[CodeGen] ExpandLargeFpConvert - don't dereference a dyn_cast result

dyn_cast is allowed to return NULL - use cast<> to assert that the cast type is valid

Fixes static analysis warning.

Author: RKSimon

llvm/lib/CodeGen/ExpandLargeFpConvert.cpp

@@ -611,7 +611,7 @@ static bool runImpl(Function &F, const TargetLowering &TLI) {
       if (I.getOperand(0)->getType()->isScalableTy())
         continue;
 
-      auto *IntTy = dyn_cast<IntegerType>(I.getType()->getScalarType());
+      auto *IntTy = cast<IntegerType>(I.getType()->getScalarType());
       if (IntTy->getIntegerBitWidth() <= MaxLegalFpConvertBitWidth)
         continue;
 
@@ -629,7 +629,7 @@ static bool runImpl(Function &F, const TargetLowering &TLI) {
         continue;
 
       auto *IntTy =
-          dyn_cast<IntegerType>(I.getOperand(0)->getType()->getScalarType());
+          cast<IntegerType>(I.getOperand(0)->getType()->getScalarType());
       if (IntTy->getIntegerBitWidth() <= MaxLegalFpConvertBitWidth)
         continue;