Hi all, I'm trying to find all places in the code generator where we assume that a pointer is tagged with a certain value. A generated code for this looks like this: mov 0x6(%rbx),%rax This moves payload[0] of the closure in %rbx to %rax, but it assumes that %rbx is tagged with 2 so it does 0x6(%rbx) instead of 0x8(%rbx). Anyone know where I should be looking at? Context: I'm implementing shorting out indirections in the concurrent collector. The code is quite similar to the current collector, except we do a cas() when updating the IND/BLACKHOLE pointer with the pointer to the indirectee. The problem is this causes all kinds of problems, in our debugging mostly caused by pointer misalignment. One concrete example of where this happens is we do mov 0x6(%rbx),%rax but the pointer in %rbx is actually tagged 3 instead of 2. The reason is I think we're breaking some invariants in the generated code where we assume certain tags from pointers (2 in the example above), but I couldn't find where in the code generator we do this. Thanks, Ömer