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Re: [PATCH GCC][1/2]Feed bound computation to folder in loop split
- From: Richard Biener <richard dot guenther at gmail dot com>
- To: Bin Cheng <Bin dot Cheng at arm dot com>
- Cc: "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>, nd <nd at arm dot com>
- Date: Fri, 16 Jun 2017 12:49:51 +0200
- Subject: Re: [PATCH GCC][1/2]Feed bound computation to folder in loop split
- Authentication-results: sourceware.org; auth=none
- References: <VI1PR0802MB2176DBE6A7DBF9A434104979E7C30@VI1PR0802MB2176.eurprd08.prod.outlook.com>
On Wed, Jun 14, 2017 at 3:07 PM, Bin Cheng <Bin.Cheng@arm.com> wrote:
> Hi,
> Loop split forces intermediate computation to gimple operands all the time when
> computing bound information. This is not good since folding opportunities are
> missed. This patch fixes the issue by feeding all computation to folder and only
> forcing to gimple operand at last.
>
> Bootstrap and test on x86_64 and AArch64. Is it OK?
Hm? It uses gimple_build () which should do the same as fold_buildN in terms
of simplification.
So where does that not work? It is supposed to be the prefered way and no
new code should use force_gimple_operand (unless dealing with generic
coming from other middle-end infrastructure like SCEV or niter analysis)
Richard.
>
> Thanks,
> bin
> 2017-06-12 Bin Cheng <bin.cheng@arm.com>
>
> * tree-ssa-loop-split.c (compute_new_first_bound): Feed bound
> computation to folder, rather than force to gimple operands too
> early.