[gcc r15-9126] profile: Another profiling musttail call fix [PR119535]

[Jakub Jelinek via Gcc-cvs]

https://gcc.gnu.org/g:b8de7704428dfe008d195d8da95d6772153b0cc7

commit r15-9126-gb8de7704428dfe008d195d8da95d6772153b0cc7
Author: Jakub Jelinek <ja...@redhat.com>
Date:   Tue Apr 1 11:45:16 2025 +0200

    profile: Another profiling musttail call fix [PR119535]
    
    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.
    
    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.

Diff:
---
 gcc/profile.cc                        |  5 ++---
 gcc/testsuite/c-c++-common/pr119535.c | 31 +++++++++++++++++++++++++++++++
 2 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/gcc/profile.cc b/gcc/profile.cc
index c0f5097726bd..550c85b9742c 100644
--- a/gcc/profile.cc
+++ b/gcc/profile.cc
@@ -1340,9 +1340,8 @@ branch_prob (bool thunk)
          EDGE_INFO (e)->ignore = 1;
          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);
diff --git a/gcc/testsuite/c-c++-common/pr119535.c 
b/gcc/testsuite/c-c++-common/pr119535.c
new file mode 100644
index 000000000000..fd88cc44d694
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/pr119535.c
@@ -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);
+}