sycl: support non-contiguous input in PAD op

[aicss-genai]

Overview

Authors

• @unrahul
• @ctao456
• @malsbat
• @YuningQiu
• @vvravi1
• @zhiqitao-intel

pad_f32 previously assumed contiguous source strides and reconstructed ne00/ne01/ne02 from ne - lp - rp. This broke when the source tensor had non-contiguous strides (common for views).

Pass s00..s03 (source strides in elements) through to the kernel and index with i03*s03 + i02*s02 + i01*s01 + i00*s00. Also switches the grid layout to sycl::range<3> order to match the rest of the backend.

Additional information

Part of work originally submitted as #22066 — splitting per reviewer request.

Requirements

• I have read and agree with the contributing guidelines
• AI usage disclosure: Yes. This work was partially produced with an agentic engineering approach: agents surface issues and explore experiments while engineers identify and reject candidates using domain knowledge. Human feedback involved.

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