[llvm-dev] 回复: ScalarEvolution invariants around wrapping flags

[陈 正 via llvm-dev]

Thank for reverting it.

For the original issue in https://reviews.llvm.org/D64868, if we want to make sure nsw can be correctly added to increment SCEV, we need to also check isLoopEntryGuardedByCond? Is this a right way to go?

BRS//
Chen Zheng
________________________________
发件人: llvm-dev <llvm-dev-bounces at lists.llvm.org> 代表 Tim Northover via llvm-dev <llvm-dev at lists.llvm.org>
发送时间: 2019年9月30日 15:45
收件人: Sanjoy Das <sanjoy at playingwithpointers.com>
抄送: LLVM Developers Mailing List <llvm-dev at lists.llvm.org>
主题: Re: [llvm-dev] ScalarEvolution invariants around wrapping flags

On Sun, 29 Sep 2019 at 19:23, Sanjoy Das <sanjoy at playingwithpointers.com> wrote:
> Your reasoning sounds correct to me.  Let's revert for now?

Sounds good, I've reverted it with r373184 (and r373185 to polly,
which fixed up some tests after the original commit).

> I don't think there is an easy fix, we'll have to do a global "must be
> executed" analysis to reapply the patch soundly.  And that's difficult
> since any external functional call can call "exit(0)".

Oh yes, that didn't even occur to me.

Cheers.

Tim.
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