[PATCH] D87034: [KnownBits] Implement accurate unsigned and signed max and min

[Jay Foad via Phabricator via llvm-commits]

foad added a comment.

In D87034#2254864 <https://reviews.llvm.org/D87034#2254864>, @lebedev.ri wrote:

> In D87034#2254852 <https://reviews.llvm.org/D87034#2254852>, @foad wrote:
>
>> In D87034#2254131 <https://reviews.llvm.org/D87034#2254131>, @RKSimon wrote:
>>
>>> In D87034#2252892 <https://reviews.llvm.org/D87034#2252892>, @foad wrote:
>>>
>>>> In D87034#2252539 <https://reviews.llvm.org/D87034#2252539>, @RKSimon wrote:
>>>>
>>>>> Can you replace the implementations in SelectionDAG::computeKnownBits with these?
>>>>
>>>> Yes, that's the idea, and the same in GlobalISel and in ValueTracking.
>>>
>>> Sorry, what I meant was are there any codegen test diffs if you replace SelectionDAG::computeKnownBits with this implementation?
>>
>> No, using it in SelectionDAG doesn't affect any existing tests.
>
> I think the question is, is this implementation expected to be identical to those, or better?
> Regardless, i believe all those implementations should be replaced to use this in *this* patch,
> to give better testing coverage.

The new implementation is supposed to be strictly better than the existing implementations -- though not necessarily in cases that occur very often in practice.


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  https://reviews.llvm.org/D87034/new/

https://reviews.llvm.org/D87034