expr.c (block_move_libcall_safe_for_call_parm): Clean up...

	* expr.c (block_move_libcall_safe_for_call_parm): Clean up,
	and add case for machines where outgoing register parameters
	get stack space.

From-SVN: r72474

gcc/ChangeLog

 2003-10-14  Geoffrey Keating  <geoffk@apple.com>
 
+	* expr.c (block_move_libcall_safe_for_call_parm): Clean up,
+	and add case for machines where outgoing register parameters
+	get stack space.
+
 	* config/darwin.c (machopic_indirect_data_reference): Use a scratch
 	register when generating indirect address.
 

gcc/expr.c

@@ -1394,18 +1394,23 @@ emit_block_move (rtx x, rtx y, rtx size, enum block_op_methods method)
 static bool
 block_move_libcall_safe_for_call_parm (void)
 {
+  /* If arguments are pushed on the stack, then they're safe.  */
   if (PUSH_ARGS)
     return true;
-  else
-    {
-      /* Check to see whether memcpy takes all register arguments.  */
-      static enum {
-	takes_regs_uninit, takes_regs_no, takes_regs_yes
-      } takes_regs = takes_regs_uninit;
 
-      switch (takes_regs)
+  /* If registers go on the stack anyway, any argument is sure to clobber 
+     an outgoing argument.  */
+#if defined (REG_PARM_STACK_SPACE) && defined (OUTGOING_REG_PARM_STACK_SPACE)
   {
-	case takes_regs_uninit:
+    tree fn = emit_block_move_libcall_fn (false);
+    (void) fn;
+    if (REG_PARM_STACK_SPACE (fn) != 0)
+      return false;
+  }
+#endif
+
+  /* If any argument goes in memory, then it might clobber an outgoing
+     argument.  */
   {
     CUMULATIVE_ARGS args_so_far;
     tree fn, arg;
@@ -1419,31 +1424,16 @@ block_move_libcall_safe_for_call_parm (void)
 	enum machine_mode mode = TYPE_MODE (TREE_VALUE (arg));
 	rtx tmp = FUNCTION_ARG (args_so_far, mode, NULL_TREE, 1);
 	if (!tmp || !REG_P (tmp))
-		  goto fail_takes_regs;
+	  return false;
 #ifdef FUNCTION_ARG_PARTIAL_NREGS
 	if (FUNCTION_ARG_PARTIAL_NREGS (args_so_far, mode,
 					NULL_TREE, 1))
-		  goto fail_takes_regs;
+	  return false;
 #endif
 	FUNCTION_ARG_ADVANCE (args_so_far, mode, NULL_TREE, 1);
       }
   }
-	  takes_regs = takes_regs_yes;
-	  /* FALLTHRU */
-
-	case takes_regs_yes:
   return true;
-
-	fail_takes_regs:
-	  takes_regs = takes_regs_no;
-	  /* FALLTHRU */
-	case takes_regs_no:
-	  return false;
-
-	default:
-	  abort ();
-	}
-    }
 }
 
 /* A subroutine of emit_block_move.  Expand a movstr pattern;