[llvm] [GlobalISel] Add `G_FSHL` and `G_FSHR` to computeKnownBits (PR #191260)

[via llvm-commits]

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@@ -603,6 +603,60 @@ KnownBits KnownBits::ashr(const KnownBits &LHS, const KnownBits &RHS,
   return Known;
 }
 
+KnownBits KnownBits::fshl(const KnownBits &LHS, const KnownBits &RHS,
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def3r wrote:

I did not port this impl from anywhere (I'm not aware if there exists an impl to be ported for `KnownBits`). After adding exhaustive unit test for funnel shift, multiple tests failed. So I looked for impl similar to `fshl`. This is based on how `KnownBits::shl` and `KnownBits::lshr` are handled.

https://github.com/llvm/llvm-project/pull/191260