tree b1da76b224f15c70e3b1c2ffb5b28b78e0f16135
parent e7738cac23c4ab2720c74c1e47c010abceb5e617
author Sanjay Patel <spatel@rotateright.com> 1555447280 +0000
committer Sanjay Patel <spatel@rotateright.com> 1555447280 +0000

[EarlyCSE] detect equivalence of selects with inverse conditions and commuted operands (PR41101)

This is 1 of the problems discussed in the post-commit thread for:
rL355741 / http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20190311/635516.html
and filed as:
https://bugs.llvm.org/show_bug.cgi?id=41101

Instcombine tries to canonicalize some of these cases (and there's room for improvement
there independently of this patch), but it can't always do that because of extra uses.
So we need to recognize these commuted operand patterns here in EarlyCSE. This is similar
to how we detect commuted compares and commuted min/max/abs.

Differential Revision: https://reviews.llvm.org/D60723

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@358523 91177308-0d34-0410-b5e6-96231b3b80d8