[PATCH] D12706: Handle non-constant shifts in computeKnownBits, and use computeKnownBits for constant folding in InstCombine/Simplify

[Hal Finkel via llvm-commits]

----- Original Message -----
> From: "James Molloy" <james at jamesmolloy.co.uk>
> To: reviews+D12706+public+8f107d44c62a13e2 at reviews.llvm.org, "Philip Reames" <listmail at philipreames.com>,
> hfinkel at anl.gov, "david majnemer" <david.majnemer at gmail.com>, sanjoy at playingwithpointers.com
> Cc: llvm-commits at lists.llvm.org, regehr at cs.utah.edu
> Sent: Thursday, October 22, 2015 8:56:51 AM
> Subject: Re: [PATCH] D12706: Handle non-constant shifts in computeKnownBits, and use computeKnownBits for constant
> folding in InstCombine/Simplify
> 
> 
> Hi Hal,
> 
> 
> I'm keen to get this committed so I can work on the follow-on
> suggestion I made myself.
> 
> 
> Will you get time to commit this soon? or is it OK if I commit it on
> your behalf instead?

I'm planning on getting to this today. I need to fixup some ubsan tests for this it seems. If I don't get to this today, I'll let you know.

 -Hal

> 
> 
> Cheers,
> 
> 
> James
> 
> 
> On Wed, 14 Oct 2015 at 18:49 Philip Reames via llvm-commits <
> llvm-commits at lists.llvm.org > wrote:
> 
> 
> reames accepted this revision.
> reames added a comment.
> This revision is now accepted and ready to land.
> 
> LGTM w/minor comment addressed
> 
> Are you planning on implementing the follow on suggestions? If not,
> we should make sure they get tracked either as TODOs or bugs.
> 
> 
> ================
> Comment at: lib/Analysis/ValueTracking.cpp:990
> @@ +989,3 @@
> +
> + computeKnownBits(I->getOperand(1), KnownZero, KnownOne, DL, Depth +
> 1, Q);
> +
> ----------------
> It would be more clearly correct to use the two temporaries for this
> calculation. The current code is correct, but slightly confusing.
> 
> 
> http://reviews.llvm.org/D12706
> 
> 
> 
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> 

-- 
Hal Finkel
Assistant Computational Scientist
Leadership Computing Facility
Argonne National Laboratory