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From: "zhendong.su at inf dot ethz.ch" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/107269] New: wrong code at -O1 and above with "-fno-tree-ccp" on x86_64-linux-gnu
Date: Fri, 14 Oct 2022 18:22:20 +0000	[thread overview]
Message-ID: <bug-107269-4@http.gcc.gnu.org/bugzilla/> (raw)

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107269

            Bug ID: 107269
           Summary: wrong code at -O1 and above with "-fno-tree-ccp" on
                    x86_64-linux-gnu
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zhendong.su at inf dot ethz.ch
  Target Milestone: ---

It appears to be a recent regression.

Compiler Explorer: https://godbolt.org/z/WdcsavxTh


[593] % gcctk -v
Using built-in specs.
COLLECT_GCC=gcctk
COLLECT_LTO_WRAPPER=/local/suz-local/software/local/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/13.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-trunk/configure --disable-bootstrap
--enable-checking=yes --prefix=/local/suz-local/software/local/gcc-trunk
--enable-sanitizers --enable-languages=c,c++ --disable-werror --enable-multilib
--with-system-zlib
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 13.0.0 20221014 (experimental) [master r13-3307-g8efc38347a7] (GCC) 
[594] % 
[594] % gcctk -O1 small.c; ./a.out
[595] % 
[595] % gcctk -O1 -fno-tree-ccp small.c
[596] % ./a.out
Floating point exception
[597] % 
[597] % cat small.c
int a, b, f;
char c = 3;
unsigned d = 1;
short e;
int main() {
  int h = 2357999721;
  char i = a = 3;
  for (; a >= 0; a--) {
    int *j = &h;
    char k = i || c;
    short l = ~h;
    b = ~(d % h);
    f = ~i / b;
    if (h >= -1936967575) {
      int m = h / d / 110000000 ^ (f & c);
      short n = c;
      if (h <= -1936967575)
        n = e;
      h = m;
      c = ~(n + f);
      d = -1;
    }
    i = ~l - k;
  }
  return 0;
}

             reply	other threads:[~2022-10-14 18:22 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-14 18:22 zhendong.su at inf dot ethz.ch [this message]
2022-10-14 18:29 ` [Bug tree-optimization/107269] " zhendong.su at inf dot ethz.ch
2022-10-15 20:45 ` zhendong.su at inf dot ethz.ch
2022-10-17  3:26 ` crazylht at gmail dot com
2022-10-17  7:48 ` rguenth at gcc dot gnu.org
2022-10-17 19:07 ` hjl.tools at gmail dot com
2022-10-18  3:31 ` crazylht at gmail dot com

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