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
7 typedef unsigned long long uint64_t;
8
main(int argc,const char * argv[])9 int 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]] = !{!"branch_weights", i32 -252645135, i32 1}
48 // CHECK-DAG: ![[IF]] = !{!"branch_weights", i32 -268435456, i32 268435456}
49 // CHECK-DAG: ![[SWITCH]] = !{!"branch_weights", i32 715827883, i32 -715827883, i32 -715827883, i32 -715827883}
50