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Re: [PATCH] Run DCE after if conversion

From: Jeff Law <law at redhat dot com>
To: Andreas Krebbel <krebbel at linux dot vnet dot ibm dot com>, Richard Biener <richard dot guenther at gmail dot com>
Cc: Steven Bosscher <stevenb dot gcc at gmail dot com>, GCC Patches <gcc-patches at gcc dot gnu dot org>
Date: Tue, 17 Mar 2015 12:29:13 -0600
Subject: Re: [PATCH] Run DCE after if conversion
Authentication-results: sourceware.org; auth=none
References: <20150310075708 dot GA7213 at maggie> <CABu31nNKjPMbzydVG_6aptQPSXm9EZ7XmDqTh6erO53tLaGXVw at mail dot gmail dot com> <54FEB70B dot 1010106 at linux dot vnet dot ibm dot com> <CAFiYyc1N=vwrNsbQb5pWXC+++H5OxacgjWZa+Ntvio7RmQqBxg at mail dot gmail dot com> <5507E334 dot 1000200 at linux dot vnet dot ibm dot com>

On 03/17/2015 02:17 AM, Andreas Krebbel wrote:


Just to have some numbers I did run a -j1 GCC bootstrap twice with and without the patch on x86_64.
Best results for both are:

clean:   21459s
patched: 21314s

There rather appears to be a trend towards reduced compile time perhaps due to the reduced number of
INSNs to be processed in the RTL passes between the two ifcvt runs (loop optimization, combine,
fwprop, dse,...)?!

I also tried to measure the testsuite runs but the results show a big variance. So what I have right
now does not qualify as a benchmark.

And reality is it's getting harder and harder to benchmark this kind ofthing with turbo modes and such. A single run isn't sufficient unlessyou've locked the box into a particular cpu frequency.


jeff

Follow-Ups:
- Re: [PATCH] Run DCE after if conversion
  - From: Richard Biener

References:
- [PATCH] Run DCE after if conversion
  - From: Andreas Krebbel
- Re: [PATCH] Run DCE after if conversion
  - From: Steven Bosscher
- Re: [PATCH] Run DCE after if conversion
  - From: Andreas Krebbel
- Re: [PATCH] Run DCE after if conversion
  - From: Richard Biener
- Re: [PATCH] Run DCE after if conversion
  - From: Andreas Krebbel

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