[PATCH, ira] Ignore some conflict cost

Zhenqiang Chen zhenqiang.chen@arm.com
Mon Sep 22 03:03:00 GMT 2014


> -----Original Message-----
> From: Marek Polacek [mailto:polacek@redhat.com]
> Sent: Wednesday, September 17, 2014 5:29 PM
> To: Zhenqiang Chen
> Cc: gcc-patches@gcc.gnu.org
> Subject: Re: [PATCH, ira] Ignore some conflict cost
> 
> On Wed, Sep 17, 2014 at 05:18:27PM +0800, Zhenqiang Chen wrote:
> > Hi,
> >
> > When assign_hard_reg, we always check_hard_reg_p, which has code
> >
> > if (! TEST_HARD_REG_BIT (profitable_regs, hard_regno))
> >   return false;
> >
> > i.e. If a hard_regno is not in profitable_regs, we can not allocate it
> > to the ira_allocno_t A.
> >
> > So the conflict on a hard_regno, which does not belong to the
> > profitable_regs, can be ignored. Please refer
> > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63210 for the detail of
> > the test case.
> >
> > Bootstrap and no make check regression on X86-64 and ARM Chromebook.
> > NO spec2k performance regression on X86-64 and ARM Chromebook.
> > CSiBE code size is 0.01% better for ARM Cortex-M0.
> 
> Note that your MUA malformed the patch, so it can't be easily applied.

Thanks for the comments. Resend it as an attachment.

-Zhenqiang
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