[gcc r14-9973] Guard longjmp in test to not inf loop [PR114720]

[gcc r14-9973] Guard longjmp in test to not inf loop [PR114720]

[J?rgen Kvalsvik]

https://gcc.gnu.org/g:18e881ebd9f4b9429c652a81b8ceee84275bdade

commit r14-9973-g18e881ebd9f4b9429c652a81b8ceee84275bdade
Author: Jørgen Kvalsvik <j@lambda.is>
Date:   Mon Apr 15 14:14:26 2024 +0200

    Guard longjmp in test to not inf loop [PR114720]
    
    Guard the longjmp to not infinitely loop. The longjmp (jump) function is
    called unconditionally to make test flow simpler, but the jump
    destination would return to a point in main that would call longjmp
    again. The longjmp is really there to exercise the then-branch of
    setjmp, to verify coverage is accurately counted in the presence of
    complex edges.
    
            PR gcov-profile/114720
    
    gcc/testsuite/ChangeLog:
    
            * gcc.misc-tests/gcov-22.c: Guard longjmp to not loop.

Diff:
---
 gcc/testsuite/gcc.misc-tests/gcov-22.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/gcc/testsuite/gcc.misc-tests/gcov-22.c b/gcc/testsuite/gcc.misc-tests/gcov-22.c
index 641791a7223..7ca78467ca3 100644
--- a/gcc/testsuite/gcc.misc-tests/gcov-22.c
+++ b/gcc/testsuite/gcc.misc-tests/gcov-22.c
@@ -87,7 +87,19 @@ setdest ()
 void
 jump ()
 {
-    longjmp (dest, 1);
+    /* Protect the longjmp so it will only be done once.  The whole purpose of
+       this function is to help test conditions and instrumentation around
+       setjmp and its complex edges, as both branches should count towards
+       coverage, even when one is taken through longjmp.  If the jump is not
+       guarded it can cause an infinite loop as setdest returns to a point in
+       main before jump (), leading to an infinite loop.  See PR
+       gcov-profile/114720.  */
+    static int called_once = 0;
+    if (!called_once) /* conditions(suppress) */
+    {
+	called_once = 1;
+	longjmp (dest, 1);
+    }
 }
 
 int