Skip redundant jump-to-epilogue

845f7ebb17e7e764b95044fbf3e7f876dc40ebc2e9a14b8589172b31380ca2f1 
When RET is in the last block.
Alexis Sellier committed ago 1 parent 60a9450d
lib/std/arch/rv64/isel.rad +7 -1
563 563 
        case il::Instr::Ret { val } => {
564 564 
            if let v = val {
565 565 
                let rs = resolveVal(s, super::SCRATCH1, v);
566 566 
                emitMv(s, super::A0, rs);
567 567 
            }
568 - 
            emit::emitReturn(s.e, frame);
568 + 
            // Skip the jump to epilogue if this RET is in the last block,
569 + 
            // since the epilogue immediately follows.
570 + 
            if frame.totalSize != 0 and blockIdx + 1 == frame.epilogueBlock {
571 + 
                // Epilogue is the next block; fallthrough is sufficient.
572 + 
            } else {
573 + 
                emit::emitReturn(s.e, frame);
574 + 
            }
569 575 
        },
570 576 
        case il::Instr::Jmp { target, args } => {
571 577 
            // Move arguments to target block's parameter registers.
572 578 
            emitBlockArgs(s, func, target, args);
573 579 
            // Skip branch if target is the next block (fallthrough).