[PATCH] D115969: [Support] improve known bits analysis for leading zeros of multiply

[Sanjay Patel via Phabricator via llvm-commits]

spatel added a comment.

In D115969#3201733 <https://reviews.llvm.org/D115969#3201733>, @lebedev.ri wrote:

> LG
> We *really* need precision tests for KnownBits / ConstantRange.

Thanks!

Side note: I was wondering how we handle the known sign bit for mul; it is not done here, but it is in the caller code in ValueTracking's `computeKnownBitsMul()`. I'm not sure if there's a reason for that.


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