tree-ssa-forwprop.c (forward_propagate_into_cond): Handle vectors.

2012-10-23  Marc Glisse  <marc.glisse@inria.fr>

gcc/
	* tree-ssa-forwprop.c (forward_propagate_into_cond): Handle vectors.
	* fold-const.c (fold_relational_const): Handle VECTOR_CST.
	* doc/generic.texi (VEC_COND_EXPR): Document current policy.

gcc/testsuite/
	* gcc.dg/tree-ssa/foldconst-6.c: New testcase.

From-SVN: r192711

gcc/ChangeLog

+2012-10-23  Marc Glisse  <marc.glisse@inria.fr>
+
+	* tree-ssa-forwprop.c (forward_propagate_into_cond): Handle vectors.
+	* fold-const.c (fold_relational_const): Handle VECTOR_CST.
+	* doc/generic.texi (VEC_COND_EXPR): Document current policy.
+
 2012-10-23  Jan Hubicka  <jh@suse.cz>
 
 	PR middle-end/54937

gcc/doc/generic.texi

@@ -1780,8 +1780,9 @@ operand is of signed integral vector type.  If an element of the first
 operand evaluates to a zero value, the corresponding element of the
 result is taken from the third operand. If it evaluates to a minus one
 value, it is taken from the second operand. It should never evaluate to
-any other value. In contrast with a @code{COND_EXPR}, all operands are
-always evaluated.
+any other value currently, but optimizations should not rely on that
+property. In contrast with a @code{COND_EXPR}, all operands are always
+evaluated.
 @end table
 
 

gcc/fold-const.c

@@ -16130,6 +16130,31 @@ fold_relational_const (enum tree_code code, tree type, tree op0, tree op1)
 	return NULL_TREE;
     }
 
+  if (TREE_CODE (op0) == VECTOR_CST && TREE_CODE (op1) == VECTOR_CST)
+    {
+      unsigned count = VECTOR_CST_NELTS (op0);
+      tree *elts =  XALLOCAVEC (tree, count);
+      gcc_assert (VECTOR_CST_NELTS (op1) == count
+		  && TYPE_VECTOR_SUBPARTS (type) == count);
+
+      for (unsigned i = 0; i < count; i++)
+	{
+	  tree elem_type = TREE_TYPE (type);
+	  tree elem0 = VECTOR_CST_ELT (op0, i);
+	  tree elem1 = VECTOR_CST_ELT (op1, i);
+
+	  tree tem = fold_relational_const (code, elem_type,
+					    elem0, elem1);
+
+	  if (tem == NULL_TREE)
+	    return NULL_TREE;
+
+	  elts[i] = build_int_cst (elem_type, integer_zerop (tem) ? 0 : -1);
+	}
+
+      return build_vector (type, elts);
+    }
+
   /* From here on we only handle LT, LE, GT, GE, EQ and NE.
 
      To compute GT, swap the arguments and do LT.

gcc/testsuite/ChangeLog

+2012-10-23  Marc Glisse  <marc.glisse@inria.fr>
+
+	* gcc.dg/tree-ssa/foldconst-6.c: New testcase.
+
 2012-10-23  Jan Hubicka  <jh@suse.cz>
 
 	PR middle-end/54937

gcc/testsuite/gcc.dg/tree-ssa/foldconst-6.c

+/* { dg-do compile } */
+/* { dg-options "-O -fdump-tree-ccp1" } */
+
+typedef long vec __attribute__ ((vector_size (2 * sizeof(long))));
+
+void f (vec *r)
+{
+  vec a = { -2, 666 };
+  vec b = { 3, 2 };
+  *r = a < b;
+}
+
+/* { dg-final { scan-tree-dump-not "666" "ccp1"} } */
+/* { dg-final { cleanup-tree-dump "ccp1" } } */

gcc/tree-ssa-forwprop.c

@@ -551,6 +551,7 @@ forward_propagate_into_cond (gimple_stmt_iterator *gsi_p)
   gimple stmt = gsi_stmt (*gsi_p);
   tree tmp = NULL_TREE;
   tree cond = gimple_assign_rhs1 (stmt);
+  enum tree_code code = gimple_assign_rhs_code (stmt);
   bool swap = false;
 
   /* We can do tree combining on SSA_NAME and comparison expressions.  */
@@ -561,23 +562,24 @@ forward_propagate_into_cond (gimple_stmt_iterator *gsi_p)
 					       TREE_OPERAND (cond, 1));
   else if (TREE_CODE (cond) == SSA_NAME)
     {
-      enum tree_code code;
+      enum tree_code def_code;
       tree name = cond;
       gimple def_stmt = get_prop_source_stmt (name, true, NULL);
       if (!def_stmt || !can_propagate_from (def_stmt))
 	return 0;
 
-      code = gimple_assign_rhs_code (def_stmt);
-      if (TREE_CODE_CLASS (code) == tcc_comparison)
+      def_code = gimple_assign_rhs_code (def_stmt);
+      if (TREE_CODE_CLASS (def_code) == tcc_comparison)
 	tmp = fold_build2_loc (gimple_location (def_stmt),
-			       code,
+			       def_code,
 			       TREE_TYPE (cond),
 			       gimple_assign_rhs1 (def_stmt),
 			       gimple_assign_rhs2 (def_stmt));
-      else if ((code == BIT_NOT_EXPR
-		&& TYPE_PRECISION (TREE_TYPE (cond)) == 1)
-	       || (code == BIT_XOR_EXPR
-		   && integer_onep (gimple_assign_rhs2 (def_stmt))))
+      else if (code == COND_EXPR
+	       && ((def_code == BIT_NOT_EXPR
+		    && TYPE_PRECISION (TREE_TYPE (cond)) == 1)
+		   || (def_code == BIT_XOR_EXPR
+		       && integer_onep (gimple_assign_rhs2 (def_stmt)))))
 	{
 	  tmp = gimple_assign_rhs1 (def_stmt);
 	  swap = true;
@@ -596,7 +598,8 @@ forward_propagate_into_cond (gimple_stmt_iterator *gsi_p)
 	  fprintf (dump_file, "'\n");
 	}
 
-      if (integer_onep (tmp))
+      if ((code == VEC_COND_EXPR) ? integer_all_onesp (tmp)
+				  : integer_onep (tmp))
 	gimple_assign_set_rhs_from_tree (gsi_p, gimple_assign_rhs2 (stmt));
       else if (integer_zerop (tmp))
 	gimple_assign_set_rhs_from_tree (gsi_p, gimple_assign_rhs3 (stmt));