Consistently try to use APFloat::toString for floating point constant comments to get rid of differences between Constant / ConstantDataSequential values - it should help stop some of the linux-windows buildbot failures matching NaN/INF etc. as well.
Not sure if this is redundant if/when D37184 lands?
You could also check for isHalfTy(); I guess it's unlikely to be relevant on x86, though.