[llvm] r316711 - [CGP] Merge empty case blocks if no extra moves are added.

[Balaram Makam via llvm-commits]

Sorry for the break, I have reverted it in r316721. I'll investigate the failure tomorrow morning.
--Balaram

-----Original Message-----
From: Friedman, Eli [mailto:efriedma at codeaurora.org] 
Sent: Thursday, October 26, 2017 8:12 PM
To: Balaram Makam <bmakam at codeaurora.org>; llvm-commits at lists.llvm.org
Subject: Re: [llvm] r316711 - [CGP] Merge empty case blocks if no extra moves are added.

On 10/26/2017 3:34 PM, Balaram Makam via llvm-commits wrote:
> Author: bmakam
> Date: Thu Oct 26 15:34:01 2017
> New Revision: 316711
>
> URL: http://llvm.org/viewvc/llvm-project?rev=316711&view=rev
> Log:
> [CGP] Merge empty case blocks if no extra moves are added.
>
> Summary:
> Currently we skip merging when extra moves may be added in the header 
> of switch instead of the case block, if the case block is used as an incoming block of a PHI. If all the incoming values of the PHIs are non-constants and the destination block is dominated by the switch block then extra moves are likely not added by ISel, so there is no need to skip merging in this case.
>
> Reviewers: efriedma, junbuml, davidxl, hfinkel, qcolombet
>
> Reviewed By: efriedma
>
> Subscribers: dberlin, kuhar, mcrosier, llvm-commits
>
> Differential Revision: https://reviews.llvm.org/D37343

It looks like this isn't updating the domtree correctly: see http://green.lab.llvm.org/green//job/clang-stage1-cmake-RA-expensive/8907/consoleFull
.

-Eli

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