diff --git a/llvm/lib/CodeGen/TailDuplicator.cpp b/llvm/lib/CodeGen/TailDuplicator.cpp --- a/llvm/lib/CodeGen/TailDuplicator.cpp +++ b/llvm/lib/CodeGen/TailDuplicator.cpp @@ -216,6 +216,9 @@ // Rewrite uses that are outside of the original def's block. MachineRegisterInfo::use_iterator UI = MRI->use_begin(VReg); + // Only remove instructions after loop, as DBG_VALUE_LISTs with multiple + // uses of VReg may invalidate the use iterator when erased. + SmallPtrSet InstrsToRemove; while (UI != MRI->use_end()) { MachineOperand &UseMO = *UI; MachineInstr *UseMI = UseMO.getParent(); @@ -225,13 +228,15 @@ // a debug instruction that is a kill. // FIXME: Should it SSAUpdate job to delete debug instructions // instead of replacing the use with undef? - UseMI->eraseFromParent(); + InstrsToRemove.insert(UseMI); continue; } if (UseMI->getParent() == DefBB && !UseMI->isPHI()) continue; SSAUpdate.RewriteUse(UseMO); } + for (auto *MI : InstrsToRemove) + MI->eraseFromParent(); } SSAUpdateVRs.clear(); diff --git a/llvm/test/CodeGen/X86/tail-dup-debugvalue.mir b/llvm/test/CodeGen/X86/tail-dup-debugvalue.mir new file mode 100644 --- /dev/null +++ b/llvm/test/CodeGen/X86/tail-dup-debugvalue.mir @@ -0,0 +1,127 @@ +# RUN: llc -run-pass=early-tailduplication -mtriple=x86_64-unknown-linux-gnu %s -o - | FileCheck %s + +# Tail Duplication may update SSA values and invalidate any DBG_VALUEs that +# use those values; those DBG_VALUEs should be deleted. This behaviour is tested +# for DBG_VALUE users, and DBG_VALUE_LISTs that use the value multiple times. + +# CHECK-NOT: DBG_VALUE +--- | + target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128" + target triple = "x86_64-unknown-linux-gnu" + + define dso_local void @main() local_unnamed_addr #0 !dbg !15 { + entry: + br label %L.outer + + L: ; preds = %L, %L.outer + %tobool2.not = icmp eq i32 undef, 0 + br i1 %tobool2.not, label %if.end4, label %L + + if.end4: ; preds = %L + call void @llvm.dbg.value(metadata !DIArgList(i32 %f.0.ph, i32 1, i32 %f.0.ph), metadata !19, metadata !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_LLVM_arg, 1, DW_OP_LLVM_arg, 2, DW_OP_and, DW_OP_or, DW_OP_stack_value)), !dbg !21 + %cmp = icmp slt i32 %f.0.ph, undef + br i1 %cmp, label %if.then5, label %if.end6 + + if.then5: ; preds = %if.end4 + call void @h() #2 + br label %L.outer + + L.outer: ; preds = %if.then5, %entry + %f.0.ph = phi i32 [ 0, %if.then5 ], [ 1, %entry ] + br label %L + + if.end6: ; preds = %if.end4 + ret void + } + + declare dso_local void @h() local_unnamed_addr + + declare void @llvm.dbg.value(metadata, metadata, metadata) + + !llvm.dbg.cu = !{!0} + !llvm.module.flags = !{!13, !14} + + !0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 13.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, globals: !3, splitDebugInlining: false, nameTableKind: None) + !1 = !DIFile(filename: "tail-dup-debugvalue.c", directory: "/tmp") + !2 = !{} + !3 = !{!4, !7, !9, !11} + !4 = !DIGlobalVariableExpression(var: !5, expr: !DIExpression()) + !5 = distinct !DIGlobalVariable(name: "a", scope: !0, file: !1, line: 2, type: !6, isLocal: false, isDefinition: true) + !6 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) + !7 = !DIGlobalVariableExpression(var: !8, expr: !DIExpression()) + !8 = distinct !DIGlobalVariable(name: "b", scope: !0, file: !1, line: 2, type: !6, isLocal: false, isDefinition: true) + !9 = !DIGlobalVariableExpression(var: !10, expr: !DIExpression()) + !10 = distinct !DIGlobalVariable(name: "c", scope: !0, file: !1, line: 2, type: !6, isLocal: false, isDefinition: true) + !11 = !DIGlobalVariableExpression(var: !12, expr: !DIExpression()) + !12 = distinct !DIGlobalVariable(name: "d", scope: !0, file: !1, line: 2, type: !6, isLocal: false, isDefinition: true) + !13 = !{i32 2, !"Debug Info Version", i32 3} + !14 = !{i32 7, !"uwtable", i32 1} + !15 = distinct !DISubprogram(name: "main", scope: !1, file: !1, line: 3, type: !16, scopeLine: 3, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !18) + !16 = !DISubroutineType(types: !17) + !17 = !{!6} + !18 = !{!19, !20} + !19 = !DILocalVariable(name: "j", scope: !15, file: !1, line: 14, type: !6) + !20 = !DILocalVariable(name: "k", scope: !15, file: !1, line: 14, type: !6) + !21 = !DILocation(line: 0, scope: !15) + +... +--- +name: main +alignment: 16 +tracksRegLiveness: true +registers: + - { id: 0, class: gr32 } + - { id: 1, class: gr32 } + - { id: 2, class: gr32 } + - { id: 3, class: gr8 } + - { id: 4, class: gr32 } + - { id: 5, class: gr32 } + - { id: 6, class: gr32 } +frameInfo: + maxAlignment: 1 + hasCalls: true +machineFunctionInfo: {} +body: | + bb.0.entry: + successors: %bb.4(0x80000000) + + %1:gr32 = MOV32ri 1 + JMP_1 %bb.4 + + bb.1.L: + successors: %bb.2(0x04000000), %bb.1(0x7c000000) + + %2:gr32 = MOV32r0 implicit-def dead $eflags + %3:gr8 = COPY %2.sub_8bit + TEST8rr %3, %3, implicit-def $eflags + JCC_1 %bb.1, 5, implicit $eflags + JMP_1 %bb.2 + + bb.2.if.end4: + successors: %bb.3(0x783e0f0f), %bb.5(0x07c1f0f1) + + DBG_VALUE_LIST !19, !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_LLVM_arg, 1, DW_OP_LLVM_arg, 2, DW_OP_and, DW_OP_or, DW_OP_stack_value), %0, 1, %0, debug-location !21 + DBG_VALUE %0, $noreg, !20, !DIExpression(), debug-location !21 + %5:gr32 = IMPLICIT_DEF + %4:gr32 = SUB32rr %0, killed %5, implicit-def $eflags + JCC_1 %bb.5, 13, implicit $eflags + JMP_1 %bb.3 + + bb.3.if.then5: + successors: %bb.4(0x80000000) + + ADJCALLSTACKDOWN64 0, 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp + CALL64pcrel32 @h, csr_64, implicit $rsp, implicit $ssp, implicit-def $rsp, implicit-def $ssp + ADJCALLSTACKUP64 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp + %6:gr32 = MOV32r0 implicit-def dead $eflags + + bb.4.L.outer: + successors: %bb.1(0x80000000) + + %0:gr32 = PHI %1, %bb.0, %6, %bb.3 + JMP_1 %bb.1 + + bb.5.if.end6: + RET 0 + +...