preheader = loop_preheader_edge (loop)->src; |
| |
| if (edges.length () == 1) |
| { |
| exit = edges[0]; |
| if (!(exit->flags & EDGE_COMPLEX)) |
| { |
| opt_info->loop_exit = split_edge (exit); |
| can_apply = true; |
| } |
| } |
| |
| if (flag_variable_expansion_in_unroller |
| && can_apply) |
| { |
| opt_info->insns_with_var_to_expand |
| = new hash_table<var_expand_hasher> (5 * loop->num_nodes); |
| opt_info->var_to_expand_head = NULL; |
| opt_info->var_to_expand_tail = &opt_info->var_to_expand_head; |
| } |
| |
| 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 = opt_info->insns_to_split->find_slot (ivts, INSERT); |
| gcc_assert (*slot1 == NULL); |
| *slot1 = ivts; |
| *opt_info->iv_to_split_tail = ivts; |
| opt_info->iv_to_split_tail = &ivts->next; |
| continue; |
| } |
| |
| if (opt_info->insns_with_var_to_expand) |
| ves = analyze_insn_to_expand_var (loop, insn); |
| |
| if (ves) |
| { |
| slot2 = opt_info->insns_with_var_to_expand->find_slot (ves, INSERT); |
| gcc_assert (*slot2 == NULL); |
| *slot2 = ves; |
| *opt_info->var_to_expand_tail = ves; |
| opt_info->var_to_expand_tail = &ves->next; |
| } |
| } |
| } |
| |
| edges.release (); |
| 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_for_fn (cfun); |
| } |
| |
| /* 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; |
| } |
| } |
| |
| /* Allocate basic variable for the induction variable chain. */ |
| |
| static void |
| allocate_basic_variable (struct iv_to_split *ivts) |
| { |
| rtx expr = SET_SRC (single_set (ivts->insn)); |
| |
| ivts->base_var = gen_reg_rtx (GET_MODE (expr)); |
| } |
| |
| /* 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 *insn) |
| { |
| rtx expr = copy_rtx (SET_SRC (single_set (insn))); |
| rtx_insn *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 *insn, unsigned delta) |
| { |
| rtx expr, *loc, incr, var; |
| rtx_insn *seq; |
| 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 = &SET_SRC (single_set (insn)); |
| |
| /* 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 = ve->var_expansions[ve->reuse_expansion - 1]; |
| |
| if (ve->var_expansions.length () == (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 *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_replace_rtx_group (SET_DEST (set), new_reg, insn); |
| if (apply_change_group ()) |
| if (really_new_expansion) |
| { |
| ve->var_expansions.safe_push (new_reg); |
| ve->expansion_count++; |
| } |
| } |
| |
| /* Initialize the variable expansions in loop preheader. PLACE is the |
| loop-preheader basic block where the initialization of the |
| expansions should take place. The expansions are initialized with |
| (-0) when the operation is plus or minus to honor sign zero. This |
| way we can prevent cases where the sign of the final result is |
| effected by the sign of the expansion. Here is an example to |
| demonstrate this: |
| |
| for (i = 0 ; i < n; i++) |
| sum += something; |
| |
| ==> |
| |
| sum += something |
| .... |
| i = i+1; |
| sum1 += something |
| .... |
| i = i+1 |
| sum2 += something; |
| .... |
| |
| When SUM is initialized with -zero and SOMETHING is also -zero; the |
| final result of sum should be -zero thus the expansions sum1 and sum2 |
| should be initialized with -zero as well (otherwise we will get +zero |
| as the final result). */ |
| |
| static void |
| insert_var_expansion_initialization (struct var_to_expand *ve, |
| basic_block place) |
| { |
| rtx_insn *seq; |
| rtx var, zero_init; |
| unsigned i; |
| machine_mode mode = GET_MODE (ve->reg); |
| bool honor_signed_zero_p = HONOR_SIGNED_ZEROS (mode); |
| |
| if (ve->var_expansions.length () == 0) |
| return; |
| |
| start_sequence (); |
| switch (ve->op) |
| { |
| case FMA: |
| /* Note that we only accumulate FMA via the ADD operand. */ |
| case PLUS: |
| case MINUS: |
| FOR_EACH_VEC_ELT (ve->var_expansions, i, var) |
| { |
| if (honor_signed_zero_p) |
| zero_init = simplify_gen_unary (NEG, mode, CONST0_RTX (mode), mode); |
| else |
| zero_init = CONST0_RTX (mode); |
| emit_move_insn (var, zero_init); |
| } |
| break; |
| |
| case MULT: |
| FOR_EACH_VEC_ELT (ve->var_expansions, i, var) |
| { |
| zero_init = CONST1_RTX (GET_MODE (var)); |
| emit_move_insn (var, zero_init); |
| } |
| break; |
| |
| default: |
| gcc_unreachable (); |
| } |
| |
| seq = get_insns (); |
| end_sequence (); |
| |
| emit_insn_after (seq, BB_END (place)); |
| } |
| |
| /* Combine the variable expansions at the loop exit. PLACE is the |
| loop exit basic block where the summation of the expansions should |
| take place. */ |
| |
| static void |
| combine_var_copies_in_loop_exit (struct var_to_expand *ve, basic_block place) |
| { |
| rtx sum = ve->reg; |
| rtx expr, var; |
| rtx_insn *seq, *insn; |
| unsigned i; |
| |
| if (ve->var_expansions.length () == 0) |
| return; |
| |
| /* ve->reg might be SUBREG or some other non-shareable RTL, and we use |
| it both here and as the destination of the assignment. */ |
| sum = copy_rtx (sum); |
| start_sequence (); |
| switch (ve->op) |
| { |
| case FMA: |
| /* Note that we only accumulate FMA via the ADD operand. */ |
| case PLUS: |
| case MINUS: |
| FOR_EACH_VEC_ELT (ve->var_expansions, i, var) |
| sum = simplify_gen_binary (PLUS, GET_MODE (ve->reg), var, sum); |
| break; |
| |
| case MULT: |
| FOR_EACH_VEC_ELT (ve->var_expansions, i, var) |
| sum = simplify_gen_binary (MULT, GET_MODE (ve->reg), var, sum); |
| break; |
| |
| default: |
| gcc_unreachable (); |
| } |
| |
| 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); |
| } |
| |
| /* Strip away REG_EQUAL notes for IVs we're splitting. |
| |
| Updating REG_EQUAL notes for IVs we split is tricky: We |
| cannot tell until after unrolling, DF-rescanning, and liveness |
| updating, whether an EQ_USE is reached by the split IV while |
| the IV reg is still live. See PR55006. |
| |
| ??? We cannot use remove_reg_equal_equiv_notes_for_regno, |
| because RTL loop-iv requires us to defer rescanning insns and |
| any notes attached to them. So resort to old techniques... */ |
| |
| static void |
| maybe_strip_eq_note_for_split_iv (struct opt_info *opt_info, rtx_insn *insn) |
| { |
| struct iv_to_split *ivts; |
| rtx note = find_reg_equal_equiv_note (insn); |
| if (! note) |
| return; |
| for (ivts = opt_info->iv_to_split_head; ivts; ivts = ivts->next) |
| if (reg_mentioned_p (ivts->orig_var, note)) |
| { |
| remove_note (insn, note); |
| return; |
| } |
| } |
| |
| /* 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 *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) |
| for (ivts = opt_info->iv_to_split_head; ivts; ivts = ivts->next) |
| allocate_basic_variable (ivts); |
| |
| for (i = opt_info->first_new_block; |
| i < (unsigned) last_basic_block_for_fn (cfun); |
| i++) |
| { |
| bb = BASIC_BLOCK_FOR_FN (cfun, 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_BB_INSNS_SAFE (bb, insn, next) |
| { |
| if (!INSN_P (insn) |
| || (DEBUG_INSN_P (insn) |
| && TREE_CODE (INSN_VAR_LOCATION_DECL (insn)) == LABEL_DECL)) |
| continue; |
| |
| while (!INSN_P (orig_insn) |
| || (DEBUG_INSN_P (orig_insn) |
| && (TREE_CODE (INSN_VAR_LOCATION_DECL (orig_insn)) |
| == LABEL_DECL))) |
| 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) |
| { |
| maybe_strip_eq_note_for_split_iv (opt_info, insn); |
| |
| ivts = opt_info->insns_to_split->find (&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 = (struct var_to_expand *) |
| opt_info->insns_with_var_to_expand->find (&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) |
| { |
| for (ves = opt_info->var_to_expand_head; ves; ves = ves->next) |
| insert_var_expansion_initialization (ves, opt_info->loop_preheader); |
| for (ves = opt_info->var_to_expand_head; ves; ves = ves->next) |
| combine_var_copies_in_loop_exit (ves, 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_for_fn (cfun); |
| i++) |
| { |
| bb = BASIC_BLOCK_FOR_FN (cfun, 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) |
| { |
| maybe_strip_eq_note_for_split_iv (opt_info, orig_insn); |
| |
| ivts = (struct iv_to_split *) |
| opt_info->insns_to_split->find (&ivts_templ); |
| if (ivts) |
| { |
| if (!delta) |
| insert_base_initialization (ivts, orig_insn); |
| split_iv (ivts, orig_insn, delta); |
| continue; |
| } |
| } |
| |
| } |
| } |
| } |
| |
| /* Release OPT_INFO. */ |
| |
| static void |
| free_opt_info (struct opt_info *opt_info) |
| { |
| delete opt_info->insns_to_split; |
| opt_info->insns_to_split = NULL; |
| if (opt_info->insns_with_var_to_expand) |
| { |
| struct var_to_expand *ves; |
| |
| for (ves = opt_info->var_to_expand_head; ves; ves = ves->next) |
| ves->var_expansions.release (); |
| delete opt_info->insns_with_var_to_expand; |
| opt_info->insns_with_var_to_expand = NULL; |
| } |
| free (opt_info); |
| } |