[PATCH] D126692: [InstCombine] Expand select+masked_load combine to include FP splats of -0.0

[David Sherwood via Phabricator via llvm-commits]

david-arm added a comment.

In D126692#3547103 <https://reviews.llvm.org/D126692#3547103>, @paulwalker-arm wrote:

> In general how safe it is to use the function's `no-signed-zeros-fp-math` attribute to infer it's safe to convert one bit pattern to another?  Fair enough if we're dealing with floating point operations then we can ignore the signedness of zero but this is just doing a select of some loaded data, which could be immediately stored out.  So it feels dangerous to just change the data in this way.

This is a good point, so I wonder if I can restrict this to single uses of the select where the user is a FP operator? We can even check the user's FMF to see how the data is going to be interpreted.


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