[Bug tree-optimization/110494] New: [14 Regression] Wrong code at -O3 on x86_64-pc-linux-gnu

[Bug tree-optimization/110494] New: [14 Regression] Wrong code at -O3 on x86_64-pc-linux-gnu

[jwzeng at nuaa dot edu.cn]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110494

            Bug ID: 110494
           Summary: [14 Regression] Wrong code at -O3 on
                    x86_64-pc-linux-gnu
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jwzeng at nuaa dot edu.cn
  Target Milestone: ---

Link to the Compiler Explorer: https://godbolt.org/z/dq38c9zea

The following code snippet:

#include <stdio.h>
unsigned long long int seed = 0;
unsigned int var_1 = 631366671U;
#define min(a, b) ((a) < (b) ? (a) : (b))
int main() {
    short a[18];
    int b = 1;
    unsigned long long int c[18];
    unsigned long long int d[18];
    for (int i = 0; i < 18; ++i)
        a[i] = 4, c[i] = 3, d[i] = 2;
    for (unsigned short i = 1; i < 16; i += var_1 - 57737)
        a[i] = (short)min(b % (~var_1), c[i] ? d[i] : (long long unsigned
int)b);
    for (int i = 0; i < 18; ++i)
        seed ^= a[i];
    printf("%llu\n", seed);
}

> $ /usr/gcc-trunk/bin/gcc -O0 bug.c; ./a.out
> 5
> $ /usr/gcc-trunk/bin/gcc -O1 bug.c; ./a.out
> 5
> $ /usr/gcc-trunk/bin/gcc -O2 bug.c; ./a.out
> 5
> $ /usr/gcc-trunk/bin/gcc -O3 bug.c; ./a.out
> 7
> $ /usr/gcc-trunk/bin/gcc -Os bug.c; ./a.out
> 5
When compiled with -O3, it prints the wrong result 7 instead of 5. Earlier GCCs
do not have this bug.

> $ /usr/gcc-trunk/bin/gcc --version
Using built-in specs.
COLLECT_GCC=/home/compilers/gcc/gcc-trunk/bin/gcc
COLLECT_LTO_WRAPPER=/home/compilers/gcc/gcc-trunk/bin/../libexec/gcc/x86_64-pc-linux-gnu/14.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-trunk-source/gcc/configure
--enable-languages=c,c++,fortran --enable-checking=release
--enable-valgrind-annotations --disable-werror --disable-libstdcxx-pch
--enable-libgomp --enable-lto --enable-gold --with-plugin-ld=gold
--prefix=/usr/local/gcc-trunk
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 14.0.0 20230619 (experimental) [master r14-1917-gf8e0270272] (GCC)

[Bug tree-optimization/110494] [14 Regression] Wrong code at -O3 on x86_64-pc-linux-gnu

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110494

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

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

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
  iftmp.3_55 = d[_57];
  iftmp.6_54 = (short int) iftmp.3_55;
  _6 = iftmp.3_55 > 1;
  _46 = (short int) _6;
  _143 = _46 | iftmp.6_54;


  # RANGE [irange] short int [0, 1] NONZERO 0x1
  iftmp.6_54 = (short intD.17) iftmp.3_55;

Another dup of bug 110252 (just a different testcase).

Tomorrow I am going to finish up the patch.

*** This bug has been marked as a duplicate of bug 110252 ***