fold-const.c (operand_equal_p): Handle matching of vector constructors.

	* fold-const.c (operand_equal_p): Handle matching of vector
	constructors.
	* gcc.dg/tree-ssa/operand-equal-2.c: New testcase.

From-SVN: r229264

gcc/ChangeLog

+2015-10-23  Jan Hubicka  <hubicka@ucw.cz>
+
+	* fold-const.c (operand_equal_p): Handle matching of vector
+	constructors.
+
 2015-10-23  David Edelsohn  <dje.gcc@gmail.com>
 
 	* doc/install.texi (*-ibm-aix*): Additional information for AIX 7.1.

gcc/fold-const.c

@@ -3149,6 +3149,56 @@ operand_equal_p (const_tree arg0, const_tree arg1, unsigned int flags)
 	      && DECL_BUILT_IN_CLASS (arg0) == DECL_BUILT_IN_CLASS (arg1)
 	      && DECL_FUNCTION_CODE (arg0) == DECL_FUNCTION_CODE (arg1));
 
+    case tcc_exceptional:
+      if (TREE_CODE (arg0) == CONSTRUCTOR)
+	{
+	  /* In GIMPLE constructors are used only to build vectors from
+	     elements.  Individual elements in the constructor must be
+	     indexed in increasing order and form an initial sequence.
+
+	     We make no effort to compare constructors in generic.
+	     (see sem_variable::equals in ipa-icf which can do so for
+	      constants).  */
+	  if (!VECTOR_TYPE_P (TREE_TYPE (arg0))
+	      || !VECTOR_TYPE_P (TREE_TYPE (arg1)))
+	    return 0;
+
+	  /* Be sure that vectors constructed have the same representation.
+	     We only tested element precision and modes to match.
+	     Vectors may be BLKmode and thus also check that the number of
+	     parts match.  */
+	  if (TYPE_VECTOR_SUBPARTS (TREE_TYPE (arg0))
+	      != TYPE_VECTOR_SUBPARTS (TREE_TYPE (arg1)))
+	    return 0;
+
+	  vec<constructor_elt, va_gc> *v0 = CONSTRUCTOR_ELTS (arg0);
+	  vec<constructor_elt, va_gc> *v1 = CONSTRUCTOR_ELTS (arg1);
+	  unsigned int len = vec_safe_length (v0);
+
+	  if (len != vec_safe_length (v1))
+	    return 0;
+
+	  for (unsigned int i = 0; i < len; i++)
+	    {
+	      constructor_elt *c0 = &(*v0)[i];
+	      constructor_elt *c1 = &(*v1)[i];
+
+	      if (!operand_equal_p (c0->value, c1->value, flags)
+		  /* In GIMPLE the indexes can be either NULL or matching i.
+		     Double check this so we won't get false
+		     positives for GENERIC.  */
+		  || (c0->index
+		      && (TREE_CODE (c0->index) != INTEGER_CST 
+			  || !compare_tree_int (c0->index, i)))
+		  || (c1->index
+		      && (TREE_CODE (c1->index) != INTEGER_CST 
+			  || !compare_tree_int (c1->index, i))))
+		return 0;
+	    }
+	  return 1;
+	}
+      return 0;
+
     default:
       return 0;
     }

gcc/testsuite/ChangeLog

+2015-10-23  Jan Hubicka  <hubicka@ucw.cz>
+
+	* gcc.dg/tree-ssa/operand-equal-2.c: New testcase.
+
 2015-10-23  Steve Ellcey  <sellcey@imgtec.com>
 	    Andrew Pinski  <apinski@cavium.com>
 

gcc/testsuite/gcc.dg/tree-ssa/operand-equal-2.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-forwprop1" } */
+
+typedef char __attribute__ ((vector_size (4))) v4qi;
+
+v4qi v;
+void ret(char a)
+{
+  v4qi c={a,a,a,a},d={a,a,a,a};
+  v = (c!=d);
+}
+/* { dg-final { scan-tree-dump "v = . 0, 0, 0, 0 ." "forwprop2"} } */