From f644a018e3452a41cb4ce49cb47179845a63b546 Mon Sep 17 00:00:00 2001 From: Bin Cheng Date: Tue, 10 Dec 2013 06:31:41 +0000 Subject: [PATCH] re PR tree-optimization/41488 (IVOpts cannot coalesce multiple induction variables) PR tree-optimization/41488 * tree-ssa-loop-ivopts.c (add_old_iv_candidates): Don't add cand for PEELED_CHREC kind IV. * tree-scalar-evolution.c: Include necessary header files. (peeled_chrec_map, simplify_peeled_chrec): New. (analyze_evolution_in_loop): New static variable. Call simplify_peeled_chrec. (scev_initialize): Initialize peeled_chrec_map. (scev_reset, scev_finalize): Reset and release peeled_chrec_map. PR tree-optimization/41488 * gcc.dg/tree-ssa/scev-7.c: New test. * gcc.dg/pr41488.c: New test. From-SVN: r205848 --- gcc/ChangeLog | 12 ++++ gcc/testsuite/ChangeLog | 6 ++ gcc/testsuite/gcc.dg/pr41488.c | 18 ++++++ gcc/testsuite/gcc.dg/tree-ssa/scev-7.c | 18 ++++++ gcc/tree-scalar-evolution.c | 90 +++++++++++++++++++++++++- gcc/tree-ssa-loop-ivopts.c | 18 ++++-- 6 files changed, 156 insertions(+), 6 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/pr41488.c create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/scev-7.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 4389a3f3cdc..27c9cd71011 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,15 @@ +2013-12-10 Bin Cheng + + PR tree-optimization/41488 + * tree-ssa-loop-ivopts.c (add_old_iv_candidates): Don't add cand + for PEELED_CHREC kind IV. + * tree-scalar-evolution.c: Include necessary header files. + (peeled_chrec_map, simplify_peeled_chrec): New. + (analyze_evolution_in_loop): New static variable. + Call simplify_peeled_chrec. + (scev_initialize): Initialize peeled_chrec_map. + (scev_reset, scev_finalize): Reset and release peeled_chrec_map. + 2013-12-09 Andrew Pinski * config/aarch64/t-aarch64 (MULTILIB_OPTIONS): Fix definition so diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 7945eac39fb..3b1ca7844e6 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,9 @@ +2013-12-10 Bin Cheng + + PR tree-optimization/41488 + * gcc.dg/tree-ssa/scev-7.c: New test. + * gcc.dg/pr41488.c: New test. + 2013-12-09 Joseph Myers PR preprocessor/55715 diff --git a/gcc/testsuite/gcc.dg/pr41488.c b/gcc/testsuite/gcc.dg/pr41488.c new file mode 100644 index 00000000000..c4bc42832b3 --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr41488.c @@ -0,0 +1,18 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fdump-tree-sccp-scev" } */ + +struct struct_t +{ + int* data; +}; + +void foo (struct struct_t* sp, int start, int end) +{ + int i; + + for (i = 0; i+start < end; i++) + sp->data[i+start] = 0; +} + +/* { dg-final { scan-tree-dump-times "Simplify PEELED_CHREC into POLYNOMIAL_CHREC" 1 "sccp" } } */ +/* { dg-final { cleanup-tree-dump "sccp" } } */ diff --git a/gcc/testsuite/gcc.dg/tree-ssa/scev-7.c b/gcc/testsuite/gcc.dg/tree-ssa/scev-7.c new file mode 100644 index 00000000000..d6ceb208258 --- /dev/null +++ b/gcc/testsuite/gcc.dg/tree-ssa/scev-7.c @@ -0,0 +1,18 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fdump-tree-sccp-scev" } */ + +struct struct_t +{ + int* data; +}; + +void foo (struct struct_t* sp, int start, int end) +{ + int i; + + for (i = 1000; i+start > end; i--) + sp->data[i+start] = 0; +} + +/* { dg-final { scan-tree-dump-times "Simplify PEELED_CHREC into POLYNOMIAL_CHREC" 1 "sccp" } } */ +/* { dg-final { cleanup-tree-dump "sccp" } } */ diff --git a/gcc/tree-scalar-evolution.c b/gcc/tree-scalar-evolution.c index 59e44cbb9c9..f114653a5fa 100644 --- a/gcc/tree-scalar-evolution.c +++ b/gcc/tree-scalar-evolution.c @@ -280,6 +280,8 @@ along with GCC; see the file COPYING3. If not see #include "tree-ssa.h" #include "cfgloop.h" #include "tree-chrec.h" +#include "pointer-set.h" +#include "tree-affine.h" #include "tree-scalar-evolution.h" #include "dumpfile.h" #include "params.h" @@ -1380,6 +1382,66 @@ follow_ssa_edge (struct loop *loop, gimple def, gimple halting_phi, } +/* Pointer map used when simplifying PEELED_CHREC into POLYNOMIAL_CHREC. */ +static pointer_map_t *peeled_chrec_map; + +/* Simplify PEELED_CHREC represented by (init_cond, arg) in LOOP. + Handle below case and return the corresponding POLYNOMIAL_CHREC: + + # i_17 = PHI + # _20 = PHI <_5(5), start_4(D)(3)> + ... + i_13 = i_17 + 1; + _5 = start_4(D) + i_13; + + Though variable _20 appears as a PEELED_CHREC in the form of + (start_4, _5)_LOOP, it's a POLYNOMIAL_CHREC like {start_4, 1}_LOOP. + + See PR41488. */ + +static tree +simplify_peeled_chrec (struct loop *loop, tree arg, tree init_cond) +{ + aff_tree aff1, aff2; + tree ev, left, right, type, step_val; + + ev = instantiate_parameters (loop, analyze_scalar_evolution (loop, arg)); + if (ev == NULL_TREE || TREE_CODE (ev) != POLYNOMIAL_CHREC) + return chrec_dont_know; + + left = CHREC_LEFT (ev); + right = CHREC_RIGHT (ev); + type = TREE_TYPE (left); + step_val = chrec_fold_plus (type, init_cond, right); + + /* Transform (init, {left, right}_LOOP)_LOOP to {init, right}_LOOP + if "left" equals to "init + right". */ + if (operand_equal_p (left, step_val, 0)) + { + if (dump_file && (dump_flags & TDF_SCEV)) + fprintf (dump_file, "Simplify PEELED_CHREC into POLYNOMIAL_CHREC.\n"); + + return build_polynomial_chrec (loop->num, init_cond, right); + } + + /* Try harder to check if they are equal. */ + tree_to_aff_combination_expand (left, type, &aff1, &peeled_chrec_map); + tree_to_aff_combination_expand (step_val, type, &aff2, &peeled_chrec_map); + aff_combination_scale (&aff2, double_int_minus_one); + aff_combination_add (&aff1, &aff2); + left = fold_convert (type, aff_combination_to_tree (&aff1)); + + /* Transform (init, {left, right}_LOOP)_LOOP to {init, right}_LOOP + if "left" equals to "init + right". */ + if (operand_equal_p (left, integer_zero_node, 0)) + { + if (dump_file && (dump_flags & TDF_SCEV)) + fprintf (dump_file, "Simplify PEELED_CHREC into POLYNOMIAL_CHREC.\n"); + + return build_polynomial_chrec (loop->num, init_cond, right); + } + return chrec_dont_know; +} /* Given a LOOP_PHI_NODE, this function determines the evolution function from LOOP_PHI_NODE to LOOP_PHI_NODE in the loop. */ @@ -1392,6 +1454,7 @@ analyze_evolution_in_loop (gimple loop_phi_node, tree evolution_function = chrec_not_analyzed_yet; struct loop *loop = loop_containing_stmt (loop_phi_node); basic_block bb; + static bool simplify_peeled_chrec_p = true; if (dump_file && (dump_flags & TDF_SCEV)) { @@ -1442,7 +1505,19 @@ analyze_evolution_in_loop (gimple loop_phi_node, all the other iterations it has the value of ARG. For the moment, PEELED_CHREC nodes are not built. */ if (res != t_true) - ev_fn = chrec_dont_know; + { + ev_fn = chrec_dont_know; + /* Try to recognize POLYNOMIAL_CHREC which appears in + the form of PEELED_CHREC, but guard the process with + a bool variable to keep the analyzer from infinite + recurrence for real PEELED_RECs. */ + if (simplify_peeled_chrec_p && TREE_CODE (arg) == SSA_NAME) + { + simplify_peeled_chrec_p = false; + ev_fn = simplify_peeled_chrec (loop, arg, init_cond); + simplify_peeled_chrec_p = true; + } + } /* When there are multiple back edges of the loop (which in fact never happens currently, but nevertheless), merge their evolutions. */ @@ -3086,6 +3161,8 @@ scev_initialize (void) initialize_scalar_evolutions_analyzer (); + peeled_chrec_map = pointer_map_create (); + FOR_EACH_LOOP (loop, 0) { loop->nb_iterations = NULL_TREE; @@ -3122,6 +3199,12 @@ scev_reset (void) scev_reset_htab (); + if (peeled_chrec_map) + { + pointer_map_destroy (peeled_chrec_map); + peeled_chrec_map = NULL; + } + if (!current_loops) return; @@ -3209,6 +3292,11 @@ scev_finalize (void) return; htab_delete (scalar_evolution_info); scalar_evolution_info = NULL; + if (peeled_chrec_map) + { + pointer_map_destroy (peeled_chrec_map); + peeled_chrec_map = NULL; + } } /* Returns true if the expression EXPR is considered to be too expensive diff --git a/gcc/tree-ssa-loop-ivopts.c b/gcc/tree-ssa-loop-ivopts.c index 1f5590a7ac2..24c9ceca8f4 100644 --- a/gcc/tree-ssa-loop-ivopts.c +++ b/gcc/tree-ssa-loop-ivopts.c @@ -2526,11 +2526,19 @@ add_old_iv_candidates (struct ivopts_data *data, struct iv *iv) /* Additionally record the possibility of leaving the original iv untouched. */ def = PHI_ARG_DEF_FROM_EDGE (phi, loop_latch_edge (data->current_loop)); - cand = add_candidate_1 (data, - iv->base, iv->step, true, IP_ORIGINAL, NULL, - SSA_NAME_DEF_STMT (def)); - cand->var_before = iv->ssa_name; - cand->var_after = def; + /* Don't add candidate if it's from another PHI node because + it's an affine iv appearing in the form of PEELED_CHREC. */ + phi = SSA_NAME_DEF_STMT (def); + if (gimple_code (phi) != GIMPLE_PHI) + { + cand = add_candidate_1 (data, + iv->base, iv->step, true, IP_ORIGINAL, NULL, + SSA_NAME_DEF_STMT (def)); + cand->var_before = iv->ssa_name; + cand->var_after = def; + } + else + gcc_assert (gimple_bb (phi) == data->current_loop->header); } }