[PATCH] D89204: Make likelihood lit test less brittle

Mark de Wever via Phabricator via cfe-commits Sun, 11 Oct 2020 07:37:36 -0700

Mordante created this revision.
Mordante added a reviewer: jmorse.
Mordante added a project: clang.
Mordante requested review of this revision.


Jeremy Morse discovered an issue with the lit test introduced in D88363 
<https://reviews.llvm.org/D88363>. The test gives different results for Sony's 
`-O1`.

The test needs to run at `-O1` otherwise the likelihood attribute will be 
ignored. Instead of running all `-O1` passes it only runs the lower-expect pass 
which is needed to lower `__builtin_expect`.

@jmorse  can you verify this fixes Sony's issue?


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D89204

Files:
  clang/test/CodeGenCXX/attr-likelihood-if-vs-builtin-expect.cpp

Index: clang/test/CodeGenCXX/attr-likelihood-if-vs-builtin-expect.cpp
===================================================================
--- clang/test/CodeGenCXX/attr-likelihood-if-vs-builtin-expect.cpp
+++ clang/test/CodeGenCXX/attr-likelihood-if-vs-builtin-expect.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -O1 -emit-llvm %s -o - -triple=x86_64-linux-gnu | FileCheck %s
+// RUN: %clang_cc1 -O1 -disable-llvm-passes -emit-llvm %s -o - -triple=x86_64-linux-gnu | opt --lower-expect -S | FileCheck %s
 
 // Verifies the output of __builtin_expect versus the output of the likelihood
 // attributes. They should generate the same probabilities for the branches.
@@ -9,9 +9,9 @@
 
 void ab1(int &i) {
   // CHECK-LABEL: define{{.*}}ab1
-  // CHECK: br {{.*}} !prof !2
-  // CHECK: br {{.*}} !prof !2
-  // CHECK: br {{.*}} !prof !2
+  // CHECK: br {{.*}} !prof !6
+  // CHECK: br {{.*}} !prof !6
+  // CHECK: br {{.*}} !prof !6
   if (__builtin_expect(a() && b() && a(), 1)) {
     ++i;
   } else {
@@ -21,9 +21,9 @@
 
 void al(int &i) {
   // CHECK-LABEL: define{{.*}}al
-  // CHECK: br {{.*}} !prof !2
-  // CHECK: br {{.*}} !prof !2
-  // CHECK: br {{.*}} !prof !2
+  // CHECK: br {{.*}} !prof !6
+  // CHECK: br {{.*}} !prof !6
+  // CHECK: br {{.*}} !prof !6
   if (a() && b() && c()) [[likely]] {
     ++i;
   } else {
@@ -33,9 +33,10 @@
 
 void ab0(int &i) {
   // CHECK-LABEL: define{{.*}}ab0
-  // CHECK: br {{.*}}else{{$}}
-  // CHECK: br {{.*}}else{{$}}
-  // CHECK: br {{.*}} !prof !8
+  // CHECK: br {{.*}}end{{$}}
+  // CHECK: br {{.*}}end{{$}}
+  // CHECK: br {{.*}}end{{$}}
+  // CHECK: br {{.*}} !prof !10
   if (__builtin_expect(a() && b() && c(), 0)) {
     ++i;
   } else {
@@ -47,7 +48,7 @@
   // CHECK-LABEL: define{{.*}}au
   // CHECK: br {{.*}}else{{$}}
   // CHECK: br {{.*}}else{{$}}
-  // CHECK: br {{.*}} !prof !8
+  // CHECK: br {{.*}} !prof !10
   if (a() && b() && c()) [[unlikely]] {
     ++i;
   } else {
@@ -59,7 +60,8 @@
   // CHECK-LABEL: define{{.*}}ob1
   // CHECK: br {{.*}}false{{$}}
   // CHECK: br {{.*}}rhs{{$}}
-  // CHECK: br {{.*}} !prof !2
+  // CHECK: br {{.*}}end{{$}}
+  // CHECK: br {{.*}} !prof !6
   if (__builtin_expect(a() || b() || a(), 1)) {
     i = 0;
   } else {
@@ -71,7 +73,7 @@
   // CHECK-LABEL: define{{.*}}ol
   // CHECK: br {{.*}}false{{$}}
   // CHECK: br {{.*}}false2{{$}}
-  // CHECK: br {{.*}} !prof !2
+  // CHECK: br {{.*}} !prof !6
   if (a() || b() || c()) [[likely]] {
     i = 0;
   } else {
@@ -81,9 +83,9 @@
 
 void ob0(int &i) {
   // CHECK-LABEL: define{{.*}}ob0
-  // CHECK: br {{.*}} !prof !8
-  // CHECK: br {{.*}} !prof !8
-  // CHECK: br {{.*}} !prof !8
+  // CHECK: br {{.*}} !prof !10
+  // CHECK: br {{.*}} !prof !10
+  // CHECK: br {{.*}} !prof !10
   if (__builtin_expect(a() || b() || c(), 0)) {
     i = 0;
   } else {
@@ -93,9 +95,9 @@
 
 void ou(int &i) {
   // CHECK-LABEL: define{{.*}}ou
-  // CHECK: br {{.*}} !prof !8
-  // CHECK: br {{.*}} !prof !8
-  // CHECK: br {{.*}} !prof !8
+  // CHECK: br {{.*}} !prof !10
+  // CHECK: br {{.*}} !prof !10
+  // CHECK: br {{.*}} !prof !10
   if (a() || b() || c()) [[unlikely]] {
     i = 0;
   } else {
@@ -105,7 +107,7 @@
 
 void nb1(int &i) {
   // CHECK-LABEL: define{{.*}}nb1
-  // CHECK: storemerge{{.*}} !prof !8
+  // CHECK: br {{.*}} !prof !6
   if (__builtin_expect(!a(), 1)) {
     ++i;
   } else {
@@ -115,8 +117,8 @@
 
 void nl(int &i) {
   // CHECK-LABEL: define{{.*}}nl
-  // CHECK: storemerge{{.*}} !prof !8
-  if (!a()) [[likely]] {
+  // CHECK: br {{.*}} !prof !6
+  if (bool d = !a()) [[likely]] {
     ++i;
   } else {
     --i;
@@ -125,7 +127,7 @@
 
 void nb0(int &i) {
   // CHECK-LABEL: define{{.*}}nb0
-  // CHECK: storemerge{{.*}} !prof !2
+  // CHECK: br {{.*}} !prof !10
   if (__builtin_expect(!a(), 0)) {
     ++i;
   } else {
@@ -135,8 +137,8 @@
 
 void nu(int &i) {
   // CHECK-LABEL: define{{.*}}nu
-  // CHECK: storemerge{{.*}} !prof !2
-  if (!a()) [[unlikely]] {
+  // CHECK: br {{.*}} !prof !10
+  if (bool d = !a()) [[unlikely]] {
     ++i;
   } else {
     --i;
@@ -148,7 +150,7 @@
   // CHECK: br {{.*}}false{{$}}
   // CHECK: br {{.*}}end{{$}}
   // CHECK: br {{.*}}end{{$}}
-  // CHECK: storemerge{{.*}} !prof !2
+  // CHECK: br {{.*}} !prof !6
   if (__builtin_expect(a() ? b() : c(), 1)) {
     ++i;
   } else {
@@ -161,7 +163,7 @@
   // CHECK: br {{.*}}false{{$}}
   // CHECK: br {{.*}}end{{$}}
   // CHECK: br {{.*}}end{{$}}
-  // CHECK: storemerge{{.*}} !prof !2
+  // CHECK: br {{.*}} !prof !6
   if (bool d = a() ? b() : c()) [[likely]] {
     ++i;
   } else {
@@ -172,8 +174,8 @@
 void tl2(int &i) {
   // CHECK-LABEL: define{{.*}}tl
   // CHECK: br {{.*}}false{{$}}
-  // CHECK: br {{.*}} !prof !2
-  // CHECK: br {{.*}} !prof !2
+  // CHECK: br {{.*}} !prof !6
+  // CHECK: br {{.*}} !prof !6
   if (a() ? b() : c()) [[likely]] {
     ++i;
   } else {
@@ -186,7 +188,7 @@
   // CHECK: br {{.*}}false{{$}}
   // CHECK: br {{.*}}end{{$}}
   // CHECK: br {{.*}}end{{$}}
-  // CHECK: storemerge{{.*}} !prof !8
+  // CHECK: br {{.*}} !prof !10
   if (__builtin_expect(a() ? b() : c(), 0)) {
     ++i;
   } else {
@@ -199,7 +201,7 @@
   // CHECK: br {{.*}}false{{$}}
   // CHECK: br {{.*}}end{{$}}
   // CHECK: br {{.*}}end{{$}}
-  // CHECK: storemerge{{.*}} !prof !8
+  // CHECK: br {{.*}} !prof !10
   if (bool d = a() ? b() : c()) [[unlikely]] {
     ++i;
   } else {
@@ -210,8 +212,8 @@
 void tu2(int &i) {
   // CHECK-LABEL: define{{.*}}tu
   // CHECK: br {{.*}}false{{$}}
-  // CHECK: br {{.*}} !prof !8
-  // CHECK: br {{.*}} !prof !8
+  // CHECK: br {{.*}} !prof !10
+  // CHECK: br {{.*}} !prof !10
   if (a() ? b() : c()) [[unlikely]] {
     ++i;
   } else {
@@ -219,5 +221,5 @@
   }
 }
 
-// CHECK: !2 = !{!"branch_weights", i32 2000, i32 1}
-// CHECK: !8 = !{!"branch_weights", i32 1, i32 2000}
+// CHECK: !6 = !{!"branch_weights", i32 2000, i32 1}
+// CHECK: !10 = !{!"branch_weights", i32 1, i32 2000}

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[PATCH] D89204: Make likelihood lit test less brittle

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