inline the trivial AddToWorkList/RemoveFromWorkList methods
into their callers. simplify ReplaceInstUsesWith. Make
EraseInstFromFunction only add operands to the worklist if
there aren't too many of them (this was a scalability win
for crazy programs that was only infrequently enforced).
Switch more code to using EraseInstFromFunction instead of
duplicating it inline. Change some fcmp/icmp optimizations
to modify fcmp/icmp in place instead of creating a new one
and deleting the old one just to change the predicate.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80483
91177308-0d34-0410-b5e6-
96231b3b80d8