https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126820
Bug ID: 126820
Summary: Different behavior at -O0 and -O2/-O3 with
__builtin_calloc
Product: gcc
Version: 17.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: stuzyf at 163 dot com
Target Milestone: ---
Target: x86-64
The following testcase behaves differently depending on the optimization level:
Reproducer: https://godbolt.org/z/c6Yv5bPMW
```
#include <stdlib.h>
int fun(int x) { volatile int y = x; return y; }
int main ()
{
if (__builtin_calloc ((~(__SIZE_TYPE__) 0) / 16, fun(64)) )
__builtin_abort ();
}
```
On x86-64 with GCC trunk, compiling with -O2 or -O3 produces a program that
terminates with SIGSEGV:
```
ASM generation compiler returned: 0
Execution build compiler returned: 0
Program returned: 139
Program terminated with signal: SIGSEGV
```
Without optimization, the program returns normally:
```
ASM generation compiler returned: 0
Execution build compiler returned: 0
Program returned: 0
```
This issue is reproducible with GCC 15.1 and later, but not with the older GCC
versions I tested.
