50 lines · c
1// Test that big branch weights get scaled down to 32-bits, rather than just2// truncated.3 4// RUN: llvm-profdata merge %S/Inputs/c-counter-overflows.proftext -o %t.profdata5// RUN: %clang_cc1 -triple x86_64-apple-macosx10.9 -main-file-name c-counter-overflows.c %s -o - -emit-llvm -fprofile-instrument-use=clang -fprofile-instrument-use-path=%t.profdata | FileCheck %s6 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 = 0xffffffff013 // scale = 0xffffffff0 / 0xffffffff + 1 = 1714 // loop-body: 0xffffffff0 / 17 + 1 = 0xf0f0f0f0 + 1 = 4042322161 => -25264513515 // loop-exit: 0x000000001 / 17 + 1 = 0x00000000 + 1 = 1 => 116 for (uint64_t I = 0; I < 0xffffffff0; ++I) {17 // max = 0xffffffff * 15 = 0xefffffff118 // scale = 0xefffffff1 / 0xffffffff + 1 = 1619 // CHECK: br {{.*}} !prof ![[IF:[0-9]+]]20 if (I & 0xf) {21 // 0xefffffff1 / 16 + 1 = 0xefffffff + 1 = 4026531840 => -26843545622 } else {23 // 0x0ffffffff / 16 + 1 = 0x0fffffff + 1 = 268435456 => 26843545624 }25 26 // max = 0xffffffff * 5 = 0x4fffffffb27 // scale = 0x4fffffffb / 0xffffffff + 1 = 628 // CHECK: ], !prof ![[SWITCH:[0-9]+]]29 switch ((I & 0xf) / 5) {30 case 0:31 // 0x4fffffffb / 6 = 0xd5555554 + 1 = 3579139413 => -71582788332 break;33 case 1:34 // 0x4fffffffb / 6 = 0xd5555554 + 1 = 3579139413 => -71582788335 break;36 case 2:37 // 0x4fffffffb / 6 = 0xd5555554 + 1 = 3579139413 => -71582788338 break;39 default:40 // 0x0ffffffff / 6 = 0x2aaaaaaa + 1 = 715827883 => 71582788341 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