[Bug rtl-optimization/32296] [4.3 Regression] Bootstrap failure in stage1 on hppa*-*-*

["spark at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #11 from spark at gcc dot gnu dot org  2007-06-14 03:53 -------
(In reply to comment #10)
> Subject: Re:  [4.3 Regression] Bootstrap failure in stage1 on hppa*-*-*
> 
> > It's my turn to ask: so what information does hppa_can_use_return_p
> > need to make the decision ?
> 
> We need to know that the return pointer (r2) is not used and that
> the function is a leaf function (i.e., that the incoming value in
> r2 is unchanged).  Calls clobber r2.
> 
> Dave

Sounds like the following patch would work:

diff -r 149399c845b5 gcc/config/pa/pa.c
--- a/gcc/config/pa/pa.c        Tue Jun 12 15:49:27 2007 -0700
+++ b/gcc/config/pa/pa.c        Wed Jun 13 18:37:17 2007 -0700
@@ -4415,7 +4415,7 @@ hppa_can_use_return_insn_p (void)
 {
   return (reload_completed
          && (compute_frame_size (get_frame_size (), 0) ? 0 : 1)
-         && df_hard_reg_used_count (2) == 1
+         && DF_REG_DEF_COUNT (2) == 0
          && ! frame_pointer_needed);
 }


This essentially checks if r2 is ever written within the function
(including the calls since r2 is included in the CALL_USED_REGS).


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32296