remove warning and always error

Author: spall

clang/include/clang/Basic/DiagnosticGroups.td

@@ -930,7 +930,6 @@ def SuperSubClassMismatch : DiagGroup<"super-class-method-mismatch">;
 def OverridingMethodMismatch : DiagGroup<"overriding-method-mismatch">;
 def VariadicMacros : DiagGroup<"variadic-macros">;
 def VectorConversion : DiagGroup<"vector-conversion">;      // clang specific
-def VectorOutOfRange : DiagGroup<"vector-out-of-range">;
 def VexingParse : DiagGroup<"vexing-parse">;
 def VLAUseStaticAssert : DiagGroup<"vla-extension-static-assert">;
 def VLACxxExtension : DiagGroup<"vla-cxx-extension", [VLAUseStaticAssert]>;

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -10637,9 +10637,6 @@ def err_sizeless_nonlocal : Error<
 
 def err_vector_index_out_of_range : Error<
   "vector element index %0 is out of bounds">;
-def warn_vector_index_out_of_range : Warning<
-  err_vector_index_out_of_range.Summary>,
-  InGroup<VectorOutOfRange>;
 
 def err_vec_builtin_non_vector : Error<
  "%select{first two|all}1 arguments to %0 must be vectors">;

clang/lib/Sema/SemaChecking.cpp

@@ -14026,8 +14026,7 @@ void Sema::CheckVectorAccess(const Expr *BaseExpr, const Expr *IndexExpr) {
   if (!IndexExpr->EvaluateAsInt(Result, Context, Expr::SE_AllowSideEffects))
     return;
 
-  unsigned DiagID = getLangOpts().HLSL ? diag::err_vector_index_out_of_range
-                                       : diag::warn_vector_index_out_of_range;
+  unsigned DiagID = diag::err_vector_index_out_of_range;
 
   llvm::APSInt index = Result.Val.getInt();
   if (index.isNegative() || index >= VTy->getNumElements())

clang/test/CodeGenCXX/x86_64-arguments.cpp

@@ -215,6 +215,6 @@ union U {
   float f1;
   char __attribute__((__vector_size__(1))) f2;
 };
-int f(union U u) { return u.f2[1]; }
+int f(union U u) { return u.f2[0]; }
 // CHECK-LABEL: define{{.*}} i32 @_ZN6test111fENS_1UE(i32
 }