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113 lines
4.1 KiB
113 lines
4.1 KiB
# RUN: llc -o - %s -mtriple=x86_64-- -run-pass=machine-cp | FileCheck %s
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# When MachineCopyPropagation eliminates a dead 'copy', its associated debug
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# information becomes invalid. as the recorded register has been removed.
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# It causes the debugger to display wrong variable value.
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#
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# When in the debugger, on the line "return read1;", the value of "read1"
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# is reported as '4', where it should be '1'.
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#
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# MIR generated with:
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# clang -S -g -O2 -emit-llvm pr38773.cpp -o pr38773.ll -mllvm
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# llc pr38773.ll -stop-after=tailduplication -simplify-mir
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#
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# // pr38773.cpp
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# int main() {
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# volatile int foo = 4;
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# int read1 = foo;
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# int read2 = foo;
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#
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# switch ((read1 == 4) ? 3 : 1) {
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# case 1:
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# read1 *= read2;
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# break;
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# case 3:
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# read1 /= read2;
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# break;
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# }
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#
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# return read1;
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# }
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#
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# Update the register for the '@llvm.dbg.value' associated with 'read1', when
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# the 'copy' is removed, to be the 'source' register.
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--- |
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; ModuleID = 'pr38773.ll'
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source_filename = "pr38773.cpp"
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target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
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target triple = "x86_64-pc-linux-gnu"
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define dso_local i32 @main() local_unnamed_addr !dbg !7 {
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entry:
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%foo = alloca i32, align 4
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store volatile i32 4, i32* %foo, align 4
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%foo.0.foo.0. = load volatile i32, i32* %foo, align 4
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%foo.0.foo.0.6 = load volatile i32, i32* %foo, align 4
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%cmp = icmp eq i32 %foo.0.foo.0., 4
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br i1 %cmp, label %sw.bb1, label %sw.bb
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sw.bb: ; preds = %entry
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%mul = mul nsw i32 %foo.0.foo.0.6, %foo.0.foo.0.
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br label %sw.epilog
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sw.bb1: ; preds = %entry
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%div = sdiv i32 4, %foo.0.foo.0.6
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call void @llvm.dbg.value(metadata i32 %div, metadata !12, metadata !DIExpression()), !dbg !13
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br label %sw.epilog
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sw.epilog: ; preds = %sw.bb1, %sw.bb
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%read1.0 = phi i32 [ %div, %sw.bb1 ], [ %mul, %sw.bb ]
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call void @llvm.dbg.value(metadata i32 %read1.0, metadata !12, metadata !DIExpression()), !dbg !13
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ret i32 %read1.0
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}
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declare void @llvm.dbg.value(metadata, metadata, metadata) #0
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!llvm.dbg.cu = !{!0}
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!llvm.module.flags = !{!3, !4, !5}
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!llvm.ident = !{!6}
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!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 8.0.0 (trunk 343183)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, nameTableKind: None)
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!1 = !DIFile(filename: "pr38773.cpp", directory: ".")
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!2 = !{}
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!3 = !{i32 2, !"Dwarf Version", i32 4}
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!4 = !{i32 2, !"Debug Info Version", i32 3}
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!5 = !{i32 1, !"wchar_size", i32 4}
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!6 = !{!"clang version 8.0.0 (trunk 343183)"}
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!7 = distinct !DISubprogram(name: "main", scope: !1, file: !1, line: 1, type: !8, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: true, unit: !0, retainedNodes: !11)
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!8 = !DISubroutineType(types: !9)
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!9 = !{!10}
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!10 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
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!11 = !{!12}
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!12 = !DILocalVariable(name: "read1", scope: !7, file: !1, line: 3, type: !10)
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!13 = !DILocation(line: 3, column: 7, scope: !7)
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...
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---
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name: main
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body: |
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bb.2.sw.bb1:
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liveins: $ecx
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$eax = MOV32ri 4
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$edx = MOV32r0 implicit-def dead $eflags
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IDIV32r killed renamable $ecx, implicit-def $eax, implicit-def dead $edx, implicit-def dead $eflags, implicit $eax, implicit killed $edx
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renamable $ecx = COPY $eax
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; CHECK: IDIV32r killed renamable $ecx
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; CHECK-NEXT: DBG_VALUE $eax, $noreg, !12, !DIExpression(), debug-location !13
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DBG_VALUE $ecx, $noreg, !12, !DIExpression(), debug-location !13
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; The following mov and DBG_VALUE have been inserted after the PR was
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; resolved to check that MCP will update debug users that are not
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; immediately after the dead copy.
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; CHECK-NEXT: $edx = MOV32r0
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$edx = MOV32r0 implicit-def dead $eflags
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; CHECK-NEXT: DBG_VALUE $eax, $noreg, !12, !DIExpression(), debug-location !13
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DBG_VALUE $ecx, $noreg, !12, !DIExpression(), debug-location !13
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$eax = COPY killed renamable $ecx
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RET 0, $eax
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...
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