From: Richard Biener Date: Mon, 18 May 2020 07:17:24 +0000 (+0200) Subject: tree-optimization/95172 - avoid mixing conditionalized and ordered SM X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=52a0f83980082c9995f2d8ec9b88548520fb8a5f;p=gcc.git tree-optimization/95172 - avoid mixing conditionalized and ordered SM The following testcase shows a missed optimization that then leads to wrong-code when issueing SMed stores on exits. When we were able to compute an ordered sequence of stores for an exit we need to emit that in the correct order and we can emit it disregarding to any conditional for whether a store actually happened (we know it did). We can also improve detection as of whether we need conditional processing at all. Both parts fix the testcase. 2020-05-18 Richard Biener PR tree-optimization/95172 * tree-ssa-loop-im.c (execute_sm): Get flag whether we eventually need the conditional processing. (execute_sm_exit): When processing an orderd sequence avoid doing any conditional processing. (hoist_memory_references): Pass down whether all edges have ordered processing for a ref to execute_sm. * gcc.dg/torture/pr95172.c: New testcase. --- diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 3a090452a96..491293d77df 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,13 @@ +2020-05-18 Richard Biener + + PR tree-optimization/95172 + * tree-ssa-loop-im.c (execute_sm): Get flag whether we + eventually need the conditional processing. + (execute_sm_exit): When processing an orderd sequence + avoid doing any conditional processing. + (hoist_memory_references): Pass down whether all edges + have ordered processing for a ref to execute_sm. + 2020-05-17 Jeff Law * config/h8300/predicates.md (pc_or_label_operand): New predicate. diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 54fbdb08b66..1123599b9a7 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2020-05-18 Richard Biener + + PR tree-optimization/95172 + * gcc.dg/torture/pr95172.c: New testcase. + 2020-05-17 H.J. Lu PR target/95021 diff --git a/gcc/testsuite/gcc.dg/torture/pr95172.c b/gcc/testsuite/gcc.dg/torture/pr95172.c new file mode 100644 index 00000000000..b39de69f08e --- /dev/null +++ b/gcc/testsuite/gcc.dg/torture/pr95172.c @@ -0,0 +1,17 @@ +/* { dg-do run } */ + +int a, d; +int *b = &a; +short c; +int main() +{ + for (; c <= 4; c--) { + for (; d;) + ; + a = 1; + *b = 0; + } + if (a != 0) + __builtin_abort (); + return 0; +} diff --git a/gcc/tree-ssa-loop-im.c b/gcc/tree-ssa-loop-im.c index 0d77aaa08a5..63f4ef8883c 100644 --- a/gcc/tree-ssa-loop-im.c +++ b/gcc/tree-ssa-loop-im.c @@ -2130,7 +2130,7 @@ struct sm_aux static void execute_sm (class loop *loop, im_mem_ref *ref, - hash_map &aux_map) + hash_map &aux_map, bool maybe_mt) { gassign *load; struct fmt_data fmt_data; @@ -2154,8 +2154,9 @@ execute_sm (class loop *loop, im_mem_ref *ref, for_each_index (&ref->mem.ref, force_move_till, &fmt_data); bool always_stored = ref_always_accessed_p (loop, ref, true); - if (bb_in_transaction (loop_preheader_edge (loop)->src) - || (! flag_store_data_races && ! always_stored)) + if (maybe_mt + && (bb_in_transaction (loop_preheader_edge (loop)->src) + || (! flag_store_data_races && ! always_stored))) multi_threaded_model_p = true; if (multi_threaded_model_p) @@ -2244,7 +2245,7 @@ execute_sm_exit (class loop *loop, edge ex, vec &seq, else { sm_aux *aux = *aux_map.get (ref); - if (!aux->store_flag) + if (!aux->store_flag || kind == sm_ord) { gassign *store; store = gimple_build_assign (unshare_expr (ref->mem.ref), @@ -2630,7 +2631,7 @@ hoist_memory_references (class loop *loop, bitmap mem_refs, EXECUTE_IF_SET_IN_BITMAP (mem_refs, 0, i, bi) { ref = memory_accesses.refs_list[i]; - execute_sm (loop, ref, aux_map); + execute_sm (loop, ref, aux_map, bitmap_bit_p (refs_not_supported, i)); } /* Materialize ordered store sequences on exits. */