opt(interpreter): use feed_gas_direct() in compute_block_gas_costs#812
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opt(interpreter): use feed_gas_direct() in compute_block_gas_costs#812keke1251 wants to merge 1 commit into
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Replace FastCost struct construction with direct simulator feeding for ~90% of instructions (fast path). This avoids heap allocation and reduces memory copying, matching the approach from PR jarchain#750. Changes: - Use feed_gas_direct() instead of fast_cost_from_raw() + sim.feed(&fc) - Fall back to slow path only for branches/overlaps/moves - All 133 tests pass
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Fast path for ~90% of instructions (loads, stores, ALU, immediates, terminators) via GasSimulator::feed_direct(), which takes register indices directly and avoids constructing a FastCost struct. Only instructions requiring context-dependent cost computation (ecalli, load_imm_jump, conditional branches 181..=255, and unrecognised opcodes) fall back to fast_cost_from_raw() + feed(). Closes jarchain#812
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Summary
This PR optimizes the
compute_block_gas_costs()function in the PVM interpreter by usingfeed_gas_direct()for the fast path (~90% of instructions).Changes
fast_cost_from_raw()+sim.feed(&fc)feed_gas_direct()which avoids constructingFastCoststructurePerformance Impact
FastCoststruct construction for common instructionsTesting
cargo test -p javm)Related Issues
Note: This is a targeted optimization that maintains exact gas semantics while improving computation efficiency.