Re: computation_cost too blind to hard regs

[DJ Delorie]

> On Jan 19, 2005, at 22:48, Richard Henderson wrote:
> > On Wed, Jan 19, 2005 at 09:19:58PM -0500, DJ Delorie wrote:
> >> -  int regno = 0;
> >> +  int regno = FIRST_PSEUDO_REGISTER;
> >
> > To be totally safe, you need LAST_VIRTUAL_REGISTER+1.
> 
> Also, this definitely needs a comment.

Ok, I'm back.  How's this?

        * tree-ssa-loop-ivopts.c (computation_cost): Start register
        numbering at LAST_VIRTUAL_REGISTER+1 to avoid possibly using hard
        registers in unsupported ways.
        * expmed.c (init_expmed): Likewise.


Index: expmed.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/expmed.c,v
retrieving revision 1.224
diff -p -U3 -r1.224 expmed.c
--- expmed.c    18 Feb 2005 12:06:00 -0000      1.224
+++ expmed.c    22 Feb 2005 00:35:19 -0000
@@ -145,7 +145,8 @@ init_expmed (void)
   memset (&all, 0, sizeof all);
 
   PUT_CODE (&all.reg, REG);
-  REGNO (&all.reg) = 10000;
+  /* Avoid using hard regs in ways which may be unsupported.  */
+  REGNO (&all.reg) = LAST_VIRTUAL_REGISTER + 1;
 
   PUT_CODE (&all.plus, PLUS);
   XEXP (&all.plus, 0) = &all.reg;
Index: tree-ssa-loop-ivopts.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/tree-ssa-loop-ivopts.c,v
retrieving revision 2.48
diff -p -U3 -r2.48 tree-ssa-loop-ivopts.c
--- tree-ssa-loop-ivopts.c      17 Feb 2005 16:19:45 -0000      2.48
+++ tree-ssa-loop-ivopts.c      22 Feb 2005 00:35:19 -0000
@@ -2427,7 +2427,8 @@ computation_cost (tree expr)
   rtx seq, rslt;
   tree type = TREE_TYPE (expr);
   unsigned cost;
-  int regno = 0;
+  /* Avoid using hard regs in ways which may be unsupported.  */
+  int regno = LAST_VIRTUAL_REGISTER + 1;
 
   walk_tree (&expr, prepare_decl_rtl, &regno, NULL);
   start_sequence ();