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Fix code size estimates wrt variadic functions
- From: Jan Hubicka <hubicka at ucw dot cz>
- To: gcc-patches at gcc dot gnu dot org, rguenther at suse dot de
- Date: Tue, 1 Jun 2010 02:02:40 +0200
- Subject: Fix code size estimates wrt variadic functions
Hi,
another common bogus inlines are trim_filename and rtl_checking_flag_failed.
They are called from error checking code that inliner should refuse to inline
because calls should be hot because of noreturn flag.
The reason for this is more stubble. The checking things takes usually many
arguments and pass them to internal_error.
When counting call cost we look into declaration arguments and thus we count
variadic function calls as cheap. This leads inliner to think that inlining
those wrappers is going to reduce code size.
Fixed as follows.
Bootstraped/regtested x86_64-linux, OK?
Honza
* tree-inline.c (estimate_num_insns): For stdarg functions look
into call statement to count cost of argument passing.
Index: tree-inline.c
===================================================================
--- tree-inline.c (revision 160079)
+++ tree-inline.c (working copy)
@@ -3367,6 +3367,7 @@
tree decl = gimple_call_fndecl (stmt);
tree addr = gimple_call_fn (stmt);
tree funtype = TREE_TYPE (addr);
+ bool stdarg = false;
if (POINTER_TYPE_P (funtype))
funtype = TREE_TYPE (funtype);
@@ -3475,17 +3476,26 @@
if (!VOID_TYPE_P (TREE_TYPE (funtype)))
cost += estimate_move_cost (TREE_TYPE (funtype));
+
+ if (funtype)
+ stdarg = stdarg_p (funtype);
+
/* Our cost must be kept in sync with
cgraph_estimate_size_after_inlining that does use function
- declaration to figure out the arguments. */
- if (decl && DECL_ARGUMENTS (decl))
+ declaration to figure out the arguments.
+
+ For functions taking variable list of arguments we must
+ look into call statement intself. This is safe because
+ we will get only higher costs and in most cases we will
+ not inline these anyway. */
+ if (decl && DECL_ARGUMENTS (decl) && !stdarg)
{
tree arg;
for (arg = DECL_ARGUMENTS (decl); arg; arg = TREE_CHAIN (arg))
if (!VOID_TYPE_P (TREE_TYPE (arg)))
cost += estimate_move_cost (TREE_TYPE (arg));
}
- else if (funtype && prototype_p (funtype))
+ else if (funtype && prototype_p (funtype) && !stdarg)
{
tree t;
for (t = TYPE_ARG_TYPES (funtype); t && t != void_list_node;