[Fixed Point Arithmetic] Fixed Point to Boolean Cast

This patch is a part of https://reviews.llvm.org/D48456 in an attempt to split
the casting logic up into smaller patches. This contains the code for casting
from fixed point types to boolean types.

Differential Revision: https://reviews.llvm.org/D53308

llvm-svn: 345063
diff --git a/clang/lib/Sema/Sema.cpp b/clang/lib/Sema/Sema.cpp
index 7e16202..d5d9228 100644
--- a/clang/lib/Sema/Sema.cpp
+++ b/clang/lib/Sema/Sema.cpp
@@ -533,8 +533,7 @@
   case Type::STK_Floating: return CK_FloatingToBoolean;
   case Type::STK_IntegralComplex: return CK_IntegralComplexToBoolean;
   case Type::STK_FloatingComplex: return CK_FloatingComplexToBoolean;
-  case Type::STK_FixedPoint:
-    llvm_unreachable("Unknown cast from FixedPoint to boolean");
+  case Type::STK_FixedPoint: return CK_FixedPointToBoolean;
   }
   llvm_unreachable("unknown scalar type kind");
 }