// This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details #include "Luau/OptimizeFinalX64.h" #include "Luau/IrUtils.h" #include namespace Luau { namespace CodeGen { // x64 assembly allows memory operands, but IR separates loads from uses // To improve final x64 lowering, we try to 'inline' single-use register/constant loads into some of our instructions // This pass might not be useful on different architectures static void optimizeMemoryOperandsX64(IrFunction& function, IrBlock& block) { LUAU_ASSERT(block.kind != IrBlockKind::Dead); for (uint32_t index = block.start; index <= block.finish; index++) { LUAU_ASSERT(index < function.instructions.size()); IrInst& inst = function.instructions[index]; switch (inst.cmd) { case IrCmd::CHECK_TAG: { if (inst.a.kind == IrOpKind::Inst) { IrInst& tag = function.instOp(inst.a); if (tag.useCount == 1 && tag.cmd == IrCmd::LOAD_TAG && (tag.a.kind == IrOpKind::VmReg || tag.a.kind == IrOpKind::VmConst)) replace(function, inst.a, tag.a); } break; } case IrCmd::ADD_NUM: case IrCmd::SUB_NUM: case IrCmd::MUL_NUM: case IrCmd::DIV_NUM: case IrCmd::MOD_NUM: case IrCmd::MIN_NUM: case IrCmd::MAX_NUM: { if (inst.b.kind == IrOpKind::Inst) { IrInst& rhs = function.instOp(inst.b); if (rhs.useCount == 1 && rhs.cmd == IrCmd::LOAD_DOUBLE && (rhs.a.kind == IrOpKind::VmReg || rhs.a.kind == IrOpKind::VmConst)) replace(function, inst.b, rhs.a); } break; } case IrCmd::JUMP_EQ_TAG: { if (inst.a.kind == IrOpKind::Inst) { IrInst& tagA = function.instOp(inst.a); if (tagA.useCount == 1 && tagA.cmd == IrCmd::LOAD_TAG && (tagA.a.kind == IrOpKind::VmReg || tagA.a.kind == IrOpKind::VmConst)) { replace(function, inst.a, tagA.a); break; } } if (inst.b.kind == IrOpKind::Inst) { IrInst& tagB = function.instOp(inst.b); if (tagB.useCount == 1 && tagB.cmd == IrCmd::LOAD_TAG && (tagB.a.kind == IrOpKind::VmReg || tagB.a.kind == IrOpKind::VmConst)) { std::swap(inst.a, inst.b); replace(function, inst.a, tagB.a); } } break; } case IrCmd::JUMP_CMP_NUM: { if (inst.a.kind == IrOpKind::Inst) { IrInst& num = function.instOp(inst.a); if (num.useCount == 1 && num.cmd == IrCmd::LOAD_DOUBLE) replace(function, inst.a, num.a); } break; } default: break; } } } void optimizeMemoryOperandsX64(IrFunction& function) { for (IrBlock& block : function.blocks) { if (block.kind == IrBlockKind::Dead) continue; optimizeMemoryOperandsX64(function, block); } } } // namespace CodeGen } // namespace Luau