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Re: 27% regression of gcc 4.3 performance on cpu2k6/calculix
- From: "H. J. Lu" <hjl at lucon dot org>
- To: Vladimir Sysoev <vladimir dot sysoev at gmail dot com>
- Cc: gcc at gcc dot gnu dot org
- Date: Thu, 8 Feb 2007 09:03:23 -0800
- Subject: Re: 27% regression of gcc 4.3 performance on cpu2k6/calculix
- References: <45C9DD96.4090101@linux.intel.com> <275bfc6c0702070632i69f99d55k6a0c2c140287d462@mail.gmail.com>
On Wed, Feb 07, 2007 at 05:32:28PM +0300, Vladimir Sysoev wrote:
> Hi!
> I create test to reproduce issue with cpu2006/454.calculix
> See attached. File e_c3d.f contains cutted subroutine from calculix.
> tr535.f main entry point of the test. you can use go-script as a
> reference how i get these results. find_stall.pl script which find
> problem instruction combinations.
>
> Problem that new compiler generates read instruction right after
> write. See some dumps below.
>
A bug report is opened:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30735
H.J.