2012-11-29 Marc Glisse <marc.glisse@inria.fr>

	PR c++/53094
gcc/
	* fold-const.c (fold): Replace a CONSTRUCTOR with a VECTOR_CST.
gcc/cp/
	* cvt.c (ocp_convert): Call convert_to_vector.
gcc/testsuite/
	* g++.dg/ext/vector20.C: New testcase.



git-svn-id: https://gcc.gnu.org/svn/gcc/trunk@193938 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 29 insertions, 0 deletions

diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index e4693cdd16a..071fb8c15ab 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -14387,6 +14387,35 @@ fold (tree expr)
 	return t;
       }
 
+      /* Return a VECTOR_CST if possible.  */
+    case CONSTRUCTOR:
+      {
+	tree type = TREE_TYPE (t);
+	if (TREE_CODE (type) != VECTOR_TYPE)
+	  return t;
+
+	tree *vec = XALLOCAVEC (tree, TYPE_VECTOR_SUBPARTS (type));
+	unsigned HOST_WIDE_INT idx, pos = 0;
+	tree value;
+
+	FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (t), idx, value)
+	  {
+	    if (!CONSTANT_CLASS_P (value))
+	      return t;
+	    if (TREE_CODE (value) == VECTOR_CST)
+	      {
+		for (unsigned i = 0; i < VECTOR_CST_NELTS (value); ++i)
+		  vec[pos++] = VECTOR_CST_ELT (value, i);
+	      }
+	    else
+	      vec[pos++] = value;
+	  }
+	for (; pos < TYPE_VECTOR_SUBPARTS (type); ++pos)
+	  vec[pos] = build_zero_cst (TREE_TYPE (type));
+
+	return build_vector (type, vec);
+      }
+
     case CONST_DECL:
       return fold (DECL_INITIAL (t));