gimplify.c (gimplify_init_constructor): Revert to using < rather than <= for sparseness test.

        * gimplify.c (gimplify_init_constructor): Revert to using < rather
        than <= for sparseness test.

From-SVN: r142618

gcc/ChangeLog

@@ -166,6 +166,9 @@
 
 2008-12-09  Jason Merrill  <jason@redhat.com>
 
+	* gimplify.c (gimplify_init_constructor): Revert to using < rather
+	than <= for sparseness test.
+
 	PR c++/38410
 	* gimplify.c (gimplify_init_constructor): Don't write out a static
 	copy of the CONSTRUCTOR for TREE_ADDRESSABLE types or small sparse

gcc/gimplify.c

@@ -3502,7 +3502,7 @@ gimplify_init_constructor (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p,
 	struct gimplify_init_ctor_preeval_data preeval_data;
 	HOST_WIDE_INT num_type_elements, num_ctor_elements;
 	HOST_WIDE_INT num_nonzero_elements;
-	bool cleared, valid_const_initializer, sparse;
+	bool cleared, valid_const_initializer;
 
 	/* Aggregate types must lower constructors to initialization of
 	   individual elements.  The exception is that a CONSTRUCTOR node
@@ -3558,9 +3558,6 @@ gimplify_init_constructor (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p,
 
 	num_type_elements = count_type_elements (type, true);
 
-	/* Are there significantly more zeros than non-zeros?  */
-	sparse = (num_nonzero_elements <= num_type_elements/4);
-
 	/* If count_type_elements could not determine number of type elements
 	   for a constant-sized object, assume clearing is needed.
 	   Don't do this for variable-sized objects, as store_constructor
@@ -3570,7 +3567,7 @@ gimplify_init_constructor (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p,
 	/* If there are "lots" of zeros, then block clear the object first.  */
 	else if (num_type_elements - num_nonzero_elements
 		 > CLEAR_RATIO (optimize_function_for_speed_p (cfun))
-		 && sparse)
+		 && num_nonzero_elements < num_type_elements/4)
 	  cleared = true;
 	/* ??? This bit ought not be needed.  For any element not present
 	   in the initializer, we should simply set them to zero.  Except
@@ -3585,9 +3582,12 @@ gimplify_init_constructor (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p,
 	   be dropped to memory, and then memcpy'd out.  Don't do this
 	   for sparse arrays, though, as it's more efficient to follow
 	   the standard CONSTRUCTOR behavior of memset followed by
-	   individual element initialization.  Also don't try to do
-	   bitwise copies of TREE_ADDRESSABLE types.  */
-	if (valid_const_initializer && !(cleared || sparse)
+	   individual element initialization.  Also don't do this for small
+	   all-zero initializers (which aren't big enough to merit
+	   clearing), and don't try to make bitwise copies of
+	   TREE_ADDRESSABLE types.  */
+	if (valid_const_initializer
+	    && !(cleared || num_nonzero_elements == 0)
 	    && !TREE_ADDRESSABLE (type))
 	  {
 	    HOST_WIDE_INT size = int_size_in_bytes (type);