With lax vector conversions (the default) make sure we convert between two

vectors that are the same size. Fix up testcases accordingly and add a new one
to make sure we still error if lax vector conversions are disabled.

Fixes rdar://8328190


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@112122 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Sema/SemaExpr.cpp

@@ -5005,7 +5005,6 @@ QualType Sema::CheckVectorOperands(SourceLocation Loc, Expr *&lex, Expr *&rex) {
   // Handle the case of a vector & extvector type of the same size and element
   // type.  It would be nice if we only had one vector type someday.
   if (getLangOptions().LaxVectorConversions) {
-    // FIXME: Should we warn here?
     if (const VectorType *LV = lhsType->getAs<VectorType>()) {
       if (const VectorType *RV = rhsType->getAs<VectorType>())
         if (LV->getElementType() == RV->getElementType() &&
@@ -5017,8 +5016,14 @@ QualType Sema::CheckVectorOperands(SourceLocation Loc, Expr *&lex, Expr *&rex) {
 
           ImpCastExprToType(lex, rhsType, CK_BitCast);
           return rhsType;
+        } else if (Context.getTypeSize(lhsType) ==Context.getTypeSize(rhsType)){
+          // If we are allowing lax vector conversions, and LHS and RHS are both
+          // vectors, the total size only needs to be the same. This is a
+          // bitcast; no bits are changed but the result type is different.
+          ImpCastExprToType(rex, lhsType, CK_BitCast);
+          return lhsType;
         }
-    }
+      }
   }
 
   // Handle the case of equivalent AltiVec and GCC vector types

test/Sema/ext_vector_casts.c

@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -fsyntax-only -verify %s
+// RUN: %clang_cc1 -fsyntax-only -verify -fno-lax-vector-conversions %s
 
 typedef __attribute__(( ext_vector_type(2) )) float float2;
 typedef __attribute__(( ext_vector_type(4) )) int int4;

test/SemaCXX/vector-no-lax.cpp

@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 -triple x86_64-apple-darwin10 -fsyntax-only -fno-lax-vector-conversions -verify %s
+typedef unsigned int __attribute__((vector_size (16))) vUInt32;
+typedef int __attribute__((vector_size (16))) vSInt32;
+
+vSInt32 foo (vUInt32 a) {
+  vSInt32 b = { 0, 0, 0, 0 };
+  b += a; // expected-error{{can't convert between vector values}}
+  return b;
+}

test/SemaCXX/vector.cpp

@@ -51,10 +51,10 @@ void conditional(bool Cond, char16 c16, longlong16 ll16, char16_e c16e,
   __typeof__(Cond? ll16 : ll16e) *ll16ep2 = &ll16e;
   __typeof__(Cond? ll16e : ll16) *ll16ep3 = &ll16e;
 
-  // Conditional operators with incompatible types.
-  (void)(Cond? c16 : ll16); // expected-error{{can't convert between vector values}}
-  (void)(Cond? ll16e : c16e); // expected-error{{can't convert between vector values}}
-  (void)(Cond? ll16e : c16); // expected-error{{can't convert between vector values}}
+  // Conditional operators with compatible types under -flax-vector-conversions (default)
+  (void)(Cond? c16 : ll16);
+  (void)(Cond? ll16e : c16e);
+  (void)(Cond? ll16e : c16);
 }
 
 // Test C++ cast'ing of vector types.
@@ -183,8 +183,10 @@ void test_implicit_conversions(bool Cond, char16 c16, longlong16 ll16,
 
   (void)(Cond? to_c16 : to_c16e);
   (void)(Cond? to_ll16e : to_ll16);
-  (void)(Cond? to_c16 : to_ll16); // expected-error{{can't convert between vector values of different size}}
-  (void)(Cond? to_c16e : to_ll16e); // expected-error{{can't convert between vector values of different size}}
+  
+  // These 2 are convertable with -flax-vector-conversions (default)
+  (void)(Cond? to_c16 : to_ll16);
+  (void)(Cond? to_c16e : to_ll16e);
 }
 
 typedef float fltx2 __attribute__((__vector_size__(8)));