[PATCH] D118387: [IPSCCP] Switch away from Instruction::isSafeToRemove()

[Nikita Popov via Phabricator via llvm-commits]

nikic added a comment.

This generally looks good to me, but I wonder whether it can be tested? I.e. does this allow eliminating (some) constrained FP intrinsics during SCCP and we can test that? Or does that require additional changes?



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Comment at: llvm/lib/Transforms/Scalar/SCCP.cpp:101
+  // TODO: Teach wouldInstructionBeTriviallyDead() about loads of
+  // TODO: atomic globals that SCCP knows are effectively constant.
+  return isa<LoadInst>(I);
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We can't really teach wouldInstructionBeTriviallyDead() about this because it requires SCCP-specific knowledge -- I think a more actionable TODO would be along these lines:

> TODO: Mark globals as being constant earlier, sowouldInstructionBeTriviallyDead() knows that atomic loads are safe to remove.


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https://reviews.llvm.org/D118387