* shader: emit float min/max as host instructions on AMD GPUs
V_MIN_F32, V_MAX_F32, V_MIN3_F32 and V_MAX3_F32 were emulated with a
classify-and-select sequence of about a dozen instructions each, to give
the guest's NaN and signed-zero results on any host. AMD GPUs execute
GLSL.std.450 NMin/NMax with those same rules, so emit them directly when
the device is AMD and supports VK_KHR_shader_float_controls2. Each
instruction is decorated FPFastMathMode None, since
SignedZeroInfNanPreserve does not cover extended instructions. MED3 keeps
its exact emulation. KYTY_EMULATED_FLOAT_MIN_MAX=1 keeps the emulation.
In SAROS the two heaviest compute shaders get 37% and 59% faster on an
RX 9070 XT (RADV), about 4 ms of GPU time per frame.
Adds VectorMinMaxF32RuntimeEdges (runtime operands, so nothing is folded)
and a --float-min-max-only mode that runs it and
VectorMinMaxF32NanAndSignedZeroEdges with the emulation and, where
supported, with host instructions.
Developed with AI assistance (Claude Code).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
* shader: gate host float min/max on RADV and check the emitted instructions
* shader: drop float controls 2 from host float min/max
* shader: drop the float min/max env override and atomic flag
* shader: pass host capabilities to the SPIR-V emitter as a profile built once per device
* shader: enable host float min/max on AMD GPUs
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Co-authored-by: arda <ardaeska@gmail.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Co-authored-by: nmzik <Nmzik@mail.ru>
* shader: pack v_cvt_pkrtz_f16_f32 with the native half conversion
The round-toward-zero pack was emulated with integer operations: about 20 to 30 operations
per half. GTA V uses it in 613 of its 656 pixel shaders, about 16 times in each G-buffer
pixel shader.
The pair is now packed with PackHalf2x16, unpacked again, and each half whose magnitude
exceeds its input's takes one unit off. Half signs and magnitudes are separate, so that is
the next value toward zero, whatever rounding the native conversion uses as long as it
returns one of the two neighbours. Same bits as before for every finite input and infinity;
a NaN stays a NaN. Checked against the old code on 2 million values on the CPU, and on an
Apple M5 GPU through Metal (400 000 values, subnormals included, safe and fast math).
GTA V on an Apple M5 (MoltenVK), 1080p, fixed script camera, three places, A B B A between
launches: -1.7 to -2.8 ms per frame (+4 to +6 %).
Scope: generic
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
* shader: remove half-pack commentary and unused shift helper
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Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Co-authored-by: nmzik <Nmzik@mail.ru>
nmzik