Finn Plummer 63e36755de [DirectX] Denote dx.resource.getpointer with IntrInaccessibleMemOnly and IntrReadMem (#193593) ...

`IntrConvergent` was originally added to `dx.resource.getpointer` to
prevent optimization passes (`SimplifyCFG`, `GVN`) from sinking the
intrinsic out of control flow branches, which would create phi nodes on
the returned pointer.

Using `IntrInaccessibleMemOnly` and `IntrReadMem` semantics still
prevent passes from merging or sinking identical calls across branches.
However, this allows the call to be moved within a single control flow
path.

Updates relevant tests and adds a new test to demonstrate a now legal
potential optimization.

This was discovered when
https://github.com/llvm/llvm-project/pull/188792 caused the following
failure:
https://github.com/llvm/llvm-project/actions/runs/24577221310/job/71865579618.
When emitting convergence control tokens, each resource access is then a
user of the convergence control tokens, which makes it's use more
unnecessarily restrictive for optimizations and in this case would
prevent a loop unroll from taking place.

Assisted by: Claude Opus 4.6

2026-04-24 16:54:23 +00:00

1.4 KiB

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