InstCombine: Simplify if(x!=0 && x!=-1).

When both constants are positive or both constants are negative,
InstCombine already simplifies comparisons like this, but when
it's exactly zero and -1, the operand sorting ends up reversed
and the pattern fails to match. Handle that special case.

Follow up for rdar://14689217

llvm-svn: 188512
2 files changed