Turn on -flax-vector-conversions by default, issue a warning whenever one is done. Add a -fnolax-vector-conversions option. Fixes PR2862.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@63447 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/Sema.h b/lib/Sema/Sema.h
index 6e3a552..45f08bc 100644
--- a/lib/Sema/Sema.h
+++ b/lib/Sema/Sema.h
@@ -1584,6 +1584,10 @@
     /// c/v/r qualifiers, which we accept as an extension.
     CompatiblePointerDiscardsQualifiers,
 
+    /// IncompatibleVectors - The assignment is between two vector types that
+    /// have the same size, which we accept as an extension.
+    IncompatibleVectors,
+    
     /// IntToBlockPointer - The assignment converts an int to a block 
     /// pointer. We disallow this.
     IntToBlockPointer,