fb02f7140a
Summary: This patch starts the implementation as discuss in the following RFC: http://lists.llvm.org/pipermail/llvm-dev/2016-October/106532.html When optimization duplicates code that will scale down the execution count of a basic block, we will record the duplication factor as part of discriminator so that the offline process tool can find the duplication factor and collect the accurate execution frequency of the corresponding source code. Two important optimization that fall into this category is loop vectorization and loop unroll. This patch records the duplication factor for these 2 optimizations. The recording will be guarded by a flag encode-duplication-in-discriminators, which is off by default. Reviewers: probinson, aprantl, davidxl, hfinkel, echristo Reviewed By: hfinkel Subscribers: mehdi_amini, anemet, mzolotukhin, llvm-commits Differential Revision: https://reviews.llvm.org/D26420 llvm-svn: 294782
102 lines
4.7 KiB
LLVM
102 lines
4.7 KiB
LLVM
; RUN: opt < %s -add-discriminators -S | FileCheck %s
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; RUN: opt < %s -passes=add-discriminators -S | FileCheck %s
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; Discriminator support for code that is written in one line:
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; #1 int foo(int i) {
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; #2 if (i == 3 || i == 5) return 100; else return 99;
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; #3 }
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; i == 3: discriminator 0
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; i == 5: discriminator 2
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; return 100: discriminator 4
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; return 99: discriminator 6
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define i32 @_Z3fooi(i32 %i) #0 !dbg !4 {
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%1 = alloca i32, align 4
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%2 = alloca i32, align 4
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store i32 %i, i32* %2, align 4, !tbaa !13
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call void @llvm.dbg.declare(metadata i32* %2, metadata !9, metadata !17), !dbg !18
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%3 = load i32, i32* %2, align 4, !dbg !19, !tbaa !13
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%4 = icmp eq i32 %3, 3, !dbg !21
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br i1 %4, label %8, label %5, !dbg !22
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; <label>:5 ; preds = %0
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%6 = load i32, i32* %2, align 4, !dbg !23, !tbaa !13
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; CHECK: %6 = load i32, i32* %2, align 4, !dbg ![[THEN1:[0-9]+]],{{.*}}
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%7 = icmp eq i32 %6, 5, !dbg !24
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; CHECK: %7 = icmp eq i32 %6, 5, !dbg ![[THEN2:[0-9]+]]
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br i1 %7, label %8, label %9, !dbg !25
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; CHECK: br i1 %7, label %8, label %9, !dbg ![[THEN3:[0-9]+]]
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; <label>:8 ; preds = %5, %0
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store i32 100, i32* %1, align 4, !dbg !26
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; CHECK: store i32 100, i32* %1, align 4, !dbg ![[ELSE:[0-9]+]]
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br label %10, !dbg !26
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; CHECK: br label %10, !dbg ![[ELSE]]
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; <label>:9 ; preds = %5
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store i32 99, i32* %1, align 4, !dbg !27
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; CHECK: store i32 99, i32* %1, align 4, !dbg ![[COMBINE:[0-9]+]]
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br label %10, !dbg !27
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; CHECK: br label %10, !dbg ![[COMBINE]]
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; <label>:10 ; preds = %9, %8
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%11 = load i32, i32* %1, align 4, !dbg !28
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ret i32 %11, !dbg !28
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}
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; Function Attrs: nounwind readnone
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declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
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attributes #0 = { nounwind uwtable "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2" "unsafe-fp-math"="false" "use-soft-float"="false" }
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attributes #1 = { nounwind readnone }
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!llvm.dbg.cu = !{!0}
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!llvm.module.flags = !{!10, !11}
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!llvm.ident = !{!12}
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!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 3.8.0 (trunk 250915)", isOptimized: true, runtimeVersion: 0, emissionKind: NoDebug, enums: !2)
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!1 = !DIFile(filename: "a.cc", directory: "/usr/local/google/home/dehao/discr")
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!2 = !{}
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!4 = distinct !DISubprogram(name: "foo", linkageName: "_Z3fooi", scope: !1, file: !1, line: 1, type: !5, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: true, unit: !0, variables: !8)
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!5 = !DISubroutineType(types: !6)
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!6 = !{!7, !7}
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!7 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
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!8 = !{!9}
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!9 = !DILocalVariable(name: "i", arg: 1, scope: !4, file: !1, line: 1, type: !7)
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!10 = !{i32 2, !"Dwarf Version", i32 4}
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!11 = !{i32 2, !"Debug Info Version", i32 3}
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!12 = !{!"clang version 3.8.0 (trunk 250915)"}
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!13 = !{!14, !14, i64 0}
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!14 = !{!"int", !15, i64 0}
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!15 = !{!"omnipotent char", !16, i64 0}
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!16 = !{!"Simple C/C++ TBAA"}
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!17 = !DIExpression()
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!18 = !DILocation(line: 1, column: 13, scope: !4)
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!19 = !DILocation(line: 2, column: 7, scope: !20)
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!20 = distinct !DILexicalBlock(scope: !4, file: !1, line: 2, column: 7)
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!21 = !DILocation(line: 2, column: 9, scope: !20)
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!22 = !DILocation(line: 2, column: 14, scope: !20)
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!23 = !DILocation(line: 2, column: 17, scope: !20)
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!24 = !DILocation(line: 2, column: 19, scope: !20)
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!25 = !DILocation(line: 2, column: 7, scope: !4)
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!26 = !DILocation(line: 2, column: 25, scope: !20)
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!27 = !DILocation(line: 2, column: 42, scope: !20)
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!28 = !DILocation(line: 3, column: 1, scope: !4)
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; CHECK: ![[F:.*]] = distinct !DISubprogram(name: "foo",
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; CHECK: ![[IF:.*]] = distinct !DILexicalBlock(scope: ![[F]],{{.*}}line: 2, column: 7)
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; CHECK: ![[THEN1]] = !DILocation(line: 2, column: 17, scope: ![[THENBLOCK:[0-9]+]])
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; CHECK: ![[THENBLOCK]] = !DILexicalBlockFile(scope: ![[IF]],{{.*}} discriminator: 2)
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; CHECK: ![[THEN2]] = !DILocation(line: 2, column: 19, scope: ![[THENBLOCK]])
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; CHECK: ![[THEN3]] = !DILocation(line: 2, column: 7, scope: ![[BRBLOCK:[0-9]+]])
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; CHECK: ![[BRBLOCK]] = !DILexicalBlockFile(scope: ![[F]],{{.*}} discriminator: 2)
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; CHECK: ![[ELSE]] = !DILocation(line: 2, column: 25, scope: ![[ELSEBLOCK:[0-9]+]])
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; CHECK: ![[ELSEBLOCK]] = !DILexicalBlockFile(scope: ![[IF]],{{.*}} discriminator: 4)
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; CHECK: ![[COMBINE]] = !DILocation(line: 2, column: 42, scope: ![[COMBINEBLOCK:[0-9]+]])
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; CHECK: ![[COMBINEBLOCK]] = !DILexicalBlockFile(scope: ![[IF]],{{.*}} discriminator: 6)
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