[DebugInfo] Fix PR37395.

DbgLabelInst has no address as its operands.

Differential Revision: https://reviews.llvm.org/D46738

Patch by Hsiangkai Wang.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@336176 91177308-0d34-0410-b5e6-96231b3b80d8

lib/IR/IntrinsicInst.cpp

@@ -45,7 +45,10 @@ Value *DbgInfoIntrinsic::getVariableLocation(bool AllowNullOp) const {
     return V->getValue();
 
   // When the value goes to null, it gets replaced by an empty MDNode.
-  assert(!cast<MDNode>(MD)->getNumOperands() && "Expected an empty MDNode");
+  assert((isa<DbgLabelInst>(this)
+          || !cast<MDNode>(MD)->getNumOperands())
+	 && "DbgValueInst Expected an empty MDNode");
+
   return nullptr;
 }
 

test/DebugInfo/Generic/PR37395.ll

@@ -0,0 +1,63 @@
+; RUN: opt -lcssa -S %s | FileCheck %s
+source_filename = "small.c"
+
+@a = common dso_local global i32 0, align 4, !dbg !0
+
+; CHECK-LABEL: @f
+define dso_local void @f() !dbg !10 {
+entry:
+  %0 = load i32, i32* @a, align 4, !dbg !17
+  %tobool1 = icmp eq i32 %0, 0, !dbg !18
+  br i1 %tobool1, label %for.end, label %for.inc.lr.ph, !dbg !18
+
+for.inc.lr.ph:                                    ; preds = %entry
+  br label %for.inc, !dbg !18
+
+for.inc:                                          ; preds = %for.inc, %for.inc.lr.ph
+  %1 = phi i32 [ %0, %for.inc.lr.ph ], [ %inc, %for.inc ]
+  call void @llvm.dbg.label(metadata !14), !dbg !19
+  %inc = add nsw i32 %1, 1, !dbg !20
+  %tobool = icmp eq i32 %inc, 0, !dbg !18
+  br i1 %tobool, label %for.cond.for.end_crit_edge, label %for.inc, !dbg !18, !llvm.loop !21
+
+for.cond.for.end_crit_edge:                       ; preds = %for.inc
+  store i32 %inc, i32* @a, align 4, !dbg !17
+  br label %for.end, !dbg !18
+
+for.end:                                          ; preds = %entry, %for.cond.for.end_crit_edge
+  ret void, !dbg !23
+}
+
+; Function Attrs: nounwind readnone speculatable
+declare void @llvm.dbg.label(metadata) #0
+
+attributes #0 = { nounwind readnone speculatable }
+
+!llvm.dbg.cu = !{!2}
+!llvm.module.flags = !{!7, !8, !9}
+
+!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
+!1 = distinct !DIGlobalVariable(name: "a", scope: !2, file: !3, line: 1, type: !6, isLocal: false, isDefinition: true)
+!2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "clang version 7.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5)
+!3 = !DIFile(filename: "small.c", directory: "./")
+!4 = !{}
+!5 = !{!0}
+!6 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!7 = !{i32 2, !"Dwarf Version", i32 4}
+!8 = !{i32 2, !"Debug Info Version", i32 3}
+!9 = !{i32 1, !"wchar_size", i32 4}
+!10 = distinct !DISubprogram(name: "f", scope: !3, file: !3, line: 3, type: !11, isLocal: false, isDefinition: true, scopeLine: 4, isOptimized: true, unit: !2, retainedNodes: !13)
+!11 = !DISubroutineType(types: !12)
+!12 = !{null}
+!13 = !{!14}
+!14 = !DILabel(scope: !15, name: "L", file: !3, line: 6)
+!15 = distinct !DILexicalBlock(scope: !16, file: !3, line: 5, column: 3)
+!16 = distinct !DILexicalBlock(scope: !10, file: !3, line: 5, column: 3)
+!17 = !DILocation(line: 5, column: 10, scope: !15)
+!18 = !DILocation(line: 5, column: 3, scope: !16)
+!19 = !DILocation(line: 6, column: 3, scope: !15)
+!20 = !DILocation(line: 5, column: 14, scope: !15)
+!21 = distinct !{!21, !18, !22}
+!22 = !DILocation(line: 6, column: 5, scope: !16)
+!23 = !DILocation(line: 7, column: 1, scope: !10)
+