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* [Bug c/110640] New: Wrong code at -O2/3 on x86_64-linux-gnu since GCC-13
@ 2023-07-12 12:45 shaohua.li at inf dot ethz.ch
  2023-07-12 13:55 ` [Bug c/110640] [13/14 Regression] " rguenth at gcc dot gnu.org
                   ` (10 more replies)
  0 siblings, 11 replies; 12+ messages in thread
From: shaohua.li at inf dot ethz.ch @ 2023-07-12 12:45 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110640

            Bug ID: 110640
           Summary: Wrong code at -O2/3 on x86_64-linux-gnu since GCC-13
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: shaohua.li at inf dot ethz.ch
  Target Milestone: ---

This looks like a regression since GCC-13. gcc produces wrong code at -O2/3.

Compiler explorer: https://godbolt.org/z/5MWe6eK8M

$ cat a.c
unsigned short a = 65535;
int b, f, g;
int *c = &b;
long d;
short e;
static int *h(int);
void i() { h(a); }
int *h(int j) {
  unsigned char k;
  for (; e != 8; e = e + 4)
    k = 0;
  for (; (unsigned char)(j-181249535) + k <= 1; k++) {
    *c = d;
    for (; f; f++)
      ;
  }
  return &g;
}
int main() { i(); }
$
$ gcc-tk -O0 a.c && ./a.out
$
$ gcc-tk -O2 a.c
$ ./a.out
Killed
$ gcc-tk -O3 a.c
$ ./a.out
Killed
$
$ gcc-tk -v
Using built-in specs.
COLLECT_GCC=gcc-tk
COLLECT_LTO_WRAPPER=/zdata/shaoli/compilers/ccbuilder-compilers/gcc-322d17ae51ea0137167424e0018d7fa355948f9f/libexec/gcc/x86_64-pc-linux-gnu/14.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../configure --disable-multilib --disable-bootstrap
--enable-languages=c,c++
--prefix=/zdata/shaoli/compilers/ccbuilder-compilers/gcc-322d17ae51ea0137167424e0018d7fa355948f9f
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 14.0.0 20230711 (experimental) (GCC)
$

^ permalink raw reply	[flat|nested] 12+ messages in thread
end of thread, other threads:[~2023-12-14  7:41 UTC | newest]

Thread overview: 12+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-07-12 12:45 [Bug c/110640] New: Wrong code at -O2/3 on x86_64-linux-gnu since GCC-13 shaohua.li at inf dot ethz.ch
2023-07-12 13:55 ` [Bug c/110640] [13/14 Regression] " rguenth at gcc dot gnu.org
2023-07-12 13:56 ` [Bug tree-optimization/110640] " rguenth at gcc dot gnu.org
2023-07-12 16:19 ` pinskia at gcc dot gnu.org
2023-07-13  8:51 ` rguenth at gcc dot gnu.org
2023-07-27  9:27 ` rguenth at gcc dot gnu.org
2023-07-30 14:49 ` shaohua.li at inf dot ethz.ch
2023-07-31  7:15 ` rguenth at gcc dot gnu.org
2023-12-13 17:03 ` jakub at gcc dot gnu.org
2023-12-14  7:37 ` [Bug tree-optimization/110640] [13 Regression] Wrong code at -O2/3 on x86_64-linux-gnu since GCC-13 since r12-1653-gcb448ade74d rguenth at gcc dot gnu.org
2023-12-14  7:39 ` rguenth at gcc dot gnu.org
2023-12-14  7:41 ` cvs-commit at gcc dot gnu.org

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