llvm-project

a4a56553 - [NFC][IR] Use `isa<ConstantPointerNull>` instead of `isNullValue` for pointer null checks (#197512)

[NFC][IR] Use `isa<ConstantPointerNull>` instead of `isNullValue` for pointer null checks (#197512) This PR replaces `isNullValue()` with `isa<ConstantPointerNull>()` in core IR files where the check is semantically testing for a null pointer rather than a generic zero value. This makes the intent explicit and prepares for future non-zero null pointer support.