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Re: [PATCH] Fix MULT_HIGHPART_EXPR folding (PR tree-optimization/56918)
- From: Jakub Jelinek <jakub at redhat dot com>
- To: Marc Glisse <marc dot glisse at inria dot fr>
- Cc: Richard Biener <rguenther at suse dot de>, Richard Henderson <rth at redhat dot com>, gcc-patches at gcc dot gnu dot org
- Date: Fri, 12 Apr 2013 10:17:49 +0200
- Subject: Re: [PATCH] Fix MULT_HIGHPART_EXPR folding (PR tree-optimization/56918)
- References: <20130411181519 dot GU16463 at tucnak dot redhat dot com> <alpine dot DEB dot 2 dot 02 dot 1304112108150 dot 18093 at stedding dot saclay dot inria dot fr> <20130412074435 dot GW16463 at tucnak dot redhat dot com> <alpine dot DEB dot 2 dot 02 dot 1304120959180 dot 28581 at stedding dot saclay dot inria dot fr>
- Reply-to: Jakub Jelinek <jakub at redhat dot com>
On Fri, Apr 12, 2013 at 10:10:45AM +0200, Marc Glisse wrote:
> unsigned_p changes the computation of the high part of the product:
> it returns early for unsigned products and adjusts the high part
> later for signed. overflow_dummy looks good. I don't remember
> exactly, but I think the overflow parameter is only there because
> the regular multiplication forwards to the wide multiplication.
Ok, I've changed the wide_mul_with_sign method call to pass uns instead of
false before committing.