In D139876#3989779, @lebedev.ri wrote:

You did not invert the branch condition.

As part of the optimization in the unreachable code, we remove tokens, thereby replacing them with undef/poison in intrinsics. But the verifier falls on the assertion, within of what it sees token poison in unreachable code, which in turn is incorrect.
The original code was in the form of a Java program that crashed on this assert. As part of the search for a bug, based on ir obtained from java, a mini test was written that reflects the problem. If you need, I can send Java code with this bug.

As part of this task, I could not use the

isa<Type_1,Type_2>(Val)

construct, because there was an error when building llvm.
Throughout llvm, the construction

isa<Type1>(Val) || isa<Type_2>(Val)

is often used. Therefore, I propose to solve the full transition problem with

isa<>() || isa<>()

to

isa<,>()

as a separate NFC patch

In D115781#3194271, @lebedev.ri wrote:

Semi-weak -1
Test?

Please check new updates in this patch.

In D109428#2989031, @lebedev.ri wrote:

Tests missing

In D108455#2957051, @nikic wrote:

This is not what the TODO is about. The TODO is about not visiting operands repeatedly if they occur multiple times.