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 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]] = 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
