[InstSimplify] make simplifyUnsignedRangeCheck commutative for ZeroICmp

[khei4]

Summary

on InstSimplify, simplifyUnsignedRangeCheck missed being commutative for inner equality comparison.
related Functional patch: https://reviews.llvm.org/D78430

Depends on https://reviews.llvm.org/D146195

[nikic]

InstCombine canonicalizes constant icmp operands to the RHS, this is why constants are not usually handled on the LHS. Unless there is some PhaseOrdering reason why it is important to handle this pattern prior to the first InstCombine run, we shouldn't do this.

llvm/lib/Analysis/InstructionSimplify.cpp

1564

You can use m_c_ICmp.

[khei4]

In D146196#4198590, @nikic wrote:

InstCombine canonicalizes constant icmp operands to the RHS, this is why constants are not usually handled on the LHS. Unless there is some PhaseOrdering reason why it is important to handle this pattern prior to the first InstCombine run, we shouldn't do this.

Oh, now I could have found that canonicalization. Thank you!