rL245171 exposed a hole in InstSimplify that manifested in a strange way in PR28466:
https://llvm.org/bugs/show_bug.cgi?id=28466
It's possible to use trunc + icmp sgt/slt in place of an and + icmp eq/ne, so we need to
recognize that pattern to eliminate selects that are choosing between some value and some
bitmasked version of that value.
Note that there is significant room for improvement (refactoring) and enhancement (more
patterns, possibly in InstCombine rather than here).
Differential Revision: https://reviews.llvm.org/D22537
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@276341 91177308-0d34-0410-b5e6-96231b3b80d8
(X & INT_MIN) ? X & INT_MAX : X into X & INT_MAX
(X & INT_MIN) ? X : X & INT_MAX into X
(X & INT_MIN) ? X | INT_MIN : X into X
(X & INT_MIN) ? X : X | INT_MIN into X | INT_MIN
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224669 91177308-0d34-0410-b5e6-96231b3b80d8
This restores our ability to optimize:
(X & C) ? X & ~C : X into X & ~C
(X & C) ? X : X & ~C into X
(X & C) ? X | C : X into X
(X & C) ? X : X | C into X | C
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222868 91177308-0d34-0410-b5e6-96231b3b80d8
