Index: llvm/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp =================================================================== --- llvm/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp +++ llvm/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp @@ -1057,12 +1057,13 @@ "first terminator cannot be a debug value"); for (MachineInstr &MI : make_early_inc_range( make_range(std::next(FirstTerm), InsertBB->end()))) { + // Only scan up to insertion point. + if (&MI == InsertPos) + break; + if (!MI.isDebugValue()) continue; - if (&MI == InsertPos) - InsertPos = std::prev(InsertPos->getIterator()); - // The DBG_VALUE was referencing a value produced by a terminator. By // moving the DBG_VALUE, the referenced value also needs invalidating. MI.getOperand(0).ChangeToRegister(0, false); Index: llvm/test/CodeGen/X86/pr53243-tail-call-fastisel.ll =================================================================== --- /dev/null +++ llvm/test/CodeGen/X86/pr53243-tail-call-fastisel.ll @@ -0,0 +1,50 @@ +; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py +; RUN: llc -O0 -fast-isel -mtriple=x86_64-- < %s | FileCheck %s + +define void @test() { +; CHECK-LABEL: test: +; CHECK: # %bb.0: +; CHECK-NEXT: jmp set_state@PLT # TAILCALL + tail call void @set_state() + call void @llvm.dbg.value(metadata i64 0, metadata !12, metadata !DIExpression()), !dbg !27 + ret void +} + +declare void @set_state() + +; Function Attrs: nofree nosync nounwind readnone speculatable willreturn +declare void @llvm.dbg.value(metadata, metadata, metadata) #0 + +attributes #0 = { nofree nosync nounwind readnone speculatable willreturn } + +!llvm.module.flags = !{!0} +!llvm.dbg.cu = !{!1} + +!0 = !{i32 2, !"Debug Info Version", i32 3} +!1 = distinct !DICompileUnit(language: DW_LANG_Rust, file: !2, producer: "clang LLVM (rustc version 1.60.0-nightly (ec4bcaac4 2022-01-15))", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !3) +!2 = !DIFile(filename: "src/lib.rs/@/bug.63e521cd-cgu.0", directory: "/tmp/rust-bug") +!3 = !{!4} +!4 = !DICompositeType(tag: DW_TAG_enumeration_type, name: "Option", scope: !6, file: !5, baseType: !8, size: 8, align: 8, flags: DIFlagEnumClass, elements: !9) +!5 = !DIFile(filename: "", directory: "") +!6 = !DINamespace(name: "option", scope: !7) +!7 = !DINamespace(name: "core", scope: null) +!8 = !DIBasicType(name: "u8", size: 8, encoding: DW_ATE_unsigned) +!9 = !{!10, !11} +!10 = !DIEnumerator(name: "None", value: 0) +!11 = !DIEnumerator(name: "Some", value: 1) +!12 = !DILocalVariable(name: "msg", arg: 2, scope: !13, file: !14, line: 689, type: !17) +!13 = distinct !DISubprogram(name: "expect<()>", linkageName: "_ZN4core6option15Option$LT$T$GT$6expect17h9a574c18f194c213E", scope: !4, file: !14, line: 689, type: !15, scopeLine: 689, flags: DIFlagPrototyped, spFlags: DISPFlagLocalToUnit | DISPFlagDefinition | DISPFlagOptimized, unit: !1, templateParams: !24, retainedNodes: !23) +!14 = !DIFile(filename: "/rustc/ec4bcaac450279b029f3480b8b8f1b82ab36a5eb/library/core/src/option.rs", directory: "", checksumkind: CSK_MD5, checksum: "4120c8557937a0772190a676ec193800") +!15 = !DISubroutineType(types: !16) +!16 = !{null, !4, !17} +!17 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "&str", file: !5, size: 128, align: 64, elements: !18, templateParams: !23, identifier: "84eec819988617519061e0b609a72fe3") +!18 = !{!19, !21} +!19 = !DIDerivedType(tag: DW_TAG_member, name: "data_ptr", scope: !17, file: !5, baseType: !20, size: 64, align: 64) +!20 = !DIDerivedType(tag: DW_TAG_pointer_type, name: "*const u8", baseType: !8, size: 64, align: 64, dwarfAddressSpace: 0) +!21 = !DIDerivedType(tag: DW_TAG_member, name: "length", scope: !17, file: !5, baseType: !22, size: 64, align: 64, offset: 64) +!22 = !DIBasicType(name: "usize", size: 64, encoding: DW_ATE_unsigned) +!23 = !{} +!24 = !{!25} +!25 = !DITemplateTypeParameter(name: "T", type: !26) +!26 = !DIBasicType(name: "()", encoding: DW_ATE_unsigned) +!27 = !DILocation(line: 0, scope: !13)