From d5a1053a0d44116b1cbd887928276517ed8f458a Mon Sep 17 00:00:00 2001
From: Marc Glisse <marc.glisse@inria.fr>
Date: Thu, 29 Nov 2012 16:40:16 +0100
Subject: [PATCH] re PR c++/53094 (constexpr vector subscripting)

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.

From-SVN: r193938
---
 gcc/ChangeLog                       |  5 +++++
 gcc/cp/ChangeLog                    |  5 +++++
 gcc/cp/cvt.c                        |  2 ++
 gcc/fold-const.c                    | 29 +++++++++++++++++++++++++++++
 gcc/testsuite/ChangeLog             |  5 +++++
 gcc/testsuite/g++.dg/ext/vector20.C |  7 +++++++
 6 files changed, 53 insertions(+)
 create mode 100644 gcc/testsuite/g++.dg/ext/vector20.C

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index b45e6e32db4..8ca3588b3ee 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2012-11-29  Marc Glisse  <marc.glisse@inria.fr>
+
+	PR c++/53094
+	* fold-const.c (fold): Replace a CONSTRUCTOR with a VECTOR_CST.
+
 2012-11-29  Richard Biener  <rguenther@suse.de>
 
 	* tree-ssa-pre.c (get_expr_value_id): Do not add expr
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 4f240e9f3b6..d8d958a579c 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,8 @@
+2012-11-29  Marc Glisse  <marc.glisse@inria.fr>
+
+	PR c++/53094
+	* cvt.c (ocp_convert): Call convert_to_vector.
+
 2012-11-29  Kai Tietz  <ktietz@redhat.com>
 
 	PR target/53912
diff --git a/gcc/cp/cvt.c b/gcc/cp/cvt.c
index 1dc789855cc..4ba7642db20 100644
--- a/gcc/cp/cvt.c
+++ b/gcc/cp/cvt.c
@@ -690,6 +690,8 @@ ocp_convert (tree type, tree expr, int convtype, int flags,
 	 conversion.  */
       else if (TREE_CODE (type) == COMPLEX_TYPE)
 	return fold_if_not_in_template (convert_to_complex (type, e));
+      else if (TREE_CODE (type) == VECTOR_TYPE)
+	return fold_if_not_in_template (convert_to_vector (type, e));
       else if (TREE_CODE (e) == TARGET_EXPR)
 	{
 	  /* Don't build a NOP_EXPR of class type.  Instead, change the
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));
 
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index d270ee0936e..4e623fb7df2 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2012-11-29  Marc Glisse  <marc.glisse@inria.fr>
+
+	PR c++/53094
+	* g++.dg/ext/vector20.C: New testcase.
+
 2012-11-28  Tobias Burnus  <burnus@net-b.de>
 
 	PR fortran/52161
diff --git a/gcc/testsuite/g++.dg/ext/vector20.C b/gcc/testsuite/g++.dg/ext/vector20.C
new file mode 100644
index 00000000000..3d7c39250cf
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/vector20.C
@@ -0,0 +1,7 @@
+/* { dg-do compile } */
+/* { dg-options "-std=c++11" } */
+
+typedef long vec __attribute__((vector_size (2 * sizeof (long))));
+constexpr vec v = { 3, 4 };
+constexpr vec s = v + v;
+constexpr vec w = __builtin_shuffle (v, v);