[AlxcBTW]

What

A compute program of 400000 SPIR-V words or more is now created with VK_PIPELINE_CREATE_DISABLE_OPTIMIZATION_BIT (APS5_HUGE_SHADER_WORDS sets the limit, 0 turns it off), and the capture format accepts that flag so such a pipeline can still be captured and replayed.

Why: a compute program captured from PPSA02429 (10 497 106 byte capture) is 2 624 211 SPIR-V words in one function of 321 blocks, and 99% of its instructions sit in five blocks. One block alone holds 447 491 instructions, a straight line of about 33 000 f32 subtractions (plus 1 500 multiplications and 1 000 additions) with no loop and no switch. Each float operation costs about 13 instructions because the emulated f32 denormal flush and NaN canonicalisation (the host has no f32 flush-to-zero mode on NVIDIA) wrap it, with bitcasts between them. The NVIDIA driver's compiler (nvgpucomp64.dll) does not finish this pipeline in 4 minutes; an AMD Radeon 880M compiles it in about 2 minutes. The other four captured compute pipelines of the run are 3.9 KB to 110 KB.

This is a mitigation, not yet shown to help on NVIDIA: whether the driver honours the flag as a faster compile is checked with the pipeline watch of #50. A follow-up in the recompiler can shrink the per-operation expansion (drop the NaN canonicalisation between chained float operations).

Tested

Unit test agc_huge_shader_policy (limit and parsing). Not run against a game or an NVIDIA device.

Checklist

• Based on current main; no other open PR implements the same functions
• One topic per PR; follow-ups go in a new PR
• No comments in code except technical debt
• Unimplemented paths throw; no silent stubs added
• No notes, investigation .md files or images added to the repository
• New third-party code is a submodule built from source: none added
• Generic behaviour, not specific to one title
• Depends on: none
• Fixes: none
• Unblocks: none
• GPUs tested: none yet (NVIDIA RTX 5070 Laptop run pending)
• AI-assisted: yes

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