[InstCombine] fold logic-of-nan-fcmps (PR41069)

[InstCombine] fold logic-of-nan-fcmps (PR41069)

Combine 2 fcmps that are checking for nan-ness:
   and (fcmp ord X, 0), (and (fcmp ord Y, 0), Z) --> and (fcmp ord X, Y), Z
   or  (fcmp uno X, 0), (or  (fcmp uno Y, 0), Z) --> or  (fcmp uno X, Y), Z

This is an exact match for a minimal reassociation pattern.
If we want to handle this more generally that should go in
the reassociate pass and allow removing this code.

This should fix:
https://bugs.llvm.org/show_bug.cgi?id=41069

llvm-svn: 356471