[Libre-soc-dev] Fwd: [PATCH] D57504: RFC: Prototype & Roadmap for vector predication in LLVM

Jacob Lifshay programmerjake at gmail.com
Fri Aug 28 14:27:40 BST 2020

On Fri, Aug 28, 2020, 06:00 lkcl <luke.leighton at gmail.com> wrote:

> jacob are you following these,

not anymore, I was getting too much email from LLVM to keep up

do you happen to know what
> get.active.lane.mask is about and how it works?

yeah, it's pretty simple:

the code:
%m = @llvm.get.active.lane.mask(%base, %n)
is basically the equivalent of the following python:
m = [base + i < n for i in range(...)]
where base is an unsigned integer; n must be > 0 and is a hint to the
backend of how many times the loop that was vectorized executes


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