Sorry, I don't buy the argument that "code is terrible to read and hence maintain" from a GLibC developer. CRLibM does have a bunch or tricky macros to work-around bugs in decade-old compilers for architectures no one cares about, but GNU LibC is not any better in this aspect.

CRLibM does not have a provably correctly-rounded pow, but univariate functions can be merged.

The paper you cited is about decimal floating-point implementation, it is not relevant to the LibM functions discussed in the article.

I have a utility for benchmarking LibM libraries here: https://bitbucket.org/MDukhan/hysteria

Some benchmarks including CRLibM and GNU LibM are here: http://www.yeppp.info/benchmarks.html