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Re: Optimizations documentation

From: Tim Prince <tprince at computer dot org>
To: Ira Rosen <IRAR at il dot ibm dot com>
Cc: ÐÐÐÑÑÐÐÑÐÐ <oks-mgn at mail dot ru>, gcc at gnu dot org
Date: Wed, 02 Jan 2008 07:00:08 -0800
Subject: Re: Optimizations documentation
References: <OF76E4EB99.31551881-ONC22573C4.00470F7F-C22573C4.00474073@il.ibm.com>

Ira Rosen wrote:

Here is the link to the vectorizer's documentation:
http://gcc.gnu.org/projects/tree-ssa/vectorization.html

Thanks, but I take what it says there with some grains of salt. Yes, -O3 implies -ftree-vectorize on x86_64, but I seem to have to specify the option on other targets. Also, I have not understood the limitations of -freassociative-math. Several gcc vectorization test cases currently throw FAIL on certain targets, but not on others. I don't know if that is a significant issue. g++-4.3 seems well ahead of other compilers in ability to vectorize STL iterators: http://softwarecommunity.intel.com/Wiki/HighPerformanceComputing/688.htm

Follow-Ups:
- Re: Optimizations documentation
  - From: Dorit Nuzman

References:
- Re: Optimizations documentation
  - From: Ira Rosen

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