Fix the construction of the magic constant for roundToIntegral to be 64-bit safe.  Fixes c-torture/execute/990826-0.c


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161885 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/APFloat.cpp b/lib/Support/APFloat.cpp
index 2139df5..5ea75a6 100644
--- a/lib/Support/APFloat.cpp
+++ b/lib/Support/APFloat.cpp
@@ -1774,8 +1774,8 @@
   // precision of our format, and then subtract it back off again.  The choice
   // of rounding modes for the addition/subtraction determines the rounding mode
   // for our integral rounding as well.
-  APInt IntegerConstant(NextPowerOf2(semanticsPrecision(*semantics)),
-                        1 << (semanticsPrecision(*semantics)-1));
+  APInt IntegerConstant(NextPowerOf2(semanticsPrecision(*semantics)), 1);
+  IntegerConstant <<= semanticsPrecision(*semantics)-1;
   APFloat MagicConstant(*semantics);
   fs = MagicConstant.convertFromAPInt(IntegerConstant, false,
                                       rmNearestTiesToEven);