| // Test that big branch weights get scaled down to 32-bits, rather than just |
| // truncated. |
| |
| // RUN: llvm-profdata merge %S/Inputs/c-counter-overflows.proftext -o %t.profdata |
| // RUN: %clang_cc1 -triple x86_64-apple-macosx10.9 -main-file-name c-counter-overflows.c %s -o - -emit-llvm -fprofile-instrument-use-path=%t.profdata | FileCheck %s |
| |
| typedef unsigned long long uint64_t; |
| |
| int main(int argc, const char *argv[]) { |
| // Need counts higher than 32-bits. |
| // CHECK: br {{.*}} !prof ![[FOR:[0-9]+]] |
| // max = 0xffffffff0 |
| // scale = 0xffffffff0 / 0xffffffff + 1 = 17 |
| // loop-body: 0xffffffff0 / 17 + 1 = 0xf0f0f0f0 + 1 = 4042322161 => -252645135 |
| // loop-exit: 0x000000001 / 17 + 1 = 0x00000000 + 1 = 1 => 1 |
| for (uint64_t I = 0; I < 0xffffffff0; ++I) { |
| // max = 0xffffffff * 15 = 0xefffffff1 |
| // scale = 0xefffffff1 / 0xffffffff + 1 = 16 |
| // CHECK: br {{.*}} !prof ![[IF:[0-9]+]] |
| if (I & 0xf) { |
| // 0xefffffff1 / 16 + 1 = 0xefffffff + 1 = 4026531840 => -268435456 |
| } else { |
| // 0x0ffffffff / 16 + 1 = 0x0fffffff + 1 = 268435456 => 268435456 |
| } |
| |
| // max = 0xffffffff * 5 = 0x4fffffffb |
| // scale = 0x4fffffffb / 0xffffffff + 1 = 6 |
| // CHECK: ], !prof ![[SWITCH:[0-9]+]] |
| switch ((I & 0xf) / 5) { |
| case 0: |
| // 0x4fffffffb / 6 = 0xd5555554 + 1 = 3579139413 => -715827883 |
| break; |
| case 1: |
| // 0x4fffffffb / 6 = 0xd5555554 + 1 = 3579139413 => -715827883 |
| break; |
| case 2: |
| // 0x4fffffffb / 6 = 0xd5555554 + 1 = 3579139413 => -715827883 |
| break; |
| default: |
| // 0x0ffffffff / 6 = 0x2aaaaaaa + 1 = 715827883 => 715827883 |
| break; |
| } |
| } |
| return 0; |
| } |
| |
| // CHECK-DAG: ![[FOR]] = !{!"branch_weights", i32 -252645135, i32 1} |
| // CHECK-DAG: ![[IF]] = !{!"branch_weights", i32 -268435456, i32 268435456} |
| // CHECK-DAG: ![[SWITCH]] = !{!"branch_weights", i32 715827883, i32 -715827883, i32 -715827883, i32 -715827883} |
