diff --git a/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
index c48e3c9f9ac..40aa7c5f454 100644
--- a/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
+++ b/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
@@ -422,7 +422,7 @@ static bool isFiniteNonZeroFp(Constant *C) {
   if (C->getType()->isVectorTy()) {
     for (unsigned I = 0, E = C->getType()->getVectorNumElements(); I != E;
          ++I) {
-      ConstantFP *CFP = dyn_cast<ConstantFP>(C->getAggregateElement(I));
+      ConstantFP *CFP = dyn_cast_or_null<ConstantFP>(C->getAggregateElement(I));
       if (!CFP || !CFP->getValueAPF().isFiniteNonZero())
         return false;
     }
@@ -437,7 +437,7 @@ static bool isNormalFp(Constant *C) {
   if (C->getType()->isVectorTy()) {
     for (unsigned I = 0, E = C->getType()->getVectorNumElements(); I != E;
          ++I) {
-      ConstantFP *CFP = dyn_cast<ConstantFP>(C->getAggregateElement(I));
+      ConstantFP *CFP = dyn_cast_or_null<ConstantFP>(C->getAggregateElement(I));
       if (!CFP || !CFP->getValueAPF().isNormal())
         return false;
     }
diff --git a/test/Transforms/InstCombine/fast-math.ll b/test/Transforms/InstCombine/fast-math.ll
index c6081c39925..4eebdbdfacf 100644
--- a/test/Transforms/InstCombine/fast-math.ll
+++ b/test/Transforms/InstCombine/fast-math.ll
@@ -267,6 +267,14 @@ define <4 x float> @fmul3_vec(<4 x float> %f1, <4 x float> %f2) {
 ; CHECK: fmul fast <4 x float> %f1, <float 3.000000e+00, float 2.000000e+00, float 1.000000e+00, float 1.000000e+00>
 }
 
+; Make sure fmul with constant expression doesn't assert.
+define <4 x float> @fmul3_vec_constexpr(<4 x float> %f1, <4 x float> %f2) {
+  %constExprMul = bitcast i128 trunc (i160 bitcast (<5 x float> <float 6.0e+3, float 6.0e+3, float 2.0e+3, float 1.0e+3, float undef> to i160) to i128) to <4 x float>  
+  %t1 = fdiv <4 x float> %f1, <float 2.0e+3, float 3.0e+3, float 2.0e+3, float 1.0e+3>
+  %t3 = fmul fast <4 x float> %t1, %constExprMul
+  ret <4 x float> %t3
+}
+
 ; Rule "X/C1 * C2 => X * (C2/C1) is not applicable if C2/C1 is either a special
 ; value of a denormal. The 0x3810000000000000 here take value FLT_MIN
 ;