Simplify expressions involving boolean constants with clang-tidy

Patch by Richard (legalize at xmission dot com).

Differential Revision: http://reviews.llvm.org/D8154

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231617 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Support/APFloat.cpp

@@ -1248,10 +1248,10 @@ APFloat::roundAwayFromZero(roundingMode rounding_mode,
     return false;
 
   case rmTowardPositive:
-    return sign == false;
+    return !sign;
 
   case rmTowardNegative:
-    return sign == true;
+    return sign;
   }
   llvm_unreachable("Invalid rounding mode found");
 }