[maleadt]

Metal.jl emits the simdgroup matrix load/store and tensor intrinsics in their newest AIR form, and rewrote them for older AIR versions in its own finish_ir! override. That rewrite depends only on the targeted AIR version, like the barrier and atomic legalization this package already does, and is the kind of thing an LLVM back-end handles for the other GPU targets. So this moves it into lower_air!, next to legalize_barrier_abi!:

• air.simdgroup_matrix_8x8_{load,store}: before AIR 2.8, the dims/strides/origin vectors become the legacy elements-per-row, origin and transpose operands. The transpose flag has to be an immediate, so one of the strides must be the literal 1 (as Metal.jl emits them); other layouts are an error rather than an assertion.
• air.init_strided_private_tensor.i32.{global,local} and air.get_extent_private_tensor.i32: before AIR 2.9, the operands AIR 2.9 appended (always null, 0, -1 and 0 in Apple's front-end) are dropped.
• The element type of the simdgroup matrix pointer operand is derived from the intrinsic name for the downgrader, as is done for atomics.

Calls already in the older form are left alone. Released versions of Metal.jl still rewrite them in finish_ir!, which runs before lower_air!, so they keep working with this version. Older forms aren't upgraded for newer targets.

Tests cover both families at the AIR versions on either side of the change, with constant and run-time operands, and that the legacy forms pass through. Validated on Julia 1.10 and 1.13. Metal.jl's simdgroup, linalg and bfloat16 tests pass with JuliaGPU/Metal.jl#1096, which removes its copy of the rewrites, including execution at macos=v"15" (AIR 2.7) on macOS 27.

[maleadt]

Closing: the AIR legalization of intrinsics Metal.jl emits stays next to the emitter in Metal.jl, so the two packages don't have to release in lockstep, and GPUCompiler doesn't need to recognize every form an older Metal.jl may emit.

[codecov]

Codecov Report

❌ Patch coverage is 98.68421% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 91.51%. Comparing base (ba243ce) to head (c60a69d).

Files with missing lines	Patch %	Lines
src/metal.jl	98.68%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1046      +/-   ##
==========================================
- Coverage   92.34%   91.51%   -0.83%     
==========================================
  Files          31       31              
  Lines        7341     7413      +72     
==========================================
+ Hits         6779     6784       +5     
- Misses        562      629      +67     

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