[llvm] [InstCombine] Generalize ignoreSignBitOfZero/NaN to handle more cases (PR #141015)

[Nikita Popov via llvm-commits]

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@@ -330,6 +330,13 @@ bool isKnownNeverNaN(const Value *V, unsigned Depth, const SimplifyQuery &SQ);
 std::optional<bool> computeKnownFPSignBit(const Value *V, unsigned Depth,
                                           const SimplifyQuery &SQ);
 
+/// Return true if the sign bit of result can be ignored when the result is
+/// zero.
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nikic wrote:

I think from a ValueTracking perspective, these APIs should check whether a given `Use &` can ignore the sign bit. The calling code should be responsible for looking at a single use, if that's what it wants to do.

https://github.com/llvm/llvm-project/pull/141015