https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111151
Bug ID: 111151
Summary: [12/13/14 Regression] Wrong code at -O0 on
x86_64-pc-linux-gnu
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
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/MY4Er6b3e
The following code snippet, gcc at -O0 produces the wrong code. I also compiled
this code with almost all versions up to and including gcc-13 and got the same
error.
$ cat test.c
int printf(const char *, ...);
short t = -32166;
unsigned long long int a, b, c;
int main()
{
a = 32739 > t + 4503599ULL ? 32739 : t + 4503599ULL;
b = -10 * a;
printf("%llu (Split calculation result)\n", b);
c = -10 * (32739 > t + 4503599ULL ? 32739 : t + 4503599ULL);
printf("%llu (Combine calculation result)\n", c);
}
$
$ gcc-tk test.c; ./a.out
18446744073664837286 (Split calculation result)
18446744073709224226 (Combine calculation result)
$
$ clang-tk test.c; ./a.out
18446744073664837286 (Split calculation result)
18446744073664837286 (Combine calculation result)
$
$ ccomp test.c; ./a.out
18446744073664837286 (Split calculation result)
18446744073664837286 (Combine calculation result)
$
$ gcc-tk --version
gcc (GCC) 14.0.0 20230823 (experimental) [master r14-3395-g6cd8527307]
$
$ clang-tk --version
Ubuntu clang version 18.0.0
(++20230821052626+634b2fd2cac2-1~exp1~20230821172748.738)
$
$ ccomp --version
The CompCert C verified compiler, version 3.12
