[llvm] [ConstantRange] Expand makeAllowedICmpRegion to use samesign to give tighter range (PR #174355)

[Adar Dagan via llvm-commits]

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Adar-Dagan wrote:

No, if the input range contains 0 then the output range will contain 1.
if there is no samesign

https://github.com/llvm/llvm-project/pull/174355