Message ID | 20220128163124.GQ2646553@tucnak |
---|---|
State | New |
Headers | show |
Series | store-merging: Fix up a -fcompare-debug bug in get_status_for_store_merging [PR104263] | expand |
On 1/28/2022 9:31 AM, Jakub Jelinek via Gcc-patches wrote: > Hi! > > As mentioned in the PRthe following testcase fails, because the last > stmt of a bb with -g is a debug stmt and get_status_for_store_merging > uses gimple_seq_last_stmt (bb_seq (bb)) when testing if it is valid > for store merging. The debug stmt isn't valid, while a stmt at that > position with -g0 is valid and so the divergence. > > As we walk the whole bb already, this patch just remembers the last > non-debug stmt, so that we don't need to skip backwards debug stmts at the > end of the bb to find last real stmt. > > Bootstrapped/regtested on powerpc64le-linux, ok for trunk? > > 2022-01-28 Jakub Jelinek <jakub@redhat.com> > > PR tree-optimization/104263 > * gimple-ssa-store-merging.cc (get_status_for_store_merging): For > cfun->can_throw_non_call_exceptions && cfun->eh test whether > last non-debug stmt in the bb is store_valid_for_store_merging_p > rather than last stmt. > > * gcc.dg/pr104263.c: New test. OK jeff
> Am 28.01.2022 um 18:36 schrieb Jeff Law <jeffreyalaw@gmail.com>: > > > >> On 1/28/2022 9:31 AM, Jakub Jelinek via Gcc-patches wrote: >> Hi! >> >> As mentioned in the PRthe following testcase fails, because the last >> stmt of a bb with -g is a debug stmt and get_status_for_store_merging >> uses gimple_seq_last_stmt (bb_seq (bb)) when testing if it is valid >> for store merging. The debug stmt isn't valid, while a stmt at that >> position with -g0 is valid and so the divergence. >> >> As we walk the whole bb already, this patch just remembers the last >> non-debug stmt, so that we don't need to skip backwards debug stmts at the >> end of the bb to find last real stmt. >> >> Bootstrapped/regtested on powerpc64le-linux, ok for trunk Ok Thanks, Richard >> 2022-01-28 Jakub Jelinek <jakub@redhat.com> >> >> PR tree-optimization/104263 >> * gimple-ssa-store-merging.cc (get_status_for_store_merging): For >> cfun->can_throw_non_call_exceptions && cfun->eh test whether >> last non-debug stmt in the bb is store_valid_for_store_merging_p >> rather than last stmt. >> >> * gcc.dg/pr104263.c: New test. > OK > jeff >
--- gcc/gimple-ssa-store-merging.cc.jj 2022-01-20 11:30:45.521578942 +0100 +++ gcc/gimple-ssa-store-merging.cc 2022-01-28 11:27:25.437947561 +0100 @@ -5364,6 +5364,7 @@ get_status_for_store_merging (basic_bloc unsigned int num_constructors = 0; gimple_stmt_iterator gsi; edge e; + gimple *last_stmt = NULL; for (gsi = gsi_after_labels (bb); !gsi_end_p (gsi); gsi_next (&gsi)) { @@ -5372,6 +5373,8 @@ get_status_for_store_merging (basic_bloc if (is_gimple_debug (stmt)) continue; + last_stmt = stmt; + if (store_valid_for_store_merging_p (stmt) && ++num_statements >= 2) break; @@ -5398,7 +5401,7 @@ get_status_for_store_merging (basic_bloc return BB_INVALID; if (cfun->can_throw_non_call_exceptions && cfun->eh - && store_valid_for_store_merging_p (gimple_seq_last_stmt (bb_seq (bb))) + && store_valid_for_store_merging_p (last_stmt) && (e = find_fallthru_edge (bb->succs)) && e->dest == bb->next_bb) return BB_EXTENDED_VALID; --- gcc/testsuite/gcc.dg/pr104263.c.jj 2022-01-28 11:32:26.718619588 +0100 +++ gcc/testsuite/gcc.dg/pr104263.c 2022-01-28 11:32:04.111944459 +0100 @@ -0,0 +1,25 @@ +/* PR tree-optimization/104263 */ +/* { dg-do compile } */ +/* { dg-options "-O2 -fcompare-debug -fnon-call-exceptions -fno-inline-small-functions" } */ + +int n; + +int +bar (void) +{ + int a; + + n = 0; + a = 0; + + return n; +} + +__attribute__ ((pure, returns_twice)) int +foo (void) +{ + n = bar () + 1; + foo (); + + return 0; +}