diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
index e9ffb730305..549c57633a4 100644
--- a/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -2781,20 +2781,18 @@ Instruction *InstCombiner::visitMul(BinaryOperator &I) {
   
   // If one of the operands of the multiply is a cast from a boolean value, then
   // we know the bool is either zero or one, so this is a 'masking' multiply.
-  // See if we can simplify things based on how the boolean was originally
-  // formed.
-  {
-    Value *BoolCast = 0, *OtherOp = 0;
-    if (ZExtInst *CI = dyn_cast<ZExtInst>(Op0))
-      if (CI->getOperand(0)->getType() == Type::getInt1Ty(*Context))
-        BoolCast = CI, OtherOp = I.getOperand(1);
-    if (!BoolCast)
-      if (ZExtInst *CI = dyn_cast<ZExtInst>(I.getOperand(1)))
-        if (CI->getOperand(0)->getType() == Type::getInt1Ty(*Context))
-          BoolCast = CI, OtherOp = Op0;
+  //   X * Y (where Y is 0 or 1) -> X & (0-Y)
+  if (!isa<VectorType>(I.getType())) {
+    // -2 is "-1 << 1" so it is all bits set except the low one.
+    APInt Negative2(I.getType()->getPrimitiveSizeInBits(), -2, true);
     
+    Value *BoolCast = 0, *OtherOp = 0;
+    if (MaskedValueIsZero(Op0, Negative2))
+      BoolCast = Op0, OtherOp = I.getOperand(1);
+    else if (MaskedValueIsZero(I.getOperand(1), Negative2))
+      BoolCast = I.getOperand(1), OtherOp = Op0;
+
     if (BoolCast) {
-      // X * Y (where Y is 0 or 1) -> X & (0-Y)
       Value *V = Builder->CreateSub(Constant::getNullValue(I.getType()),
                                     BoolCast, "tmp");
       return BinaryOperator::CreateAnd(V, OtherOp);
diff --git a/test/Transforms/InstCombine/mul.ll b/test/Transforms/InstCombine/mul.ll
index d8e623c4834..53a56434aed 100644
--- a/test/Transforms/InstCombine/mul.ll
+++ b/test/Transforms/InstCombine/mul.ll
@@ -105,5 +105,12 @@ define i32 @test16(i32 %b, i1 %c) {
         ret i32 %e
 }
 
+; X * Y (when Y is 0 or 1) --> x & (0-Y)
+define i32 @test17(i32 %a, i32 %b) {
+  %a.lobit = lshr i32 %a, 31
+  %e = mul i32 %a.lobit, %b
+  ret i32 %e
+}
+