[Bug c/112996] New: Improperly evaluated value of the s390x conditional expression

[Bug c/112996] New: Improperly evaluated value of the s390x conditional expression

[22s302h0659 at sonline20 dot sen.go.kr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112996

            Bug ID: 112996
           Summary: Improperly evaluated value of the s390x conditional
                    expression
           Product: gcc
           Version: 11.4.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: 22s302h0659 at sonline20 dot sen.go.kr
  Target Milestone: ---

# Environment

- Compiler: s390x-linux-gnu-gcc (64bit)
- Version: gcc version 11.4.0 (Ubuntu 11.4.0-1ubuntu1~22.04)
- Platform: Windows 11_5.15.90.1-microsoft-standard-WSL2
- Build Optimization Options: O0, O1, O2, O3

I installed the s390x-linux-gnu toolchain using the 'apt' package manager in
Ubuntu and utilized s390x-linux-gnu-gcc (version 11.4.0) from it.

# build script & excution script

```c
s390x-linux-gnu-gcc -o bug0 bug.c -O0 -fsanitize=undefined 
s390x-linux-gnu-gcc -o bug1 bug.c -O1 -fsanitize=undefined 
s390x-linux-gnu-gcc -o bug2 bug.c -O2 -fsanitize=undefined 
s390x-linux-gnu-gcc -o bug3 bug.c -O3 -fsanitize=undefined 
```

```c
qemu-s390x-static -L /usr/s390x-linux-gnu/ ./bug0
qemu-s390x-static -L /usr/s390x-linux-gnu/ ./bug1
qemu-s390x-static -L /usr/s390x-linux-gnu/ ./bug2
qemu-s390x-static -L /usr/s390x-linux-gnu/ ./bug3
```

This is the build script and the execution script.

# Source Code

```c
#include <stdio.h>

signed short v1 = 1;
signed int v2 = 2;
unsigned long long bug = 0;

int main ()
{
    if ((v1 < v2))
    {
        bug = v2;
    }
    printf("bug = %llu\n", bug);    

    return 0;
}
```

The C code built with GCC on the s390x architecture returns incorrect values.
The evaluated value of the conditional expression in the 'if' statement should
be true, but with the O2 and O3 options, it returns false.

# output

```c
Expected output
O0: 2
O1: 2
O2: 2
O3: 2

Actual output
O0: 2
O1: 2
O2: 0
O3: 0
```

[Bug target/112996] Improperly evaluated value of the s390x conditional expression

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112996

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |wrong-code
                 CC|                            |krebbel at gcc dot gnu.org

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
I wonder if anybody from the s390 folks could have a look at this (and similar
bugs filed throughout the year).  Is anybody monitoring s390 target bugs?

[Bug target/112996] Improperly evaluated value of the s390x conditional expression

[krebbel at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112996

Andreas Krebbel <krebbel at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
                 CC|                            |iii at linux dot ibm.com
         Resolution|---                         |DUPLICATE

--- Comment #2 from Andreas Krebbel <krebbel at gcc dot gnu.org> ---
Same as with PR112986. Confirmed with qemu. Runs fine on real hardware.

*** This bug has been marked as a duplicate of bug 112986 ***