1// Test that big branch weights get scaled down to 32-bits, rather than just
2// truncated.
3
4// RUN: llvm-profdata merge %S/Inputs/c-counter-overflows.proftext -o %t.profdata
5// RUN: %clang_cc1 -triple x86_64-apple-macosx10.9 -main-file-name c-counter-overflows.c %s -o - -emit-llvm -fprofile-instr-use=%t.profdata | FileCheck %s
6
7typedef unsigned long long uint64_t;
8
9int main(int argc, const char *argv[]) {
10  // Need counts higher than 32-bits.
11  // CHECK: br {{.*}} !prof ![[FOR:[0-9]+]]
12  // max   = 0xffffffff0
13  // scale = 0xffffffff0 / 0xffffffff + 1 = 17
14  // loop-body: 0xffffffff0 / 17 + 1 = 0xf0f0f0f0 + 1 = 4042322161 => -252645135
15  // loop-exit: 0x000000001 / 17 + 1 = 0x00000000 + 1 =          1 =>          1
16  for (uint64_t I = 0; I < 0xffffffff0; ++I) {
17    // max   = 0xffffffff * 15 = 0xefffffff1
18    // scale = 0xefffffff1 / 0xffffffff + 1 = 16
19    // CHECK: br {{.*}} !prof ![[IF:[0-9]+]]
20    if (I & 0xf) {
21      // 0xefffffff1 / 16 + 1 = 0xefffffff + 1 = 4026531840 => -268435456
22    } else {
23      // 0x0ffffffff / 16 + 1 = 0x0fffffff + 1 =  268435456 =>  268435456
24    }
25
26    // max   = 0xffffffff * 5 = 0x4fffffffb
27    // scale = 0x4fffffffb / 0xffffffff + 1 = 6
28    // CHECK: ], !prof ![[SWITCH:[0-9]+]]
29    switch ((I & 0xf) / 5) {
30    case 0:
31      // 0x4fffffffb / 6 = 0xd5555554 + 1 = 3579139413 => -715827883
32      break;
33    case 1:
34      // 0x4fffffffb / 6 = 0xd5555554 + 1 = 3579139413 => -715827883
35      break;
36    case 2:
37      // 0x4fffffffb / 6 = 0xd5555554 + 1 = 3579139413 => -715827883
38      break;
39    default:
40      // 0x0ffffffff / 6 = 0x2aaaaaaa + 1 =  715827883 =>  715827883
41      break;
42    }
43  }
44  return 0;
45}
46
47// CHECK-DAG: ![[FOR]] = metadata !{metadata !"branch_weights", i32 -252645135, i32 1}
48// CHECK-DAG: ![[IF]]  = metadata !{metadata !"branch_weights", i32 -268435456, i32 268435456}
49// CHECK-DAG: ![[SWITCH]] = metadata !{metadata !"branch_weights", i32 715827883, i32 -715827883, i32 -715827883, i32 -715827883}
50