[PATCH] Fix bootstrap fail on spu vs. ira.c/genpreds

[Vladimir Makarov]

Dave Korn wrote:
>     Hello all,
>
>
>   As discussed on the main list earlier today[*], there is currently an
> implicit assumption in ira.c that every backend implements at least one
> define_register_constraint; when the backend doesn't, genpreds does not output
> any definition for regclass_for_constraint and then ira.c (which refers to it
> unguarded) fails to link.
>
>
> gcc/ChangeLog
>
> 	* ira.c (setup_cover_and_important_classes):  Use safe macro
> 	REG_CLASS_FOR_CONSTRAINT instead of calling regclass_for_constraint
> 	directly.
> 	* genpreds.c (write_tm_preds_h):  Output suitable definition of
> 	REG_CLASS_FOR_CONSTRAINT.
>
>   The attached patch fixes the reported bug according to Revital; I'm putting
> it through a bootstrap right now (all languages except for Ada), on
> i686-pc-cygwin, which is a platform that won't hit the new code paths, so can
> I skip running the testsuites?  Ok for trunk?
>
>   
The patch posted in

http://gcc.gnu.org/ml/gcc/2009-04/msg00698.html

is done for older version of ira.c.  In the change context for ira.c 
instead of

 #ifdef CONSTRAINT__LIMIT

should be

#ifdef CONSTRAINT_NUM_DEFINED_P


Other than that the patch is ok.  Although, personally, I'd prefer the following
patch (because it does not create a new macro which is used only in one place
of the compiler):

2009-04-27  Vladimir Makarov  <vmakarov@redhat.com>

	* genpreds.c (write_enum_constraint_num): Output
	REG_CONSTRAINT_DEFINED_P instead of CONSTRAINT_NUM_DEFINED_P and
	only if there are register constraints.
	* ira.c (setup_cover_and_important_classes): Use
	REG_CONSTRAINT_DEFINED_P instead of CONSTRAINT_NUM_DEFINED_P.

Index: genpreds.c
===================================================================
--- genpreds.c	(revision 146793)
+++ genpreds.c	(working copy)
@@ -954,7 +954,8 @@ write_enum_constraint_num (void)
 {
   struct constraint_data *c;
 
-  fputs ("#define CONSTRAINT_NUM_DEFINED_P 1\n", stdout);
+  if (have_register_constraints)
+    fputs ("#define REG_CONSTRAINT_DEFINED_P 1\n", stdout);
   fputs ("enum constraint_num\n"
 	 "{\n"
 	 "  CONSTRAINT__UNKNOWN = 0", stdout);
Index: ira.c
===================================================================
--- ira.c	(revision 146793)
+++ ira.c	(working copy)
@@ -754,7 +754,7 @@ setup_cover_and_important_classes (void)
 	{
 	  if (i == NO_REGS)
 	    continue;
-#ifdef CONSTRAINT_NUM_DEFINED_P
+#ifdef REG_CONSTRAINT_DEFINED_P
 	  for (j = 0; j < CONSTRAINT__LIMIT; j++)
 	    if ((int) regclass_for_constraint ((enum constraint_num) j) == i)
 	      break;