[llvm][CodeGen] Avoid implicit cast of TypeSize to integer in `initActions`.

[efriedma]

The extra assertion doesn't seem helpful; the one in getFixedSize() should be enough.

[fpetrogalli]

Thank you @efriedma for the review!

[efriedma]

LGTM

llvm/lib/CodeGen/TargetLoweringBase.cpp

void TargetLoweringBase::initActions() {
   memset(TruncStoreActions, 0, sizeof(TruncStoreActions));
   memset(IndexedModeActions, 0, sizeof(IndexedModeActions));
   memset(CondCodeActions, 0, sizeof(CondCodeActions));
   std::fill(std::begin(RegClassForVT), std::end(RegClassForVT), nullptr);
   std::fill(std::begin(TargetDAGCombineArray),
             std::end(TargetDAGCombineArray), 0);
 
   for (MVT VT : MVT::fp_valuetypes()) {
-    MVT IntVT = MVT::getIntegerVT(VT.getSizeInBits());
+    MVT IntVT = MVT::getIntegerVT(VT.getSizeInBits().getFixedSize());
     if (IntVT.isValid()) {
       setOperationAction(ISD::ATOMIC_SWAP, VT, Promote);
       AddPromotedToType(ISD::ATOMIC_SWAP, VT, IntVT);
     }
   }
 
   // Set default actions for various operations.
   for (MVT VT : MVT::all_valuetypes()) {