unions-region.m revision 566a6faa54235590ab8d7d177dfac08586f545b0 
1// RUN: clang-cc -analyze -checker-cfref -analyzer-store=region -analyzer-constraints=range %s -verify
2
3//===-- unions-region.m ---------------------------------------------------===//
4//
5// This file tests the analyzer's reasoning about unions.
6//
7//===----------------------------------------------------------------------===//
8
9// [testA] When using RegionStore, this test case previously had a
10// false positive of a 'pass-by-value argument is uninitialized'
11// warning at the call to 'testA_aux' and 'testA_aux_2'.
12union u_testA {
13  unsigned i;
14  float f;
15};
16 
17float testA(float f) {
18  int testA_aux(unsigned x);
19  int testA_aux_2(union u_testA z);
20  
21  union u_testA swap;
22  swap.f = f;
23
24  if (testA_aux(swap.i))  // no-warning
25    swap.i = ((swap.i & 0xffff0000) >> 16) | ((swap.i & 0x0000fffff) << 16);
26
27  testA_aux_2(swap); // no-warning
28
29  return swap.f;  
30}
31
32// [testB] When using RegionStore, this test case previously had a
33// false positive of a 'pass-by-value argument is uninitialized'
34// warning at the call to 'testB_aux'.
35void testB(int i) {
36  void testB_aux(short z);
37  union { short x[2]; unsigned y; } val;  
38  val.y = 10;
39  testB_aux(val.x[1]); // no-warning
40}
41
42