re PR tree-optimization/92645 (Hand written vector code is 450 times slower when…

re PR tree-optimization/92645 (Hand written vector code is 450 times slower when compiled with GCC compared to Clang)

2019-12-03  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/92645
	* tree-ssa.c (execute_update_addresses_taken): Avoid representing
	a full def of a vector via a BIT_INSERT_EXPR.

From-SVN: r278920

gcc/ChangeLog

+2019-12-03  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/92645
+	* tree-ssa.c (execute_update_addresses_taken): Avoid representing
+	a full def of a vector via a BIT_INSERT_EXPR.
+
 2019-12-02  Bill Schmidt  <wschmidt@linux.ibm.com>
 
         * config/rs6000/rs6000-call.c (rs6000_invalid_builtin): Make

gcc/tree-ssa.c

@@ -1899,6 +1899,11 @@ execute_update_addresses_taken (void)
 		    && bitmap_bit_p (suitable_for_renaming, DECL_UID (sym))
 		    && VECTOR_TYPE_P (TREE_TYPE (sym))
 		    && TYPE_MODE (TREE_TYPE (sym)) != BLKmode
+		    /* If it is a full replacement we can do better below.  */
+		    && maybe_ne (wi::to_poly_offset
+				   (TYPE_SIZE_UNIT (TREE_TYPE (lhs))),
+				 wi::to_poly_offset
+                                   (TYPE_SIZE_UNIT (TREE_TYPE (sym))))
 		    && known_ge (mem_ref_offset (lhs), 0)
 		    && known_gt (wi::to_poly_offset
 				   (TYPE_SIZE_UNIT (TREE_TYPE (sym))),