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Re: PATCH - [tree-ssa] regrouping of expression tree for single multiply add.
- From: law at redhat dot com
- To: Diego Novillo <dnovillo at redhat dot com>
- Cc: Fariborz Jahanian <fjahanian at apple dot com>, "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>, Roger Sayle <roger at eyesopen dot com>
- Date: Wed, 24 Mar 2004 12:17:50 -0700
- Subject: Re: PATCH - [tree-ssa] regrouping of expression tree for single multiply add.
- Reply-to: law at redhat dot com
In message <email@example.com>, Diego Novillo wr
>On Mon, 2004-03-22 at 21:25, Fariborz Jahanian wrote:
>> tree-ssa because it is an 'improvement' patch and I believe mainline is
>> frozen for improvement patches.
>On the contrary. It is tree-ssa the frozen one. mainline is in
>stage1. If this goes in mainline, tree-ssa will inherit it at the next
>> OK for tree-ssa?
>No. Try mainline.
And I think there's an excellent argument against this kind of transformation
for the mainline as well, at least for FP types.
This kind of transformation makes sense for integers though :-) THere's
some mips targets that have integer madd and several targets now have
> 1 integer multiply pipeline. Thus stuff like
a * b * c * d which is implemented as (((a * b) * c) * d) can be
profitably turned into (a * b) * (c * d).