v2: Describe interactions with the capabilities added by
SPV_INTEL_shader_atomic_float_minmax
v3: Remove 64-bit float support.
v4: Explain NaN issues. Explain issues with atomicMin(-0, +0) and
atomicMax(-0, +0).
v5: Fix whitespace issues noticed by Caio.
Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>