vulkan: fix fp16 Flash Attention on Windows AMD RDNA2 and below#19921
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vulkan: fix fp16 Flash Attention on Windows AMD RDNA2 and below#19921
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For some reason a f16vec4 subgroupShuffleXor is broken on RDNA2 and lower. I found a workaround by shuffling vec4 instead. This also fixes fp16 Flash Attention on AMD GCN, so I removed the fp32 fallback.
Fixes #19881 and also the issue reported here: #19625 (comment)
@masamaru-san @DeryabinIvan Please try this fix and let me know if it works for you.