51d4c7ceea
hasOnlyColdCalls skipped over calls to intrinsics, but it did so after checking the linkage of the called function. This meant that the presence of a call to a debug intrinsic could affect the outcome of the optimization. In my original reproducer (for an out of tree target) it was particularly interesting, because the actual IR after GlobalOpt was not different with debug instrinsics present, so -print-after-all printouts didn't show anything there. However, without debuginfo, GlobalOpt went further and ran BlockFrequencyAnalysis and (more importanly) LoopAnalysis, and later on in the pipeline, instcombine behaved in different ways when LoopInfo was present. So a call to a dbg.declare prevented running LoopAnalysis in GlobalOpt, which later prevented InstCombine from doing an optimization. The dbg-intrinsic-loopanalysis.ll testcase tries to expose this. Then I also noted that adding a dbg.declare actually made the existing testcase colccc_coldsites.ll generate different code, so I modified that to now test it behaves the same way with and without the dbg.declare. Reviewed By: nikic, fhahn Differential Revision: https://reviews.llvm.org/D133193
47 lines
2.1 KiB
LLVM
47 lines
2.1 KiB
LLVM
; RUN: opt -passes="globalopt" < %s -o /dev/null -debug-pass-manager 2>&1 | FileCheck %s
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; RUN: opt -strip-debug -S < %s | opt -passes="globalopt" -o /dev/null -debug-pass-manager 2>&1 | FileCheck %s
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; Make sure that the call to dbg.declare does not prevent running BlockFrequency
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; and (especially) Loop Analysis.
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; Later passes (e.g. instcombine) may behave in different ways depending on if
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; LoopInfo is available or not. Therefore, letting GlobalOpt run or not run
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; LoopAnalysis depending on the presence of a dbg.declare may make the compiler
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; generate different code with and without debug info.
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; CHECK: Running pass: GlobalOptPass on [module]
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; CHECK: Running analysis: BlockFrequencyAnalysis on h
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; CHECK: Running analysis: LoopAnalysis on h
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define i16 @h(ptr %k) {
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entry:
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call void @llvm.dbg.declare(metadata ptr %k, metadata !1, metadata !DIExpression()), !dbg !22
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%call = call i16 @gaz()
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ret i16 %call
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}
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; Function Attrs: nocallback nofree nosync nounwind readnone speculatable willreturn
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declare void @llvm.dbg.declare(metadata, metadata, metadata) #0
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define internal i16 @gaz() {
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entry:
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ret i16 0
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}
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attributes #0 = { nocallback nofree nosync nounwind readnone speculatable willreturn }
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!llvm.dbg.cu = !{!17}
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!llvm.module.flags = !{!0}
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!0 = !{i32 2, !"Debug Info Version", i32 3}
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!1 = !DILocalVariable(name: "k", arg: 1, scope: !2, file: !3, line: 13, type: !19)
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!2 = distinct !DISubprogram(name: "h", scope: !3, file: !3, line: 13, type: !4, scopeLine: 13, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagLocalToUnit | DISPFlagDefinition | DISPFlagOptimized, unit: !17, retainedNodes: !21)
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!3 = !DIFile(filename: "foo2.c", directory: "/bar")
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!4 = !DISubroutineType(types: !5)
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!5 = !{!19}
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!17 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "clang version 16", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, retainedTypes: !18, globals: !20, splitDebugInlining: false, nameTableKind: None)
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!18 = !{!19}
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!19 = !DIBasicType(name: "int", size: 16, encoding: DW_ATE_signed)
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!20 = !{}
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!21 = !{!1}
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!22 = !DILocation(line: 13, column: 27, scope: !2)
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