The integer emulation of the round-to-nearest-even float-to-half
conversion is exact but costly: a compute shader with about 3600
conversions never finished compiling on NVIDIA. When the device enables
shaderFloat16 and guarantees shaderRoundingModeRTEFloat16,
shaderDenormPreserveFloat16 and shaderSignedZeroInfNanPreserveFloat16,
it advertises Float16, RoundingModeRTE and DenormPreserve, and the
recompiler emits OpFConvert under the 16-bit RoundingModeRTE,
DenormPreserve and SignedZeroInfNanPreserve execution modes instead.
NaNs keep the emulated quiet NaN with the high payload bits. Devices
without these guarantees keep the emulation.
Graphics validation accepts the RoundingModeRTE, DenormPreserve and
SignedZeroInfNanPreserve execution modes for 16-, 32- and 64-bit floats,
so vertex and pixel shaders with a native conversion still draw.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
MathiasDevelopes