pa reload problem

[John David Anglin]

> Hi Dave,
>   Richard and I had wandered off-topic in the above exchange, and were
> talking about modutils and stubs, in particular stub calls to millicode.
> 
> Getting back on topic, the reload problem _does_ affect 32 bit hppa code.
> Compiling my testcase with -O2 -fPIC -S, gives
> 
>         copy %r19,%r4
>         bl foo,%r2
>         stw %r19,-32(%r30)
>         addil LT'cpu_hz,%r4
>         copy %r1,%r21
>         addil LT'.LC0,%r19		! oops

For some reason, I only saw this with the 64 bit version.

There is one other bit of code in rtlanal.c related to the patch which
bothers me.  I am wondering if it is ok or needs changing:

#ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
      /* ??? When call-clobbered, the value is stable modulo the restore
         that must happen after a call.  This currently screws up local-alloc
         into believing that the restore is not needed.  */
      if (x == pic_offset_table_rtx)
        return 0;
#endif

This is in rtx_unstable_p and rtx_varies_p.  Possibly, now that there is
a use until reload is complete, this problem is fixed and the
pic_offset_table_rtx should be stable even when
PIC_OFFSET_TABLE_REG_CALL_CLOBBERED?  See comment at beginning of
rtx_varies_p.

Dave
-- 
J. David Anglin                                  dave.anglin@nrc.ca
National Research Council of Canada              (613) 990-0752 (FAX: 952-6605)