!fixup, fix assertion of getResultType().

Author: ElvisWang123

llvm/lib/Transforms/Vectorize/VPlan.h

@@ -2642,8 +2642,10 @@ class VPMulAccumulateReductionRecipe : public VPReductionRecipe {
             MulAcc->getCondOp(), MulAcc->isOrdered(),
             WrapFlagsTy(MulAcc->hasNoUnsignedWrap(), MulAcc->hasNoSignedWrap()),
             MulAcc->getDebugLoc()),
-        ExtOp(MulAcc->getExtOpcode()), IsNonNeg(MulAcc->isNonNeg()),
-        ResultTy(MulAcc->getResultType()) {}
+        ExtOp(MulAcc->getExtOpcode()), IsNonNeg(MulAcc->isNonNeg()) {
+    if (MulAcc->isExtended())
+      ResultTy = MulAcc->getResultType();
+  }
 
 public:
   VPMulAccumulateReductionRecipe(VPReductionRecipe *R, VPWidenRecipe *Mul,