mirror of
https://github.com/c64scene-ar/llvm-6502.git
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26e46f2283
Summary: When computing branch weights in BPI, we used to disallow branches with weight 0. This is a minor nuisance, because a branch with weight 0 is different to "don't have information". In the context of instrumentation, it may mean "never executed", in the context of sampling, it means "never or seldom executed". In allowing 0 weight branches, I ran into issues with the switch expansion code in selection DAG. It is currently hardwired to not handle branches with weight 0. To maintain the current behaviour, I changed it to use 1 when it finds 0, but perhaps the algorithm needs changes to tolerate branches with weight zero. Reviewers: hansw Subscribers: llvm-commits Differential Revision: http://reviews.llvm.org/D9533 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@236617 91177308-0d34-0410-b5e6-96231b3b80d8
144 lines
7.5 KiB
LLVM
144 lines
7.5 KiB
LLVM
; RUN: opt < %s -sample-profile -sample-profile-file=%S/Inputs/branch.prof | opt -analyze -branch-prob | FileCheck %s
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; Original C++ code for this test case:
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;
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; #include <stdio.h>
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; #include <stdlib.h>
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;
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; int main(int argc, char *argv[]) {
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; if (argc < 2)
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; return 1;
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; double result;
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; int limit = atoi(argv[1]);
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; if (limit > 100) {
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; double s = 23.041968;
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; for (int u = 0; u < limit; u++) {
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; double x = s;
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; s = x + 3.049 + (double)u;
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; s -= s + 3.94 / x * 0.32;
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; }
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; result = s;
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; } else {
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; result = 0;
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; }
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; printf("result is %lf\n", result);
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; return 0;
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; }
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@.str = private unnamed_addr constant [15 x i8] c"result is %lf\0A\00", align 1
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; Function Attrs: nounwind uwtable
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define i32 @main(i32 %argc, i8** nocapture readonly %argv) #0 {
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; CHECK: Printing analysis 'Branch Probability Analysis' for function 'main':
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entry:
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tail call void @llvm.dbg.value(metadata i32 %argc, i64 0, metadata !13, metadata !DIExpression()), !dbg !27
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tail call void @llvm.dbg.value(metadata i8** %argv, i64 0, metadata !14, metadata !DIExpression()), !dbg !27
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%cmp = icmp slt i32 %argc, 2, !dbg !28
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br i1 %cmp, label %return, label %if.end, !dbg !28
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; CHECK: edge entry -> return probability is 0 / 1 = 0%
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; CHECK: edge entry -> if.end probability is 1 / 1 = 100%
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if.end: ; preds = %entry
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%arrayidx = getelementptr inbounds i8*, i8** %argv, i64 1, !dbg !30
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%0 = load i8*, i8** %arrayidx, align 8, !dbg !30, !tbaa !31
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%call = tail call i32 @atoi(i8* %0) #4, !dbg !30
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tail call void @llvm.dbg.value(metadata i32 %call, i64 0, metadata !17, metadata !DIExpression()), !dbg !30
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%cmp1 = icmp sgt i32 %call, 100, !dbg !35
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br i1 %cmp1, label %for.body, label %if.end6, !dbg !35
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; CHECK: edge if.end -> for.body probability is 0 / 1 = 0%
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; CHECK: edge if.end -> if.end6 probability is 1 / 1 = 100%
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for.body: ; preds = %if.end, %for.body
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%u.016 = phi i32 [ %inc, %for.body ], [ 0, %if.end ]
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%s.015 = phi double [ %sub, %for.body ], [ 0x40370ABE6A337A81, %if.end ]
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%add = fadd double %s.015, 3.049000e+00, !dbg !36
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%conv = sitofp i32 %u.016 to double, !dbg !36
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%add4 = fadd double %add, %conv, !dbg !36
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tail call void @llvm.dbg.value(metadata double %add4, i64 0, metadata !18, metadata !DIExpression()), !dbg !36
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%div = fdiv double 3.940000e+00, %s.015, !dbg !37
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%mul = fmul double %div, 3.200000e-01, !dbg !37
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%add5 = fadd double %add4, %mul, !dbg !37
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%sub = fsub double %add4, %add5, !dbg !37
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tail call void @llvm.dbg.value(metadata double %sub, i64 0, metadata !18, metadata !DIExpression()), !dbg !37
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%inc = add nsw i32 %u.016, 1, !dbg !38
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tail call void @llvm.dbg.value(metadata i32 %inc, i64 0, metadata !21, metadata !DIExpression()), !dbg !38
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%exitcond = icmp eq i32 %inc, %call, !dbg !38
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br i1 %exitcond, label %if.end6, label %for.body, !dbg !38
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; CHECK: edge for.body -> if.end6 probability is 0 / 10226 = 0%
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; CHECK: edge for.body -> for.body probability is 10226 / 10226 = 100% [HOT edge]
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if.end6: ; preds = %for.body, %if.end
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%result.0 = phi double [ 0.000000e+00, %if.end ], [ %sub, %for.body ]
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%call7 = tail call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([15 x i8], [15 x i8]* @.str, i64 0, i64 0), double %result.0), !dbg !39
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br label %return, !dbg !40
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; CHECK: edge if.end6 -> return probability is 16 / 16 = 100% [HOT edge]
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return: ; preds = %entry, %if.end6
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%retval.0 = phi i32 [ 0, %if.end6 ], [ 1, %entry ]
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ret i32 %retval.0, !dbg !41
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}
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; Function Attrs: nounwind readonly
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declare i32 @atoi(i8* nocapture) #1
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; Function Attrs: nounwind
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declare i32 @printf(i8* nocapture readonly, ...) #2
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; Function Attrs: nounwind readnone
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declare void @llvm.dbg.value(metadata, i64, metadata, metadata) #3
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attributes #0 = { nounwind uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
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attributes #1 = { nounwind readonly "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
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attributes #2 = { nounwind "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
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attributes #3 = { nounwind readnone }
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attributes #4 = { nounwind readonly }
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!llvm.dbg.cu = !{!0}
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!llvm.module.flags = !{!25, !42}
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!llvm.ident = !{!26}
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!0 = !DICompileUnit(language: DW_LANG_C_plus_plus, producer: "clang version 3.4 (trunk 192896) (llvm/trunk 192895)", isOptimized: true, emissionKind: 0, file: !1, enums: !2, retainedTypes: !2, subprograms: !3, globals: !2, imports: !2)
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!1 = !DIFile(filename: "branch.cc", directory: ".")
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!2 = !{}
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!3 = !{!4}
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!4 = !DISubprogram(name: "main", line: 4, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: true, scopeLine: 4, file: !1, scope: !5, type: !6, function: i32 (i32, i8**)* @main, variables: !12)
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!5 = !DIFile(filename: "branch.cc", directory: ".")
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!6 = !DISubroutineType(types: !7)
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!7 = !{!8, !8, !9}
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!8 = !DIBasicType(tag: DW_TAG_base_type, name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
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!9 = !DIDerivedType(tag: DW_TAG_pointer_type, size: 64, align: 64, baseType: !10)
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!10 = !DIDerivedType(tag: DW_TAG_pointer_type, size: 64, align: 64, baseType: !11)
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!11 = !DIBasicType(tag: DW_TAG_base_type, name: "char", size: 8, align: 8, encoding: DW_ATE_signed_char)
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!12 = !{!13, !14, !15, !17, !18, !21, !23}
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!13 = !DILocalVariable(tag: DW_TAG_arg_variable, name: "argc", line: 4, arg: 1, scope: !4, file: !5, type: !8)
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!14 = !DILocalVariable(tag: DW_TAG_arg_variable, name: "argv", line: 4, arg: 2, scope: !4, file: !5, type: !9)
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!15 = !DILocalVariable(tag: DW_TAG_auto_variable, name: "result", line: 7, scope: !4, file: !5, type: !16)
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!16 = !DIBasicType(tag: DW_TAG_base_type, name: "double", size: 64, align: 64, encoding: DW_ATE_float)
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!17 = !DILocalVariable(tag: DW_TAG_auto_variable, name: "limit", line: 8, scope: !4, file: !5, type: !8)
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!18 = !DILocalVariable(tag: DW_TAG_auto_variable, name: "s", line: 10, scope: !19, file: !5, type: !16)
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!19 = distinct !DILexicalBlock(line: 9, column: 0, file: !1, scope: !20)
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!20 = distinct !DILexicalBlock(line: 9, column: 0, file: !1, scope: !4)
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!21 = !DILocalVariable(tag: DW_TAG_auto_variable, name: "u", line: 11, scope: !22, file: !5, type: !8)
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!22 = distinct !DILexicalBlock(line: 11, column: 0, file: !1, scope: !19)
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!23 = !DILocalVariable(tag: DW_TAG_auto_variable, name: "x", line: 12, scope: !24, file: !5, type: !16)
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!24 = distinct !DILexicalBlock(line: 11, column: 0, file: !1, scope: !22)
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!25 = !{i32 2, !"Dwarf Version", i32 4}
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!26 = !{!"clang version 3.4 (trunk 192896) (llvm/trunk 192895)"}
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!27 = !DILocation(line: 4, scope: !4)
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!28 = !DILocation(line: 5, scope: !29)
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!29 = distinct !DILexicalBlock(line: 5, column: 0, file: !1, scope: !4)
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!30 = !DILocation(line: 8, scope: !4)
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!31 = !{!32, !32, i64 0}
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!32 = !{!"any pointer", !33, i64 0}
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!33 = !{!"omnipotent char", !34, i64 0}
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!34 = !{!"Simple C/C++ TBAA"}
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!35 = !DILocation(line: 9, scope: !20)
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!36 = !DILocation(line: 13, scope: !24)
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!37 = !DILocation(line: 14, scope: !24)
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!38 = !DILocation(line: 11, scope: !22)
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!39 = !DILocation(line: 20, scope: !4)
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!40 = !DILocation(line: 21, scope: !4)
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!41 = !DILocation(line: 22, scope: !4)
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!42 = !{i32 1, !"Debug Info Version", i32 3}
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