[Bug optimization/12209] [3.4 Regression] GCC fails to bootstrap Cygwin with -funit-at-a-time

[dannysmith at gcc dot gnu dot org]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12209



------- Additional Comments From dannysmith at gcc dot gnu dot org  2003-10-09 22:41 -------
Hi,

My rather naive attempt to fix for unit-at-a-time optimization is just to mimic 
fastcall.

The following patch seems to work on simple testcase, but I'm sure I missed 
something. Bootstrap in progress.  The building of libgcj will take some time 
(overnight on my machine)

	* config/i386.c (ix86_function_regparm): Return 2 for cgraph
	local function optimization if TARGET_STACK_PROBE.
	(init_cum_args): Set cum->fastcall for cgraph local function
	optimization if TARGET_STACK_PROBE.


Index: i386.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/i386/i386.c,v
retrieving revision 1.605
diff -c -3 -p -r1.605 i386.c
*** i386.c	6 Oct 2003 23:18:31 -0000	1.605
--- i386.c	9 Oct 2003 22:11:54 -0000
*************** ix86_function_regparm (tree type, tree d
*** 1699,1706 ****
  	  if (i && i->local)
  	    {
  	      /* We can't use regparm(3) for nested functions as these use
! 		 static chain pointer in third argument.  */
! 	      if (DECL_CONTEXT (decl) && !DECL_NO_STATIC_CHAIN (decl))
  		regparm = 2;
  	      else
  		regparm = 3;
--- 1699,1708 ----
  	  if (i && i->local)
  	    {
  	      /* We can't use regparm(3) for nested functions as these use
! 		 static chain pointer in third argument.
! 		 If maybe probing stack, use fastcall to avoid eax clobber.  */
! 	      if ((DECL_CONTEXT (decl) && !DECL_NO_STATIC_CHAIN (decl))
! 		  || TARGET_STACK_PROBE)
  		regparm = 2;
  	      else
  		regparm = 3;
*************** init_cumulative_args (CUMULATIVE_ARGS *c
*** 1855,1860 ****
--- 1857,1874 ----
        || (fntype && !TYPE_ARG_TYPES (fntype)))
      cum->maybe_vaarg = 1;
  
+   if (TARGET_STACK_PROBE && flag_unit_at_a_time
+       && !cum->fastcall
+       && cum->nregs)
+     {
+       struct cgraph_local_info *i = cgraph_local_info (fndecl);
+       if (i && i->local)
+ 	{
+ 	  cum->nregs = 2;
+ 	  cum->fastcall = 1;
+ 	}
+     }
+ 
    if (TARGET_DEBUG_ARG)
      fprintf (stderr, ", nregs=%d )\n", cum->nregs);