1251cac62a
Summary: Bug: https://bugs.llvm.org/show_bug.cgi?id=39024 The bug reports that a vectorized loop is stepped through 4 times and each step through the loop seemed to show a different path. I found two problems here: A) An incorrect line number on a preheader block (for.body.preheader) instruction causes a step into the loop before it begins. B) Instructions in the middle block have different line numbers which give the impression of another iteration. In this patch I give all of the middle block instructions the line number of the scalar loop latch terminator branch. This seems to provide the smoothest debugging experience because the vectorized loops will always end on this line before dropping into the scalar loop. To solve problem A I have altered llvm::SplitBlockPredecessors to accommodate loop header blocks. I have set up a separate review D61933 for a fix which is required for this patch. Reviewers: samsonov, vsk, aprantl, probinson, anemet, hfinkel, jmorse Reviewed By: hfinkel, jmorse Subscribers: jmorse, javed.absar, eraman, kcc, bjope, jmellorcrummey, hfinkel, gbedwell, hiraditya, zzheng, llvm-commits Tags: #llvm, #debug-info Differential Revision: https://reviews.llvm.org/D60831 > llvm-svn: 363046 llvm-svn: 363786
113 lines
5.8 KiB
LLVM
113 lines
5.8 KiB
LLVM
; RUN: opt < %s -loop-vectorize -pass-remarks-missed='loop-vectorize' -mtriple=x86_64-unknown-linux -S 2>&1 | FileCheck %s
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; Verify analysis remarks are generated when interleaving is not beneficial.
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; CHECK: remark: vectorization-remarks-profitable.c:5:17: the cost-model indicates that vectorization is not beneficial
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; CHECK: remark: vectorization-remarks-profitable.c:5:17: the cost-model indicates that interleaving is not beneficial and is explicitly disabled or interleave count is set to 1
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; CHECK: remark: vectorization-remarks-profitable.c:11:3: the cost-model indicates that vectorization is not beneficial
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; CHECK: remark: vectorization-remarks-profitable.c:11:3: the cost-model indicates that interleaving is not beneficial
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; First loop.
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; #pragma clang loop interleave(disable) unroll(disable)
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; for(int i = 0; i < n; i++) {
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; out[i] = *in[i];
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; }
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; Second loop.
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; #pragma clang loop unroll(disable)
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; for(int i = 0; i < n; i++) {
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; out[i] = *in[i];
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; }
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; ModuleID = 'vectorization-remarks-profitable.ll'
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target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
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target triple = "x86_64-apple-macosx10.10.0"
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; Function Attrs: nounwind uwtable
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define void @do_not_interleave(float** noalias nocapture readonly %in, float* noalias nocapture %out, i32 %size) #0 !dbg !4 {
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entry:
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%cmp.4 = icmp eq i32 %size, 0, !dbg !10
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br i1 %cmp.4, label %for.end, label %for.body.preheader, !dbg !11
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for.body.preheader: ; preds = %entry
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br label %for.body, !dbg !12
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for.body: ; preds = %for.body.preheader, %for.body
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%indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ 0, %for.body.preheader ]
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%arrayidx = getelementptr inbounds float*, float** %in, i64 %indvars.iv, !dbg !12
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%0 = bitcast float** %arrayidx to i32**, !dbg !12
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%1 = load i32*, i32** %0, align 8, !dbg !12
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%2 = load i32, i32* %1, align 4, !dbg !13
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%arrayidx2 = getelementptr inbounds float, float* %out, i64 %indvars.iv, !dbg !14
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%3 = bitcast float* %arrayidx2 to i32*, !dbg !15
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store i32 %2, i32* %3, align 4, !dbg !15
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%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1, !dbg !11
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%lftr.wideiv = trunc i64 %indvars.iv.next to i32, !dbg !11
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%exitcond = icmp eq i32 %lftr.wideiv, %size, !dbg !11
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br i1 %exitcond, label %for.end.loopexit, label %for.body, !dbg !11, !llvm.loop !16
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for.end.loopexit: ; preds = %for.body
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br label %for.end, !dbg !19
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for.end: ; preds = %for.end.loopexit, %entry
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ret void, !dbg !19
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}
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; Function Attrs: nounwind uwtable
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define void @interleave_not_profitable(float** noalias nocapture readonly %in, float* noalias nocapture %out, i32 %size) #0 !dbg !6 {
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entry:
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%cmp.4 = icmp eq i32 %size, 0, !dbg !20
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br i1 %cmp.4, label %for.end, label %for.body, !dbg !21
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for.body: ; preds = %entry, %for.body
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%indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ 0, %entry ]
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%arrayidx = getelementptr inbounds float*, float** %in, i64 %indvars.iv, !dbg !22
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%0 = bitcast float** %arrayidx to i32**, !dbg !22
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%1 = load i32*, i32** %0, align 8, !dbg !22
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%2 = load i32, i32* %1, align 4, !dbg !23
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%arrayidx2 = getelementptr inbounds float, float* %out, i64 %indvars.iv, !dbg !24
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%3 = bitcast float* %arrayidx2 to i32*, !dbg !25
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store i32 %2, i32* %3, align 4, !dbg !25
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%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1, !dbg !21
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%lftr.wideiv = trunc i64 %indvars.iv.next to i32, !dbg !21
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%exitcond = icmp eq i32 %lftr.wideiv, %size, !dbg !21
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br i1 %exitcond, label %for.end, label %for.body, !dbg !21, !llvm.loop !26
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for.end: ; preds = %for.body, %entry
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ret void, !dbg !27
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}
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attributes #0 = { nounwind 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"="+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 = !{!7, !8}
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!llvm.ident = !{!9}
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!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 3.8.0 (trunk 250016)", isOptimized: false, runtimeVersion: 0, emissionKind: LineTablesOnly, enums: !2)
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!1 = !DIFile(filename: "vectorization-remarks-profitable.c", directory: "")
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!2 = !{}
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!4 = distinct !DISubprogram(name: "do_not_interleave", scope: !1, file: !1, line: 1, type: !5, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !2)
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!5 = !DISubroutineType(types: !2)
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!6 = distinct !DISubprogram(name: "interleave_not_profitable", scope: !1, file: !1, line: 8, type: !5, isLocal: false, isDefinition: true, scopeLine: 8, flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !2)
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!7 = !{i32 2, !"Dwarf Version", i32 4}
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!8 = !{i32 2, !"Debug Info Version", i32 3}
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!9 = !{!"clang version 3.8.0 (trunk 250016)"}
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!10 = !DILocation(line: 4, column: 23, scope: !4)
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!11 = !DILocation(line: 4, column: 3, scope: !4)
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!12 = !DILocation(line: 5, column: 17, scope: !4)
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!13 = !DILocation(line: 5, column: 16, scope: !4)
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!14 = !DILocation(line: 5, column: 7, scope: !4)
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!15 = !DILocation(line: 5, column: 14, scope: !4)
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!16 = distinct !{!16, !17, !18}
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!17 = !{!"llvm.loop.interleave.count", i32 1}
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!18 = !{!"llvm.loop.unroll.disable"}
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!19 = !DILocation(line: 6, column: 1, scope: !4)
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!20 = !DILocation(line: 11, column: 23, scope: !6)
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!21 = !DILocation(line: 11, column: 3, scope: !6)
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!22 = !DILocation(line: 12, column: 17, scope: !6)
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!23 = !DILocation(line: 12, column: 16, scope: !6)
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!24 = !DILocation(line: 12, column: 7, scope: !6)
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!25 = !DILocation(line: 12, column: 14, scope: !6)
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!26 = distinct !{!26, !18}
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!27 = !DILocation(line: 13, column: 1, scope: !6)
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