Eliminate a bitwise 'not' op of 'not' min/max by inverting the min/max.

Bitwise 'not' of the min/max could be eliminated in the pattern:

%notx = xor i32 %x, -1
%cmp1 = icmp sgt[slt/ugt/ult] i32 %notx, %y
%smax = select i1 %cmp1, i32 %notx, i32 %y
%res = xor i32 %smax, -1

https://rise4fun.com/Alive/lCN

Reviewers: spatel

Reviewed by: spatel

Subscribers: a.elovikov, llvm-commits

Differential Revision: https://reviews.llvm.org/D45317

llvm-svn: 329791