Use MutableArrayRef for APFloat::convertToInteger

As discussed on D31074, use MutableArrayRef for destination integer buffers to help assert before stack overflows happen.

llvm-svn: 298253

llvm/lib/Analysis/ConstantFolding.cpp

@@ -1518,9 +1518,9 @@ Constant *ConstantFoldSSEConvertToInt(const APFloat &Val, bool roundTowardZero,
   bool isExact = false;
   APFloat::roundingMode mode = roundTowardZero? APFloat::rmTowardZero
                                               : APFloat::rmNearestTiesToEven;
-  APFloat::opStatus status = Val.convertToInteger(&UIntVal, ResultWidth,
-                                                  /*isSigned=*/true, mode,
-                                                  &isExact);
+  APFloat::opStatus status =
+      Val.convertToInteger(makeMutableArrayRef(UIntVal), ResultWidth,
+                           /*isSigned=*/true, mode, &isExact);
   if (status != APFloat::opOK &&
       (!roundTowardZero || status != APFloat::opInexact))
     return nullptr;