[PATCH] Re: fold_builtin_memcpy cannot optimize <retval>? (take 2)

[Jakub Jelinek <jakub at redhat dot com>]

On Fri, Jan 21, 2005 at 10:03:53AM -0800, Mark Mitchell wrote:
> Jeffrey A Law wrote:
> 
> >I'm not an expert on the differences in the semantics of POINTER_TYPE
> >and REFERENCE_TYPE, but I do know that I've been treating them as
> >effectively the same.
> 
> The only difference is that a REFERENCE_TYPE object can never be NULL. 
> Other than that, they are identical.  (In C++, you cannot assign to a 
> reference, but that is expressed by TREE_READONLY on the object.)
> 
> I think that it makes sense to use POINTER_TYPE_P almost everywhere in 
> the middle-end.  The other choices is to introduce explicit NOP_EXPRs to 
> do the conversions -- but that's just a waste of memory, in my opinion.

Is this ok to commit then assuming bootstrap/regtest are ok?
Certainly cures the testcase.

2005-01-21  Jakub Jelinek  <jakub@redhat.com>

	* builtins.c (get_pointer_alignment, gimplify_va_arg_expr,
	expand_builtin_printf, expand_builtin_fprintf,
	expand_builtin_sprintf): Use POINTER_TYPE_P instead TREE_CODE
	checking against POINTER_TYPE.
	(validate_arglist): Handle POINTER_TYPE code by checking
	POINTER_TYPE_P.
	* g++.dg/tree-ssa/empty-1.C: New test.

--- gcc/builtins.c.jj	2005-01-13 21:25:42.000000000 +0100
+++ gcc/builtins.c	2005-01-21 22:46:16.495272151 +0100
@@ -201,7 +201,7 @@ get_pointer_alignment (tree exp, unsigne
 {
   unsigned int align, inner;
 
-  if (TREE_CODE (TREE_TYPE (exp)) != POINTER_TYPE)
+  if (! POINTER_TYPE_P (TREE_TYPE (exp)))
     return 0;
 
   align = TYPE_ALIGN (TREE_TYPE (TREE_TYPE (exp)));
@@ -215,7 +215,7 @@ get_pointer_alignment (tree exp, unsigne
 	case CONVERT_EXPR:
 	case NON_LVALUE_EXPR:
 	  exp = TREE_OPERAND (exp, 0);
-	  if (TREE_CODE (TREE_TYPE (exp)) != POINTER_TYPE)
+	  if (! POINTER_TYPE_P (TREE_TYPE (exp)))
 	    return align;
 
 	  inner = TYPE_ALIGN (TREE_TYPE (TREE_TYPE (exp)));
@@ -3988,7 +3988,7 @@ gimplify_va_arg_expr (tree *expr_p, tree
          In that case, unwrap both types so that we can compare the
 	 underlying records.  */
       if (TREE_CODE (have_va_type) == ARRAY_TYPE
-	  || TREE_CODE (have_va_type) == POINTER_TYPE)
+	  || POINTER_TYPE_P (have_va_type))
 	{
 	  want_va_type = TREE_TYPE (want_va_type);
 	  have_va_type = TREE_TYPE (have_va_type);
@@ -4486,7 +4486,7 @@ expand_builtin_printf (tree arglist, rtx
   if (! arglist)
     return 0;
   fmt = TREE_VALUE (arglist);
-  if (TREE_CODE (TREE_TYPE (fmt)) != POINTER_TYPE)
+  if (! POINTER_TYPE_P (TREE_TYPE (fmt)))
     return 0;
   arglist = TREE_CHAIN (arglist);
 
@@ -4499,7 +4499,7 @@ expand_builtin_printf (tree arglist, rtx
   if (strcmp (fmt_str, "%s\n") == 0)
     {
       if (! arglist
-          || TREE_CODE (TREE_TYPE (TREE_VALUE (arglist))) != POINTER_TYPE
+          || ! POINTER_TYPE_P (TREE_TYPE (TREE_VALUE (arglist)))
 	  || TREE_CHAIN (arglist))
 	return 0;
       fn = fn_puts;
@@ -4588,13 +4588,13 @@ expand_builtin_fprintf (tree arglist, rt
   if (! arglist)
     return 0;
   fp = TREE_VALUE (arglist);
-  if (TREE_CODE (TREE_TYPE (fp)) != POINTER_TYPE)
+  if (! POINTER_TYPE_P (TREE_TYPE (fp)))
     return 0;
   arglist = TREE_CHAIN (arglist);
   if (! arglist)
     return 0;
   fmt = TREE_VALUE (arglist);
-  if (TREE_CODE (TREE_TYPE (fmt)) != POINTER_TYPE)
+  if (! POINTER_TYPE_P (TREE_TYPE (fmt)))
     return 0;
   arglist = TREE_CHAIN (arglist);
 
@@ -4607,7 +4607,7 @@ expand_builtin_fprintf (tree arglist, rt
   if (strcmp (fmt_str, "%s") == 0)
     {
       if (! arglist
-          || TREE_CODE (TREE_TYPE (TREE_VALUE (arglist))) != POINTER_TYPE
+          || ! POINTER_TYPE_P (TREE_TYPE (TREE_VALUE (arglist)))
 	  || TREE_CHAIN (arglist))
 	return 0;
       arg = TREE_VALUE (arglist);
@@ -4675,13 +4675,13 @@ expand_builtin_sprintf (tree arglist, rt
   if (! arglist)
     return 0;
   dest = TREE_VALUE (arglist);
-  if (TREE_CODE (TREE_TYPE (dest)) != POINTER_TYPE)
+  if (! POINTER_TYPE_P (TREE_TYPE (dest)))
     return 0;
   arglist = TREE_CHAIN (arglist);
   if (! arglist)
     return 0;
   fmt = TREE_VALUE (arglist);
-  if (TREE_CODE (TREE_TYPE (fmt)) != POINTER_TYPE)
+  if (! POINTER_TYPE_P (TREE_TYPE (fmt)))
     return 0;
   arglist = TREE_CHAIN (arglist);
 
@@ -4717,7 +4717,7 @@ expand_builtin_sprintf (tree arglist, rt
       if (! arglist || TREE_CHAIN (arglist))
 	return 0;
       arg = TREE_VALUE (arglist);
-      if (TREE_CODE (TREE_TYPE (arg)) != POINTER_TYPE)
+      if (! POINTER_TYPE_P (TREE_TYPE (arg)))
 	return 0;
 
       if (target != const0_rtx)
@@ -8054,6 +8054,15 @@ validate_arglist (tree arglist, ...)
 	     true, otherwise return false.  */
 	  res = arglist == 0;
 	  goto end;
+	case POINTER_TYPE:
+	  /* If no parameters remain or the parameter's code does not
+	     match the specified code, return false.  Otherwise continue
+	     checking any remaining arguments.  POINTER_TYPE is handled
+	     specially, because REFERENCE_TYPE should match it as well.  */
+	  if (arglist == 0
+	      || ! POINTER_TYPE_P (TREE_TYPE (TREE_VALUE (arglist))))
+	    goto end;
+	  break;
 	default:
 	  /* If no parameters remain or the parameter's code does not
 	     match the specified code, return false.  Otherwise continue
--- gcc/testsuite/g++.dg/tree-ssa/empty-1.C.jj	2005-01-21 15:45:06.000000000 +0100
+++ gcc/testsuite/g++.dg/tree-ssa/empty-1.C	2005-01-21 15:46:07.000000000 +0100
@@ -0,0 +1,13 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+struct S {};
+S bar (const S &a)
+{
+  S s;
+  s = a;
+  return s;
+}
+
+/* Test whether memcpy call has been optimized out.  */
+/* { dg-final { scan-tree-dump-times "memcpy" 0 "optimized"} } */

	Jakub