fix: ensure query, key, value tensors are contiguous for Flash Attent…
Author: Priyanshjain10
Pull request: yes
Labels: name: Code agent slop

…ion 3 compatibility with CLIP

Fixes #42137

When using Flash Attention 3 with CLIP models, an AssertionError was thrown about non-contiguous memory layout in tensors. This occurs because after transposing query, key, and value tensors, they may not be contiguous in memory, which is required by the flash attention CUDA kernels.

The fix adds .contiguous() calls after the transpose operations to ensure proper memory layout, similar to what is already done in flash_paged.py for the flash_attn_varlen_func.

Changes:
- Line 56: query = query.transpose(1, 2).contiguous()
- Line 57: key = key.transpose(1, 2).contiguous()
- Line 58: value = value.transpose(1, 2).contiguous()

This allows Flash Attention 3 to properly handle CLIP model attention with the correct tensor memory layout.

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