diff --git a/llvm/lib/CodeGen/BranchFolding.cpp b/llvm/lib/CodeGen/BranchFolding.cpp
index f160efd4a0d5..d1dd7430f865 100644
--- a/llvm/lib/CodeGen/BranchFolding.cpp
+++ b/llvm/lib/CodeGen/BranchFolding.cpp
@@ -1356,6 +1356,51 @@ static DebugLoc getBranchDebugLoc(MachineBasicBlock &MBB) {
   return DebugLoc();
 }
 
+static void copyDebugInfoToPredecessor(const TargetInstrInfo *TII,
+                                       MachineBasicBlock &MBB,
+                                       MachineBasicBlock &PredMBB) {
+  auto InsertBefore = PredMBB.getFirstTerminator();
+  for (MachineInstr &MI : MBB.instrs())
+    if (MI.isDebugValue()) {
+      TII->duplicate(PredMBB, InsertBefore, MI);
+      DEBUG(dbgs() << "Copied debug value from empty block to pred: " << MI);
+    }
+}
+
+static void copyDebugInfoToSuccessor(const TargetInstrInfo *TII,
+                                     MachineBasicBlock &MBB,
+                                     MachineBasicBlock &SuccMBB) {
+  auto InsertBefore = SuccMBB.SkipPHIsAndLabels(SuccMBB.begin());
+  for (MachineInstr &MI : MBB.instrs())
+    if (MI.isDebugValue()) {
+      TII->duplicate(SuccMBB, InsertBefore, MI);
+      DEBUG(dbgs() << "Copied debug value from empty block to succ: " << MI);
+    }
+}
+
+// Try to salvage DBG_VALUE instructions from an otherwise empty block. If such
+// a basic block is removed we would lose the debug information unless we have
+// copied the information to a predecessor/successor.
+//
+// TODO: This function only handles some simple cases. An alternative would be
+// to run a heavier analysis, such as the LiveDebugValues pass, before we do
+// branch folding.
+static void salvageDebugInfoFromEmptyBlock(const TargetInstrInfo *TII,
+                                           MachineBasicBlock &MBB) {
+  assert(IsEmptyBlock(&MBB) && "Expected an empty block (except debug info).");
+  // If this MBB is the only predecessor of a successor it is legal to copy
+  // DBG_VALUE instructions to the beginning of the successor.
+  for (MachineBasicBlock *SuccBB : MBB.successors())
+    if (SuccBB->pred_size() == 1)
+      copyDebugInfoToSuccessor(TII, MBB, *SuccBB);
+  // If this MBB is the only successor of a predecessor it is legal to copy the
+  // DBG_VALUE instructions to the end of the predecessor (just before the
+  // terminators, assuming that the terminator isn't affecting the DBG_VALUE).
+  for (MachineBasicBlock *PredBB : MBB.predecessors())
+    if (PredBB->succ_size() == 1)
+      copyDebugInfoToPredecessor(TII, MBB, *PredBB);
+}
+
 bool BranchFolder::OptimizeBlock(MachineBasicBlock *MBB) {
   bool MadeChange = false;
   MachineFunction &MF = *MBB->getParent();
@@ -1380,6 +1425,7 @@ ReoptimizeBlock:
   // optimized away.
   if (IsEmptyBlock(MBB) && !MBB->isEHPad() && !MBB->hasAddressTaken() &&
       SameFunclet) {
+    salvageDebugInfoFromEmptyBlock(TII, *MBB);
     // Dead block?  Leave for cleanup later.
     if (MBB->pred_empty()) return MadeChange;
 
diff --git a/llvm/test/DebugInfo/X86/PR37234.ll b/llvm/test/DebugInfo/X86/PR37234.ll
new file mode 100644
index 000000000000..083fedd001c2
--- /dev/null
+++ b/llvm/test/DebugInfo/X86/PR37234.ll
@@ -0,0 +1,125 @@
+; RUN: llc %s -o - | FileCheck %s
+
+; This test case was generated by running
+;
+;   clang++ -O2 -g PR37234.cpp -S -save-temps
+;   opt -O2 -S PR37234.bc -o PR37234.ll
+;
+; using the following PR37234.cpp program
+;
+;    int main() {
+;            const char* buffer = "aaa";
+;            unsigned aa = 0;
+;            while (char c = *buffer++) {
+;                    if (c == 'a')
+;                            ++aa;  // DexWatch('aa')
+;            }
+;            return aa;
+;    }
+
+
+; CHECK-LABEL: # %bb.{{.*}}:
+; CHECK:        #DEBUG_VALUE: main:aa <- 0
+; CHECK: 	#DEBUG_VALUE: main:aa <- $[[REG:[0-9a-z]+]]
+; CHECK: 	jmp	.LBB0_1
+; CHECK: .LBB0_3:
+; CHECK: 	#DEBUG_VALUE: main:aa <- $[[REG]]
+; CHECK: 	incl	%[[REG]]
+; CHECK: 	#DEBUG_VALUE: main:aa <- $[[REG]]
+; CHECK: .LBB0_1:
+; CHECK: 	#DEBUG_VALUE: main:aa <- $[[REG]]
+; CHECK: 	je	.LBB0_4
+; CHECK: # %bb.{{.*}}:
+; CHECK: 	#DEBUG_VALUE: main:aa <- $[[REG]]
+; CHECK: 	jne	.LBB0_1
+; CHECK: 	jmp	.LBB0_3
+; CHECK: .LBB0_4:
+; CHECK: 	#DEBUG_VALUE: main:aa <- $[[REG]]
+; CHECK: 	retq
+
+source_filename = "PR37234.cpp"
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+@.str = private unnamed_addr constant [4 x i8] c"aaa\00", align 1
+
+; Function Attrs: norecurse nounwind readonly uwtable
+define dso_local i32 @main() local_unnamed_addr #0 !dbg !7 {
+entry:
+  call void @llvm.dbg.value(metadata i32 0, metadata !16, metadata !DIExpression()), !dbg !19
+  br label %while.cond.outer, !dbg !20
+
+while.cond.outer:                                 ; preds = %if.then, %entry
+  %buffer.0.ph = phi i8* [ %incdec.ptr, %if.then ], [ getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i64 0, i64 0), %entry ]
+  %aa.0.ph = phi i32 [ %inc, %if.then ], [ 0, %entry ]
+  br label %while.cond, !dbg !21
+
+while.cond:                                       ; preds = %while.cond.outer, %while.cond
+  %buffer.0 = phi i8* [ %incdec.ptr, %while.cond ], [ %buffer.0.ph, %while.cond.outer ], !dbg !22
+  call void @llvm.dbg.value(metadata i32 %aa.0.ph, metadata !16, metadata !DIExpression()), !dbg !19
+  call void @llvm.dbg.value(metadata i8* %buffer.0, metadata !12, metadata !DIExpression()), !dbg !23
+  %incdec.ptr = getelementptr inbounds i8, i8* %buffer.0, i64 1, !dbg !21
+  call void @llvm.dbg.value(metadata i8* %incdec.ptr, metadata !12, metadata !DIExpression()), !dbg !23
+  %0 = load i8, i8* %buffer.0, align 1, !dbg !24, !tbaa !25
+  call void @llvm.dbg.value(metadata i8 %0, metadata !18, metadata !DIExpression()), !dbg !28
+  switch i8 %0, label %while.cond [
+    i8 0, label %while.end
+    i8 97, label %if.then
+  ], !dbg !20
+
+if.then:                                          ; preds = %while.cond
+  %inc = add i32 %aa.0.ph, 1, !dbg !29
+  call void @llvm.dbg.value(metadata i32 %inc, metadata !16, metadata !DIExpression()), !dbg !19
+  br label %while.cond.outer, !dbg !29
+
+while.end:                                        ; preds = %while.cond
+  call void @llvm.dbg.value(metadata i32 %aa.0.ph, metadata !16, metadata !DIExpression()), !dbg !19
+  call void @llvm.dbg.value(metadata i32 %aa.0.ph, metadata !16, metadata !DIExpression()), !dbg !19
+  call void @llvm.dbg.value(metadata i32 %aa.0.ph, metadata !16, metadata !DIExpression()), !dbg !19
+  call void @llvm.dbg.value(metadata i32 %aa.0.ph, metadata !16, metadata !DIExpression()), !dbg !19
+  ret i32 %aa.0.ph, !dbg !32
+}
+
+; Function Attrs: nounwind readnone speculatable
+declare void @llvm.dbg.value(metadata, metadata, metadata) #1
+
+attributes #0 = { norecurse nounwind readonly uwtable }
+attributes #1 = { nounwind readnone speculatable }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5}
+!llvm.ident = !{!6}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 7.0.0 (trunk 330946) (llvm/trunk 330952)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
+!1 = !DIFile(filename: "PR37234.cpp", directory: "")
+!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 7.0.0 (trunk 330946) (llvm/trunk 330952)"}
+!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, variables: !11)
+!8 = !DISubroutineType(types: !9)
+!9 = !{!10}
+!10 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!11 = !{!12, !16, !18}
+!12 = !DILocalVariable(name: "buffer", scope: !7, file: !1, line: 2, type: !13)
+!13 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !14, size: 64)
+!14 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !15)
+!15 = !DIBasicType(name: "char", size: 8, encoding: DW_ATE_signed_char)
+!16 = !DILocalVariable(name: "aa", scope: !7, file: !1, line: 3, type: !17)
+!17 = !DIBasicType(name: "unsigned int", size: 32, encoding: DW_ATE_unsigned)
+!18 = !DILocalVariable(name: "c", scope: !7, file: !1, line: 4, type: !15)
+!19 = !DILocation(line: 3, column: 18, scope: !7)
+!20 = !DILocation(line: 4, column: 9, scope: !7)
+!21 = !DILocation(line: 4, column: 32, scope: !7)
+!22 = !DILocation(line: 0, scope: !7)
+!23 = !DILocation(line: 2, column: 21, scope: !7)
+!24 = !DILocation(line: 4, column: 25, scope: !7)
+!25 = !{!26, !26, i64 0}
+!26 = !{!"omnipotent char", !27, i64 0}
+!27 = !{!"Simple C++ TBAA"}
+!28 = !DILocation(line: 4, column: 21, scope: !7)
+!29 = !DILocation(line: 6, column: 25, scope: !30)
+!30 = distinct !DILexicalBlock(scope: !31, file: !1, line: 5, column: 21)
+!31 = distinct !DILexicalBlock(scope: !7, file: !1, line: 4, column: 36)
+!32 = !DILocation(line: 9, column: 1, scope: !7)