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Date: Mon, 13 May 2019 10:33:00 -0000
From: Richard Biener <rguenther@suse.de>
To: Segher Boessenkool <segher@kernel.crashing.org>
cc: Jiufu Guo <guojiufu@linux.ibm.com>, Jeff Law <law@redhat.com>,     gcc-patches@gcc.gnu.org, jakub@redhat.com, dberlin@dberlin.org,     wschmidt@linux.ibm.com
Subject: Re: [PATCH] Eliminates phi on branch for CMP result
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On Mon, 13 May 2019, Segher Boessenkool wrote:

> On Sun, May 12, 2019 at 10:07:28PM -0500, Jiufu Guo wrote:
> > To elimiate the instructions which moving result of CMP to GPR, I'm
> > wondering maybe we could do a combine(or a peephole) after bbro to let
> > the condition jump directly using the result of CMP.
> 
> It will have to be a peephole.  And peepholes are machine-specific.
> 
> You will also not get any further optimisations in those blocks, that way;
> not combine etc.
> 
> It really should be done on gimple, not rtl.

Agreed.