expr.c (expand_expr, [...]): Do not replace an array element with the known…

expr.c (expand_expr, [...]): Do not replace an array element with the known initializing value if...

	* expr.c (expand_expr, case ARRAY_REF): Do not replace
	an array element with the known initializing value if it has
	side-effects.

	* toplev.c (rest_of_compilation): Remove dead code before
	purge_addressof.

From-SVN: r43120

gcc/ChangeLog

+2001-06-09  Mark Mitchell  <mark@codesourcery.com>
+
+	* expr.c (expand_expr, case ARRAY_REF): Do not replace
+	an array element with the known initializing value if it has
+	side-effects.
+
+	* toplev.c (rest_of_compilation): Remove dead code before
+	purge_addressof.
+	
 2001-06-09  Neil Booth  <neil@daikokuya.demon.co.uk>
 
 	* cppinit.c (print_help): Document -fpreprocessed.

gcc/expr.c

@@ -6891,7 +6891,7 @@ expand_expr (exp, target, tmode, modifier)
 			 elem = TREE_CHAIN (elem))
 		      ;
 
-		    if (elem)
+		    if (elem && !TREE_SIDE_EFFECTS (elem))
 		      return expand_expr (fold (TREE_VALUE (elem)), target,
 					  tmode, ro_modifier);
 		  }

gcc/toplev.c

@@ -3031,6 +3031,16 @@ rest_of_compilation (decl)
 	  timevar_pop (TV_JUMP);
 	}
 
+      /* It's important to remove dead code before we call
+	 purge_addressof.  Sometimes, the only ADDRESSOFs for a REG
+	 will be dead, and if we don't get rid of them, we will end up
+	 committing ourselves to dumping the REG to the stack
+	 unnecessarily.  */
+      find_basic_blocks (insns, max_reg_num (), rtl_dump_file);
+      cleanup_cfg ();
+      life_analysis (insns, rtl_dump_file, 
+		     PROP_SCAN_DEAD_CODE | PROP_KILL_DEAD_CODE);
+      
       /* The second pass of jump optimization is likely to have
          removed a bunch more instructions.  */
       renumber_insns (rtl_dump_file);