llvm-project/llvm/test/FrontendC/2003-11-08-PointerSubNotGetelementptr.c

// RUN: %llvmgcc -xc %s -S -o - | grep getelementptr

char *test(char* C) {
  return C-1;   // Should turn into a GEP
}

int *test2(int* I) {
  return I-1;
}