On Tue, 1 Apr 2025, Jakub Jelinek wrote:
> Hi!
>
> As the following testcase shows, EDGE_FAKE edges from musttail calls to
> EXIT aren't the only edges we should ignore, we need to ignore also
> edges created by the splitting of blocks for the EDGE_FAKE creation that
> point from the musttail calls to the fallthrough block, which typically does
> the return or with PHIs for the return value.
>
> Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
> trunk?
OK
> 2025-04-01 Jakub Jelinek <ja...@redhat.com>
>
> PR gcov-profile/119535
> * profile.cc (branch_prob): Ignore any edges from bbs ending with
> musttail call, rather than only EDGE_FAKE edges from those to EXIT.
>
> * c-c++-common/pr119535.c: New test.
>
> --- gcc/profile.cc.jj 2025-03-27 09:29:37.112574359 +0100
> +++ gcc/profile.cc 2025-03-31 10:24:39.593446405 +0200
> @@ -1341,8 +1341,7 @@ branch_prob (bool thunk)
> ignored_edges++;
> }
> - /* Ignore fake edges after musttail calls. */
> - if ((e->flags & EDGE_FAKE)
> - && e->dest == EXIT_BLOCK_PTR_FOR_FN (cfun))
> + /* Ignore edges after musttail calls. */
> + if (e->src != ENTRY_BLOCK_PTR_FOR_FN (cfun))
> {
> gimple_stmt_iterator gsi = gsi_last_bb (e->src);
> gimple *stmt = gsi_stmt (gsi);
> --- gcc/testsuite/c-c++-common/pr119535.c.jj 2025-03-31 10:36:18.844758921
> +0200
> +++ gcc/testsuite/c-c++-common/pr119535.c 2025-04-01 09:12:08.998801814
> +0200
> @@ -0,0 +1,31 @@
> +/* PR gcov-profile/119535
> +/* { dg-do compile { target musttail } } */
> +/* { dg-options "-fprofile-generate -O2" } */
> +/* { dg-require-profiling "-fprofile-generate" } */
> +
> +[[gnu::noipa]] int
> +foo (int x)
> +{
> + return 42 + x;
> +}
> +
> +int
> +bar (int x)
> +{
> + foo (x);
> + foo (2);
> + [[clang::musttail]] return foo (3);
> +}
> +
> +int
> +baz (int x)
> +{
> + if (x == 42)
> + return -1;
> + else if (x == 15)
> + return 25;
> + else if (x == 26)
> + [[clang::musttail]] return foo (4);
> + else
> + [[clang::musttail]] return foo (5);
> +}
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)
