[PATCH] D134975: [SCCP] try to convert sitofp to uitofp

[Sanjay Patel via Phabricator via llvm-commits]

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This is another small extension of the signed->unsigned logic. This can enable subsequent FP folds because it eliminates negative FP values. Example:
https://alive2.llvm.org/ce/z/tnwfVk

Codegen can invert the transform if it can see that the input signbit is clear.

There was a comment on a test saying not to try this, but I don't see a reason to avoid it. I adjusted one of the existing tests to show that we are not miscompiling when the range includes a negative value.


https://reviews.llvm.org/D134975

Files:
  llvm/lib/Transforms/Scalar/SCCP.cpp
  llvm/test/Transforms/SCCP/ip-ranges-casts.ll
  llvm/test/Transforms/SCCP/sitofp.ll

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