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https://github.com/Gericom/teak-llvm.git
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0b6985a3c6
When the original binary is executed and sampled, the resulting profile contains information on the original inline stack. We currently follow the original inline plan if we notice that the inlined callsite has more than 0 samples to it. A better way is to determine whether the callsite is actually worth inlining. If the callsite accumulates a small fraction of the samples spent in the parent function, then we don't want to bother inlining it (as it means that the callsite is actually cold). This patch introduces a threshold expressed in percentage of samples in relation to the parent function. If the callsite uses less than N% of the total samples used by its parent, the original inline decision is not re-applied. I've set the threshold to the very arbitrary value of 5%. I'm yet to do any actual experiments to see what's a good value. I wanted to separate the basic mechanism from the tuning. llvm-svn: 254034
109 lines
4.1 KiB
LLVM
109 lines
4.1 KiB
LLVM
; RUN: opt < %s -sample-profile -sample-profile-file=%S/Inputs/inline.prof -sample-profile-inline-hot-threshold=1 -S | FileCheck %s
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; Original C++ test case
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;
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; #include <stdio.h>
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;
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; int sum(int x, int y) {
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; return x + y;
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; }
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;
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; int main() {
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; int s, i = 0;
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; while (i++ < 20000 * 20000)
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; if (i != 100) s = sum(i, s); else s = 30;
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; printf("sum is %d\n", s);
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; return 0;
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; }
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;
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@.str = private unnamed_addr constant [11 x i8] c"sum is %d\0A\00", align 1
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; Function Attrs: nounwind uwtable
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define i32 @_Z3sumii(i32 %x, i32 %y) !dbg !4 {
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entry:
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%x.addr = alloca i32, align 4
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%y.addr = alloca i32, align 4
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store i32 %x, i32* %x.addr, align 4
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store i32 %y, i32* %y.addr, align 4
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%0 = load i32, i32* %x.addr, align 4, !dbg !11
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%1 = load i32, i32* %y.addr, align 4, !dbg !11
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%add = add nsw i32 %0, %1, !dbg !11
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ret i32 %add, !dbg !11
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}
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; Function Attrs: uwtable
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define i32 @main() !dbg !7 {
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entry:
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%retval = alloca i32, align 4
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%s = alloca i32, align 4
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%i = alloca i32, align 4
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store i32 0, i32* %retval
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store i32 0, i32* %i, align 4, !dbg !12
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br label %while.cond, !dbg !13
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while.cond: ; preds = %if.end, %entry
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%0 = load i32, i32* %i, align 4, !dbg !14
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%inc = add nsw i32 %0, 1, !dbg !14
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store i32 %inc, i32* %i, align 4, !dbg !14
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%cmp = icmp slt i32 %0, 400000000, !dbg !14
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br i1 %cmp, label %while.body, label %while.end, !dbg !14
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while.body: ; preds = %while.cond
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%1 = load i32, i32* %i, align 4, !dbg !16
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%cmp1 = icmp ne i32 %1, 100, !dbg !16
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br i1 %cmp1, label %if.then, label %if.else, !dbg !16
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if.then: ; preds = %while.body
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%2 = load i32, i32* %i, align 4, !dbg !18
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%3 = load i32, i32* %s, align 4, !dbg !18
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%call = call i32 @_Z3sumii(i32 %2, i32 %3), !dbg !18
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; CHECK-NOT: call i32 @_Z3sumii
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store i32 %call, i32* %s, align 4, !dbg !18
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br label %if.end, !dbg !18
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if.else: ; preds = %while.body
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store i32 30, i32* %s, align 4, !dbg !20
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br label %if.end
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if.end: ; preds = %if.else, %if.then
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br label %while.cond, !dbg !22
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while.end: ; preds = %while.cond
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%4 = load i32, i32* %s, align 4, !dbg !24
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%call2 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([11 x i8], [11 x i8]* @.str, i32 0, i32 0), i32 %4), !dbg !24
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ret i32 0, !dbg !25
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}
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declare i32 @printf(i8*, ...) #2
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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, producer: "clang version 3.5 ", isOptimized: false, emissionKind: 0, file: !1, enums: !2, retainedTypes: !2, subprograms: !3, globals: !2, imports: !2)
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!1 = !DIFile(filename: "calls.cc", directory: ".")
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!2 = !{}
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!3 = !{!4, !7}
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!4 = distinct !DISubprogram(name: "sum", line: 3, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: false, scopeLine: 3, file: !1, scope: !5, type: !6, variables: !2)
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!5 = !DIFile(filename: "calls.cc", directory: ".")
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!6 = !DISubroutineType(types: !2)
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!7 = distinct !DISubprogram(name: "main", line: 7, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: false, scopeLine: 7, file: !1, scope: !5, type: !6, variables: !2)
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!8 = !{i32 2, !"Dwarf Version", i32 4}
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!9 = !{i32 1, !"Debug Info Version", i32 3}
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!10 = !{!"clang version 3.5 "}
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!11 = !DILocation(line: 4, scope: !4)
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!12 = !DILocation(line: 8, scope: !7)
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!13 = !DILocation(line: 9, scope: !7)
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!14 = !DILocation(line: 9, scope: !15)
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!15 = !DILexicalBlockFile(discriminator: 1, file: !1, scope: !7)
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!16 = !DILocation(line: 10, scope: !17)
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!17 = distinct !DILexicalBlock(line: 10, column: 0, file: !1, scope: !7)
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!18 = !DILocation(line: 10, scope: !19)
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!19 = !DILexicalBlockFile(discriminator: 1, file: !1, scope: !17)
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!20 = !DILocation(line: 10, scope: !21)
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!21 = !DILexicalBlockFile(discriminator: 2, file: !1, scope: !17)
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!22 = !DILocation(line: 10, scope: !23)
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!23 = !DILexicalBlockFile(discriminator: 3, file: !1, scope: !17)
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!24 = !DILocation(line: 11, scope: !7)
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!25 = !DILocation(line: 12, scope: !7)
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