paulkirth created this revision.
Herald added subscribers: abrachet, ormris, dexonsmith, wenlei, phosek,
hiraditya, mgorny.
paulkirth updated this revision to Diff 394995.
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paulkirth updated this revision to Diff 394997.
paulkirth added reviewers: phosek, mcgrathr, leonardchan, lebedev.ri.
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[misexpect] Fix Typo
paulkirth added a comment.
Fix bad diff in arctool
paulkirth added a comment.
Ready for review
Reimplements MisExpect diagnostics to reconstruct its original checking
methodology only using MD_prof branch_weights metadata.
New checks rely on 2 invariants:
1. for frontend instrumentation, MD_prof branch_weights will always be
populated before llvm.expect intrinsics are lowered.
2. for IR and sample profiling, llvm.expect intrinsics will always be lowered
before branch_weights are populated from the IR profiles.
These invariants allow the checking to assume how the existing branch
weights are populated depending on the profiling method used, and emit
the correct diagnostics. If these invariants are ever invalidated, the
MisExpect related checks would need to be updated, potentially by
re-introducing MD_misexpect metadata, and ensuring it always will be
transformed the same way as branch_weights in other optimization passes.
Frontend based profiling is now enabled without using LLVM Args, by
introducing a new CodeGen option, and checking if the -Wmisexpect flag
has been passed on the command line.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D115907
Files:
clang/include/clang/Basic/CodeGenOptions.def
clang/include/clang/Basic/DiagnosticFrontendKinds.td
clang/include/clang/Basic/DiagnosticGroups.td
clang/lib/CodeGen/BackendUtil.cpp
clang/lib/CodeGen/CodeGenAction.cpp
clang/lib/Frontend/CompilerInvocation.cpp
clang/test/Profile/Inputs/misexpect-branch.proftext
clang/test/Profile/misexpect-branch-cold.c
clang/test/Profile/misexpect-branch-unpredictable.c
clang/test/Profile/misexpect-branch.c
llvm/docs/MisExpect.rst
llvm/include/llvm/IR/DiagnosticInfo.h
llvm/include/llvm/IR/LLVMContext.h
llvm/include/llvm/Target/TargetOptions.h
llvm/include/llvm/Transforms/Utils/MisExpect.h
llvm/lib/IR/DiagnosticInfo.cpp
llvm/lib/IR/LLVMContext.cpp
llvm/lib/IR/LLVMContextImpl.h
llvm/lib/Transforms/IPO/SampleProfile.cpp
llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp
llvm/lib/Transforms/Scalar/LowerExpectIntrinsic.cpp
llvm/lib/Transforms/Utils/CMakeLists.txt
llvm/lib/Transforms/Utils/MisExpect.cpp
llvm/test/Transforms/PGOProfile/Inputs/misexpect-branch-correct.proftext
llvm/test/Transforms/PGOProfile/Inputs/misexpect-branch.proftext
llvm/test/Transforms/PGOProfile/Inputs/misexpect-switch-correct.proftext
llvm/test/Transforms/PGOProfile/Inputs/misexpect-switch.proftext
llvm/test/Transforms/PGOProfile/misexpect-branch-correct.ll
llvm/test/Transforms/PGOProfile/misexpect-branch-stripped.ll
llvm/test/Transforms/PGOProfile/misexpect-branch-unpredictable.ll
llvm/test/Transforms/PGOProfile/misexpect-branch.ll
llvm/test/Transforms/PGOProfile/misexpect-switch-default.ll
llvm/test/Transforms/PGOProfile/misexpect-switch.ll
Index: llvm/test/Transforms/PGOProfile/misexpect-switch.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/PGOProfile/misexpect-switch.ll
@@ -0,0 +1,290 @@
+; RUN: llvm-profdata merge %S/Inputs/misexpect-switch.proftext -o %t.profdata
+; RUN: llvm-profdata merge %S/Inputs/misexpect-switch-correct.proftext -o %t.c.profdata
+
+; RUN: opt < %s -lower-expect -pgo-instr-use -pgo-test-profile-file=%t.profdata -S -pgo-warn-misexpect 2>&1 | FileCheck %s --check-prefix=WARNING
+; RUN: opt < %s -lower-expect -pgo-instr-use -pgo-test-profile-file=%t.profdata -S -pass-remarks=misexpect 2>&1 | FileCheck %s --check-prefix=REMARK
+; RUN: opt < %s -lower-expect -pgo-instr-use -pgo-test-profile-file=%t.profdata -S -pgo-warn-misexpect -pass-remarks=misexpect 2>&1 | FileCheck %s --check-prefix=BOTH
+; RUN: opt < %s -lower-expect -pgo-instr-use -pgo-test-profile-file=%t.profdata -S 2>&1 | FileCheck %s --check-prefix=DISABLED
+
+; New PM
+; RUN: opt < %s -passes="function(lower-expect),pgo-instr-use" -pgo-test-profile-file=%t.profdata -pgo-warn-misexpect -S 2>&1 | FileCheck %s --check-prefix=WARNING
+; RUN: opt < %s -passes="function(lower-expect),pgo-instr-use" -pgo-test-profile-file=%t.profdata -pass-remarks=misexpect -S 2>&1 | FileCheck %s --check-prefix=REMARK
+; RUN: opt < %s -passes="function(lower-expect),pgo-instr-use" -pgo-test-profile-file=%t.profdata -pgo-warn-misexpect -pass-remarks=misexpect -S 2>&1 | FileCheck %s --check-prefix=BOTH
+; RUN: opt < %s -passes="function(lower-expect),pgo-instr-use" -pgo-test-profile-file=%t.profdata -S 2>&1 | FileCheck %s --check-prefix=DISABLED
+
+; RUN: opt < %s -lower-expect -pgo-instr-use -pgo-test-profile-file=%t.c.profdata -S -pgo-warn-misexpect -pass-remarks=misexpect 2>&1 | FileCheck %s --check-prefix=CORRECT
+; RUN: opt < %s -passes="function(lower-expect),pgo-instr-use" -pgo-test-profile-file=%t.c.profdata -pgo-warn-misexpect -pass-remarks=misexpect -S 2>&1 | FileCheck %s --check-prefix=CORRECT
+
+; WARNING-DAG: warning: misexpect-switch.c:26:5: 0.00%
+; WARNING-NOT: remark: misexpect-switch.c:26:5: Potential performance regression from use of the llvm.expect intrinsic: Annotation was correct on 0.00% (0 / 8112) of profiled executions.
+
+; REMARK-NOT: warning: misexpect-switch.c:26:5: 0.00%
+; REMARK-DAG: remark: misexpect-switch.c:26:5: Potential performance regression from use of the llvm.expect intrinsic: Annotation was correct on 0.00% (0 / 8112) of profiled executions.
+
+; BOTH-DAG: warning: misexpect-switch.c:26:5: 0.00%
+; BOTH-DAG: remark: misexpect-switch.c:26:5: Potential performance regression from use of the llvm.expect intrinsic: Annotation was correct on 0.00% (0 / 8112) of profiled executions.
+
+; DISABLED-NOT: warning: misexpect-switch.c:26:5: 0.00%
+; DISABLED-NOT: remark: misexpect-switch.c:26:5: Potential performance regression from use of the llvm.expect intrinsic: Annotation was correct on 0.00% (0 / 8112) of profiled executions.
+
+; DISABLED-NOT: warning: misexpect-switch.c:26:5: 0.00%
+; DISABLED-NOT: remark: misexpect-switch.c:26:5: Potential performance regression from use of the llvm.expect intrinsic: Annotation was correct on 0.00% (0 / 8112) of profiled executions.
+
+; CORRECT-NOT: warning: {{.*}}
+; CORRECT-NOT: remark: {{.*}}
+
+
+; ModuleID = 'misexpect-switch.c'
+source_filename = "misexpect-switch.c"
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+@inner_loop = dso_local constant i32 1000, align 4, !dbg !0
+@outer_loop = dso_local constant i32 20, align 4, !dbg !6
+@arry_size = dso_local constant i32 25, align 4, !dbg !10
+@arry = dso_local global [25 x i32] zeroinitializer, align 16, !dbg !12
+
+; Function Attrs: nounwind uwtable
+define dso_local void @init_arry() #0 !dbg !21 {
+entry:
+ %i = alloca i32, align 4
+ %0 = bitcast i32* %i to i8*, !dbg !26
+ call void @llvm.lifetime.start.p0i8(i64 4, i8* %0) #6, !dbg !26
+ call void @llvm.dbg.declare(metadata i32* %i, metadata !25, metadata !DIExpression()), !dbg !27
+ store i32 0, i32* %i, align 4, !dbg !28, !tbaa !30
+ br label %for.cond, !dbg !34
+
+for.cond: ; preds = %for.inc, %entry
+ %1 = load i32, i32* %i, align 4, !dbg !35, !tbaa !30
+ %cmp = icmp slt i32 %1, 25, !dbg !37
+ br i1 %cmp, label %for.body, label %for.end, !dbg !38
+
+for.body: ; preds = %for.cond
+ %call = call i32 @rand() #6, !dbg !39
+ %rem = srem i32 %call, 10, !dbg !41
+ %2 = load i32, i32* %i, align 4, !dbg !42, !tbaa !30
+ %idxprom = sext i32 %2 to i64, !dbg !43
+ %arrayidx = getelementptr inbounds [25 x i32], [25 x i32]* @arry, i64 0, i64 %idxprom, !dbg !43
+ store i32 %rem, i32* %arrayidx, align 4, !dbg !44, !tbaa !30
+ br label %for.inc, !dbg !45
+
+for.inc: ; preds = %for.body
+ %3 = load i32, i32* %i, align 4, !dbg !46, !tbaa !30
+ %inc = add nsw i32 %3, 1, !dbg !46
+ store i32 %inc, i32* %i, align 4, !dbg !46, !tbaa !30
+ br label %for.cond, !dbg !47, !llvm.loop !48
+
+for.end: ; preds = %for.cond
+ %4 = bitcast i32* %i to i8*, !dbg !50
+ call void @llvm.lifetime.end.p0i8(i64 4, i8* %4) #6, !dbg !50
+ ret void, !dbg !50
+}
+
+; Function Attrs: argmemonly nounwind willreturn
+declare void @llvm.lifetime.start.p0i8(i64 immarg, i8* nocapture) #1
+
+; Function Attrs: nounwind readnone speculatable willreturn
+declare void @llvm.dbg.declare(metadata, metadata, metadata) #2
+
+; Function Attrs: nounwind
+declare dso_local i32 @rand() #3
+
+; Function Attrs: argmemonly nounwind willreturn
+declare void @llvm.lifetime.end.p0i8(i64 immarg, i8* nocapture) #1
+
+; Function Attrs: nounwind uwtable
+define dso_local i32 @main() #0 !dbg !51 {
+entry:
+ %retval = alloca i32, align 4
+ %val = alloca i32, align 4
+ %j = alloca i32, align 4
+ %condition = alloca i32, align 4
+ store i32 0, i32* %retval, align 4
+ call void @init_arry(), !dbg !62
+ %0 = bitcast i32* %val to i8*, !dbg !63
+ call void @llvm.lifetime.start.p0i8(i64 4, i8* %0) #6, !dbg !63
+ call void @llvm.dbg.declare(metadata i32* %val, metadata !55, metadata !DIExpression()), !dbg !64
+ store i32 0, i32* %val, align 4, !dbg !64, !tbaa !30
+ %1 = bitcast i32* %j to i8*, !dbg !65
+ call void @llvm.lifetime.start.p0i8(i64 4, i8* %1) #6, !dbg !65
+ call void @llvm.dbg.declare(metadata i32* %j, metadata !56, metadata !DIExpression()), !dbg !66
+ store i32 0, i32* %j, align 4, !dbg !67, !tbaa !30
+ br label %for.cond, !dbg !68
+
+for.cond: ; preds = %for.inc, %entry
+ %2 = load i32, i32* %j, align 4, !dbg !69, !tbaa !30
+ %cmp = icmp slt i32 %2, 20000, !dbg !70
+ br i1 %cmp, label %for.body, label %for.end, !dbg !71
+
+for.body: ; preds = %for.cond
+ %3 = bitcast i32* %condition to i8*, !dbg !72
+ call void @llvm.lifetime.start.p0i8(i64 4, i8* %3) #6, !dbg !72
+ call void @llvm.dbg.declare(metadata i32* %condition, metadata !57, metadata !DIExpression()), !dbg !73
+ %call = call i32 @rand() #6, !dbg !74
+ %rem = srem i32 %call, 5, !dbg !75
+ store i32 %rem, i32* %condition, align 4, !dbg !73, !tbaa !30
+ %4 = load i32, i32* %condition, align 4, !dbg !76, !tbaa !30
+ %conv = zext i32 %4 to i64, !dbg !76
+ %expval = call i64 @llvm.expect.i64(i64 %conv, i64 0), !dbg !77
+ switch i64 %expval, label %sw.default [
+ i64 0, label %sw.bb
+ i64 1, label %sw.bb2
+ i64 2, label %sw.bb2
+ i64 3, label %sw.bb2
+ i64 4, label %sw.bb3
+ ], !dbg !78
+
+sw.bb: ; preds = %for.body
+ %call1 = call i32 @sum(i32* getelementptr inbounds ([25 x i32], [25 x i32]* @arry, i64 0, i64 0), i32 25), !dbg !79
+ %5 = load i32, i32* %val, align 4, !dbg !81, !tbaa !30
+ %add = add nsw i32 %5, %call1, !dbg !81
+ store i32 %add, i32* %val, align 4, !dbg !81, !tbaa !30
+ br label %sw.epilog, !dbg !82
+
+sw.bb2: ; preds = %for.body, %for.body, %for.body
+ br label %sw.epilog, !dbg !83
+
+sw.bb3: ; preds = %for.body
+ %call4 = call i32 @random_sample(i32* getelementptr inbounds ([25 x i32], [25 x i32]* @arry, i64 0, i64 0), i32 25), !dbg !84
+ %6 = load i32, i32* %val, align 4, !dbg !85, !tbaa !30
+ %add5 = add nsw i32 %6, %call4, !dbg !85
+ store i32 %add5, i32* %val, align 4, !dbg !85, !tbaa !30
+ br label %sw.epilog, !dbg !86
+
+sw.default: ; preds = %for.body
+ unreachable, !dbg !87
+
+sw.epilog: ; preds = %sw.bb3, %sw.bb2, %sw.bb
+ %7 = bitcast i32* %condition to i8*, !dbg !88
+ call void @llvm.lifetime.end.p0i8(i64 4, i8* %7) #6, !dbg !88
+ br label %for.inc, !dbg !89
+
+for.inc: ; preds = %sw.epilog
+ %8 = load i32, i32* %j, align 4, !dbg !90, !tbaa !30
+ %inc = add nsw i32 %8, 1, !dbg !90
+ store i32 %inc, i32* %j, align 4, !dbg !90, !tbaa !30
+ br label %for.cond, !dbg !91, !llvm.loop !92
+
+for.end: ; preds = %for.cond
+ %9 = bitcast i32* %j to i8*, !dbg !94
+ call void @llvm.lifetime.end.p0i8(i64 4, i8* %9) #6, !dbg !94
+ %10 = bitcast i32* %val to i8*, !dbg !94
+ call void @llvm.lifetime.end.p0i8(i64 4, i8* %10) #6, !dbg !94
+ ret i32 0, !dbg !95
+}
+
+; Function Attrs: nounwind readnone willreturn
+declare i64 @llvm.expect.i64(i64, i64) #4
+
+declare dso_local i32 @sum(i32*, i32) #5
+
+declare dso_local i32 @random_sample(i32*, i32) #5
+
+attributes #0 = { nounwind uwtable "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "frame-pointer"="none" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { argmemonly nounwind willreturn }
+attributes #2 = { nounwind readnone speculatable willreturn }
+attributes #3 = { nounwind "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "frame-pointer"="none" "less-precise-fpmad"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #4 = { nounwind readnone willreturn }
+attributes #5 = { "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "frame-pointer"="none" "less-precise-fpmad"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #6 = { nounwind }
+
+!llvm.dbg.cu = !{!2}
+!llvm.module.flags = !{!17, !18, !19}
+!llvm.ident = !{!20}
+
+!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
+!1 = distinct !DIGlobalVariable(name: "inner_loop", scope: !2, file: !3, line: 7, type: !8, isLocal: false, isDefinition: true)
+!2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "clang version 10.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5, nameTableKind: None)
+!3 = !DIFile(filename: "misexpect-switch.c", directory: ".")
+!4 = !{}
+!5 = !{!0, !6, !10, !12}
+!6 = !DIGlobalVariableExpression(var: !7, expr: !DIExpression())
+!7 = distinct !DIGlobalVariable(name: "outer_loop", scope: !2, file: !3, line: 8, type: !8, isLocal: false, isDefinition: true)
+!8 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !9)
+!9 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!10 = !DIGlobalVariableExpression(var: !11, expr: !DIExpression())
+!11 = distinct !DIGlobalVariable(name: "arry_size", scope: !2, file: !3, line: 9, type: !8, isLocal: false, isDefinition: true)
+!12 = !DIGlobalVariableExpression(var: !13, expr: !DIExpression())
+!13 = distinct !DIGlobalVariable(name: "arry", scope: !2, file: !3, line: 11, type: !14, isLocal: false, isDefinition: true)
+!14 = !DICompositeType(tag: DW_TAG_array_type, baseType: !9, size: 800, elements: !15)
+!15 = !{!16}
+!16 = !DISubrange(count: 25)
+!17 = !{i32 2, !"Dwarf Version", i32 4}
+!18 = !{i32 2, !"Debug Info Version", i32 3}
+!19 = !{i32 1, !"wchar_size", i32 4}
+!20 = !{!"clang version 10.0.0"}
+!21 = distinct !DISubprogram(name: "init_arry", scope: !3, file: !3, line: 13, type: !22, scopeLine: 13, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !2, retainedNodes: !24)
+!22 = !DISubroutineType(types: !23)
+!23 = !{null}
+!24 = !{!25}
+!25 = !DILocalVariable(name: "i", scope: !21, file: !3, line: 14, type: !9)
+!26 = !DILocation(line: 14, column: 3, scope: !21)
+!27 = !DILocation(line: 14, column: 7, scope: !21)
+!28 = !DILocation(line: 15, column: 10, scope: !29)
+!29 = distinct !DILexicalBlock(scope: !21, file: !3, line: 15, column: 3)
+!30 = !{!31, !31, i64 0}
+!31 = !{!"int", !32, i64 0}
+!32 = !{!"omnipotent char", !33, i64 0}
+!33 = !{!"Simple C/C++ TBAA"}
+!34 = !DILocation(line: 15, column: 8, scope: !29)
+!35 = !DILocation(line: 15, column: 15, scope: !36)
+!36 = distinct !DILexicalBlock(scope: !29, file: !3, line: 15, column: 3)
+!37 = !DILocation(line: 15, column: 17, scope: !36)
+!38 = !DILocation(line: 15, column: 3, scope: !29)
+!39 = !DILocation(line: 16, column: 15, scope: !40)
+!40 = distinct !DILexicalBlock(scope: !36, file: !3, line: 15, column: 35)
+!41 = !DILocation(line: 16, column: 22, scope: !40)
+!42 = !DILocation(line: 16, column: 10, scope: !40)
+!43 = !DILocation(line: 16, column: 5, scope: !40)
+!44 = !DILocation(line: 16, column: 13, scope: !40)
+!45 = !DILocation(line: 17, column: 3, scope: !40)
+!46 = !DILocation(line: 15, column: 30, scope: !36)
+!47 = !DILocation(line: 15, column: 3, scope: !36)
+!48 = distinct !{!48, !38, !49}
+!49 = !DILocation(line: 17, column: 3, scope: !29)
+!50 = !DILocation(line: 18, column: 1, scope: !21)
+!51 = distinct !DISubprogram(name: "main", scope: !3, file: !3, line: 20, type: !52, scopeLine: 20, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !2, retainedNodes: !54)
+!52 = !DISubroutineType(types: !53)
+!53 = !{!9}
+!54 = !{!55, !56, !57}
+!55 = !DILocalVariable(name: "val", scope: !51, file: !3, line: 22, type: !9)
+!56 = !DILocalVariable(name: "j", scope: !51, file: !3, line: 23, type: !9)
+!57 = !DILocalVariable(name: "condition", scope: !58, file: !3, line: 25, type: !61)
+!58 = distinct !DILexicalBlock(scope: !59, file: !3, line: 24, column: 49)
+!59 = distinct !DILexicalBlock(scope: !60, file: !3, line: 24, column: 3)
+!60 = distinct !DILexicalBlock(scope: !51, file: !3, line: 24, column: 3)
+!61 = !DIBasicType(name: "unsigned int", size: 32, encoding: DW_ATE_unsigned)
+!62 = !DILocation(line: 21, column: 3, scope: !51)
+!63 = !DILocation(line: 22, column: 3, scope: !51)
+!64 = !DILocation(line: 22, column: 7, scope: !51)
+!65 = !DILocation(line: 23, column: 3, scope: !51)
+!66 = !DILocation(line: 23, column: 7, scope: !51)
+!67 = !DILocation(line: 24, column: 10, scope: !60)
+!68 = !DILocation(line: 24, column: 8, scope: !60)
+!69 = !DILocation(line: 24, column: 15, scope: !59)
+!70 = !DILocation(line: 24, column: 17, scope: !59)
+!71 = !DILocation(line: 24, column: 3, scope: !60)
+!72 = !DILocation(line: 25, column: 5, scope: !58)
+!73 = !DILocation(line: 25, column: 14, scope: !58)
+!74 = !DILocation(line: 25, column: 26, scope: !58)
+!75 = !DILocation(line: 25, column: 33, scope: !58)
+!76 = !DILocation(line: 26, column: 30, scope: !58)
+!77 = !DILocation(line: 26, column: 13, scope: !58)
+!78 = !DILocation(line: 26, column: 5, scope: !58)
+!79 = !DILocation(line: 28, column: 14, scope: !80)
+!80 = distinct !DILexicalBlock(scope: !58, file: !3, line: 26, column: 45)
+!81 = !DILocation(line: 28, column: 11, scope: !80)
+!82 = !DILocation(line: 29, column: 7, scope: !80)
+!83 = !DILocation(line: 33, column: 7, scope: !80)
+!84 = !DILocation(line: 35, column: 14, scope: !80)
+!85 = !DILocation(line: 35, column: 11, scope: !80)
+!86 = !DILocation(line: 36, column: 7, scope: !80)
+!87 = !DILocation(line: 38, column: 7, scope: !80)
+!88 = !DILocation(line: 40, column: 3, scope: !59)
+!89 = !DILocation(line: 40, column: 3, scope: !58)
+!90 = !DILocation(line: 24, column: 44, scope: !59)
+!91 = !DILocation(line: 24, column: 3, scope: !59)
+!92 = distinct !{!92, !71, !93}
+!93 = !DILocation(line: 40, column: 3, scope: !60)
+!94 = !DILocation(line: 43, column: 1, scope: !51)
+!95 = !DILocation(line: 42, column: 3, scope: !51)
Index: llvm/test/Transforms/PGOProfile/misexpect-switch-default.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/PGOProfile/misexpect-switch-default.ll
@@ -0,0 +1,193 @@
+; RUN: llvm-profdata merge %S/Inputs/misexpect-switch.proftext -o %t.profdata
+
+; RUN: opt < %s -lower-expect -pgo-instr-use -pgo-test-profile-file=%t.profdata -S -pgo-warn-misexpect 2>&1 | FileCheck %s --check-prefix=WARNING
+; RUN: opt < %s -lower-expect -pgo-instr-use -pgo-test-profile-file=%t.profdata -S -pass-remarks=misexpect 2>&1 | FileCheck %s --check-prefix=REMARK
+; RUN: opt < %s -lower-expect -pgo-instr-use -pgo-test-profile-file=%t.profdata -S -pgo-warn-misexpect -pass-remarks=misexpect 2>&1 | FileCheck %s --check-prefix=BOTH
+; RUN: opt < %s -lower-expect -pgo-instr-use -pgo-test-profile-file=%t.profdata -S 2>&1 | FileCheck %s --check-prefix=DISABLED
+
+; New PM
+; RUN: opt < %s -passes="function(lower-expect),pgo-instr-use" -pgo-test-profile-file=%t.profdata -pgo-warn-misexpect -S 2>&1 | FileCheck %s --check-prefix=WARNING
+; RUN: opt < %s -passes="function(lower-expect),pgo-instr-use" -pgo-test-profile-file=%t.profdata -pass-remarks=misexpect -S 2>&1 | FileCheck %s --check-prefix=REMARK
+; RUN: opt < %s -passes="function(lower-expect),pgo-instr-use" -pgo-test-profile-file=%t.profdata -pgo-warn-misexpect -pass-remarks=misexpect -S 2>&1 | FileCheck %s --check-prefix=BOTH
+; RUN: opt < %s -passes="function(lower-expect),pgo-instr-use" -pgo-test-profile-file=%t.profdata -S 2>&1 | FileCheck %s --check-prefix=DISABLED
+
+; WARNING-DAG: warning: <unknown>:0:0: 0.00%
+; WARNING-NOT: remark: <unknown>:0:0: Potential performance regression from use of the llvm.expect intrinsic: Annotation was correct on 0.00% (0 / 27943) of profiled executions.
+
+; REMARK-NOT: warning: <unknown>:0:0: 0.00%
+; REMARK-DAG: remark: <unknown>:0:0: Potential performance regression from use of the llvm.expect intrinsic: Annotation was correct on 0.00% (0 / 27943) of profiled executions.
+
+; BOTH-DAG: warning: <unknown>:0:0: 0.00%
+; BOTH-DAG: remark: <unknown>:0:0: Potential performance regression from use of the llvm.expect intrinsic: Annotation was correct on 0.00% (0 / 27943) of profiled executions.
+
+; DISABLED-NOT: warning: <unknown>:0:0: 0.00%
+; DISABLED-NOT: remark: <unknown>:0:0: Potential performance regression from use of the llvm.expect intrinsic: Annotation was correct on 0.00% (0 / 27943) of profiled executions.
+
+; DISABLED-NOT: warning: <unknown>:0:0: 0.00%
+; DISABLED-NOT: remark: <unknown>:0:0: Potential performance regression from use of the llvm.expect intrinsic: Annotation was correct on 0.00% (0 / 27943) of profiled executions.
+
+; CORRECT-NOT: warning: {{.*}}
+; CORRECT-NOT: remark: {{.*}}
+
+
+; ModuleID = 'misexpect-switch.c'
+source_filename = "misexpect-switch.c"
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+@inner_loop = dso_local constant i32 1000, align 4
+@outer_loop = dso_local constant i32 20, align 4
+@arry_size = dso_local constant i32 25, align 4
+@arry = dso_local global [25 x i32] zeroinitializer, align 16
+
+; Function Attrs: nounwind uwtable
+define dso_local void @init_arry() #0 {
+entry:
+ %i = alloca i32, align 4
+ %0 = bitcast i32* %i to i8*
+ call void @llvm.lifetime.start.p0i8(i64 4, i8* %0) #6
+ store i32 0, i32* %i, align 4, !tbaa !4
+ br label %for.cond
+
+for.cond: ; preds = %for.inc, %entry
+ %1 = load i32, i32* %i, align 4, !tbaa !4
+ %cmp = icmp slt i32 %1, 25
+ br i1 %cmp, label %for.body, label %for.end
+
+for.body: ; preds = %for.cond
+ %call = call i32 @rand() #6
+ %rem = srem i32 %call, 10
+ %2 = load i32, i32* %i, align 4, !tbaa !4
+ %idxprom = sext i32 %2 to i64
+ %arrayidx = getelementptr inbounds [25 x i32], [25 x i32]* @arry, i64 0, i64 %idxprom
+ store i32 %rem, i32* %arrayidx, align 4, !tbaa !4
+ br label %for.inc
+
+for.inc: ; preds = %for.body
+ %3 = load i32, i32* %i, align 4, !tbaa !4
+ %inc = add nsw i32 %3, 1
+ store i32 %inc, i32* %i, align 4, !tbaa !4
+ br label %for.cond
+
+for.end: ; preds = %for.cond
+ %4 = bitcast i32* %i to i8*
+ call void @llvm.lifetime.end.p0i8(i64 4, i8* %4) #6
+ ret void
+}
+
+; Function Attrs: argmemonly nounwind willreturn
+declare void @llvm.lifetime.start.p0i8(i64 immarg, i8* nocapture) #1
+
+; Function Attrs: nounwind readnone speculatable willreturn
+declare void @llvm.dbg.declare(metadata, metadata, metadata) #2
+
+; Function Attrs: nounwind
+declare dso_local i32 @rand() #3
+
+; Function Attrs: argmemonly nounwind willreturn
+declare void @llvm.lifetime.end.p0i8(i64 immarg, i8* nocapture) #1
+
+; Function Attrs: nounwind uwtable
+define dso_local i32 @main() #0 {
+entry:
+ %retval = alloca i32, align 4
+ %val = alloca i32, align 4
+ %j = alloca i32, align 4
+ %condition = alloca i32, align 4
+ store i32 0, i32* %retval, align 4
+ call void @init_arry()
+ %0 = bitcast i32* %val to i8*
+ call void @llvm.lifetime.start.p0i8(i64 4, i8* %0) #6
+ store i32 0, i32* %val, align 4, !tbaa !4
+ %1 = bitcast i32* %j to i8*
+ call void @llvm.lifetime.start.p0i8(i64 4, i8* %1) #6
+ store i32 0, i32* %j, align 4, !tbaa !4
+ br label %for.cond
+
+for.cond: ; preds = %for.inc, %entry
+ %2 = load i32, i32* %j, align 4, !tbaa !4
+ %cmp = icmp slt i32 %2, 20000
+ br i1 %cmp, label %for.body, label %for.end
+
+for.body: ; preds = %for.cond
+ %3 = bitcast i32* %condition to i8*
+ call void @llvm.lifetime.start.p0i8(i64 4, i8* %3) #6
+ %call = call i32 @rand() #6
+ %rem = srem i32 %call, 5
+ store i32 %rem, i32* %condition, align 4, !tbaa !4
+ %4 = load i32, i32* %condition, align 4, !tbaa !4
+ %conv = zext i32 %4 to i64
+ %expval = call i64 @llvm.expect.i64(i64 %conv, i64 6)
+ switch i64 %expval, label %sw.default [
+ i64 0, label %sw.bb
+ i64 1, label %sw.bb2
+ i64 2, label %sw.bb2
+ i64 3, label %sw.bb2
+ i64 4, label %sw.bb3
+ ]
+
+sw.bb: ; preds = %for.body
+ %call1 = call i32 @sum(i32* getelementptr inbounds ([25 x i32], [25 x i32]* @arry, i64 0, i64 0), i32 25)
+ %5 = load i32, i32* %val, align 4, !tbaa !4
+ %add = add nsw i32 %5, %call1
+ store i32 %add, i32* %val, align 4, !tbaa !4
+ br label %sw.epilog
+
+sw.bb2: ; preds = %for.body, %for.body, %for.body
+ br label %sw.epilog
+
+sw.bb3: ; preds = %for.body
+ %call4 = call i32 @random_sample(i32* getelementptr inbounds ([25 x i32], [25 x i32]* @arry, i64 0, i64 0), i32 25)
+ %6 = load i32, i32* %val, align 4, !tbaa !4
+ %add5 = add nsw i32 %6, %call4
+ store i32 %add5, i32* %val, align 4, !tbaa !4
+ br label %sw.epilog
+
+sw.default: ; preds = %for.body
+ unreachable
+
+sw.epilog: ; preds = %sw.bb3, %sw.bb2, %sw.bb
+ %7 = bitcast i32* %condition to i8*
+ call void @llvm.lifetime.end.p0i8(i64 4, i8* %7) #6
+ br label %for.inc
+
+for.inc: ; preds = %sw.epilog
+ %8 = load i32, i32* %j, align 4, !tbaa !4
+ %inc = add nsw i32 %8, 1
+ store i32 %inc, i32* %j, align 4, !tbaa !4
+ br label %for.cond
+
+for.end: ; preds = %for.cond
+ %9 = bitcast i32* %j to i8*
+ call void @llvm.lifetime.end.p0i8(i64 4, i8* %9) #6
+ %10 = bitcast i32* %val to i8*
+ call void @llvm.lifetime.end.p0i8(i64 4, i8* %10) #6
+ ret i32 0
+}
+
+; Function Attrs: nounwind readnone willreturn
+declare i64 @llvm.expect.i64(i64, i64) #4
+
+declare dso_local i32 @sum(i32*, i32) #5
+
+declare dso_local i32 @random_sample(i32*, i32) #5
+
+attributes #0 = { nounwind uwtable "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "frame-pointer"="none" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { argmemonly nounwind willreturn }
+attributes #2 = { nounwind readnone speculatable willreturn }
+attributes #3 = { nounwind "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "frame-pointer"="none" "less-precise-fpmad"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #4 = { nounwind readnone willreturn }
+attributes #5 = { "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "frame-pointer"="none" "less-precise-fpmad"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #6 = { nounwind }
+
+!llvm.module.flags = !{!0, !1, !2}
+!llvm.ident = !{!3}
+
+!0 = !{i32 2, !"Dwarf Version", i32 4}
+!1 = !{i32 2, !"Debug Info Version", i32 3}
+!2 = !{i32 1, !"wchar_size", i32 4}
+!3 = !{!"clang version 10.0.0 (60b79b85b1763d3d25630261e5cd1adb7f0835bc)"}
+!4 = !{!5, !5, i64 0}
+!5 = !{!"int", !6, i64 0}
+!6 = !{!"omnipotent char", !7, i64 0}
+!7 = !{!"Simple C/C++ TBAA"}
Index: llvm/test/Transforms/PGOProfile/misexpect-branch.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/PGOProfile/misexpect-branch.ll
@@ -0,0 +1,127 @@
+; RUN: llvm-profdata merge %S/Inputs/misexpect-branch.proftext -o %t.profdata
+
+
+; RUN: opt < %s -lower-expect -pgo-instr-use -pgo-test-profile-file=%t.profdata -S -pgo-warn-misexpect 2>&1 | FileCheck %s --check-prefix=WARNING
+; RUN: opt < %s -lower-expect -pgo-instr-use -pgo-test-profile-file=%t.profdata -S -pass-remarks=misexpect 2>&1 | FileCheck %s --check-prefix=REMARK
+; RUN: opt < %s -lower-expect -pgo-instr-use -pgo-test-profile-file=%t.profdata -S -pgo-warn-misexpect -pass-remarks=misexpect 2>&1 | FileCheck %s --check-prefix=BOTH
+; RUN: opt < %s -lower-expect -pgo-instr-use -pgo-test-profile-file=%t.profdata -S 2>&1 | FileCheck %s --check-prefix=DISABLED
+
+; New PM
+; RUN: opt < %s -passes="function(lower-expect),pgo-instr-use" -pgo-test-profile-file=%t.profdata -pgo-warn-misexpect -S 2>&1 | FileCheck %s --check-prefix=WARNING
+; RUN: opt < %s -passes="function(lower-expect),pgo-instr-use" -pgo-test-profile-file=%t.profdata -pass-remarks=misexpect -S 2>&1 | FileCheck %s --check-prefix=REMARK
+; RUN: opt < %s -passes="function(lower-expect),pgo-instr-use" -pgo-test-profile-file=%t.profdata -pgo-warn-misexpect -pass-remarks=misexpect -S 2>&1 | FileCheck %s --check-prefix=BOTH
+; RUN: opt < %s -passes="function(lower-expect),pgo-instr-use" -pgo-test-profile-file=%t.profdata -S 2>&1 | FileCheck %s --check-prefix=DISABLED
+
+
+
+; WARNING-DAG: warning: misexpect-branch.c:22:0: 19.98%
+; WARNING-NOT: remark: misexpect-branch.c:22:0: Potential performance regression from use of the llvm.expect intrinsic: Annotation was correct on 19.98% (399668 / 2000000) of profiled executions.
+
+; REMARK-NOT: warning: misexpect-branch.c:22:0: 19.98%
+; REMARK-DAG: remark: misexpect-branch.c:22:0: Potential performance regression from use of the llvm.expect intrinsic: Annotation was correct on 19.98% (399668 / 2000000) of profiled executions.
+
+; BOTH-DAG: warning: misexpect-branch.c:22:0: 19.98%
+; BOTH-DAG: remark: misexpect-branch.c:22:0: Potential performance regression from use of the llvm.expect intrinsic: Annotation was correct on 19.98% (399668 / 2000000) of profiled executions.
+
+; DISABLED-NOT: warning: misexpect-branch.c:22:0: 19.98%
+; DISABLED-NOT: remark: misexpect-branch.c:22:0: Potential performance regression from use of the llvm.expect intrinsic: Annotation was correct on 19.98% (399668 / 2000000) of profiled executions.
+
+
+
+; ModuleID = 'misexpect-branch.c'
+source_filename = "misexpect-branch.c"
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+@inner_loop = constant i32 100, align 4
+@outer_loop = constant i32 2000, align 4
+
+; Function Attrs: nounwind
+define i32 @bar() #0 !dbg !6 {
+entry:
+ %rando = alloca i32, align 4
+ %x = alloca i32, align 4
+ %0 = bitcast i32* %rando to i8*, !dbg !9
+ call void @llvm.lifetime.start.p0i8(i64 4, i8* %0) #4, !dbg !9
+ %call = call i32 (...) @buzz(), !dbg !9
+ store i32 %call, i32* %rando, align 4, !dbg !9, !tbaa !10
+ %1 = bitcast i32* %x to i8*, !dbg !14
+ call void @llvm.lifetime.start.p0i8(i64 4, i8* %1) #4, !dbg !14
+ store i32 0, i32* %x, align 4, !dbg !14, !tbaa !10
+ %2 = load i32, i32* %rando, align 4, !dbg !15, !tbaa !10
+ %rem = srem i32 %2, 200000, !dbg !15
+ %cmp = icmp eq i32 %rem, 0, !dbg !15
+ %lnot = xor i1 %cmp, true, !dbg !15
+ %lnot1 = xor i1 %lnot, true, !dbg !15
+ %lnot.ext = zext i1 %lnot1 to i32, !dbg !15
+ %conv = sext i32 %lnot.ext to i64, !dbg !15
+ %expval = call i64 @llvm.expect.i64(i64 %conv, i64 1), !dbg !15
+ %tobool = icmp ne i64 %expval, 0, !dbg !15
+ br i1 %tobool, label %if.then, label %if.else, !dbg !15
+
+if.then: ; preds = %entry
+ %3 = load i32, i32* %rando, align 4, !dbg !16, !tbaa !10
+ %call2 = call i32 @baz(i32 %3), !dbg !16
+ store i32 %call2, i32* %x, align 4, !dbg !16, !tbaa !10
+ br label %if.end, !dbg !17
+
+if.else: ; preds = %entry
+ %call3 = call i32 @foo(i32 50), !dbg !18
+ store i32 %call3, i32* %x, align 4, !dbg !18, !tbaa !10
+ br label %if.end
+
+if.end: ; preds = %if.else, %if.then
+ %4 = load i32, i32* %x, align 4, !dbg !19, !tbaa !10
+ %5 = bitcast i32* %x to i8*, !dbg !20
+ call void @llvm.lifetime.end.p0i8(i64 4, i8* %5) #4, !dbg !20
+ %6 = bitcast i32* %rando to i8*, !dbg !20
+ call void @llvm.lifetime.end.p0i8(i64 4, i8* %6) #4, !dbg !20
+ ret i32 %4, !dbg !19
+}
+
+; Function Attrs: argmemonly nounwind willreturn
+declare void @llvm.lifetime.start.p0i8(i64 immarg, i8* nocapture) #1
+
+declare i32 @buzz(...) #2
+
+; Function Attrs: nounwind readnone willreturn
+declare i64 @llvm.expect.i64(i64, i64) #3
+
+declare i32 @baz(i32) #2
+
+declare i32 @foo(i32) #2
+
+; Function Attrs: argmemonly nounwind willreturn
+declare void @llvm.lifetime.end.p0i8(i64 immarg, i8* nocapture) #1
+
+attributes #0 = { nounwind "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "frame-pointer"="none" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-features"="+cx8,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { argmemonly nounwind willreturn }
+attributes #2 = { "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "frame-pointer"="none" "less-precise-fpmad"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-features"="+cx8,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #3 = { nounwind readnone willreturn }
+attributes #4 = { nounwind }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4}
+!llvm.ident = !{!5}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 10.0.0 (trunk c20270bfffc9d6965219de339d66c61e9fe7d82d)", isOptimized: true, runtimeVersion: 0, emissionKind: LineTablesOnly, enums: !2, nameTableKind: None)
+!1 = !DIFile(filename: "<stdin>", directory: ".")
+!2 = !{}
+!3 = !{i32 2, !"Debug Info Version", i32 3}
+!4 = !{i32 1, !"wchar_size", i32 4}
+!5 = !{!"clang version 10.0.0 (trunk c20270bfffc9d6965219de339d66c61e9fe7d82d)"}
+!6 = distinct !DISubprogram(name: "bar", scope: !7, file: !7, line: 19, type: !8, scopeLine: 19, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2)
+!7 = !DIFile(filename: "misexpect-branch.c", directory: ".")
+!8 = !DISubroutineType(types: !2)
+!9 = !DILocation(line: 20, scope: !6)
+!10 = !{!11, !11, i64 0}
+!11 = !{!"int", !12, i64 0}
+!12 = !{!"omnipotent char", !13, i64 0}
+!13 = !{!"Simple C/C++ TBAA"}
+!14 = !DILocation(line: 21, scope: !6)
+!15 = !DILocation(line: 22, scope: !6)
+!16 = !DILocation(line: 23, scope: !6)
+!17 = !DILocation(line: 24, scope: !6)
+!18 = !DILocation(line: 25, scope: !6)
+!19 = !DILocation(line: 27, scope: !6)
+!20 = !DILocation(line: 28, scope: !6)
Index: llvm/test/Transforms/PGOProfile/misexpect-branch-unpredictable.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/PGOProfile/misexpect-branch-unpredictable.ll
@@ -0,0 +1,88 @@
+; RUN: llvm-profdata merge %S/Inputs/misexpect-branch-correct.proftext -o %t.profdata
+
+; RUN: opt < %s -lower-expect -pgo-instr-use -pgo-test-profile-file=%t.profdata -S -pgo-warn-misexpect -pass-remarks=misexpect 2>&1 | FileCheck %s
+
+; New PM
+; RUN: opt < %s -passes="function(lower-expect),pgo-instr-use" -pgo-test-profile-file=%t.profdata -pgo-warn-misexpect -pass-remarks=misexpect -S 2>&1 | FileCheck %s
+
+; CHECK-NOT: warning: {{.*}}
+; CHECK-NOT: remark: {{.*}}
+
+
+; ModuleID = 'misexpect-branch-unpredictable.c'
+source_filename = "clang/test/Profile/misexpect-branch-unpredictable.c"
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+@inner_loop = constant i32 100, align 4
+@outer_loop = constant i32 2000, align 4
+
+; Function Attrs: nounwind
+define i32 @bar() #0 {
+entry:
+ %rando = alloca i32, align 4
+ %x = alloca i32, align 4
+ %0 = bitcast i32* %rando to i8*
+ call void @llvm.lifetime.start.p0i8(i64 4, i8* %0) #3
+ %call = call i32 (...) @buzz()
+ store i32 %call, i32* %rando, align 4, !tbaa !2
+ %1 = bitcast i32* %x to i8*
+ call void @llvm.lifetime.start.p0i8(i64 4, i8* %1) #3
+ store i32 0, i32* %x, align 4, !tbaa !2
+ %2 = load i32, i32* %rando, align 4, !tbaa !2
+ %rem = srem i32 %2, 200000
+ %cmp = icmp eq i32 %rem, 0
+ %lnot = xor i1 %cmp, true
+ %lnot1 = xor i1 %lnot, true
+ %lnot.ext = zext i1 %lnot1 to i32
+ %conv = sext i32 %lnot.ext to i64
+ %tobool = icmp ne i64 %conv, 0
+ br i1 %tobool, label %if.then, label %if.else, !unpredictable !6
+
+if.then: ; preds = %entry
+ %3 = load i32, i32* %rando, align 4, !tbaa !2
+ %call2 = call i32 @baz(i32 %3)
+ store i32 %call2, i32* %x, align 4, !tbaa !2
+ br label %if.end
+
+if.else: ; preds = %entry
+ %call3 = call i32 @foo(i32 50)
+ store i32 %call3, i32* %x, align 4, !tbaa !2
+ br label %if.end
+
+if.end: ; preds = %if.else, %if.then
+ %4 = load i32, i32* %x, align 4, !tbaa !2
+ %5 = bitcast i32* %x to i8*
+ call void @llvm.lifetime.end.p0i8(i64 4, i8* %5) #3
+ %6 = bitcast i32* %rando to i8*
+ call void @llvm.lifetime.end.p0i8(i64 4, i8* %6) #3
+ ret i32 %4
+}
+
+; Function Attrs: argmemonly nounwind willreturn
+declare void @llvm.lifetime.start.p0i8(i64 immarg, i8* nocapture) #1
+
+declare i32 @buzz(...) #2
+
+declare i32 @baz(i32) #2
+
+declare i32 @foo(i32) #2
+
+; Function Attrs: argmemonly nounwind willreturn
+declare void @llvm.lifetime.end.p0i8(i64 immarg, i8* nocapture) #1
+
+attributes #0 = { nounwind "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "frame-pointer"="none" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-features"="+cx8,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { argmemonly nounwind willreturn }
+attributes #2 = { "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "frame-pointer"="none" "less-precise-fpmad"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-features"="+cx8,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #3 = { nounwind }
+
+!llvm.module.flags = !{!0}
+!llvm.ident = !{!1}
+
+!0 = !{i32 1, !"wchar_size", i32 4}
+!1 = !{!"Fuchsia clang version 10.0.0 (153b453014c94291c8c6cf6320b2f46df40f26f3) (based on LLVM 10.0.0svn)"}
+!2 = !{!3, !3, i64 0}
+!3 = !{!"int", !4, i64 0}
+!4 = !{!"omnipotent char", !5, i64 0}
+!5 = !{!"Simple C/C++ TBAA"}
+!6 = !{}
Index: llvm/test/Transforms/PGOProfile/misexpect-branch-stripped.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/PGOProfile/misexpect-branch-stripped.ll
@@ -0,0 +1,111 @@
+; RUN: llvm-profdata merge %S/Inputs/misexpect-branch.proftext -o %t.profdata
+
+
+; RUN: opt < %s -lower-expect -pgo-instr-use -pgo-test-profile-file=%t.profdata -S -pgo-warn-misexpect 2>&1 | FileCheck %s --check-prefix=WARNING
+; RUN: opt < %s -lower-expect -pgo-instr-use -pgo-test-profile-file=%t.profdata -S -pass-remarks=misexpect 2>&1 | FileCheck %s --check-prefix=REMARK
+; RUN: opt < %s -lower-expect -pgo-instr-use -pgo-test-profile-file=%t.profdata -S -pgo-warn-misexpect -pass-remarks=misexpect 2>&1 | FileCheck %s --check-prefix=BOTH
+; RUN: opt < %s -lower-expect -pgo-instr-use -pgo-test-profile-file=%t.profdata -S 2>&1 | FileCheck %s --check-prefix=DISABLED
+
+; New PM
+; RUN: opt < %s -passes="function(lower-expect),pgo-instr-use" -pgo-test-profile-file=%t.profdata -pgo-warn-misexpect -S 2>&1 | FileCheck %s --check-prefix=WARNING
+; RUN: opt < %s -passes="function(lower-expect),pgo-instr-use" -pgo-test-profile-file=%t.profdata -pass-remarks=misexpect -S 2>&1 | FileCheck %s --check-prefix=REMARK
+; RUN: opt < %s -passes="function(lower-expect),pgo-instr-use" -pgo-test-profile-file=%t.profdata -pgo-warn-misexpect -pass-remarks=misexpect -S 2>&1 | FileCheck %s --check-prefix=BOTH
+; RUN: opt < %s -passes="function(lower-expect),pgo-instr-use" -pgo-test-profile-file=%t.profdata -S 2>&1 | FileCheck %s --check-prefix=DISABLED
+
+
+
+; WARNING-DAG: warning: <unknown>:0:0: 19.98%
+; WARNING-NOT: remark: <unknown>:0:0: Potential performance regression from use of the llvm.expect intrinsic: Annotation was correct on 19.98% (399668 / 2000000) of profiled executions.
+
+; REMARK-NOT: warning: <unknown>:0:0: 19.98%
+; REMARK-DAG: remark: <unknown>:0:0: Potential performance regression from use of the llvm.expect intrinsic: Annotation was correct on 19.98% (399668 / 2000000) of profiled executions.
+
+; BOTH-DAG: warning: <unknown>:0:0: 19.98%
+; BOTH-DAG: remark: <unknown>:0:0: Potential performance regression from use of the llvm.expect intrinsic: Annotation was correct on 19.98% (399668 / 2000000) of profiled executions.
+
+; DISABLED-NOT: warning: <unknown>:0:0: 19.98%
+; DISABLED-NOT: remark: <unknown>:0:0: Potential performance regression from use of the llvm.expect intrinsic: Annotation was correct on 19.98% (399668 / 2000000) of profiled executions.
+
+
+; ModuleID = 'misexpect-branch.c'
+source_filename = "misexpect-branch.c"
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+@inner_loop = constant i32 100, align 4
+@outer_loop = constant i32 2000, align 4
+
+; Function Attrs: nounwind
+define i32 @bar() #0 {
+entry:
+ %rando = alloca i32, align 4
+ %x = alloca i32, align 4
+ %0 = bitcast i32* %rando to i8*
+ call void @llvm.lifetime.start.p0i8(i64 4, i8* %0) #4
+ %call = call i32 (...) @buzz()
+ store i32 %call, i32* %rando, align 4, !tbaa !3
+ %1 = bitcast i32* %x to i8*
+ call void @llvm.lifetime.start.p0i8(i64 4, i8* %1) #4
+ store i32 0, i32* %x, align 4, !tbaa !3
+ %2 = load i32, i32* %rando, align 4, !tbaa !3
+ %rem = srem i32 %2, 200000
+ %cmp = icmp eq i32 %rem, 0
+ %lnot = xor i1 %cmp, true
+ %lnot1 = xor i1 %lnot, true
+ %lnot.ext = zext i1 %lnot1 to i32
+ %conv = sext i32 %lnot.ext to i64
+ %expval = call i64 @llvm.expect.i64(i64 %conv, i64 1)
+ %tobool = icmp ne i64 %expval, 0
+ br i1 %tobool, label %if.then, label %if.else
+
+if.then: ; preds = %entry
+ %3 = load i32, i32* %rando, align 4, !tbaa !3
+ %call2 = call i32 @baz(i32 %3)
+ store i32 %call2, i32* %x, align 4, !tbaa !3
+ br label %if.end
+
+if.else: ; preds = %entry
+ %call3 = call i32 @foo(i32 50)
+ store i32 %call3, i32* %x, align 4, !tbaa !3
+ br label %if.end
+
+if.end: ; preds = %if.else, %if.then
+ %4 = load i32, i32* %x, align 4, !tbaa !3
+ %5 = bitcast i32* %x to i8*
+ call void @llvm.lifetime.end.p0i8(i64 4, i8* %5) #4
+ %6 = bitcast i32* %rando to i8*
+ call void @llvm.lifetime.end.p0i8(i64 4, i8* %6) #4
+ ret i32 %4
+}
+
+; Function Attrs: argmemonly nounwind willreturn
+declare void @llvm.lifetime.start.p0i8(i64 immarg, i8* nocapture) #1
+
+declare i32 @buzz(...) #2
+
+; Function Attrs: nounwind readnone willreturn
+declare i64 @llvm.expect.i64(i64, i64) #3
+
+declare i32 @baz(i32) #2
+
+declare i32 @foo(i32) #2
+
+; Function Attrs: argmemonly nounwind willreturn
+declare void @llvm.lifetime.end.p0i8(i64 immarg, i8* nocapture) #1
+
+attributes #0 = { nounwind "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "frame-pointer"="none" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-features"="+cx8,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { argmemonly nounwind willreturn }
+attributes #2 = { "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "frame-pointer"="none" "less-precise-fpmad"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-features"="+cx8,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #3 = { nounwind readnone willreturn }
+attributes #4 = { nounwind }
+
+!llvm.module.flags = !{!0, !1}
+!llvm.ident = !{!2}
+
+!0 = !{i32 2, !"Debug Info Version", i32 3}
+!1 = !{i32 1, !"wchar_size", i32 4}
+!2 = !{!"clang version 10.0.0 (trunk c20270bfffc9d6965219de339d66c61e9fe7d82d)"}
+!3 = !{!4, !4, i64 0}
+!4 = !{!"int", !5, i64 0}
+!5 = !{!"omnipotent char", !6, i64 0}
+!6 = !{!"Simple C/C++ TBAA"}
Index: llvm/test/Transforms/PGOProfile/misexpect-branch-correct.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/PGOProfile/misexpect-branch-correct.ll
@@ -0,0 +1,94 @@
+; RUN: llvm-profdata merge %S/Inputs/misexpect-branch-correct.proftext -o %t.profdata
+
+; RUN: opt < %s -lower-expect -pgo-instr-use -pgo-test-profile-file=%t.profdata -S -pgo-warn-misexpect -pass-remarks=misexpect 2>&1 | FileCheck %s
+
+; New PM
+; RUN: opt < %s -passes="function(lower-expect),pgo-instr-use" -pgo-test-profile-file=%t.profdata -pgo-warn-misexpect -pass-remarks=misexpect -S 2>&1 | FileCheck %s
+
+; CHECK-NOT: warning: {{.*}}
+; CHECK-NOT: remark: {{.*}}
+; CHECK: !{!"branch_weights", i32 0, i32 200000}
+
+
+; ModuleID = 'misexpect-branch-correct.c'
+source_filename = "misexpect-branch-correct.c"
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+@inner_loop = constant i32 100, align 4
+@outer_loop = constant i32 2000, align 4
+
+; Function Attrs: nounwind
+define i32 @bar() #0 {
+entry:
+ %rando = alloca i32, align 4
+ %x = alloca i32, align 4
+ %0 = bitcast i32* %rando to i8*
+ call void @llvm.lifetime.start.p0i8(i64 4, i8* %0) #4
+ %call = call i32 (...) @buzz()
+ store i32 %call, i32* %rando, align 4, !tbaa !3
+ %1 = bitcast i32* %x to i8*
+ call void @llvm.lifetime.start.p0i8(i64 4, i8* %1) #4
+ store i32 0, i32* %x, align 4, !tbaa !3
+ %2 = load i32, i32* %rando, align 4, !tbaa !3
+ %rem = srem i32 %2, 200000
+ %cmp = icmp eq i32 %rem, 0
+ %lnot = xor i1 %cmp, true
+ %lnot1 = xor i1 %lnot, true
+ %lnot.ext = zext i1 %lnot1 to i32
+ %conv = sext i32 %lnot.ext to i64
+ %expval = call i64 @llvm.expect.i64(i64 %conv, i64 0)
+ %tobool = icmp ne i64 %expval, 0
+ br i1 %tobool, label %if.then, label %if.else
+
+if.then: ; preds = %entry
+ %3 = load i32, i32* %rando, align 4, !tbaa !3
+ %call2 = call i32 @baz(i32 %3)
+ store i32 %call2, i32* %x, align 4, !tbaa !3
+ br label %if.end
+
+if.else: ; preds = %entry
+ %call3 = call i32 @foo(i32 50)
+ store i32 %call3, i32* %x, align 4, !tbaa !3
+ br label %if.end
+
+if.end: ; preds = %if.else, %if.then
+ %4 = load i32, i32* %x, align 4, !tbaa !3
+ %5 = bitcast i32* %x to i8*
+ call void @llvm.lifetime.end.p0i8(i64 4, i8* %5) #4
+ %6 = bitcast i32* %rando to i8*
+ call void @llvm.lifetime.end.p0i8(i64 4, i8* %6) #4
+ ret i32 %4
+}
+
+; Function Attrs: argmemonly nounwind willreturn
+declare void @llvm.lifetime.start.p0i8(i64 immarg, i8* nocapture) #1
+
+declare i32 @buzz(...) #2
+
+; Function Attrs: nounwind readnone willreturn
+declare i64 @llvm.expect.i64(i64, i64) #3
+
+declare i32 @baz(i32) #2
+
+declare i32 @foo(i32) #2
+
+; Function Attrs: argmemonly nounwind willreturn
+declare void @llvm.lifetime.end.p0i8(i64 immarg, i8* nocapture) #1
+
+attributes #0 = { nounwind "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "frame-pointer"="none" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-features"="+cx8,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { argmemonly nounwind willreturn }
+attributes #2 = { "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "frame-pointer"="none" "less-precise-fpmad"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-features"="+cx8,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #3 = { nounwind readnone willreturn }
+attributes #4 = { nounwind }
+
+!llvm.module.flags = !{!0, !1}
+!llvm.ident = !{!2}
+
+!0 = !{i32 2, !"Debug Info Version", i32 3}
+!1 = !{i32 1, !"wchar_size", i32 4}
+!2 = !{!"clang version 10.0.0 (c20270bfffc9d6965219de339d66c61e9fe7d82d)"}
+!3 = !{!4, !4, i64 0}
+!4 = !{!"int", !5, i64 0}
+!5 = !{!"omnipotent char", !6, i64 0}
+!6 = !{!"Simple C/C++ TBAA"}
Index: llvm/test/Transforms/PGOProfile/Inputs/misexpect-switch.proftext
===================================================================
--- /dev/null
+++ llvm/test/Transforms/PGOProfile/Inputs/misexpect-switch.proftext
@@ -0,0 +1,15 @@
+# IR level Instrumentation Flag
+:ir
+main
+# Func Hash:
+391331300939170156
+# Num Counters:
+7
+# Counter Values:
+3973
+3970
+0
+11889
+8111
+1
+0
Index: llvm/test/Transforms/PGOProfile/Inputs/misexpect-switch-correct.proftext
===================================================================
--- /dev/null
+++ llvm/test/Transforms/PGOProfile/Inputs/misexpect-switch-correct.proftext
@@ -0,0 +1,15 @@
+# IR level Instrumentation Flag
+:ir
+main
+# Func Hash:
+391331300939170156
+# Num Counters:
+7
+# Counter Values:
+0
+0
+20000
+0
+0
+1
+0
Index: llvm/test/Transforms/PGOProfile/Inputs/misexpect-branch.proftext
===================================================================
--- /dev/null
+++ llvm/test/Transforms/PGOProfile/Inputs/misexpect-branch.proftext
@@ -0,0 +1,38 @@
+# IR level Instrumentation Flag
+:ir
+bar
+# Func Hash:
+146835647075900052
+# Num Counters:
+2
+# Counter Values:
+399668
+1600332
+
+baz
+# Func Hash:
+12884901887
+# Num Counters:
+1
+# Counter Values:
+399668
+
+foo
+# Func Hash:
+29212902728
+# Num Counters:
+2
+# Counter Values:
+40803991
+1600332
+
+main
+# Func Hash:
+41605652536
+# Num Counters:
+3
+# Counter Values:
+2000000
+2000
+1
+
Index: llvm/test/Transforms/PGOProfile/Inputs/misexpect-branch-correct.proftext
===================================================================
--- /dev/null
+++ llvm/test/Transforms/PGOProfile/Inputs/misexpect-branch-correct.proftext
@@ -0,0 +1,38 @@
+# IR level Instrumentation Flag
+:ir
+bar
+# Func Hash:
+146835647075900052
+# Num Counters:
+2
+# Counter Values:
+200000
+0
+
+baz
+# Func Hash:
+12884901887
+# Num Counters:
+1
+# Counter Values:
+399668
+
+foo
+# Func Hash:
+29212902728
+# Num Counters:
+2
+# Counter Values:
+40803991
+1600332
+
+main
+# Func Hash:
+41605652536
+# Num Counters:
+3
+# Counter Values:
+2000000
+2000
+1
+
Index: llvm/lib/Transforms/Utils/MisExpect.cpp
===================================================================
--- /dev/null
+++ llvm/lib/Transforms/Utils/MisExpect.cpp
@@ -0,0 +1,224 @@
+//===--- MisExpect.cpp - Check the use of llvm.expect with PGO data -------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This contains code to emit warnings for potentially incorrect usage of the
+// llvm.expect intrinsic. This utility extracts the threshold values from
+// metadata associated with the instrumented Branch or Switch instruction. The
+// threshold values are then used to determine if a warning should be emmited.
+//
+// MisExpect's implementation relies on two assumptions about how branch weights
+// are managed in LLVM.
+//
+// 1) Frontend profiling weights are always in place before llvm.expect is
+// lowered in LowerExpectIntrinsic.cpp. Frontend based instrumentation therefore
+// needs to extract the branch weights and then compare them to the weights
+// being added by the llvm.expect intrinsic lowering.
+//
+// 2) Sampling and IR based profiles will *only* have branch weight metadata
+// before profiling data is consulted if they are from a lowered llvm.expect
+// intrinsic. These profiles thus always extract the expected weights and then
+// compare them to the weights collected during profiling to determine if a
+// diagnostic message is warranted.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Transforms/Utils/MisExpect.h"
+#include "llvm/ADT/Twine.h"
+#include "llvm/Analysis/OptimizationRemarkEmitter.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DiagnosticInfo.h"
+#include "llvm/IR/Instruction.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/Support/BranchProbability.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/FormatVariadic.h"
+#include <cstdint>
+#include <functional>
+#include <numeric>
+
+#define DEBUG_TYPE "misexpect"
+
+using namespace llvm;
+using namespace misexpect;
+
+namespace llvm {
+
+// Command line option to enable/disable the warning when profile data suggests
+// a mismatch with the use of the llvm.expect intrinsic
+static cl::opt<bool> PGOWarnMisExpect(
+ "pgo-warn-misexpect", cl::init(false), cl::Hidden,
+ cl::desc("Use this option to turn on/off "
+ "warnings about incorrect usage of llvm.expect intrinsics."));
+
+} // namespace llvm
+
+namespace {
+
+bool isMisExpectDiagEnabled(LLVMContext &Ctx) {
+ return PGOWarnMisExpect || Ctx.getMisExpectWarningRequested();
+}
+
+Instruction *getOprndOrInst(Instruction *I) {
+ assert(I != nullptr && "MisExpect target Instruction cannot be nullptr");
+ Instruction *Ret = nullptr;
+ if (auto *B = dyn_cast<BranchInst>(I)) {
+ Ret = dyn_cast<Instruction>(B->getCondition());
+ }
+ // TODO: Find a way to resolve condition location for switches
+ // Using the condition of the switch seems to often resolve to an earlier
+ // point in the program, i.e. the calculation of the switch condition, rather
+ // than the switch's location in the source code. Thus, we should use the
+ // instruction to get source code locations rather than the condition to
+ // improve diagnostic output, such as the caret. If the same problem exists
+ // for branch instructions, then we should remove this function and directly
+ // use the instruction
+ //
+ // else if (auto S = dyn_cast<SwitchInst>(I)) {
+ // Ret = I;
+ //}
+ return Ret ? Ret : I;
+}
+
+void emitMisexpectDiagnostic(Instruction *I, LLVMContext &Ctx,
+ uint64_t ProfCount, uint64_t TotalCount) {
+ double PercentageCorrect = (double)ProfCount / TotalCount;
+ auto PerString =
+ formatv("{0:P} ({1} / {2})", PercentageCorrect, ProfCount, TotalCount);
+ auto RemStr = formatv(
+ "Potential performance regression from use of the llvm.expect intrinsic: "
+ "Annotation was correct on {0} of profiled executions.",
+ PerString);
+ Twine Msg(PerString);
+ Instruction *Cond = getOprndOrInst(I);
+ if (isMisExpectDiagEnabled(Ctx))
+ Ctx.diagnose(DiagnosticInfoMisExpect(Cond, Msg));
+ OptimizationRemarkEmitter ORE(I->getParent()->getParent());
+ ORE.emit(OptimizationRemark(DEBUG_TYPE, "misexpect", Cond) << RemStr.str());
+}
+
+} // namespace
+
+namespace llvm {
+namespace misexpect {
+
+Optional<SmallVector<uint32_t, 4>> extractWeights(Instruction *I,
+ LLVMContext &Ctx) {
+ assert(I && "extractWeights given invalid Instruction pointer");
+
+ auto *ProfileData = I->getMetadata(LLVMContext::MD_prof);
+ if (!ProfileData)
+ return None;
+
+ unsigned NOps = ProfileData->getNumOperands();
+ if (NOps < 3)
+ return None;
+
+ auto *ProfDataName = dyn_cast<MDString>(ProfileData->getOperand(0));
+ if (!ProfDataName || !ProfDataName->getString().equals("branch_weights"))
+ return None;
+
+ SmallVector<uint32_t, 4> ExpectedWeights(NOps - 1);
+ for (unsigned i = 1; i < NOps; i++) {
+ ConstantInt *Value =
+ mdconst::dyn_extract<ConstantInt>(ProfileData->getOperand(i));
+ uint32_t V = Value->getZExtValue();
+ ExpectedWeights[i - 1] = V;
+ }
+
+ return ExpectedWeights;
+}
+
+void verifyMisExpect(Instruction *I, ArrayRef<uint32_t> RealWeights,
+ ArrayRef<uint32_t> ExpectedWeights, LLVMContext &Ctx) {
+ uint32_t Max = 0, Min = std::numeric_limits<uint32_t>::max();
+ size_t MaxId = 0, MinId = 0;
+ for (unsigned i = 0, e = ExpectedWeights.size(); i < e; i++) {
+ uint32_t V = ExpectedWeights[i];
+ if (Max < V) {
+ Max = V;
+ MaxId = i;
+ }
+ if (Min > V) {
+ Min = V;
+ MinId = i;
+ }
+ }
+
+ const uint64_t Index = MaxId;
+ const uint64_t LikelyBranchWeight = ExpectedWeights[MaxId];
+ const uint64_t UnlikelyBranchWeight = ExpectedWeights[MinId];
+ const uint64_t ProfileCount = RealWeights[Index];
+ const uint64_t CaseTotal =
+ std::accumulate(RealWeights.begin(), RealWeights.end(), (uint64_t)0,
+ std::plus<uint64_t>());
+ const uint64_t NumUnlikelyTargets = RealWeights.size() - 1;
+
+ const uint64_t TotalBranchWeight =
+ LikelyBranchWeight + (UnlikelyBranchWeight * NumUnlikelyTargets);
+
+ const llvm::BranchProbability LikelyThreshold(LikelyBranchWeight,
+ TotalBranchWeight);
+ uint64_t ScaledThreshold = LikelyThreshold.scale(CaseTotal);
+
+ if (ProfileCount < ScaledThreshold)
+ emitMisexpectDiagnostic(I, Ctx, ProfileCount, CaseTotal);
+}
+
+void checkBackendInstrumentation(Instruction *I,
+ const SmallVector<uint32_t, 4> &RealWeights,
+ LLVMContext &Ctx) {
+ assert(I && "VerifyMisExpect given invalid pointer");
+
+ auto *ProfileData = I->getMetadata(LLVMContext::MD_prof);
+ if (!ProfileData)
+ return;
+
+ unsigned NOps = ProfileData->getNumOperands();
+ if (NOps < 3)
+ return;
+
+ auto *ProfDataName = dyn_cast<MDString>(ProfileData->getOperand(0));
+ if (!ProfDataName || !ProfDataName->getString().equals("branch_weights"))
+ return;
+
+ auto ExpectedWeightsOpt = extractWeights(I, Ctx);
+ if (!ExpectedWeightsOpt.hasValue())
+ return;
+ auto ExpectedWeights = ExpectedWeightsOpt.getValue();
+ verifyMisExpect(I, RealWeights, ExpectedWeights, Ctx);
+}
+
+void checkFrontendInstrumentation(Instruction &I,
+ ArrayRef<uint32_t> ExpectedWeights) {
+ auto *ProfileData = I.getMetadata(LLVMContext::MD_prof);
+ if (!ProfileData)
+ return;
+
+ auto NOps = ProfileData->getNumOperands();
+ if (NOps < 3)
+ return;
+
+ // Operand 0 is a string tag "branch_weights"
+ auto *ProfDataName = dyn_cast<MDString>(ProfileData->getOperand(0));
+ if (!ProfDataName || !ProfDataName->getString().equals("branch_weights"))
+ return;
+
+ SmallVector<uint32_t, 4> RealWeights(NOps - 1);
+ for (unsigned i = 1; i < NOps; i++) {
+ ConstantInt *Value =
+ mdconst::dyn_extract<ConstantInt>(ProfileData->getOperand(i));
+ RealWeights[i - 1] = Value->getZExtValue();
+ }
+ verifyMisExpect(&I, RealWeights, ExpectedWeights, I.getContext());
+}
+
+} // namespace misexpect
+} // namespace llvm
+#undef DEBUG_TYPE
Index: llvm/lib/Transforms/Utils/CMakeLists.txt
===================================================================
--- llvm/lib/Transforms/Utils/CMakeLists.txt
+++ llvm/lib/Transforms/Utils/CMakeLists.txt
@@ -51,6 +51,7 @@
MemoryOpRemark.cpp
Mem2Reg.cpp
MetaRenamer.cpp
+ MisExpect.cpp
ModuleUtils.cpp
NameAnonGlobals.cpp
PredicateInfo.cpp
Index: llvm/lib/Transforms/Scalar/LowerExpectIntrinsic.cpp
===================================================================
--- llvm/lib/Transforms/Scalar/LowerExpectIntrinsic.cpp
+++ llvm/lib/Transforms/Scalar/LowerExpectIntrinsic.cpp
@@ -27,6 +27,7 @@
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Utils/MisExpect.h"
using namespace llvm;
@@ -101,11 +102,12 @@
uint64_t Index = (Case == *SI.case_default()) ? 0 : Case.getCaseIndex() + 1;
Weights[Index] = LikelyBranchWeightVal;
- SI.setCondition(ArgValue);
-
+ misexpect::checkFrontendInstrumentation(SI, Weights);
SI.setMetadata(LLVMContext::MD_prof,
MDBuilder(CI->getContext()).createBranchWeights(Weights));
+ SI.setCondition(ArgValue);
+
return true;
}
@@ -315,13 +317,16 @@
std::tie(LikelyBranchWeightVal, UnlikelyBranchWeightVal) =
getBranchWeight(Fn->getIntrinsicID(), CI, 2);
+ SmallVector<uint32_t, 4> ExpectedWeights;
if ((ExpectedValue->getZExtValue() == ValueComparedTo) ==
(Predicate == CmpInst::ICMP_EQ)) {
Node =
MDB.createBranchWeights(LikelyBranchWeightVal, UnlikelyBranchWeightVal);
+ ExpectedWeights = {LikelyBranchWeightVal, UnlikelyBranchWeightVal};
} else {
Node =
MDB.createBranchWeights(UnlikelyBranchWeightVal, LikelyBranchWeightVal);
+ ExpectedWeights = {UnlikelyBranchWeightVal, LikelyBranchWeightVal};
}
if (CmpI)
@@ -329,6 +334,8 @@
else
BSI.setCondition(ArgValue);
+ misexpect::checkFrontendInstrumentation(BSI, ExpectedWeights);
+
BSI.setMetadata(LLVMContext::MD_prof, Node);
return true;
@@ -409,7 +416,7 @@
bool runOnFunction(Function &F) override { return lowerExpectIntrinsic(F); }
};
-}
+} // namespace
char LowerExpectIntrinsic::ID = 0;
INITIALIZE_PASS(LowerExpectIntrinsic, "lower-expect",
Index: llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp
===================================================================
--- llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp
+++ llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp
@@ -110,6 +110,7 @@
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/Instrumentation.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
+#include "llvm/Transforms/Utils/MisExpect.h"
#include "llvm/Transforms/Utils/ModuleUtils.h"
#include <algorithm>
#include <cassert>
@@ -2051,6 +2052,8 @@
dbgs() << W << " ";
} dbgs() << "\n";);
+ misexpect::checkBackendInstrumentation(TI, Weights, TI->getContext());
+
TI->setMetadata(LLVMContext::MD_prof, MDB.createBranchWeights(Weights));
if (EmitBranchProbability) {
std::string BrCondStr = getBranchCondString(TI);
Index: llvm/lib/Transforms/IPO/SampleProfile.cpp
===================================================================
--- llvm/lib/Transforms/IPO/SampleProfile.cpp
+++ llvm/lib/Transforms/IPO/SampleProfile.cpp
@@ -84,6 +84,7 @@
#include "llvm/Transforms/Instrumentation.h"
#include "llvm/Transforms/Utils/CallPromotionUtils.h"
#include "llvm/Transforms/Utils/Cloning.h"
+#include "llvm/Transforms/Utils/MisExpect.h"
#include "llvm/Transforms/Utils/SampleProfileInference.h"
#include "llvm/Transforms/Utils/SampleProfileLoaderBaseImpl.h"
#include "llvm/Transforms/Utils/SampleProfileLoaderBaseUtil.h"
@@ -1716,6 +1717,8 @@
}
}
+ misexpect::checkBackendInstrumentation(TI, Weights, TI->getContext());
+
uint64_t TempWeight;
// Only set weights if there is at least one non-zero weight.
// In any other case, let the analyzer set weights.
Index: llvm/lib/IR/LLVMContextImpl.h
===================================================================
--- llvm/lib/IR/LLVMContextImpl.h
+++ llvm/lib/IR/LLVMContextImpl.h
@@ -1363,6 +1363,7 @@
///
/// If threshold option is not specified, it is disabled (0) by default.
Optional<uint64_t> DiagnosticsHotnessThreshold = 0;
+ bool MisExpectWarningRequested = false;
/// The specialized remark streamer used by LLVM's OptimizationRemarkEmitter.
std::unique_ptr<LLVMRemarkStreamer> LLVMRS;
Index: llvm/lib/IR/LLVMContext.cpp
===================================================================
--- llvm/lib/IR/LLVMContext.cpp
+++ llvm/lib/IR/LLVMContext.cpp
@@ -135,7 +135,12 @@
void LLVMContext::setDiagnosticsHotnessThreshold(Optional<uint64_t> Threshold) {
pImpl->DiagnosticsHotnessThreshold = Threshold;
}
-
+void LLVMContext::setMisExpectWarningRequested(bool Requested) {
+ pImpl->MisExpectWarningRequested = Requested;
+}
+bool LLVMContext::getMisExpectWarningRequested() const {
+ return pImpl->MisExpectWarningRequested;
+}
uint64_t LLVMContext::getDiagnosticsHotnessThreshold() const {
return pImpl->DiagnosticsHotnessThreshold.getValueOr(UINT64_MAX);
}
Index: llvm/lib/IR/DiagnosticInfo.cpp
===================================================================
--- llvm/lib/IR/DiagnosticInfo.cpp
+++ llvm/lib/IR/DiagnosticInfo.cpp
@@ -397,6 +397,17 @@
return OS.str();
}
+DiagnosticInfoMisExpect::DiagnosticInfoMisExpect(const Instruction *Inst,
+ Twine &Msg)
+ : DiagnosticInfoWithLocationBase(DK_MisExpect, DS_Warning,
+ *Inst->getParent()->getParent(),
+ Inst->getDebugLoc()),
+ Msg(Msg) {}
+
+void DiagnosticInfoMisExpect::print(DiagnosticPrinter &DP) const {
+ DP << getLocationStr() << ": " << getMsg();
+}
+
void OptimizationRemarkAnalysisFPCommute::anchor() {}
void OptimizationRemarkAnalysisAliasing::anchor() {}
Index: llvm/include/llvm/Transforms/Utils/MisExpect.h
===================================================================
--- /dev/null
+++ llvm/include/llvm/Transforms/Utils/MisExpect.h
@@ -0,0 +1,66 @@
+//===--- MisExpect.h - Check the use of llvm.expect with PGO data ---------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This contains code to emit diagnostic messages for potentially incorrect
+// usage of the llvm.expect intrinsic. This utility extracts the threshold
+// values from metadata associated with the instrumented Branch or Switch
+// instruction. The threshold values are then used to determine if a diagnostic
+// should be emitted.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/LLVMContext.h"
+
+namespace llvm {
+namespace misexpect {
+
+/// checkBackendInstrumentation - compares PGO counters to the thresholds used
+/// for llvm.expect and warns if the PGO counters are outside of the expected
+/// range. It extracts the expected weights from the MD_prof weights attatched
+/// to the instruction, which are are assumed to come from lowered llvm.expect
+/// intrinsics. The RealWeights parameter and the extracted expected weights are
+/// then passed to verifyMisexpect() for verification
+///
+/// \param I The Instruction being checked
+/// \param RealWeights A vector of profile weights for each target block
+/// \param Ctx The current LLVM context
+void checkBackendInstrumentation(
+ llvm::Instruction *I, const llvm::SmallVector<uint32_t, 4> &RealWeights,
+ llvm::LLVMContext &Ctx);
+
+/// checkBackendInstrumentation - compares PGO counters to the thresholds used
+/// for llvm.expect and warns if the PGO counters are outside of the expected
+/// range. It extracts the expected weights from the MD_prof weights attatched
+/// to the instruction, which are are assumed to come from profiling data
+/// attached by the frontend prior to llvm.expect intrinsic lowering. The
+/// ExpectedWeights parameter and the extracted real weights are then passed to
+/// verifyMisexpect() for verification
+///
+/// \param I the Instruction being checked
+/// \param ExpectedWeights A vector of the expected weights for each target
+/// block, this is determined by the threshold values
+void checkFrontendInstrumentation(Instruction &I,
+ ArrayRef<uint32_t> ExpectedWeights);
+
+/// veryifyMisExpect - compares RealWeights to the thresholds used
+/// for llvm.expect and warns if the PGO counters are outside of the expected
+/// range.
+///
+/// \param I The Instruction being checked
+/// \param RealWeights A vector of profile weights for each target block
+/// \param ExpectedWeights A vector of the expected weights for each target
+/// block, this is determined by the threshold values
+/// \param Ctx The current LLVM context
+void verifyMisExpect(Instruction *I, ArrayRef<uint32_t> RealWeights,
+ ArrayRef<uint32_t> ExpectedWeights, LLVMContext &Ctx);
+
+} // namespace misexpect
+} // namespace llvm
Index: llvm/include/llvm/Target/TargetOptions.h
===================================================================
--- llvm/include/llvm/Target/TargetOptions.h
+++ llvm/include/llvm/Target/TargetOptions.h
@@ -140,9 +140,9 @@
EnableMachineFunctionSplitter(false), SupportsDefaultOutlining(false),
EmitAddrsig(false), EmitCallSiteInfo(false),
SupportsDebugEntryValues(false), EnableDebugEntryValues(false),
- ValueTrackingVariableLocations(false),
- ForceDwarfFrameSection(false), XRayOmitFunctionIndex(false),
- DebugStrictDwarf(false),
+ ValueTrackingVariableLocations(false), ForceDwarfFrameSection(false),
+ XRayOmitFunctionIndex(false), DebugStrictDwarf(false),
+ MisExpect(false),
FPDenormalMode(DenormalMode::IEEE, DenormalMode::IEEE) {}
/// DisableFramePointerElim - This returns true if frame pointer elimination
@@ -342,6 +342,10 @@
/// By default, it is set to false.
unsigned DebugStrictDwarf : 1;
+ /// When set to true, enable MisExpect Diagnostics
+ /// By default, it is set to false
+ unsigned MisExpect : 1;
+
/// Name of the stack usage file (i.e., .su file) if user passes
/// -fstack-usage. If empty, it can be implied that -fstack-usage is not
/// passed on the command line.
Index: llvm/include/llvm/IR/LLVMContext.h
===================================================================
--- llvm/include/llvm/IR/LLVMContext.h
+++ llvm/include/llvm/IR/LLVMContext.h
@@ -202,6 +202,9 @@
/// diagnostics.
void setDiagnosticsHotnessRequested(bool Requested);
+ bool getMisExpectWarningRequested() const;
+ void setMisExpectWarningRequested(bool Requested);
+
/// Return the minimum hotness value a diagnostic would need in order
/// to be included in optimization diagnostics.
///
Index: llvm/include/llvm/IR/DiagnosticInfo.h
===================================================================
--- llvm/include/llvm/IR/DiagnosticInfo.h
+++ llvm/include/llvm/IR/DiagnosticInfo.h
@@ -81,6 +81,7 @@
DK_Unsupported,
DK_SrcMgr,
DK_DontCall,
+ DK_MisExpect,
DK_FirstPluginKind // Must be last value to work with
// getNextAvailablePluginDiagnosticKind
};
@@ -1028,6 +1029,25 @@
void print(DiagnosticPrinter &DP) const override;
};
+/// Diagnostic information for MisExpect analysis.
+class DiagnosticInfoMisExpect : public DiagnosticInfoWithLocationBase {
+public:
+ DiagnosticInfoMisExpect(const Instruction *Inst, Twine &Msg);
+
+ /// \see DiagnosticInfo::print.
+ void print(DiagnosticPrinter &DP) const override;
+
+ static bool classof(const DiagnosticInfo *DI) {
+ return DI->getKind() == DK_MisExpect;
+ }
+
+ const Twine &getMsg() const { return Msg; }
+
+private:
+ /// Message to report.
+ const Twine &Msg;
+};
+
static DiagnosticSeverity getDiagnosticSeverity(SourceMgr::DiagKind DK) {
switch (DK) {
case llvm::SourceMgr::DK_Error:
Index: llvm/docs/MisExpect.rst
===================================================================
--- /dev/null
+++ llvm/docs/MisExpect.rst
@@ -0,0 +1,73 @@
+===================
+Misexpect
+===================
+.. contents::
+
+.. toctree::
+ :maxdepth: 1
+
+When developers use ``llvm.expect`` intrinsics, i.e., through use of
+``__builtin_expect(...)``, they are trying to communicate how their code is
+expected to behave at runtime to the optimizer. These annotations, however, can
+be incorrect for a variety of reasons: changes to the code base invalidate them
+silently, the developer mis-annotated them (e.g., using ``LIKELY`` instead of
+``UNLIKELY``), or perhaps they assumed something incorrectly when they wrote
+the annotation. Regardless of why, it is useful to detect these situations so
+that the optimizer can make more useful decisions about the code. MisExpect
+diagnostics are intended to help developers identify and address these
+situations, by comparing the use of the ``llvm.expect`` intrinsic to the ground
+truth provided by a profiling input.
+
+The MisExpect checks in the LLVM backend follow a simple procedure: if the
+profiling counter associated with an instruction using the ``llvm.expect``
+intrinsic was too low along the expected path, then it emits a diagnostic
+message to the user.
+
+The most natural place to perform the verification is just prior to when
+branch weights being assigned to the target instruction in the form of
+branch weight metadata.
+
+There are 3 key places in the LLVM backend where branch weights are
+created and assigned based on profiling information or the use of the
+``llvm.expect`` intrinsic, and our implementation focuses on these
+places to perform the verification.
+
+We calculate the threshold for emitting MisExpect related diagnostics
+based on the values the compiler assigns to ``llvm.expect`` intrinsics,
+which can be set through the ``-likely-branch-weight`` and
+``-unlikely-branch-weight`` LLVM options. During verification, if the
+profile count is less than the calculated threshold, then we will emit a
+remark or warning detailing a potential performance regression. The
+diagnostic also reports the percentage of the time the annotation was
+correct during profiling to help developers reason about how to proceed.
+
+The diagnostics are also available in the form of optimization remarks,
+which can be serialized and processed through the ``opt-viewer.py``
+scripts in LLVM.
+
+.. option:: -pass-remarks=misexpect
+
+ Enables optimization remarks for misexpect when profiling data conflicts with
+ use of ``llvm.expect`` intrinsics.
+
+
+.. option:: -pgo-warn-misexpect
+
+ Enables misexpect warnings when profiling data conflicts with use of
+ ``llvm.expect`` intrinsics.
+
+LLVM supports 4 types of profile formats: Frontend, IR, CS-IR, and
+Sampling. MisExpect Diagnostics are compatible with all Profiling formats.
+
++----------------+--------------------------------------------------------------------------------------+
+| Profile Type | Description |
++================+======================================================================================+
+| Frontend | Profiling instrumentation added during compilation by the frontend, i.e. ``clang`` |
++----------------+--------------------------------------------------------------------------------------+
+| IR | Profiling instrumentation added during by the LLVM backend |
++----------------+--------------------------------------------------------------------------------------+
+| CS-IR | Context Sensitive IR based profiles |
++----------------+--------------------------------------------------------------------------------------+
+| Sampling | Profiles collected through sampling with external tools, such as ``perf`` on Linux |
++----------------+--------------------------------------------------------------------------------------+
+
Index: clang/test/Profile/misexpect-branch.c
===================================================================
--- /dev/null
+++ clang/test/Profile/misexpect-branch.c
@@ -0,0 +1,28 @@
+// Test that misexpect detects mis-annotated branches
+
+// RUN: llvm-profdata merge %S/Inputs/misexpect-branch.proftext -o %t.profdata
+// RUN: %clang_cc1 %s -O2 -o - -emit-llvm -fprofile-instrument-use-path=%t.profdata -verify=imprecise -Wmisexpect
+// RUN: %clang_cc1 %s -O2 -o - -emit-llvm -fprofile-instrument-use-path=%t.profdata -verify=exact -Wmisexpect -debug-info-kind=line-tables-only
+// RUN: %clang_cc1 %s -O2 -o - -disable-llvm-passes -emit-llvm -fprofile-instrument-use-path=%t.profdata -verify=foo
+
+// foo-no-diagnostics
+#define likely(x) __builtin_expect(!!(x), 1)
+#define unlikely(x) __builtin_expect(!!(x), 0)
+
+int foo(int);
+int baz(int);
+int buzz();
+
+const int inner_loop = 100;
+const int outer_loop = 2000;
+
+int bar() { // imprecise-warning-re {{Potential performance regression from use of __builtin_expect(): Annotation was correct on {{.+}}% ({{[0-9]+ / [0-9]+}}) of profiled executions.}}
+ int rando = buzz();
+ int x = 0;
+ if (likely(rando % (outer_loop * inner_loop) == 0)) { // exact-warning-re {{Potential performance regression from use of __builtin_expect(): Annotation was correct on {{.+}}% ({{[0-9]+ / [0-9]+}}) of profiled executions.}}
+ x = baz(rando);
+ } else {
+ x = foo(50);
+ }
+ return x;
+}
Index: clang/test/Profile/misexpect-branch-unpredictable.c
===================================================================
--- /dev/null
+++ clang/test/Profile/misexpect-branch-unpredictable.c
@@ -0,0 +1,25 @@
+// Test that misexpect emits no warning when prediction is correct
+
+// RUN: llvm-profdata merge %S/Inputs/misexpect-branch.proftext -o %t.profdata
+// RUN: %clang_cc1 %s -O2 -o - -disable-llvm-passes -emit-llvm -fprofile-instrument-use-path=%t.profdata -verify -Wmisexpect
+
+// expected-no-diagnostics
+#define unpredictable(x) __builtin_unpredictable(!!(x))
+
+int foo(int);
+int baz(int);
+int buzz();
+
+const int inner_loop = 100;
+const int outer_loop = 2000;
+
+int bar() {
+ int rando = buzz();
+ int x = 0;
+ if (unpredictable(rando % (outer_loop * inner_loop) == 0)) {
+ x = baz(rando);
+ } else {
+ x = foo(50);
+ }
+ return x;
+}
Index: clang/test/Profile/misexpect-branch-cold.c
===================================================================
--- /dev/null
+++ clang/test/Profile/misexpect-branch-cold.c
@@ -0,0 +1,26 @@
+// Test that misexpect emits no warning when prediction is correct
+
+// RUN: llvm-profdata merge %S/Inputs/misexpect-branch.proftext -o %t.profdata
+// RUN: %clang_cc1 %s -O2 -o - -disable-llvm-passes -emit-llvm -fprofile-instrument-use-path=%t.profdata -verify -Wmisexpect
+
+// expected-no-diagnostics
+#define likely(x) __builtin_expect(!!(x), 1)
+#define unlikely(x) __builtin_expect(!!(x), 0)
+
+int foo(int);
+int baz(int);
+int buzz();
+
+const int inner_loop = 100;
+const int outer_loop = 2000;
+
+int bar() {
+ int rando = buzz();
+ int x = 0;
+ if (unlikely(rando % (outer_loop * inner_loop) == 0)) {
+ x = baz(rando);
+ } else {
+ x = foo(50);
+ }
+ return x;
+}
Index: clang/test/Profile/Inputs/misexpect-branch.proftext
===================================================================
--- /dev/null
+++ clang/test/Profile/Inputs/misexpect-branch.proftext
@@ -0,0 +1,8 @@
+bar
+# Func Hash:
+45795613684824
+# Num Counters:
+2
+# Counter Values:
+200000
+0
Index: clang/lib/Frontend/CompilerInvocation.cpp
===================================================================
--- clang/lib/Frontend/CompilerInvocation.cpp
+++ clang/lib/Frontend/CompilerInvocation.cpp
@@ -4475,6 +4475,13 @@
if (Res.getFrontendOpts().ProgramAction == frontend::RewriteObjC)
LangOpts.ObjCExceptions = 1;
+ for (auto Warning : Res.getDiagnosticOpts().Warnings) {
+ if (Warning == "misexpect" &&
+ !Diags.isIgnored(diag::warn_profile_data_misexpect, SourceLocation())) {
+ Res.getCodeGenOpts().MisExpect = true;
+ }
+ }
+
if (LangOpts.CUDA) {
// During CUDA device-side compilation, the aux triple is the
// triple used for host compilation.
Index: clang/lib/CodeGen/CodeGenAction.cpp
===================================================================
--- clang/lib/CodeGen/CodeGenAction.cpp
+++ clang/lib/CodeGen/CodeGenAction.cpp
@@ -333,6 +333,9 @@
return;
}
+ if (CodeGenOpts.MisExpect) {
+ Ctx.setMisExpectWarningRequested(true);
+ }
std::unique_ptr<llvm::ToolOutputFile> OptRecordFile =
std::move(*OptRecordFileOrErr);
@@ -440,6 +443,9 @@
void OptimizationFailureHandler(
const llvm::DiagnosticInfoOptimizationFailure &D);
void DontCallDiagHandler(const DiagnosticInfoDontCall &D);
+ /// Specialized handler for misexpect warnings.
+ /// Note that misexpect remarks are emitted through ORE
+ void MisExpectDiagHandler(const llvm::DiagnosticInfoMisExpect &D);
};
void BackendConsumer::anchor() {}
@@ -822,6 +828,25 @@
<< llvm::demangle(D.getFunctionName().str()) << D.getNote();
}
+void BackendConsumer::MisExpectDiagHandler(
+ const llvm::DiagnosticInfoMisExpect &D) {
+ StringRef Filename;
+ unsigned Line, Column;
+ bool BadDebugInfo = false;
+ FullSourceLoc Loc =
+ getBestLocationFromDebugLoc(D, BadDebugInfo, Filename, Line, Column);
+
+ Diags.Report(Loc, diag::warn_profile_data_misexpect) << D.getMsg().str();
+
+ if (BadDebugInfo)
+ // If we were not able to translate the file:line:col information
+ // back to a SourceLocation, at least emit a note stating that
+ // we could not translate this location. This can happen in the
+ // case of #line directives.
+ Diags.Report(Loc, diag::note_fe_backend_invalid_loc)
+ << Filename << Line << Column;
+}
+
/// This function is invoked when the backend needs
/// to report something to the user.
void BackendConsumer::DiagnosticHandlerImpl(const DiagnosticInfo &DI) {
@@ -896,6 +921,9 @@
case llvm::DK_DontCall:
DontCallDiagHandler(cast<DiagnosticInfoDontCall>(DI));
return;
+ case llvm::DK_MisExpect:
+ MisExpectDiagHandler(cast<DiagnosticInfoMisExpect>(DI));
+ return;
default:
// Plugin IDs are not bound to any value as they are set dynamically.
ComputeDiagRemarkID(Severity, backend_plugin, DiagID);
@@ -1172,6 +1200,10 @@
std::unique_ptr<llvm::ToolOutputFile> OptRecordFile =
std::move(*OptRecordFileOrErr);
+ if (CodeGenOpts.MisExpect) {
+ Ctx.setMisExpectWarningRequested(true);
+ }
+
EmitBackendOutput(Diagnostics, CI.getHeaderSearchOpts(), CodeGenOpts,
TargetOpts, CI.getLangOpts(),
CI.getTarget().getDataLayoutString(), TheModule.get(), BA,
Index: clang/lib/CodeGen/BackendUtil.cpp
===================================================================
--- clang/lib/CodeGen/BackendUtil.cpp
+++ clang/lib/CodeGen/BackendUtil.cpp
@@ -640,6 +640,7 @@
Options.MCOptions.Argv0 = CodeGenOpts.Argv0;
Options.MCOptions.CommandLineArgs = CodeGenOpts.CommandLineArgs;
Options.DebugStrictDwarf = CodeGenOpts.DebugStrictDwarf;
+ Options.MisExpect = CodeGenOpts.MisExpect;
return true;
}
Index: clang/include/clang/Basic/DiagnosticGroups.td
===================================================================
--- clang/include/clang/Basic/DiagnosticGroups.td
+++ clang/include/clang/Basic/DiagnosticGroups.td
@@ -1245,6 +1245,7 @@
def ProfileInstrMissing : DiagGroup<"profile-instr-missing">;
def ProfileInstrOutOfDate : DiagGroup<"profile-instr-out-of-date">;
def ProfileInstrUnprofiled : DiagGroup<"profile-instr-unprofiled">;
+def MisExpect : DiagGroup<"misexpect">;
// AddressSanitizer frontend instrumentation remarks.
def SanitizeAddressRemarks : DiagGroup<"sanitize-address">;
Index: clang/include/clang/Basic/DiagnosticFrontendKinds.td
===================================================================
--- clang/include/clang/Basic/DiagnosticFrontendKinds.td
+++ clang/include/clang/Basic/DiagnosticFrontendKinds.td
@@ -311,6 +311,11 @@
def warn_profile_data_unprofiled : Warning<
"no profile data available for file \"%0\"">,
InGroup<ProfileInstrUnprofiled>;
+def warn_profile_data_misexpect : Warning<
+ "Potential performance regression from use of __builtin_expect(): "
+ "Annotation was correct on %0 of profiled executions.">,
+ BackendInfo,
+ InGroup<MisExpect>;
} // end of instrumentation issue category
}
Index: clang/include/clang/Basic/CodeGenOptions.def
===================================================================
--- clang/include/clang/Basic/CodeGenOptions.def
+++ clang/include/clang/Basic/CodeGenOptions.def
@@ -169,6 +169,7 @@
CODEGENOPT(FatalWarnings , 1, 0) ///< Set when -Wa,--fatal-warnings is
///< enabled.
CODEGENOPT(NoWarn , 1, 0) ///< Set when -Wa,--no-warn is enabled.
+CODEGENOPT(MisExpect , 1, 0) ///< Set -Wmisexpect is enabled
CODEGENOPT(EnableSegmentedStacks , 1, 0) ///< Set when -fsplit-stack is enabled.
CODEGENOPT(NoInlineLineTables, 1, 0) ///< Whether debug info should contain
///< inline line tables.
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