re PR java/39940 (failure in jc1 on i686-apple-darwin9 host)

2009-05-02  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/39940
	* tree-ssa-pre.c (eliminate): Make sure we may propagate before
	doing so.

From-SVN: r147065

gcc/ChangeLog

 2009-05-02  Richard Guenther  <rguenther@suse.de>
 
+	PR tree-optimization/39940
+	* tree-ssa-pre.c (eliminate): Make sure we may propagate before
+	doing so.
+
+2009-05-02  Richard Guenther  <rguenther@suse.de>
+
 	PR middle-end/40001
 	* tree-ssa.c (execute_update_addresses_taken): Properly check
 	if we can mark a variable DECL_GIMPLE_REG_P.

gcc/tree-ssa-pre.c

@@ -4215,7 +4215,9 @@ eliminate (void)
       /* If there is a single use only, propagate the equivalency
 	 instead of keeping the copy.  */
       if (TREE_CODE (lhs) == SSA_NAME
-	  && single_imm_use (lhs, &use_p, &use_stmt))
+	  && single_imm_use (lhs, &use_p, &use_stmt)
+	  && may_propagate_copy (USE_FROM_PTR (use_p),
+				 gimple_assign_rhs1 (stmt)))
 	{
 	  SET_USE (use_p, gimple_assign_rhs1 (stmt));
 	  update_stmt (use_stmt);