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
73 lines
3.3 KiB
LLVM
73 lines
3.3 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 diamond-shaped CFG.:
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; #1 void bar(int);
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; #2
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; #3 void foo(int i) {
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; #4 if (i > 10)
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; #5 bar(5); else bar(3);
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; #6 }
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; bar(5): discriminator 0
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; bar(3): discriminator 2
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; Function Attrs: uwtable
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define void @_Z3fooi(i32 %i) #0 !dbg !4 {
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%1 = alloca i32, align 4
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store i32 %i, i32* %1, align 4
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call void @llvm.dbg.declare(metadata i32* %1, metadata !11, metadata !12), !dbg !13
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%2 = load i32, i32* %1, align 4, !dbg !14
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%3 = icmp sgt i32 %2, 10, !dbg !16
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br i1 %3, label %4, label %5, !dbg !17
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; <label>:4 ; preds = %0
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call void @_Z3bari(i32 5), !dbg !18
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br label %6, !dbg !18
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; <label>:5 ; preds = %0
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call void @_Z3bari(i32 3), !dbg !19
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; CHECK: call void @_Z3bari(i32 3), !dbg ![[ELSE:[0-9]+]]
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br label %6
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; <label>:6 ; preds = %5, %4
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ret void, !dbg !20
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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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declare void @_Z3bari(i32) #2
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attributes #0 = { uwtable "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "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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attributes #2 = { "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "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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!llvm.dbg.cu = !{!0}
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!llvm.module.flags = !{!8, !9}
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!llvm.ident = !{!10}
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!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 3.8.0 (trunk 253273)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
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!1 = !DIFile(filename: "a.cc", directory: "/tmp")
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!2 = !{}
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!4 = distinct !DISubprogram(name: "foo", linkageName: "_Z3fooi", scope: !1, file: !1, line: 3, type: !5, isLocal: false, isDefinition: true, scopeLine: 3, flags: DIFlagPrototyped, isOptimized: false, unit: !0, variables: !2)
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!5 = !DISubroutineType(types: !6)
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!6 = !{null, !7}
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!7 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
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!8 = !{i32 2, !"Dwarf Version", i32 4}
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!9 = !{i32 2, !"Debug Info Version", i32 3}
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!10 = !{!"clang version 3.8.0 (trunk 253273)"}
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!11 = !DILocalVariable(name: "i", arg: 1, scope: !4, file: !1, line: 3, type: !7)
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!12 = !DIExpression()
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!13 = !DILocation(line: 3, column: 14, scope: !4)
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!14 = !DILocation(line: 4, column: 7, scope: !15)
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!15 = distinct !DILexicalBlock(scope: !4, file: !1, line: 4, column: 7)
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!16 = !DILocation(line: 4, column: 9, scope: !15)
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!17 = !DILocation(line: 4, column: 7, scope: !4)
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!18 = !DILocation(line: 5, column: 5, scope: !15)
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!19 = !DILocation(line: 5, column: 18, scope: !15)
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!20 = !DILocation(line: 6, column: 1, scope: !4)
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; CHECK: ![[ELSE]] = !DILocation(line: 5, column: 18, scope: ![[ELSEBLOCK:[0-9]+]])
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; CHECK: ![[ELSEBLOCK]] = !DILexicalBlockFile({{.*}} discriminator: 2)
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