llvm-project/clang/test/CodeGen/2009-02-13-zerosize-union-field.c

// RUN: %clang_cc1 %s -triple i686-apple-darwin -emit-llvm -o - | FileCheck %s
// Every printf has 'i32 0' for the GEP of the string; no point counting those.
typedef unsigned int Foo __attribute__((aligned(32)));
typedef union{Foo:0;}a;
typedef union{int x; Foo:0;}b;
extern int printf(const char*, ...);
int main() {
  // CHECK: getelementptr inbounds ([5 x i8], [5 x i8]* @.str, i32 0, i32 0), i32 0
  printf("%ld\n", sizeof(a));
  // CHECK: getelementptr inbounds ([5 x i8], [5 x i8]* @.str, i32 0, i32 0), i32 1
  printf("%ld\n", __alignof__(a));
  // CHECK: getelementptr inbounds ([5 x i8], [5 x i8]* @.str, i32 0, i32 0), i32 4
  printf("%ld\n", sizeof(b));
  // CHECK: getelementptr inbounds ([5 x i8], [5 x i8]* @.str, i32 0, i32 0), i32 4
  printf("%ld\n", __alignof__(b));
}