From bd9cc42bb85bef57fb5ae6639599966c3b0468b6 Mon Sep 17 00:00:00 2001 From: Bin Cheng Date: Wed, 15 Nov 2017 16:20:21 +0000 Subject: [PATCH] re PR tree-optimization/82726 (ICE in verify_ssa during GIMPLE pass: pcom) PR tree-optimization/82726 PR tree-optimization/70754 * tree-predcom.c (order_drefs_by_pos): New function. (combine_chains): Move code setting has_max_use_after to... (try_combine_chains): ...here. New parameter. Sort combined chains according to position information. (tree_predictive_commoning_loop): Update call to above function. (update_pos_for_combined_chains, pcom_stmt_dominates_stmt_p): New. gcc/testsuite * gcc.dg/tree-ssa/pr82726.c: New test. From-SVN: r254778 --- gcc/ChangeLog | 17 +++ gcc/testsuite/gcc.dg/tree-ssa/pr82726.c | 26 +++++ gcc/tree-predcom.c | 138 +++++++++++++++++++++--- 3 files changed, 165 insertions(+), 16 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr82726.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 001614046da..3807073525e 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,20 @@ +2017-11-15 Bin Cheng + + PR tree-optimization/82726 + PR tree-optimization/70754 + * tree-predcom.c (order_drefs_by_pos): New function. + (combine_chains): Move code setting has_max_use_after to... + (try_combine_chains): ...here. New parameter. Sort combined chains + according to position information. + (tree_predictive_commoning_loop): Update call to above function. + (update_pos_for_combined_chains, pcom_stmt_dominates_stmt_p): New. + +gcc/testsuite +2017-11-15 Bin Cheng + + PR tree-optimization/82726 + * gcc.dg/tree-ssa/pr82726.c: New test. + 2017-11-15 Bin Cheng PR tree-optimization/82726 diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr82726.c b/gcc/testsuite/gcc.dg/tree-ssa/pr82726.c new file mode 100644 index 00000000000..22bc59dacc8 --- /dev/null +++ b/gcc/testsuite/gcc.dg/tree-ssa/pr82726.c @@ -0,0 +1,26 @@ +/* { dg-do compile } */ +/* { dg-options "-O3 --param tree-reassoc-width=4" } */ +/* { dg-additional-options "-mavx2" { target { x86_64-*-* i?86-*-* } } } */ + +#define N 40 +#define M 128 +unsigned int in[N+M]; +unsigned short out[N]; + +/* Outer-loop vectorization. */ + +void +foo (){ + int i,j; + unsigned int diff; + + for (i = 0; i < N; i++) { + diff = 0; + for (j = 0; j < M; j+=8) { + diff += in[j+i]; + } + out[i]=(unsigned short)diff; + } + + return; +} diff --git a/gcc/tree-predcom.c b/gcc/tree-predcom.c index 6dccbc17bf5..747c1b82d37 100644 --- a/gcc/tree-predcom.c +++ b/gcc/tree-predcom.c @@ -1020,6 +1020,17 @@ order_drefs (const void *a, const void *b) return (*da)->pos - (*db)->pos; } +/* Compares two drefs A and B by their position. Callback for qsort. */ + +static int +order_drefs_by_pos (const void *a, const void *b) +{ + const dref *const da = (const dref *) a; + const dref *const db = (const dref *) b; + + return (*da)->pos - (*db)->pos; +} + /* Returns root of the CHAIN. */ static inline dref @@ -2640,7 +2651,6 @@ combine_chains (chain_p ch1, chain_p ch2) bool swap = false; chain_p new_chain; unsigned i; - gimple *root_stmt; tree rslt_type = NULL_TREE; if (ch1 == ch2) @@ -2682,31 +2692,55 @@ combine_chains (chain_p ch1, chain_p ch2) new_chain->refs.safe_push (nw); } - new_chain->has_max_use_after = false; - root_stmt = get_chain_root (new_chain)->stmt; - for (i = 1; new_chain->refs.iterate (i, &nw); i++) - { - if (nw->distance == new_chain->length - && !stmt_dominates_stmt_p (nw->stmt, root_stmt)) - { - new_chain->has_max_use_after = true; - break; - } - } - ch1->combined = true; ch2->combined = true; return new_chain; } -/* Try to combine the CHAINS. */ +/* Recursively update position information of all offspring chains to ROOT + chain's position information. */ + +static void +update_pos_for_combined_chains (chain_p root) +{ + chain_p ch1 = root->ch1, ch2 = root->ch2; + dref ref, ref1, ref2; + for (unsigned j = 0; (root->refs.iterate (j, &ref) + && ch1->refs.iterate (j, &ref1) + && ch2->refs.iterate (j, &ref2)); ++j) + ref1->pos = ref2->pos = ref->pos; + + if (ch1->type == CT_COMBINATION) + update_pos_for_combined_chains (ch1); + if (ch2->type == CT_COMBINATION) + update_pos_for_combined_chains (ch2); +} + +/* Returns true if statement S1 dominates statement S2. */ + +static bool +pcom_stmt_dominates_stmt_p (gimple *s1, gimple *s2) +{ + basic_block bb1 = gimple_bb (s1), bb2 = gimple_bb (s2); + + if (!bb1 || s1 == s2) + return true; + + if (bb1 == bb2) + return gimple_uid (s1) < gimple_uid (s2); + + return dominated_by_p (CDI_DOMINATORS, bb2, bb1); +} + +/* Try to combine the CHAINS in LOOP. */ static void -try_combine_chains (vec *chains) +try_combine_chains (struct loop *loop, vec *chains) { unsigned i, j; chain_p ch1, ch2, cch; auto_vec worklist; + bool combined_p = false; FOR_EACH_VEC_ELT (*chains, i, ch1) if (chain_can_be_combined_p (ch1)) @@ -2728,6 +2762,78 @@ try_combine_chains (vec *chains) { worklist.safe_push (cch); chains->safe_push (cch); + combined_p = true; + break; + } + } + } + if (!combined_p) + return; + + /* Setup UID for all statements in dominance order. */ + basic_block *bbs = get_loop_body (loop); + renumber_gimple_stmt_uids_in_blocks (bbs, loop->num_nodes); + free (bbs); + + /* Re-association in combined chains may generate statements different to + order of references of the original chain. We need to keep references + of combined chain in dominance order so that all uses will be inserted + after definitions. Note: + A) This is necessary for all combined chains. + B) This is only necessary for ZERO distance references because other + references inherit value from loop carried PHIs. + + We first update position information for all combined chains. */ + dref ref; + for (i = 0; chains->iterate (i, &ch1); ++i) + { + if (ch1->type != CT_COMBINATION || ch1->combined) + continue; + + for (j = 0; ch1->refs.iterate (j, &ref); ++j) + ref->pos = gimple_uid (ref->stmt); + + update_pos_for_combined_chains (ch1); + } + /* Then sort references according to newly updated position information. */ + for (i = 0; chains->iterate (i, &ch1); ++i) + { + if (ch1->type != CT_COMBINATION && !ch1->combined) + continue; + + /* Find the first reference with non-ZERO distance. */ + if (ch1->length == 0) + j = ch1->refs.length(); + else + { + for (j = 0; ch1->refs.iterate (j, &ref); ++j) + if (ref->distance != 0) + break; + } + + /* Sort all ZERO distance references by position. */ + qsort (&ch1->refs[0], j, sizeof (ch1->refs[0]), order_drefs_by_pos); + + if (ch1->combined) + continue; + + /* For ZERO length chain, has_max_use_after must be true since root + combined stmt must dominates others. */ + if (ch1->length == 0) + { + ch1->has_max_use_after = true; + continue; + } + /* Check if there is use at max distance after root for combined chains + and set flag accordingly. */ + ch1->has_max_use_after = false; + gimple *root_stmt = get_chain_root (ch1)->stmt; + for (j = 1; ch1->refs.iterate (j, &ref); ++j) + { + if (ref->distance == ch1->length + && !pcom_stmt_dominates_stmt_p (ref->stmt, root_stmt)) + { + ch1->has_max_use_after = true; break; } } @@ -3065,7 +3171,7 @@ tree_predictive_commoning_loop (struct loop *loop) loop_closed_ssa = prepare_finalizers (loop, chains); /* Try to combine the chains that are always worked with together. */ - try_combine_chains (&chains); + try_combine_chains (loop, &chains); insert_init_seqs (loop, chains); -- 2.30.2