[llvm-bugs] [Bug 47788] New: [InstCombiner] fatal error: error in backend: Instruction Combining seems stuck in an infinite loop

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=47788

            Bug ID: 47788
           Summary: [InstCombiner] fatal error: error in backend:
                    Instruction Combining seems stuck in an infinite loop
           Product: libraries
           Version: trunk
          Hardware: PC
                OS: Linux
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: Scalar Optimizations
          Assignee: unassignedbugs at nondot.org
          Reporter: paulsson at linux.vnet.ibm.com
                CC: llvm-bugs at lists.llvm.org

Created attachment 24041
  --> https://bugs.llvm.org/attachment.cgi?id=24041&action=edit
original preprocessed test case (csmith)

clang -O3 -march=arch13 crash2.i -o a.out -w -mllvm -unroll-count=10 -mllvm
-enable-tbaa=false -mllvm -instcombine-infinite-loop-threshold=200

crash2.i (reduced):

short a, b, d;
int c, e;
long f;
short(g)() { return a < 0 || c ? : 0; }
void h(int *i) {
  long *j = &f;
  d = 0;
  for (; d != 34; d++) {
    b = -7;
    for (; b; b = b + 1) {
      e &= g() | 5;
      e |= 0 >= 0;
      *i |= d;
      *j = *i;
    }
  }
}
void main() {}

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