diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index e08adc2384b..538a116902e 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -8459,6 +8459,11 @@ SDValue X86TargetLowering::LowerShiftParts(SDValue Op, SelectionDAG &DAG) const{
   SDValue ShOpLo = Op.getOperand(0);
   SDValue ShOpHi = Op.getOperand(1);
   SDValue ShAmt  = Op.getOperand(2);
+  // X86ISD::SHLD and X86ISD::SHRD have defined overflow behavior but the
+  // generic ISD nodes haven't. Insert an AND to be safe, it's optimized away
+  // during isel.
+  SDValue SafeShAmt = DAG.getNode(ISD::AND, dl, MVT::i8, ShAmt,
+                                  DAG.getConstant(VTBits - 1, MVT::i8));
   SDValue Tmp1 = isSRA ? DAG.getNode(ISD::SRA, dl, VT, ShOpHi,
                                      DAG.getConstant(VTBits - 1, MVT::i8))
                        : DAG.getConstant(0, VT);
@@ -8466,12 +8471,15 @@ SDValue X86TargetLowering::LowerShiftParts(SDValue Op, SelectionDAG &DAG) const{
   SDValue Tmp2, Tmp3;
   if (Op.getOpcode() == ISD::SHL_PARTS) {
     Tmp2 = DAG.getNode(X86ISD::SHLD, dl, VT, ShOpHi, ShOpLo, ShAmt);
-    Tmp3 = DAG.getNode(ISD::SHL, dl, VT, ShOpLo, ShAmt);
+    Tmp3 = DAG.getNode(ISD::SHL, dl, VT, ShOpLo, SafeShAmt);
   } else {
     Tmp2 = DAG.getNode(X86ISD::SHRD, dl, VT, ShOpLo, ShOpHi, ShAmt);
-    Tmp3 = DAG.getNode(isSRA ? ISD::SRA : ISD::SRL, dl, VT, ShOpHi, ShAmt);
+    Tmp3 = DAG.getNode(isSRA ? ISD::SRA : ISD::SRL, dl, VT, ShOpHi, SafeShAmt);
   }
 
+  // If the shift amount is larger or equal than the width of a part we can't
+  // rely on the results of shld/shrd. Insert a test and select the appropriate
+  // values for large shift amounts.
   SDValue AndNode = DAG.getNode(ISD::AND, dl, MVT::i8, ShAmt,
                                 DAG.getConstant(VTBits, MVT::i8));
   SDValue Cond = DAG.getNode(X86ISD::CMP, dl, MVT::i32,
diff --git a/test/CodeGen/X86/legalize-shift-64.ll b/test/CodeGen/X86/legalize-shift-64.ll
index 77364688afe..64460bb9118 100644
--- a/test/CodeGen/X86/legalize-shift-64.ll
+++ b/test/CodeGen/X86/legalize-shift-64.ll
@@ -64,3 +64,31 @@ define <2 x i64> @test5(<2 x i64> %A, <2 x i64> %B) {
 ; CHECK: shl
 ; CHECK: shldl
 }
+
+; PR16108
+define i32 @test6() {
+  %x = alloca i32, align 4
+  %t = alloca i64, align 8
+  store i32 1, i32* %x, align 4
+  store i64 1, i64* %t, align 8  ;; DEAD
+  %load = load i32* %x, align 4
+  %shl = shl i32 %load, 8
+  %add = add i32 %shl, -224
+  %sh_prom = zext i32 %add to i64
+  %shl1 = shl i64 1, %sh_prom
+  %cmp = icmp ne i64 %shl1, 4294967296
+  br i1 %cmp, label %if.then, label %if.end
+
+if.then:                                          ; preds = %entry
+  ret i32 1
+
+if.end:                                           ; preds = %entry
+  ret i32 0
+
+; CHECK-LABEL: test6:
+; CHECK-NOT: andb $31
+; CHECK: sete
+; CHECK: movzbl
+; CHECK: xorl $1
+; CHECK: orl
+}