[Bug rtl-optimization/50101] GCC 4.5 and 4.6 generate suboptimal code on ppc for countdown loops when the CTR register cannot be used

[meissner at linux dot vnet.ibm.com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50101

--- Comment #8 from Michael Meissner <meissner at linux dot vnet.ibm.com> 2011-08-19 14:05:51 UTC ---
On Thu, Aug 18, 2011 at 08:58:28AM +0000, rguenth at gcc dot gnu.org wrote:
> Did you try pessimizing the non-ctr reg alternatives (and the memory
> alternative even more)?  Like adding ! to the non-ctr alternatives
> and ? to the memory one?  Not sure if those markers are looked at
> by IRA though.

Yes, I should have mentioned that I tried various combinations of ?, !, and *
and the combinations I tried aborted.  I've certainly suspected that IRA now
longer looks at !, ?, and * like the previous register allocator did
previously.  It may be that it is  special due to being a JUMP_INSN.