This pass converts cascaded chains of arithmetic and logic cells ($add,
$mul, $and, $or, $xor) into balanced binary trees to improve timing
performance in hardware synthesis.
The optimization uses a breadth-first search approach to identify chains
of compatible cells, then recursively constructs balanced trees that
reduce the critical path depth.
Features:
- Supports arithmetic cells: $add, $mul
- Supports logic cells: $and, $or, $xor
- Command-line options: -arith (arithmetic only), -logic (logic only)
- Preserves signed/unsigned semantics
- Comprehensive test suite with 30 test cases
Original implementation by Akash Levy <akash@silimate.com> for Silimate.
Upstreamed from https://github.com/Silimate/yosys
8b6925c5b0