This is the mail archive of the gcc-patches@gcc.gnu.org mailing list for the GCC project.

Index Nav:	[Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav:	[Date Prev] [Date Next]	[Thread Prev] [Thread Next]
Other format:	[Raw text]

Re: Remove redundant AND from count reduction loop

From: Jeff Law <law at redhat dot com>
To: Richard Biener <richard dot guenther at gmail dot com>, GCC Patches <gcc-patches at gcc dot gnu dot org>, richard dot sandiford at arm dot com
Date: Wed, 24 Jun 2015 10:05:33 -0600
Subject: Re: Remove redundant AND from count reduction loop
Authentication-results: sourceware.org; auth=none
References: <87pp4m8mkp dot fsf at e105548-lin dot cambridge dot arm dot com> <alpine dot DEB dot 2 dot 20 dot 1506232307180 dot 1715 at laptop-mg dot saclay dot inria dot fr> <CAFiYyc0F3YqAjr2+EMf8STUBrVN+bE3aYpC+1nnstSaf2oiaDg at mail dot gmail dot com> <87egl1sa2p dot fsf at e105548-lin dot cambridge dot arm dot com> <CAFiYyc0_JiQSZ=M1NqZAaDgh6kYy_EXtpZp9cd2NJOtTG46ang at mail dot gmail dot com> <87a8vps6p1 dot fsf at e105548-lin dot cambridge dot arm dot com> <CAFiYyc1M4-j8QOWSkowHp8fh5D9ScYACEDPQ0KHH52tEBrP54g at mail dot gmail dot com>

On 06/24/2015 05:43 AM, Richard Biener wrote:

Note that ISTR code performing exactly the opposite transform in
fold-const.c ...


That's another reason why I'm worried about just doing the (negate ...)
thing without knowing whether the negate can be folded into anything else.


I'm not aware of anything here.

It's worth looking at -- I've certainly seen cases where we end upinfinite recursion because we've got a transformation in once place (saymatch.pd) and its inverse elsewhere (fold-const.c).


Jeff

References:
- Remove redundant AND from count reduction loop
  - From: Richard Sandiford
- Re: Remove redundant AND from count reduction loop
  - From: Marc Glisse
- Re: Remove redundant AND from count reduction loop
  - From: Richard Biener
- Re: Remove redundant AND from count reduction loop
  - From: Richard Sandiford
- Re: Remove redundant AND from count reduction loop
  - From: Richard Biener
- Re: Remove redundant AND from count reduction loop
  - From: Richard Sandiford
- Re: Remove redundant AND from count reduction loop
  - From: Richard Biener

Index Nav:	[Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav:	[Date Prev] [Date Next]	[Thread Prev] [Thread Next]