Open
Description
This appears to affect clang 5.* and later, so a quite long-latent regression.
% clangtk -v
clang version 15.0.0 (https://github.com/llvm/llvm-project.git 4d2eda2bb3156cee63ea486be34b01164b178e10)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /local/suz-local/opfuzz/bin
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/8
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/10
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/11
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6.5.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7.5.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/8
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/11
Candidate multilib: .;@m64
Selected multilib: .;@m64
%
% clangtk -O0 small.c; ./a.out
% clangtk -O3 small.c; ./a.out
%
% clangtk -O3 -mllvm -enable-newgvn small.c
% timeout -s 9 5 ./a.out
Killed
%
% cat small.c
int printf(const char *, ...);
int a;
short b;
int main() {
short d = 0;
a = 9;
for (; a > 5; a--)
;
short e = a;
void *f();
if (e < 7) {
L:
d = a;
a = ~(d & (&f || a));
}
while (a >= d)
;
while (a == d)
printf("0");
if (b <= a)
goto L;
return 0;
}Compiler Explorer: https://godbolt.org/z/sT1G5seEP