[llvm] [Analysis] Adding convert_from_arbitrary_fp support in computeKnownFPClass. (PR #208585)

[Chirag Patel via llvm-commits]

ChiragPatel8 wrote:

the LnagRef says about Inf flag, "Infinity values are preserved as infinity. If a value exceeds the representable range of the target type (for example, converting Float8E8M0FNU with large exponents to half), the result is converted to infinity with the appropriate sign."  Does it mean I should check one more condition before handling Inf flag `APFloat::isRepresentableBy(SrcSemantics, DstSemantics) `

https://github.com/llvm/llvm-project/pull/208585