[PATCH] Disable tree-stdarg on a per-target basis

[Eric Botcazou <ebotcazou at libertysurf dot fr>]

Hi,

This patch adds a new target flag, TARGET_STDARG_OPTIMIZE_DISABLE, to make it 
possible to disable the tree-level stdarg optimization pass, and defines it to 
true on SPARC (I think the RTL CSE + DCE passes already eliminate as much 
stdarg overhead as tree-stdarg would there).

Tested on sparc-sun-solaris2.10.  OK for mainline?


2005-05-26  Eric Botcazou  <ebotcazou@libertysurf.fr>

	* target.h (gcc_target): New field stdarg_optimize_disable.
	* target-def.h (TARGET_STDARG_OPTIMIZE_DISABLE): New
	hook defaulting to false.
	(TARGET_INITIALIZER): Add it.
	* doc/tm.texi (Varargs): Document it.
	* tree-stdarg.c (gate_optimize_stdarg): Unconditionally return
	false if TARGET_STDARG_OPTIMIZE_DISABLE.
	* config/sparc/sparc.c (TARGET_STDARG_OPTIMIZE_DISABLE): Define
	to true.


-- 
Eric Botcazou

Index: target-def.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/target-def.h,v
retrieving revision 1.121
diff -u -p -r1.121 target-def.h
--- target-def.h	2 May 2005 16:02:22 -0000	1.121
+++ target-def.h	26 May 2005 08:56:57 -0000
@@ -386,6 +386,7 @@ Foundation, 59 Temple Place - Suite 330,
 
 #define TARGET_DWARF_HANDLE_FRAME_UNSPEC 0
 
+#define TARGET_STDARG_OPTIMIZE_DISABLE false
 #define TARGET_STDARG_OPTIMIZE_HOOK 0
 
 #define TARGET_PROMOTE_FUNCTION_ARGS hook_bool_tree_false
@@ -565,6 +566,7 @@ Foundation, 59 Temple Place - Suite 330,
   TARGET_HANDLE_PRAGMA_REDEFINE_EXTNAME,	\
   TARGET_HANDLE_PRAGMA_EXTERN_PREFIX,		\
   TARGET_RELAXED_ORDERING,			\
+  TARGET_STDARG_OPTIMIZE_DISABLE,		\
 }
 
 #include "hooks.h"
Index: target.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/target.h,v
retrieving revision 1.133
diff -u -p -r1.133 target.h
--- target.h	2 May 2005 16:02:23 -0000	1.133
+++ target.h	26 May 2005 08:56:57 -0000
@@ -650,6 +650,9 @@ struct gcc_target
      synchronization is explicitly requested.  */
   bool relaxed_ordering;
 
+  /* True if the tree-stdarg pass need no be run.  */
+  bool stdarg_optimize_disable;
+
   /* Leave the boolean fields at the end.  */
 };
 
Index: tree-stdarg.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/tree-stdarg.c,v
retrieving revision 2.4
diff -u -p -r2.4 tree-stdarg.c
--- tree-stdarg.c	28 Apr 2005 02:25:22 -0000	2.4
+++ tree-stdarg.c	26 May 2005 08:56:57 -0000
@@ -596,6 +596,9 @@ check_all_va_list_escapes (struct stdarg
 static bool
 gate_optimize_stdarg (void)
 {
+  if (targetm.stdarg_optimize_disable)
+    return false;
+
   /* This optimization is only for stdarg functions.  */
   return current_function_stdarg != 0;
 }
Index: doc/tm.texi
===================================================================
RCS file: /cvs/gcc/gcc/gcc/doc/tm.texi,v
retrieving revision 1.427
diff -u -p -r1.427 tm.texi
--- doc/tm.texi	4 May 2005 16:27:21 -0000	1.427
+++ doc/tm.texi	26 May 2005 08:57:01 -0000
@@ -4685,6 +4685,11 @@ defined, then define this hook to return
 Otherwise, you should not define this hook.
 @end deftypefn
 
+@deftypefn {Target Hook} bool TARGET_STDARG_OPTIMIZE_DISABLE
+If the tree-level stdarg optimization pass need not be run, define this
+flag to @code{true}.
+@end deftypefn
+
 @node Trampolines
 @section Trampolines for Nested Functions
 @cindex trampolines for nested functions
Index: config/sparc/sparc.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/sparc/sparc.c,v
retrieving revision 1.373
diff -u -p -r1.373 sparc.c
--- config/sparc/sparc.c	25 May 2005 07:03:59 -0000	1.373
+++ config/sparc/sparc.c	26 May 2005 08:57:02 -0000
@@ -518,6 +518,9 @@ static bool fpu_option_set = false;
 #undef TARGET_ASM_FILE_END
 #define TARGET_ASM_FILE_END sparc_file_end
 
+#undef TARGET_STDARG_OPTIMIZE_DISABLE
+#define TARGET_STDARG_OPTIMIZE_DISABLE true
+
 struct gcc_target targetm = TARGET_INITIALIZER;
 
 /* Implement TARGET_HANDLE_OPTION.  */