[PATCH] D107354: [MachineMemOperand] learn about ptr_provenance

[Jeroen Dobbelaere via Phabricator via llvm-commits]

jeroen.dobbelaere added a comment.

In D107354#3495878 <https://reviews.llvm.org/D107354#3495878>, @jeroen.dobbelaere wrote:

> In D107354#3494239 <https://reviews.llvm.org/D107354#3494239>, @Zoxc wrote:
>
>> Given that the provenance gets dropped in https://reviews.llvm.org/D107356, how does it end up in machine operands?
>
> Good question. The provenance embedded in the MachineOperand here originates from the ptr_provenance operand in load/store instructions.
> Your question does point out that https://reviews.llvm.org/D107356 (aka CodeGen/IntrinsicLowering) is too early  if we want to track the more complex forms
> of provenance after lowering.

Having looked deeper into it: `IntrinsicLowering.cpp` seems only to be used for the interpreter. There it makes sense to eliminate the noalias/ptr_provenance intrinsics.
During code generation, SelectionDAG is taking care of seeing through the intrinsics while lowering. But, the original llvm-IR (with intrinsics) stays available for the alias analysis. So the machine operands must be able to see it.
(Although you might need to enable AA analysis on machine ir)


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