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87393cfd6b
Summary: When the sample profiles include discriminator information, use the discriminator values to distinguish instruction weights in different basic blocks. This modifies the BodySamples mapping to map <line, discriminator> pairs to weights. Instructions on the same line but different blocks, will use different discriminator values. This, in turn, means that the blocks may have different weights. Other changes in this patch: - Add tests for positive values of line offset, discriminator and samples. - Change data types from uint32_t to unsigned and int and do additional validation. Reviewers: chandlerc CC: llvm-commits Differential Revision: http://llvm-reviews.chandlerc.com/D2857 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203508 91177308-0d34-0410-b5e6-96231b3b80d8
91 lines
4.3 KiB
LLVM
91 lines
4.3 KiB
LLVM
; RUN: opt < %s -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 {
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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* %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 100 / 101 = 99.0099% [HOT edge]
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; CHECK: edge while.cond -> while.end probability is 1 / 101 = 0.990099%
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while.body: ; preds = %while.cond
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%1 = load 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 5 / 100 = 5%
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; CHECK: edge while.body -> if.end probability is 95 / 100 = 95% [HOT edge]
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if.then: ; preds = %while.body
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%2 = load 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* %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* %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 = metadata !{i32 786449, metadata !1, i32 12, metadata !"clang version 3.5 ", i1 false, metadata !"", i32 0, metadata !2, metadata !2, metadata !3, metadata !2, metadata !2, metadata !""} ; [ DW_TAG_compile_unit ] [discriminator.c] [DW_LANG_C99]
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!1 = metadata !{metadata !"discriminator.c", metadata !"."}
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!2 = metadata !{}
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!3 = metadata !{metadata !4}
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!4 = metadata !{i32 786478, metadata !1, metadata !5, metadata !"foo", metadata !"foo", metadata !"", i32 1, metadata !6, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 false, i32 (i32)* @foo, null, null, metadata !2, i32 1} ; [ DW_TAG_subprogram ] [line 1] [def] [foo]
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!5 = metadata !{i32 786473, metadata !1} ; [ DW_TAG_file_type ] [discriminator.c]
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!6 = metadata !{i32 786453, i32 0, null, metadata !"", i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !2, i32 0, null, null, null} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
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!7 = metadata !{i32 2, metadata !"Dwarf Version", i32 4}
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!8 = metadata !{i32 1, metadata !"Debug Info Version", i32 1}
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!9 = metadata !{metadata !"clang version 3.5 "}
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!10 = metadata !{i32 2, i32 0, metadata !4, null}
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!11 = metadata !{i32 3, i32 0, metadata !4, null}
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!12 = metadata !{i32 3, i32 0, metadata !13, null}
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!13 = metadata !{i32 786443, metadata !1, metadata !4, i32 3, i32 0, i32 1, i32 2} ; [ DW_TAG_lexical_block ] [discriminator.c]
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!14 = metadata !{i32 4, i32 0, metadata !15, null}
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!15 = metadata !{i32 786443, metadata !1, metadata !16, i32 4, i32 0, i32 0, i32 1} ; [ DW_TAG_lexical_block ] [discriminator.c]
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!16 = metadata !{i32 786443, metadata !1, metadata !4, i32 3, i32 0, i32 0, i32 0} ; [ DW_TAG_lexical_block ] [discriminator.c]
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!17 = metadata !{i32 4, i32 0, metadata !18, null}
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!18 = metadata !{i32 786443, metadata !1, metadata !15, i32 4, i32 0, i32 1, i32 3} ; [ DW_TAG_lexical_block ] [discriminator.c]
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!19 = metadata !{i32 5, i32 0, metadata !16, null}
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!20 = metadata !{i32 6, i32 0, metadata !16, null}
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!21 = metadata !{i32 7, i32 0, metadata !4, null}
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