Index: lib/Target/X86/X86FrameLowering.cpp
===================================================================
--- lib/Target/X86/X86FrameLowering.cpp
+++ lib/Target/X86/X86FrameLowering.cpp
@@ -371,8 +371,16 @@
     return 0;
 
   MachineBasicBlock::iterator PI = doMergeWithPrevious ? std::prev(MBBI) : MBBI;
+  // Skip debug values.
+  while (PI != MBB.begin() && PI->isDebugValue())
+    --PI;
+
   MachineBasicBlock::iterator NI = doMergeWithPrevious ? nullptr
                                                        : std::next(MBBI);
+  // Skip debug values.
+  while (NI != nullptr && NI != MBB.end() && NI->isDebugValue())
+    ++NI;
+
   unsigned Opc = PI->getOpcode();
   int Offset = 0;
 
@@ -2587,6 +2595,10 @@
   uint64_t InternalAmt = (isDestroy || Amount) ? I->getOperand(1).getImm() : 0;
   I = MBB.erase(I);
 
+  // Skip debug values.
+  while (I != MBB.end() && I->isDebugValue())
+    ++I;
+
   if (!reserveCallFrame) {
     // If the stack pointer can be changed after prologue, turn the
     // adjcallstackup instruction into a 'sub ESP, <amt>' and the
Index: test/CodeGen/X86/frame-lowering-debug-intrinsic-2.ll
===================================================================
--- /dev/null
+++ test/CodeGen/X86/frame-lowering-debug-intrinsic-2.ll
@@ -0,0 +1,72 @@
+; Test ensuring debug intrinsics do not affect generated function prologue.
+;
+; RUN: llc -O1 -mtriple=x86_64-unknown-unknown -o - %s | FileCheck %s
+
+@a = local_unnamed_addr global i64 0, align 8
+
+define void @noDebug() {
+entry:
+  %0 = load i64, i64* @a, align 8
+  %1 = load i64, i64* @a, align 8
+  %2 = load i64, i64* @a, align 8
+  %3 = tail call { i64, i1 } @llvm.uadd.with.overflow.i64(i64 %0, i64 %1)
+  %4 = extractvalue { i64, i1 } %3, 0
+  %5 = tail call i64 @fn1(i64 %4, i64 %2)
+  tail call void (...) @printf()
+  tail call void (...) @printf(i64 1, i64 2, i64 3, i64 4, i32 0, i64 0, i64 %4, i64 %5)
+  ret void
+}
+
+; CHECK-LABEL: noDebug
+; CHECK: addq  $24, %rsp
+; CHECK: popq  %rbx
+; CHECK: popq  %r14
+; CHECK: retq
+
+
+define void @withDebug() !dbg !18 {
+entry:
+  %0 = load i64, i64* @a, align 8
+  %1 = load i64, i64* @a, align 8
+  %2 = load i64, i64* @a, align 8
+  %3 = tail call { i64, i1 } @llvm.uadd.with.overflow.i64(i64 %0, i64 %1)
+  %4 = extractvalue { i64, i1 } %3, 0
+  %5 = tail call i64 @fn1(i64 %4, i64 %2)
+  tail call void @llvm.dbg.value(metadata i64 %4, i64 0, metadata !23, metadata !33), !dbg !34
+  tail call void @llvm.dbg.value(metadata i64 %5, i64 0, metadata !22, metadata !33), !dbg !35
+  tail call void (...) @printf()
+  tail call void (...) @printf(i64 1, i64 2, i64 3, i64 4, i32 0, i64 0, i64 %4, i64 %5)
+  ret void
+}
+
+; CHECK-LABEL: withDebug
+; CHECK: #DEBUG_VALUE: test:j <- %RBX
+; CHECK: addq  $24, %rsp
+; CHECK: popq  %rbx
+; CHECK: popq  %r14
+; CHECK: retq
+
+declare { i64, i1 } @llvm.uadd.with.overflow.i64(i64, i64)
+declare i64 @fn1(i64, i64)
+
+declare void @printf(...)
+
+declare void @llvm.dbg.value(metadata, i64, metadata, metadata)
+
+
+!llvm.dbg.cu = !{!1}
+!llvm.module.flags = !{!15, !16}
+
+!1 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !2, producer: "clang version 4.0.0")
+!2 = !DIFile(filename: "test.cpp", directory: "")
+!11 = !DIBasicType(name: "long int", size: 64, encoding: DW_ATE_signed)
+!15 = !{i32 2, !"Dwarf Version", i32 4}
+!16 = !{i32 2, !"Debug Info Version", i32 3}
+!18 = distinct !DISubprogram(name: "test", scope: !2, file: !2, line: 5, unit: !1)
+!22 = !DILocalVariable(name: "i", scope: !18, file: !2, line: 6, type: !11)
+!23 = !DILocalVariable(name: "j", scope: !18, file: !2, line: 7, type: !11)
+!33 = !DIExpression()
+!34 = !DILocation(line: 7, column: 17, scope: !18)
+!35 = !DILocation(line: 6, column: 8, scope: !18)
+!36 = !DILocation(line: 9, column: 3, scope: !18)
+!37 = !DILocation(line: 10, column: 10, scope: !18)
Index: test/CodeGen/X86/frame-lowering-debug-intrinsic.ll
===================================================================
--- test/CodeGen/X86/frame-lowering-debug-intrinsic.ll
+++ test/CodeGen/X86/frame-lowering-debug-intrinsic.ll
@@ -2,31 +2,56 @@
 ;
 ; RUN: llc -O1 -mtriple=x86_64-unknown-unknown -o - %s | FileCheck %s
 
-
-define i64 @noDebug(i64 %a) {
+define i64 @fn1NoDebug(i64 %a) {
   %call = call i64 @fn(i64 %a, i64 0)
   ret i64 %call
 }
 
-; CHECK-LABEL: noDebug
+; CHECK-LABEL: fn1NoDebug
 ; CHECK: popq %rcx
-; CHECK: ret
-
+; CHECK-NEXT: ret
 
-define i64 @withDebug(i64 %a) !dbg !4 {
+define i64 @fn1WithDebug(i64 %a) !dbg !4 {
   %call = call i64 @fn(i64 %a, i64 0)
   tail call void @llvm.dbg.value(metadata i64 %call, i64 0, metadata !5, metadata !6), !dbg !7
   ret i64 %call
 }
 
-; CHECK-LABEL: withDebug
+; CHECK-LABEL: fn1WithDebug
 ; CHECK: popq %rcx
-; CHECK: ret
+; CHECK-NEXT: ret
+
+%struct.Buffer = type { i8, [63 x i8] }
+
+define void @fn2NoDebug(%struct.Buffer* byval align 64 %p1) {
+  ret void
+}
+
+; CHECK-LABEL: fn2NoDebug
+; CHECK: and
+; CHECK-NOT: add
+; CHECK-NOT: sub
+; CHECK: mov
+; CHECK-NEXT: pop
+; CHECK-NEXT: ret
+
+define void @fn2WithDebug(%struct.Buffer* byval align 64 %p1) !dbg !4 {
+  call void @llvm.dbg.declare(metadata %struct.Buffer* %p1, metadata !5, metadata !6), !dbg !7
+  ret void
+}
 
+; CHECK-LABEL: fn2WithDebug
+; CHECK: and
+; CHECK-NOT: add
+; CHECK-NOT: sub
+; CHECK: mov
+; CHECK-NEXT: pop
+; CHECK-NEXT: ret
 
 declare i64 @fn(i64, i64)
 
 declare void @llvm.dbg.value(metadata, i64, metadata, metadata)
+declare void @llvm.dbg.declare(metadata, metadata, metadata)
 
 !llvm.dbg.cu = !{!0}
 !llvm.module.flags = !{!2,!3}