emit-rtl.c (change_address_1): Do not re-generate the RTX if nothing change.

	* emit-rtl.c (change_address_1):  Do not re-generate the RTX if nothing
	change.

From-SVN: r76457

gcc/ChangeLog

 2004-01-23  Jan Hubicka  <jh@suse.cz>
 
+	* emit-rtl.c (change_address_1):  Do not re-generate the RTX if nothing
+	change.
+
 	* alloc-pool.c (align_four): Kill.
 	(create_alloc_pool): Align size to eight.
 	(free_alloc_pool, free_pool): Invalidate deallocated data.

gcc/emit-rtl.c

@@ -1840,6 +1840,9 @@ change_address_1 (rtx memref, enum machine_mode mode, rtx addr, int validate)
     mode = GET_MODE (memref);
   if (addr == 0)
     addr = XEXP (memref, 0);
+  if (mode == GET_MODE (memref) && addr == XEXP (memref, 0)
+      && (!validate || memory_address_p (mode, addr)))
+    return memref;
 
   if (validate)
     {