91 lines
3.8 KiB
LLVM
91 lines
3.8 KiB
LLVM
; RUN: opt < %s -sample-profile -sample-profile-file=%S/Inputs/discriminator.prof | opt -analyze -branch-prob | FileCheck %s
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; RUN: opt < %s -passes=sample-profile -sample-profile-file=%S/Inputs/discriminator.prof | opt -analyze -branch-prob | FileCheck %s
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; Original code
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;
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; 1 int foo(int i) {
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; 2 int x = 0;
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; 3 while (i < 100) {
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; 4 if (i < 5) x--;
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; 5 i++;
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; 6 }
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; 7 return x;
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; 8 }
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;
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; In this test, if the loop is executed 100 times, the decrement operation
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; at line 4 should only execute 5 times. This is reflected in the profile
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; data for line offset 3. In Inputs/discriminator.prof, we have:
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;
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; 3: 100
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; 3.1: 5
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;
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; This means that the predicate 'i < 5' (line 3) is executed 100 times,
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; but the then branch (line 3.1) is only executed 5 times.
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define i32 @foo(i32 %i) #0 !dbg !4 {
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; CHECK: Printing analysis 'Branch Probability Analysis' for function 'foo':
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entry:
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%i.addr = alloca i32, align 4
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%x = alloca i32, align 4
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store i32 %i, i32* %i.addr, align 4
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store i32 0, i32* %x, align 4, !dbg !10
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br label %while.cond, !dbg !11
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while.cond: ; preds = %if.end, %entry
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%0 = load i32, i32* %i.addr, align 4, !dbg !12
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%cmp = icmp slt i32 %0, 100, !dbg !12
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br i1 %cmp, label %while.body, label %while.end, !dbg !12
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; CHECK: edge while.cond -> while.body probability is 0x7d83ba68 / 0x80000000 = 98.06% [HOT edge]
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; CHECK: edge while.cond -> while.end probability is 0x027c4598 / 0x80000000 = 1.94%
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while.body: ; preds = %while.cond
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%1 = load i32, i32* %i.addr, align 4, !dbg !14
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%cmp1 = icmp slt i32 %1, 50, !dbg !14
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br i1 %cmp1, label %if.then, label %if.end, !dbg !14
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; CHECK: edge while.body -> if.then probability is 0x07878788 / 0x80000000 = 5.88%
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; CHECK: edge while.body -> if.end probability is 0x78787878 / 0x80000000 = 94.12% [HOT edge]
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if.then: ; preds = %while.body
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%2 = load i32, i32* %x, align 4, !dbg !17
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%dec = add nsw i32 %2, -1, !dbg !17
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store i32 %dec, i32* %x, align 4, !dbg !17
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br label %if.end, !dbg !17
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if.end: ; preds = %if.then, %while.body
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%3 = load i32, i32* %i.addr, align 4, !dbg !19
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%inc = add nsw i32 %3, 1, !dbg !19
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store i32 %inc, i32* %i.addr, align 4, !dbg !19
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br label %while.cond, !dbg !20
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while.end: ; preds = %while.cond
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%4 = load i32, i32* %x, align 4, !dbg !21
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ret i32 %4, !dbg !21
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}
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!llvm.dbg.cu = !{!0}
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!llvm.module.flags = !{!7, !8}
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!llvm.ident = !{!9}
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!0 = distinct !DICompileUnit(language: DW_LANG_C99, producer: "clang version 3.5 ", isOptimized: false, emissionKind: NoDebug, file: !1, enums: !2, retainedTypes: !2, globals: !2, imports: !2)
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!1 = !DIFile(filename: "discriminator.c", directory: ".")
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!2 = !{}
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!4 = distinct !DISubprogram(name: "foo", line: 1, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: false, unit: !0, scopeLine: 1, file: !1, scope: !5, type: !6, retainedNodes: !2)
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!5 = !DIFile(filename: "discriminator.c", directory: ".")
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!6 = !DISubroutineType(types: !2)
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!7 = !{i32 2, !"Dwarf Version", i32 4}
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!8 = !{i32 1, !"Debug Info Version", i32 3}
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!9 = !{!"clang version 3.5 "}
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!10 = !DILocation(line: 2, scope: !4)
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!11 = !DILocation(line: 3, scope: !4)
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!12 = !DILocation(line: 3, scope: !13)
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!13 = !DILexicalBlockFile(discriminator: 2, file: !1, scope: !4)
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!14 = !DILocation(line: 4, scope: !15)
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!15 = distinct !DILexicalBlock(line: 4, column: 0, file: !1, scope: !16)
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!16 = distinct !DILexicalBlock(line: 3, column: 0, file: !1, scope: !4)
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!17 = !DILocation(line: 4, scope: !18)
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!18 = !DILexicalBlockFile(discriminator: 2, file: !1, scope: !15)
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!19 = !DILocation(line: 5, scope: !16)
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!20 = !DILocation(line: 6, scope: !16)
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!21 = !DILocation(line: 7, scope: !4)
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