update stdarch submodule

[dgbo]

This commit update the src/stdarch submodule, we primarily want to include https://github.com/rust-lang/stdarch/pull/918 which provides prefetch hints for aarch64. This PR could deliver ~20% performance gain on our aarch64 server in Filecoin. Wish this could be used as soon as possible.

Thanks.

[rust-highfive]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @kennytm (or someone else) soon.

If any changes to this PR are deemed necessary, please add them as extra commits. This ensures that the reviewer can see what has changed since they last reviewed the code. Due to the way GitHub handles out-of-date commits, this should also make it reasonably obvious what issues have or haven't been addressed. Large or tricky changes may require several passes of review and changes.

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[rust-highfive]

⚠️ Warning ⚠️

• These commits modify submodules.

[kennytm]

This PR updates the stdarch dependency to the current master rust-lang/stdarch@7895ab1 (rust-lang/stdarch#917), but the CI at that commit is currently failing because const_fn_transmute is declared twice in https://github.com/rust-lang/stdarch/blob/master/crates/core_arch/src/lib.rs#L41.

error[E0636]: the feature `const_fn_transmute` has already been declared
  --> crates/core_arch/src/lib.rs:41:5
   |
41 |     const_fn_transmute
   |     ^^^^^^^^^^^^^^^^^^

error: aborting due to previous error

Please either change the commit to rust-lang/stdarch@b422b01 or remove the redundant const_fn_transmute feature.

[dgbo]

This PR updates the stdarch dependency to the current master rust-lang/stdarch@7895ab1 (rust-lang/stdarch#917), but the CI at that commit is currently failing because const_fn_transmute is declared twice in https://github.com/rust-lang/stdarch/blob/master/crates/core_arch/src/lib.rs#L41.

error[E0636]: the feature `const_fn_transmute` has already been declared
  --> crates/core_arch/src/lib.rs:41:5
   |
41 |     const_fn_transmute
   |     ^^^^^^^^^^^^^^^^^^

error: aborting due to previous error

Please either change the commit to rust-lang/stdarch@b422b01 or remove the redundant const_fn_transmute feature.

Thanks for the quick review. The commit is changed to rust-lang/stdarch@b422b01.

@rustbot modify labels: -S-waiting-on-author +S-waiting-on-review

[kennytm]

@bors r+ rollup=iffy

[bors]

📌 Commit 2e64ff9 has been approved by kennytm

[bors]

⌛ Testing commit 2e64ff9 with merge 1d216fe...

[bors]

☀️ Test successful - checks-actions, checks-azure
Approved by: kennytm
Pushing 1d216fe to master...