NV_gpu_shader5 does not support "f16mat4"?

my input is GLSL,i have use the extension of "GL_EXT_shader_explicit_arithmetic_types_float16"
then the "half4x4" is translated to f16mat4.
But it cause an error
error C1503: undefined variable "f16mat4",
it seems that the extension "NV_gpu_shader5" does not support "f16mat4"?
How can i resolve this problem？Or should i use “mat4“” instead？

Start by reproducing the GLSL input using GL_EXT_shader_explicit_arithmetic_types_float16 and the translation to f16mat4 in glslang. Check how NV_gpu_shader5 handles f16mat4 and determine whether the compiler should support it or report the required alternative; the issue is resolved when the behavior and expected usage are verified.

Written by the indexing model from the issue text.