have basic_block types GCed from RTL

[Geoffrey Keating]

I experienced a bootstrap failure building builtins.c, because
the basic block of some NOTE_INSN had been GCed.  This fixes it, or at
least ensures that the memory accessed has not been freed.

Bootstrapped & tested on powerpc-darwin8.

-- 
- Geoffrey Keating <geoffk@apple.com>

===File ~/patches/gcc-gengtype-basicblockgc.patch===========
2005-06-16  Geoffrey Keating  <geoffk@apple.com>

	* gengtype.c (adjust_field_rtx_def): Don't add a skip to
	basic_block types.

Index: gengtype.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/gengtype.c,v
retrieving revision 1.75
diff -u -p -u -p -r1.75 gengtype.c
--- gengtype.c	17 May 2005 20:11:42 -0000	1.75
+++ gengtype.c	16 Jun 2005 22:09:31 -0000
@@ -628,14 +628,6 @@ adjust_field_rtx_def (type_p t, options_
 	      subfields->opt->name = "desc";
 	      subfields->opt->info = "NOTE_LINE_NUMBER (&%0)";
 	    }
-	  else if (t == basic_block_tp)
-	    {
-	      /* We don't presently GC basic block structures...  */
-	      subfields->opt = XNEW (struct options);
-	      subfields->opt->next = nodot;
-	      subfields->opt->name = "skip";
-	      subfields->opt->info = NULL;
-	    }
 	  else
 	    subfields->opt = nodot;
 	}
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