[Bug sanitizer/108885] New: Missing sanitization checks for optimized integer

[Bug sanitizer/108885] New: Missing sanitization checks for optimized integer

[cbossut21 at gatech dot edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108885

            Bug ID: 108885
           Summary: Missing sanitization checks for optimized integer
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: sanitizer
          Assignee: unassigned at gcc dot gnu.org
          Reporter: cbossut21 at gatech dot edu
                CC: dodji at gcc dot gnu.org, dvyukov at gcc dot gnu.org,
                    jakub at gcc dot gnu.org, kcc at gcc dot gnu.org, marxin at gcc dot gnu.org
  Target Milestone: ---

I noticed the following behavior for the following code in test.c:

=====
#include "stdio.h"
int a = 6;
int main() { 
  int c = a * 936722028; 
  printf("%d\n", a);
}
=====

$ gcc-trunk -fsanitize=signed-integer-overflow -O3 -msse4.2  test.c -o test

$ ./test
6

$ gcc-trunk -v
gcc version 13.0.1 20230218 (experimental) [master r13-6132-g32b5875c911] (GCC) 

There are no sanitization checks inserted in this case, despite overflow
occurring on the first line of main. It seems like the check is optimized out.
However, the same code produces a signed integer overflow error at runtime when
compiled with clang using the same flags. 

Is this expected behavior for GCC? Thanks!

[Bug sanitizer/108885] Missing sanitization checks for optimized integer

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108885

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |INVALID

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
The signed integer overflow is in dead code and so is dead code eliminated.
It would be reported with -O0 -fsanitize=undefined