50 lines
1.9 KiB
C
50 lines
1.9 KiB
C
// 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-instr-use=%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]] = metadata !{metadata !"branch_weights", i32 -252645135, i32 1}
|
|
// CHECK-DAG: ![[IF]] = metadata !{metadata !"branch_weights", i32 -268435456, i32 268435456}
|
|
// CHECK-DAG: ![[SWITCH]] = metadata !{metadata !"branch_weights", i32 715827883, i32 -715827883, i32 -715827883, i32 -715827883}
|