[Fixed Point Arithmetic] Fixed Point and Integer Conversions

This patch includes the necessary code for converting between a fixed point type and integer.
This also includes constant expression evaluation for conversions with these types.

Differential Revision: https://reviews.llvm.org/D56900

llvm-svn: 355462
diff --git a/clang/lib/CodeGen/CGExprConstant.cpp b/clang/lib/CodeGen/CGExprConstant.cpp
index 62cc12c..64ad582 100644
--- a/clang/lib/CodeGen/CGExprConstant.cpp
+++ b/clang/lib/CodeGen/CGExprConstant.cpp
@@ -876,6 +876,8 @@
     case CK_FloatingCast:
     case CK_FixedPointCast:
     case CK_FixedPointToBoolean:
+    case CK_FixedPointToIntegral:
+    case CK_IntegralToFixedPoint:
     case CK_ZeroToOCLOpaqueType:
       return nullptr;
     }