[llvm-bugs] [Bug 51241] New: clang crashes on valid code at -O1 and above: Instruction does not dominate all uses!

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=51241

            Bug ID: 51241
           Summary: clang crashes on valid code at -O1 and above:
                    Instruction does not dominate all uses!
           Product: libraries
           Version: trunk
          Hardware: PC
                OS: All
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: Common Code Generator Code
          Assignee: unassignedbugs at nondot.org
          Reporter: zhendong.su at inf.ethz.ch
                CC: llvm-bugs at lists.llvm.org

It appears to be a recent regression.

[515] % clangtk -v
clang version 14.0.0 (https://github.com/llvm/llvm-project.git
0a1ca2ad4ce239abc8d844f33048af58648edb80)
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/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/7.5.0
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Candidate multilib: x32;@mx32
Selected multilib: .;@m64
[516] % 
[516] % clangtk -O0 small.c
[517] % 
[517] % clangtk -O1 small.c
Instruction does not dominate all uses!
  %div = sdiv i32 7, %0
  store i32 %div, i32* @b, align 4, !tbaa !3
in function main
fatal error: error in backend: Broken function found, compilation aborted!
clang-14: error: clang frontend command failed with exit code 70 (use -v to see
invocation)
clang version 14.0.0 (https://github.com/llvm/llvm-project.git
0a1ca2ad4ce239abc8d844f33048af58648edb80)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /local/suz-local/opfuzz/bin
clang-14: note: diagnostic msg: 
********************

PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
Preprocessed source(s) and associated run script(s) are located at:
clang-14: note: diagnostic msg: /tmp/small-52fa75.c
clang-14: note: diagnostic msg: /tmp/small-52fa75.sh
clang-14: note: diagnostic msg: 

********************
[518] % 
[518] % cat small.c
int a, b, c = 1, d;
int main() {
  a = c;
  int f = d && b % c && 7 % c, g = 7 / c;
  c = f;
  b = g;
  return 0;
}

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