[InstCombine] Fold Select with AND/OR condition
Summary:
Fold
```
%A = icmp ne i8 %X, %V1
%B = icmp ne i8 %X, %V2
%C = or i1 %A, %B
%D = select i1 %C, i8 %X, i8 %V1
ret i8 %D
=>
ret i8 %X
Fixes https://bugs.llvm.org/show_bug.cgi?id=38334
Proof: https://rise4fun.com/Alive/plI8
Reviewers: spatel, lebedev.ri
Reviewed By: lebedev.ri
Subscribers: craig.topper, llvm-commits
Differential Revision: https://reviews.llvm.org/D49919
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@338191
91177308-0d34-0410-b5e6-
96231b3b80d8