[llvm] [ValueTracking] Handle not cond to assume. (PR #127140)

[Andreas Jonson via llvm-commits]

andjo403 wrote:

> I'm suggesting to do that not just for direct assume arguments, but for all instructions. I assume this will have some kind of negative fallout, but I'd like to understand what it is.

As I understand it isEphemeralValueOf will effectively always return true in that case as it is only called when the value E is before the assume and all instructions that builds up the condition to the assume will be ephemeral.

maybe an other way to make isEphemeralValueOf is to use `findValuesAffectedByCondition` function to make the ephemeral check like this:
```
  SmallVector<const Value *, 8> Affected;
  auto InsertAffected = [&Affected](Value *V) { Affected.push_back(V); };
  findValuesAffectedByCondition(Assume->getArgOperand(0), /*IsAssume=*/true,
                                InsertAffected);

  return is_contained(Affected, E) &&
         llvm::all_of(E->users(),
                      [&](const User *U) { return is_contained(Affected, U); });
```
avoids the need for special handling of not




https://github.com/llvm/llvm-project/pull/127140