diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp --- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp @@ -5553,8 +5553,14 @@ for (auto RegAndSize : SplitRegs) { auto FragmentExpr = DIExpression::createFragmentExpression( Expr, Offset, RegAndSize.second); - if (!FragmentExpr) + // If a valid fragment expression cannot be created, the variable's + // correct value cannot be determined and so it is set as Undef. + if (!FragmentExpr) { + SDDbgValue *SDV = DAG.getConstantDbgValue( + Variable, Expr, UndefValue::get(V->getType()), DL, SDNodeOrder); + DAG.AddDbgValue(SDV, nullptr, false); continue; + } assert(!IsDbgDeclare && "DbgDeclare operand is not in memory?"); FuncInfo.ArgDbgValues.push_back( BuildMI(MF, DL, TII->get(TargetOpcode::DBG_VALUE), false, diff --git a/llvm/test/CodeGen/ARM/debuginfo-split-carryexpr.ll b/llvm/test/CodeGen/ARM/debuginfo-split-carryexpr.ll new file mode 100644 --- /dev/null +++ b/llvm/test/CodeGen/ARM/debuginfo-split-carryexpr.ll @@ -0,0 +1,51 @@ +; RUN: llc < %s -mtriple=armv7-linux-gnueabihf -stop-before=finalize-isel | FileCheck %s + +; When splitting-up integers during CodeGen, if the debug info contains +; an expression with carry operators (i.e. arithmetic and shift ops), the +; debug information will be dropped as these operators cannot be correctly +; expressed across different registers. + +; CHECK: [[HIGH:![0-9]+]] = !DILocalVariable(name: "high" +; CHECK: [[LOW:![0-9]+]] = !DILocalVariable(name: "low" +; +; As the debug information for "high" contains an arithmetic shift, while for +; "low" it does not, only the former should be undefined. +; CHECK-LABEL: body: +; CHECK: [[LOWR:%[0-9]+]]:gpr = COPY $r0 +; CHECK: DBG_VALUE [[LOWR]], $noreg, [[LOW]] +; CHECK: DBG_VALUE $noreg, $noreg, [[HIGH]] +; CHECK: DBG_VALUE $noreg, $noreg, [[HIGH]] + +define dso_local i64 @_Z2fnx(i64 returned %value) local_unnamed_addr !dbg !7 { +entry: + call void @llvm.dbg.value(metadata i64 %value, metadata !13, metadata !DIExpression()), !dbg !17 + call void @llvm.dbg.value(metadata i64 %value, metadata !14, metadata !DIExpression(DW_OP_constu, 32, DW_OP_shra, DW_OP_LLVM_convert, 64, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_stack_value)), !dbg !17 + call void @llvm.dbg.value(metadata i64 %value, metadata !16, metadata !DIExpression(DW_OP_LLVM_convert, 64, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_stack_value)), !dbg !17 + ret i64 %value, !dbg !18 +} + +declare void @llvm.dbg.value(metadata, metadata, metadata) + +!llvm.dbg.cu = !{!0} +!llvm.module.flags = !{!3, !4, !5} +!llvm.ident = !{!6} + +!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, producer: "clang version 10.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, nameTableKind: None) +!1 = !DIFile(filename: "test.cpp", directory: "/tmp") +!2 = !{} +!3 = !{i32 2, !"Dwarf Version", i32 4} +!4 = !{i32 2, !"Debug Info Version", i32 3} +!5 = !{i32 1, !"wchar_size", i32 4} +!6 = !{!"clang version 10.0.0"} +!7 = distinct !DISubprogram(name: "fn", linkageName: "_Z2fnx", scope: !8, file: !8, line: 2, type: !9, scopeLine: 2, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !12) +!8 = !DIFile(filename: "test.cpp", directory: "/tmp") +!9 = !DISubroutineType(types: !10) +!10 = !{!11, !11} +!11 = !DIBasicType(name: "long long int", size: 64, encoding: DW_ATE_signed) +!12 = !{!13, !14, !16} +!13 = !DILocalVariable(name: "value", arg: 1, scope: !7, file: !8, line: 2, type: !11) +!14 = !DILocalVariable(name: "high", scope: !7, file: !8, line: 3, type: !15) +!15 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) +!16 = !DILocalVariable(name: "low", scope: !7, file: !8, line: 4, type: !15) +!17 = !DILocation(line: 0, scope: !7) +!18 = !DILocation(line: 5, column: 3, scope: !7)