The testcase for PR51447, on x86_64, uses rbx as a global register
variable for the global PTR variable.
A runtime system might legitimately hold in rbx a value expected to be
preserved across the call to main, but its use as a global register
variable stops main from preserving it.
We've observed failures of this test on x86_64-wrs-vxworks7r2, because
of this problem, and this patch fixes them. I've also tested it on
x86_64-linux-gnu, -m64 and -m32. Ok to install?
Since main is not supposed to be callable, I suppose we might instead
prevent global register variables from affecting the registers saved or
restored by main, but I don't have a patch for that. I could give it a
shot, if there's consensus that that would be a better fix.
for gcc/testsuite/ChangeLog
PR rtl-optimization/51447
* gcc.c-torture/execute/pr51447.c (main): Preserve call-saved
register.
---
gcc/testsuite/gcc.c-torture/execute/pr51447.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/gcc/testsuite/gcc.c-torture/execute/pr51447.c
b/gcc/testsuite/gcc.c-torture/execute/pr51447.c
index 887ddb7..1d00953 100644
--- a/gcc/testsuite/gcc.c-torture/execute/pr51447.c
+++ b/gcc/testsuite/gcc.c-torture/execute/pr51447.c
@@ -14,6 +14,9 @@ int
main (void)
{
__label__ nonlocal_lab;
+#ifdef __x86_64__
+ void *save = ptr;
+#endif
__attribute__((noinline, noclone)) void
bar (void *func)
{
@@ -25,5 +28,8 @@ main (void)
nonlocal_lab:
if (ptr != &&nonlocal_lab)
abort ();
+#ifdef __x86_64__
+ ptr = save; /* Restore the call-saved register. */
+#endif
return 0;
}
--
Alexandre Oliva, freedom fighter he/him https://FSFLA.org/blogs/lxo/
Free Software Evangelist Stallman was right, but he's left :(
GNU Toolchain Engineer Live long and free, and prosper ethically
