Support AH/FIZ from FEAT_AFP for independent DAZ and FTZ?

[MikhailRyazanov]

The flags for input and output denormals (DAZ and FTZ) are currently translated into the single FZ flag:

sse2neon/sse2neon.h

Lines 3272 to 3284 in 1741f18

	// ARM Platform Behavior:
	// - ARM FPCR/FPSCR bit 24 provides unified FZ+DAZ behavior. Setting either
	// _MM_FLUSH_ZERO_ON or _MM_DENORMALS_ZERO_ON enables the same ARM bit.
	// - ARMv7 NEON: "Flush-to-zero mode always enabled" per ARM ARM (impl may vary)
	// - ARMv8: FPCR.FZ correctly controls denormal handling for NEON operations
	FORCE_INLINE void _mm_setcsr(unsigned int a)
	{
	_MM_SET_ROUNDING_MODE(a & _MM_ROUND_MASK);
	// ARM FPCR.bit24 handles both FZ and DAZ - set if either is requested
	_MM_SET_FLUSH_ZERO_MODE(
	(a & _MM_FLUSH_ZERO_MASK) |
	((a & _MM_DENORMALS_ZERO_MASK) ? _MM_FLUSH_ZERO_ON : 0));
	}

However, Armv8.7 introduced FEAT_AFP with the new flags AH (Alternate Handling) and FIZ (Flush Inputs to Zero) in the FPCR register that make the independent control of flushing denormal inputs and/or outputs to zero possible. Are there any plans to use this for a more correct translation of DAZ and FTZ?