[mlir][acc] Add OffloadLiveInValueCanonicalization pass (#174671) Introduce a pass to canonicalize live-in values for regions that will be outlined for device execution. When a region is outlined, values defined outside but used inside become arguments to the outlined function. However, some values cannot or should not be passed as arguments: - Synthetic types (shape metadata, field indices) - Constants better recreated inside the region - Address-of operations for device-resident globals This pass identifies such values and either sinks the defining operation into the region (when all uses are inside) or clones it inside (when uses exist both inside and outside). To identify target regions in a dialect-agnostic way, this patch introduces `OffloadRegionOpInterface`. This marker interface allows the pass to work uniformly across OpenACC compute constructs, GPU operations, and other offload dialects without hardcoding operation types. The interface is attached to `acc.parallel`, `acc.kernels`, and `acc.serial` directly through TableGen. It is also being attached to `gpu.launch` and `cuf.kernel`, the latter through the FIR OpenACC extensions. The pass leverages existing interfaces for candidate detection: `OutlineRematerializationOpInterface` marks operations producing non-argument-passable values, while `ViewLikeOpInterface` and `PartialEntityAccessOpInterface` allow tracing through casts and views to find original defining operations. OpenACCSupport analysis provides symbol validation for address-of operations.
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