> Am 04.04.2025 um 19:37 schrieb Jakub Jelinek <ja...@redhat.com>:
>
> Hi!
>
> As the following testcase shows, sometimes we can have debug stmts
> after a musttail call and profile.cc in that case would incorrectly
> allow the edge from that, causing musttail error and -fcompare-debug
> failure (because if there are no debug stmts after it, then musttail
> is found there and the edge is ignored).
>
> The following patch uses gsi_last_nondebug_bb instead of gsi_last_bb
> to find the musttail call. And so that we don't uselessly skip over
> debug stmts at the end of many bbs, the patch limits it to
> cfun->has_musttail functions.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
Ok
Richard
> 2025-04-04 Jakub Jelinek <ja...@redhat.com>
>
> PR gcov-profile/119618
> * profile.cc (branch_prob): Only check for musttail calls if
> cfun->has_musttail. Use gsi_last_nondebug_bb instead of gsi_last_bb.
>
> * c-c++-common/pr119618.c: New test.
>
> --- gcc/profile.cc.jj 2025-04-03 20:51:20.744542139 +0200
> +++ gcc/profile.cc 2025-04-04 10:05:33.120871284 +0200
> @@ -1341,9 +1341,10 @@ branch_prob (bool thunk)
> ignored_edges++;
> }
> /* Ignore edges after musttail calls. */
> - if (e->src != ENTRY_BLOCK_PTR_FOR_FN (cfun))
> + if (cfun->has_musttail
> + && e->src != ENTRY_BLOCK_PTR_FOR_FN (cfun))
> {
> - gimple_stmt_iterator gsi = gsi_last_bb (e->src);
> + gimple_stmt_iterator gsi = gsi_last_nondebug_bb (e->src);
> gimple *stmt = gsi_stmt (gsi);
> if (stmt
> && is_gimple_call (stmt)
> --- gcc/testsuite/c-c++-common/pr119618.c.jj 2025-04-04 10:09:21.179905955
> +0200
> +++ gcc/testsuite/c-c++-common/pr119618.c 2025-04-04 10:10:50.924919610
> +0200
> @@ -0,0 +1,21 @@
> +/* PR gcov-profile/119618 */
> +/* { dg-do compile { target musttail } } */
> +/* { dg-options "-fcompare-debug -fprofile-generate -O1" } */
> +/* { dg-require-profiling "-fprofile-generate" } */
> +
> +struct S { char s; };
> +int foo (void);
> +int *(*fn) (void);
> +
> +int *
> +bar (void)
> +{
> + if (foo ())
> + return 0;
> + {
> + struct S s;
> + do
> + [[gnu::musttail]] return fn ();
> + while (0);
> + }
> +}
>
> Jakub
>
