ChatGPT5's investigation revealed builder position management issues:
- Added verbose logging for block lowering and terminator emission
- Enhanced position_at_end calls before all terminator operations
- Added debug output for emit_jump/emit_branch operations
- Improved snapshot vs vmap fallback reporting in seal_block
Key findings:
- Sealed SSA snapshot mechanism is working correctly
- Block terminator issues persist due to builder position drift
- Main.has_in_stack/2 shows terminator missing after emit
Next steps:
- Add immediate terminator verification after each emit
- Track builder position changes in complex operations
- Investigate specific functions where builder drift occurs
This commit adds diagnostic infrastructure to pinpoint
where LLVM IR builder position gets misaligned.
696b282ae8