[llvm] r343270 - [ScalarizeMaskedMemIntrin] Handle the case where the mask is an all zero vector.

[Topper, Craig via llvm-commits]

I'm not sure we can guarantee it won't be ConstantExpr. I'm also not sure an individual element can't be a ConstantExpr, but that issue existed in the original code. Should I just pre-check that it’s a vector ConstantInts before doing any IR emission. Is there any helper in Constant that already does that?

-----Original Message-----
From: Friedman, Eli [mailto:efriedma at codeaurora.org] 
Sent: Thursday, September 27, 2018 2:37 PM
To: Topper, Craig <craig.topper at intel.com>; llvm-commits at lists.llvm.org
Subject: Re: [llvm] r343270 - [ScalarizeMaskedMemIntrin] Handle the case where the mask is an all zero vector.

On 9/27/2018 2:28 PM, Craig Topper via llvm-commits wrote:
> Author: ctopper
> Date: Thu Sep 27 14:28:46 2018
> New Revision: 343270
>
> URL: http://llvm.org/viewvc/llvm-project?rev=343270&view=rev
> Log:
> [ScalarizeMaskedMemIntrin] Handle the case where the mask is an all zero vector.
>
> This shouldn't really happen in practice I hope, but we tried to handle other constant cases. We missed this one because we checked for ConstantVector without realizing that zero becomes ConstantAggregateZero instead.
>
> So instead just check for Constant and use getAggregateElement which will do the dirty work for us.

getAggregateElement will fail (return null) on a ConstantExpr; is it 
possible to end up with one here?

-Eli

-- 
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project