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Re: [PATCH] rs6000: Improve rtx_costs for EQ a bit (PR30967)
- From: David Edelsohn <dje dot gcc at gmail dot com>
- To: Segher Boessenkool <segher at kernel dot crashing dot org>
- Cc: GCC Patches <gcc-patches at gcc dot gnu dot org>
- Date: Thu, 14 May 2015 09:51:18 -0400
- Subject: Re: [PATCH] rs6000: Improve rtx_costs for EQ a bit (PR30967)
- Authentication-results: sourceware.org; auth=none
- References: <3d6c05579541bab52972a84232e5767a8b1b79ad dot 1431536316 dot git dot segher at kernel dot crashing dot org> <CAGWvny=SWe=mnk91_gxkoR7+q6EbJW+69DKnCjSkdbS700ZcHQ at mail dot gmail dot com> <20150513172909 dot GE16798 at gate dot crashing dot org>
On Wed, May 13, 2015 at 1:29 PM, Segher Boessenkool
<segher@kernel.crashing.org> wrote:
> On Wed, May 13, 2015 at 01:25:16PM -0400, David Edelsohn wrote:
>> > PR rtl-optimization/30967
>> > * config/rs6000/rs6000.c (rs6000_rtx_costs): Don't consider
>> > destination mode for the cost of scc patterns.
>>
>> Okay.
>>
>> Should this be applied to GCC 5 branch?
>
> [ Testing is still in progress. ]
>
> It should be prefectly safe to backport; OTOH, it is just one of very
> many cases where we generate an extra sign-extend, so I don't think it
> is particularly useful. Your choice :-)
The other prereqs are backported, so probably should backport this also.
Fixing this is a process, not an event.
- David