diff --git a/Cargo.lock b/Cargo.lock
index 100434ac..20f1053a 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1175,6 +1175,17 @@ dependencies = [
  "rustc-hash",
 ]
 
+[[package]]
+name = "oxide_liveness"
+version = "0.1.0"
+dependencies = [
+ "oxide_bytecode",
+ "oxide_cfg",
+ "oxide_emit",
+ "oxide_ir",
+ "oxide_parser",
+]
+
 [[package]]
 name = "oxide_log"
 version = "0.1.0"
diff --git a/Cargo.toml b/Cargo.toml
index 15fc2cea..5a63569a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,6 +10,7 @@ members = [
     "crates/oxide_ir",
     "crates/oxide_cfg",
     "crates/oxide_dce",
+    "crates/oxide_liveness",
     "crates/oxide_types",
     "crates/oxide_vm",
     "crates/oxide_kernel",
diff --git a/crates/oxide_liveness/Cargo.toml b/crates/oxide_liveness/Cargo.toml
new file mode 100644
index 00000000..e7c1760f
--- /dev/null
+++ b/crates/oxide_liveness/Cargo.toml
@@ -0,0 +1,16 @@
+[package]
+name = "oxide_liveness"
+version.workspace = true
+edition.workspace = true
+license.workspace = true
+rust-version.workspace = true
+description = "OxideJS - liveness analysis pass over IR (CFG dataflow + per-instruction live ranges)"
+
+[dependencies]
+oxide_ir = { path = "../oxide_ir" }
+oxide_cfg = { path = "../oxide_cfg" }
+
+[dev-dependencies]
+oxide_parser = { path = "../oxide_parser" }
+oxide_emit = { path = "../oxide_emit" }
+oxide_bytecode = { path = "../oxide_bytecode" }
diff --git a/crates/oxide_liveness/src/dataflow.rs b/crates/oxide_liveness/src/dataflow.rs
new file mode 100644
index 00000000..91a8e642
--- /dev/null
+++ b/crates/oxide_liveness/src/dataflow.rs
@@ -0,0 +1,258 @@
+//! 块级数据流迭代：gen/kill + reverse_postorder 不动点。
+//!
+//! gen/kill 直接消费 `oxide_ir::contract` 的 `def_reg`/`use_regs`（D-22），
+//! None→0 / This→254 / NewTarget→255 / CALL 隐式 reg0 全内置，不重复建。
+//! Exception 边当普通边参与迭代（D-13）；Exception 目标块入口 reg 0 隐式 def
+//! （异常展开写 regs[0]，vm_runtime.rs:204-205）在此建模：gen.remove(0)+kill.insert(0)。
+
+use oxide_cfg::{Cfg, EdgeKind};
+use oxide_ir::IRFunction;
+
+/// 块级 liveness：返回 (block_live_in, block_live_out, reg_count)。
+/// reg_count = 全部 def/use 最大 reg 号（bitset 长度 = reg_count+1）。
+pub(super) fn block_liveness(f: &IRFunction, cfg: &Cfg) -> (Vec<Vec<bool>>, Vec<Vec<bool>>, usize) {
+    // 1. reg_count 上界扫描（不信任 f.n_registers，动态求上界，照 iter_sweep 先例）
+    let mut reg_count = 255usize; // 兜底 This/NewTarget 254/255
+    for inst in &f.insts {
+        if let Some(d) = inst.def_reg() {
+            reg_count = reg_count.max(d as usize);
+        }
+        for u in inst.use_regs() {
+            reg_count = reg_count.max(u as usize);
+        }
+    }
+
+    let bits = reg_count + 1;
+    let n = cfg.blocks.len();
+
+    // 2. 每块 gen/kill
+    let mut gen: Vec<Vec<bool>> = vec![vec![false; bits]; n];
+    let mut kill: Vec<Vec<bool>> = vec![vec![false; bits]; n];
+    for (b, block) in cfg.blocks.iter().enumerate() {
+        // gen：块内反向扫描，kill 先于 gen（`live = (live − def) ∪ use`）。
+        // 顺序理由：COMPOUND_ADD 等读-写同寄存器指令 use 含 rd（contract.rs:137），
+        // gen 先于 kill 会把 rd 旧值从 live_before 错误剔除。
+        let mut live = vec![false; bits];
+        for i in block.inst_range.clone().rev() {
+            if let Some(d) = f.insts[i].def_reg() {
+                live[d as usize] = false;
+            }
+            for u in f.insts[i].use_regs() {
+                live[u as usize] = true;
+            }
+        }
+        gen[b] = live;
+
+        // kill：块内正向扫描，def_reg 非 None 即插入
+        for i in block.inst_range.clone() {
+            if let Some(d) = f.insts[i].def_reg() {
+                kill[b][d as usize] = true;
+            }
+        }
+
+        // Exception 目标块：入口 reg 0 隐式 def（异常展开在块外写 regs[0]）。
+        // gen 去 0 防"无 def use"把活度污染到函数入口；kill 插 0 防 0 从任何 pred 流入。
+        // 注：preds 是 Vec<BBId>（无 EdgeKind），须从源块 succs 侧检测 Exception 边。
+        let is_exception_target = cfg
+            .blocks
+            .iter()
+            .any(|src| src.succs.iter().any(|&(dst, k)| dst == b && k == EdgeKind::Exception));
+        if is_exception_target {
+            gen[b][0] = false;
+            kill[b][0] = true;
+        }
+    }
+
+    // 3. reverse_postorder（确定性，禁 HashMap 迭代序——B010）
+    let rpo = reverse_postorder(cfg);
+
+    // 4. 不动点迭代
+    let mut live_in = vec![vec![false; bits]; n];
+    let mut live_out = vec![vec![false; bits]; n];
+    let mut iters = 0usize;
+    loop {
+        let mut changed = false;
+        for &b in &rpo {
+            // live_out[b] = ∪ live_in[s]（全部 succs，含 Exception 边——D-13 当普通边）
+            let mut out = vec![false; bits];
+            for &(succ, _kind) in &cfg.blocks[b].succs {
+                for (r, &v) in live_in[succ].iter().enumerate() {
+                    if v {
+                        out[r] = true;
+                    }
+                }
+            }
+            // live_in[b] = gen[b] | (live_out[b] − kill[b])
+            let mut input = vec![false; bits];
+            for r in 0..bits {
+                input[r] = gen[b][r] || (out[r] && !kill[b][r]);
+            }
+            if input != live_in[b] || out != live_out[b] {
+                changed = true;
+                live_in[b] = input;
+                live_out[b] = out;
+            }
+        }
+        if !changed {
+            break;
+        }
+        iters += 1;
+        debug_assert!(iters < cfg.blocks.len() * 2 + 16, "liveness 不动点疑似不收敛");
+    }
+
+    (live_in, live_out, reg_count)
+}
+
+/// 从 entry 出发 DFS 沿 succs 存储序（确定序）收集 postorder 后反转；
+/// 不可达块按升序追加在末尾。纯 Vec + visited 位图（B010）。
+fn reverse_postorder(cfg: &Cfg) -> Vec<usize> {
+    let n = cfg.blocks.len();
+    let mut visited = vec![false; n];
+    let mut postorder = Vec::with_capacity(n);
+    fn dfs(cfg: &Cfg, visited: &mut [bool], postorder: &mut Vec<usize>, b: usize) {
+        visited[b] = true;
+        for &(succ, _) in &cfg.blocks[b].succs {
+            if !visited[succ] {
+                dfs(cfg, visited, postorder, succ);
+            }
+        }
+        postorder.push(b);
+    }
+    dfs(cfg, &mut visited, &mut postorder, cfg.entry);
+    postorder.reverse();
+    for (b, &vis) in visited.iter().enumerate() {
+        if !vis {
+            postorder.push(b);
+        }
+    }
+    postorder
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use oxide_ir::inst::Inst;
+    use oxide_ir::operand::Operand;
+    use oxide_bytecode::opcode::OpCode;
+
+    fn set(v: &[bool], regs: &[u32]) -> bool {
+        regs.iter().all(|&r| v[r as usize])
+    }
+
+    fn empty_function() -> IRFunction {
+        IRFunction::new()
+    }
+
+    #[test]
+    fn linear_function_liveness() {
+        let mut f = empty_function();
+        f.insts.push(Inst::new(OpCode::ADD, Operand::Reg(2), Operand::Reg(0), Operand::Reg(1)));
+        f.insts.push(Inst::new(OpCode::RETURN, Operand::Reg(2), Operand::None, Operand::None));
+        let cfg = oxide_cfg::build_cfg(&f);
+        let (live_in, live_out, reg_count) = block_liveness(&f, &cfg);
+        assert!(reg_count >= 2);
+        assert!(set(&live_in[0], &[0, 1]), "entry liveIn 应含 0、1");
+        assert!(!live_in[0][2], "r2 是 def 不应在 liveIn");
+        assert!(set(&live_out[0], &[]), "live_out 空");
+        // exit 哨兵为空块，live 全空
+        let exit = cfg.exit;
+        assert!(live_in[exit].iter().all(|&v| !v));
+        assert!(live_out[exit].iter().all(|&v| !v));
+    }
+
+    #[test]
+    fn if_else_join_unions_live_sets() {
+        // 0: jmp_if_false(1, L1)   cond=Reg(1)
+        // 1: ADD r3=r3+r2           def 3 use {3,2}
+        // 2: jmp L2
+        // 3: SUB r4=r4+r5           def 4 use {4,5}
+        // 4: NOP
+        // 5: RETURN Reg(6)
+        let mut f = empty_function();
+        f.insts.push(Inst::jmp_if_false(1, 1));
+        f.insts.push(Inst::new(OpCode::ADD, Operand::Reg(3), Operand::Reg(3), Operand::Reg(2)));
+        f.insts.push(Inst::jmp(2));
+        f.insts.push(Inst::new(OpCode::SUB, Operand::Reg(4), Operand::Reg(4), Operand::Reg(5)));
+        f.insts.push(Inst::new(OpCode::NOP, Operand::None, Operand::None, Operand::None));
+        f.insts.push(Inst::new(OpCode::RETURN, Operand::Reg(6), Operand::None, Operand::None));
+        f.label_pos = vec![None, Some(3), Some(4)];
+        f.label_count = 3;
+        let cfg = oxide_cfg::build_cfg(&f);
+        let (live_in, _, _) = block_liveness(&f, &cfg);
+        // join 块（NOP 所在块）liveIn 含 6（RETURN 用）
+        let join = cfg.blocks.iter().position(|b| b.inst_range == (4..6usize)).unwrap();
+        assert!(live_in[join][6], "join 块 liveIn 应含 r6");
+        // then 分支块 liveIn 含 2、3，不含 5
+        let then = cfg.blocks.iter().position(|b| b.inst_range == (1..3usize)).unwrap();
+        assert!(set(&live_in[then], &[2, 3]));
+        assert!(!live_in[then][5]);
+        // else 分支块 liveIn 含 4、5，不含 2
+        let els = cfg.blocks.iter().position(|b| b.inst_range == (3..4usize)).unwrap();
+        assert!(set(&live_in[els], &[4, 5]));
+        assert!(!live_in[els][2]);
+    }
+
+    #[test]
+    fn loop_back_edge_keeps_value_alive() {
+        // 0: jmp_if_false(1, L1)
+        // 1: ADD r3=r3+r2
+        // 2: jmp L0
+        // 3: NOP
+        // 4: RETURN Reg(6)
+        let mut f = empty_function();
+        f.insts.push(Inst::jmp_if_false(1, 1));
+        f.insts.push(Inst::new(OpCode::ADD, Operand::Reg(3), Operand::Reg(3), Operand::Reg(2)));
+        f.insts.push(Inst::jmp(0));
+        f.insts.push(Inst::new(OpCode::NOP, Operand::None, Operand::None, Operand::None));
+        f.insts.push(Inst::new(OpCode::RETURN, Operand::Reg(6), Operand::None, Operand::None));
+        f.label_pos = vec![Some(0), Some(3)];
+        f.label_count = 2;
+        let cfg = oxide_cfg::build_cfg(&f);
+        let (live_in, _, _) = block_liveness(&f, &cfg);
+        // header 块（含 inst 0）liveIn 含 2（r2 跨回边存活）与 1（cond）
+        assert!(live_in[0][1], "header liveIn 应含 cond r1");
+        assert!(live_in[0][2], "header liveIn 应含 r2（跨回边存活）");
+        // body 块 liveIn 含 2
+        let body = cfg.blocks.iter().position(|b| b.inst_range == (1..3usize)).unwrap();
+        assert!(live_in[body][2]);
+        // 测试通过本身即不动点收敛证明
+    }
+
+    #[test]
+    fn try_catch_reg0_not_polluting_entry() {
+        // 0: try_begin(L_catch)
+        // 1: ADD r3=r3+r2
+        // 2: RETURN Reg(3)
+        // 3: STORE_VAR(Reg(5), None, None)   catch 入口：a=None→0 读 reg 0
+        // 4: RETURN Reg(5)
+        let mut f = empty_function();
+        f.insts.push(Inst::try_begin(3));
+        f.insts.push(Inst::new(OpCode::ADD, Operand::Reg(3), Operand::Reg(3), Operand::Reg(2)));
+        f.insts.push(Inst::new(OpCode::RETURN, Operand::Reg(3), Operand::None, Operand::None));
+        f.insts.push(Inst::new(OpCode::STORE_VAR, Operand::Reg(5), Operand::None, Operand::None));
+        f.insts.push(Inst::new(OpCode::RETURN, Operand::Reg(5), Operand::None, Operand::None));
+        f.label_pos = vec![None, None, None, Some(3)];
+        f.label_count = 1;
+        let cfg = oxide_cfg::build_cfg(&f);
+        let (live_in, _, _) = block_liveness(&f, &cfg);
+        // catch 块 liveIn 不含 0（隐式 def 截断）
+        let catch = cfg.blocks.iter().position(|b| b.inst_range == (3..5usize)).unwrap();
+        assert!(!live_in[catch][0], "catch 块入口 reg0 应被隐式 def 截断");
+        // try 块（entry）liveIn 不含 0（未污染入口）
+        assert!(!live_in[0][0], "reg0 use 不得污染函数入口");
+        // try 块 liveIn 含 2（正常变量照常存活）
+        assert!(live_in[0][2], "try 块 liveIn 应含 r2");
+    }
+
+    #[test]
+    fn none_operand_maps_to_reg0() {
+        // 0: LOAD_VAR(Reg(5), None, None)   def 5 use {0}
+        // 1: HALT(None, None, None)          contract.rs HALT 读 regs[0]
+        let mut f = empty_function();
+        f.insts.push(Inst::new(OpCode::LOAD_VAR, Operand::Reg(5), Operand::None, Operand::None));
+        f.insts.push(Inst::new(OpCode::HALT, Operand::None, Operand::None, Operand::None));
+        let cfg = oxide_cfg::build_cfg(&f);
+        let (live_in, _, _) = block_liveness(&f, &cfg);
+        assert!(live_in[0][0], "None→0 映射由 contract.rs 消费生效");
+    }
+}
diff --git a/crates/oxide_liveness/src/lib.rs b/crates/oxide_liveness/src/lib.rs
new file mode 100644
index 00000000..f33a3a3b
--- /dev/null
+++ b/crates/oxide_liveness/src/lib.rs
@@ -0,0 +1,31 @@
+//! liveness 分析 pass：IRFunction + CFG → LiveInfo（只读，D-15）。
+//!
+//! 消费 `oxide_ir::IRFunction`（只读）与 `oxide_cfg::Cfg`（preds/succs + exit 哨兵，D-12），
+//! 产出 LiveInfo 分析视图（D-01：pass 输出不住进 IR）。两阶段：`dataflow`（块级
+//! liveIn/liveOut 不动点）→ `ranges`（块内反向扫描逐指令 live 集）。gen/kill 直接消费
+//! contract.rs def_reg/use_regs（D-22），None→0 / This→254 / NewTarget→255 零重复映射。
+
+mod dataflow;
+mod live_info;
+mod ranges;
+
+pub use live_info::LiveInfo;
+
+use oxide_cfg::Cfg;
+use oxide_ir::IRFunction;
+
+/// 计算 liveness：`&IRFunction + &Cfg → LiveInfo`。纯函数，只读 IR（D-15）。
+/// 空 IRFunction 退化：返回 LiveInfo::new()（照 oxide_dce 空函数先例）。
+pub fn liveness(f: &IRFunction, cfg: &Cfg) -> LiveInfo {
+    if f.insts.is_empty() {
+        return LiveInfo::new();
+    }
+    let (block_in, block_out, reg_count) = dataflow::block_liveness(f, cfg);
+    let (inst_before, inst_after) = ranges::inst_liveness(f, cfg, &block_out, &block_in, reg_count);
+    LiveInfo {
+        block_live_in: block_in,
+        block_live_out: block_out,
+        inst_live_before: inst_before,
+        inst_live_after: inst_after,
+    }
+}
diff --git a/crates/oxide_liveness/src/live_info.rs b/crates/oxide_liveness/src/live_info.rs
new file mode 100644
index 00000000..595a1a53
--- /dev/null
+++ b/crates/oxide_liveness/src/live_info.rs
@@ -0,0 +1,50 @@
+//! LiveInfo：liveness 分析输出视图（D-15：pass 输出，不住进 IR）。
+//!
+//! 全部 live 集为按 reg 号索引的 bitset（`Vec<bool>`，长度 = reg_count+1，由
+//! dataflow 求上界）。四字段语义：
+//! - `block_live_in` / `block_live_out`：块级数据流迭代结果（05-06 精确 DCE 消费）
+//! - `inst_live_before` / `inst_live_after`：逐指令活集（05-07 干涉图消费 live_before）
+
+/// liveness 输出：块级 liveIn/liveOut + 逐指令 live_before/live_after。
+#[derive(Debug, Clone)]
+pub struct LiveInfo {
+    pub block_live_in: Vec<Vec<bool>>,
+    pub block_live_out: Vec<Vec<bool>>,
+    pub inst_live_before: Vec<Vec<bool>>,
+    pub inst_live_after: Vec<Vec<bool>>,
+}
+
+impl LiveInfo {
+    /// 构造空 LiveInfo：全空 vec，等价于 Default。
+    pub fn new() -> Self {
+        Self {
+            block_live_in: Vec::new(),
+            block_live_out: Vec::new(),
+            inst_live_before: Vec::new(),
+            inst_live_after: Vec::new(),
+        }
+    }
+}
+
+impl Default for LiveInfo {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn live_info_new_is_empty() {
+        let info = LiveInfo::new();
+        assert!(info.block_live_in.is_empty());
+        assert!(info.block_live_out.is_empty());
+        assert!(info.inst_live_before.is_empty());
+        assert!(info.inst_live_after.is_empty());
+        let default = LiveInfo::default();
+        assert!(default.block_live_in.is_empty());
+        assert!(default.block_live_out.is_empty());
+    }
+}
diff --git a/crates/oxide_liveness/src/ranges.rs b/crates/oxide_liveness/src/ranges.rs
new file mode 100644
index 00000000..b3a68c9d
--- /dev/null
+++ b/crates/oxide_liveness/src/ranges.rs
@@ -0,0 +1,128 @@
+//! 块内反向扫描：块级 liveOut → 逐指令 live_before/live_after。
+//!
+//! 起点是 **block_live_out**（非 liveIn，RESEARCH 伪代码笔误已修正——从 liveIn
+//! 出发会得到错误放大的逐指令集）。反向扫描 **kill 先于 gen**（`live = (live − def)
+//! ∪ use`）：COMPOUND_ADD 等读-写同寄存器指令 use 含 rd（contract.rs:137），
+//! gen 先于 kill 会把 rd 旧值从 live_before 错误剔除。Exception 目标块入口
+//! reg 0 隐式 def 在此截断，并以 `debug_assert_eq!(live, block_live_in[b])`
+//! 校验与 dataflow 一致性。
+
+use oxide_cfg::{Cfg, EdgeKind};
+use oxide_ir::IRFunction;
+
+/// 逐指令 liveness：返回 (inst_live_before, inst_live_after)，长度 = insts.len()。
+pub(super) fn inst_liveness(
+    f: &IRFunction, cfg: &Cfg, block_live_out: &[Vec<bool>], block_live_in: &[Vec<bool>], reg_count: usize,
+) -> (Vec<Vec<bool>>, Vec<Vec<bool>>) {
+    let bits = reg_count + 1;
+    let mut before = vec![vec![false; bits]; f.insts.len()];
+    let mut after = vec![vec![false; bits]; f.insts.len()];
+    for (b, block) in cfg.blocks.iter().enumerate() {
+        let mut live = block_live_out[b].clone(); // 从块级 liveOut 出发（非 liveIn）
+        for i in block.inst_range.clone().rev() {
+            after[i] = live.clone();
+            // kill 先于 gen：本指令先写后读（COMPOUND_ADD 等读-写同寄存器，contract.rs:137）
+            if let Some(d) = f.insts[i].def_reg() {
+                live[d as usize] = false;
+            }
+            for u in f.insts[i].use_regs() {
+                live[u as usize] = true;
+            }
+            before[i] = live.clone();
+        }
+        // Exception 目标块：入口 reg 0 隐式 def（异常展开写 regs[0]）截断无 def use。
+        // preds 是 Vec<BBId>（无 EdgeKind），从源块 succs 侧检测 Exception 边。
+        let is_exception_target = cfg
+            .blocks
+            .iter()
+            .any(|src| src.succs.iter().any(|&(dst, k)| dst == b && k == EdgeKind::Exception));
+        if is_exception_target {
+            live[0] = false;
+        }
+        debug_assert_eq!(live, block_live_in[b], "ranges 反向扫描与 dataflow liveIn 不一致，块 {b}");
+    }
+    (before, after)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::dataflow::block_liveness;
+    use oxide_ir::inst::Inst;
+    use oxide_ir::operand::Operand;
+    use oxide_bytecode::opcode::OpCode;
+
+    fn empty_function() -> IRFunction {
+        IRFunction::new()
+    }
+
+    #[test]
+    fn linear_block_instruction_sets() {
+        // 0: ADD r2=r0+r1    1: RETURN r2
+        let mut f = empty_function();
+        f.insts.push(Inst::new(OpCode::ADD, Operand::Reg(2), Operand::Reg(0), Operand::Reg(1)));
+        f.insts.push(Inst::new(OpCode::RETURN, Operand::Reg(2), Operand::None, Operand::None));
+        let cfg = oxide_cfg::build_cfg(&f);
+        let (live_in, live_out, rc) = block_liveness(&f, &cfg);
+        let (before, after) = inst_liveness(&f, &cfg, &live_out, &live_in, rc);
+        assert!(after[0][2], "ADD 后 r2 存活（RETURN 用）");
+        assert!(before[0][0] && before[0][1], "ADD 前 r0、r1 存活");
+        assert!(!before[0][2], "ADD 前 r2 不死");
+        assert!(after[1].iter().all(|&v| !v), "RETURN 后无存活");
+        assert!(before[1][2], "RETURN 前 r2 存活");
+    }
+
+    #[test]
+    fn read_modify_write_kills_before_gen() {
+        // 0: COMPOUND_ADD rd=1, a=2    def {1} use {1,2}
+        // 1: RETURN r1
+        let mut f = empty_function();
+        f.insts.push(Inst::new(OpCode::COMPOUND_ADD, Operand::Reg(1), Operand::Reg(2), Operand::None));
+        f.insts.push(Inst::new(OpCode::RETURN, Operand::Reg(1), Operand::None, Operand::None));
+        let cfg = oxide_cfg::build_cfg(&f);
+        let (live_in, live_out, rc) = block_liveness(&f, &cfg);
+        let (before, _) = inst_liveness(&f, &cfg, &live_out, &live_in, rc);
+        assert!(before[0][1], "COMPOUND_ADD 前 r1 旧值在读（kill 先于 gen）");
+        assert!(before[0][2], "COMPOUND_ADD 前 r2 存活");
+        assert!(live_in[0][1] && live_in[0][2], "块级 liveIn 含 r1、r2");
+    }
+
+    #[test]
+    fn call_result_reg0_range_is_short() {
+        // 0: call(callee=1, this=2, first_arg=3, nargs=1)   def {0} use {1,2,3}
+        // 1: LOAD_VAR(Reg(4), None, None)                   def {4} use {0}
+        // 2: RETURN r4
+        let mut f = empty_function();
+        f.insts.push(Inst::call(Operand::Reg(1), Operand::Reg(2), Operand::Reg(3), 1));
+        f.insts.push(Inst::new(OpCode::LOAD_VAR, Operand::Reg(4), Operand::None, Operand::None));
+        f.insts.push(Inst::new(OpCode::RETURN, Operand::Reg(4), Operand::None, Operand::None));
+        let cfg = oxide_cfg::build_cfg(&f);
+        let (live_in, live_out, rc) = block_liveness(&f, &cfg);
+        let (before, after) = inst_liveness(&f, &cfg, &live_out, &live_in, rc);
+        assert!(before[1][0], "LOAD_VAR 前读 CALL 结果 reg0");
+        assert!(after[0][0], "CALL 后 reg0 存活（结果）");
+        assert!(!before[0][0], "CALL 前 reg0 不死（区间仅 [CALL, LOAD_VAR)）");
+        assert!(!live_in[0][0], "reg0 不污染块入口");
+    }
+
+    #[test]
+    fn catch_entry_reg0_not_live_before_block() {
+        // 0: try_begin(3)   1: ADD r3=r3+r2   2: RETURN r3
+        // 3: STORE_VAR(r5, None, None)   4: RETURN r5
+        let mut f = empty_function();
+        f.insts.push(Inst::try_begin(3));
+        f.insts.push(Inst::new(OpCode::ADD, Operand::Reg(3), Operand::Reg(3), Operand::Reg(2)));
+        f.insts.push(Inst::new(OpCode::RETURN, Operand::Reg(3), Operand::None, Operand::None));
+        f.insts.push(Inst::new(OpCode::STORE_VAR, Operand::Reg(5), Operand::None, Operand::None));
+        f.insts.push(Inst::new(OpCode::RETURN, Operand::Reg(5), Operand::None, Operand::None));
+        f.label_pos = vec![None, None, None, Some(3)];
+        f.label_count = 1;
+        let cfg = oxide_cfg::build_cfg(&f);
+        let (live_in, live_out, rc) = block_liveness(&f, &cfg);
+        let (before, _) = inst_liveness(&f, &cfg, &live_out, &live_in, rc);
+        assert!(before[3][0], "catch 块内 STORE_VAR 读 reg0（异常值，正确）");
+        let catch_block = cfg.blocks.iter().position(|b| b.inst_range == (3..5usize)).unwrap();
+        assert!(!live_in[catch_block][0], "catch 块入口 reg0 被隐式 def 截断");
+        assert!(!live_in[0][0], "try 块（entry）reg0 不污染入口");
+    }
+}
diff --git a/crates/oxide_liveness/tests/smoke.rs b/crates/oxide_liveness/tests/smoke.rs
new file mode 100644
index 00000000..b5011717
--- /dev/null
+++ b/crates/oxide_liveness/tests/smoke.rs
@@ -0,0 +1,61 @@
+//! 集成冒烟：真实编译产物（parse→emit→build_cfg→liveness）跑不崩 + 维度一致性 + try/catch reg0 断言 + 确定性。
+
+use oxide_cfg::build_cfg;
+use oxide_liveness::{liveness, LiveInfo};
+
+fn run_liveness(src: &str) -> (LiveInfo, oxide_cfg::Cfg, usize) {
+    let allocator = oxide_parser::Allocator::default();
+    let program = oxide_parser::parse(&allocator, src).expect("parse");
+    let ir = oxide_emit::Emitter::new().emit_program(&program).expect("emit");
+    let cfg = build_cfg(&ir);
+    let info = liveness(&ir, &cfg);
+    (info, cfg, ir.insts.len())
+}
+
+fn smoke(src: &str) {
+    let (info, cfg, inst_len) = run_liveness(src);
+    assert_eq!(info.block_live_in.len(), cfg.blocks.len(), "block 维度一致");
+    assert_eq!(info.block_live_out.len(), cfg.blocks.len(), "block 维度一致");
+    assert_eq!(info.inst_live_before.len(), inst_len, "inst 维度一致");
+    assert_eq!(info.inst_live_after.len(), inst_len, "inst 维度一致");
+}
+
+#[test]
+fn smoke_simple_function() {
+    smoke("function f(a, b) { return a + b; } f(1, 2)");
+}
+
+#[test]
+fn smoke_if_else() {
+    smoke("function f(x) { if (x > 0) { return 1; } else { return 2; } } f(5)");
+}
+
+#[test]
+fn smoke_loop_with_variables() {
+    smoke("function f(n) { var s = 0; for (var i = 0; i < n; i++) { s = s + i; } return s; } f(10)");
+}
+
+#[test]
+fn smoke_try_catch() {
+    let (info, cfg, _) = run_liveness(
+        "function x() {} function y(e) {} function f() { try { x(); } catch (e) { y(e); } } f()",
+    );
+    // entry 块 liveIn 不含 reg 0（异常边 reg0 截断在真实产物上成立）
+    assert!(!info.block_live_in[cfg.entry][0], "entry 块 liveIn 不得含 reg0");
+}
+
+#[test]
+fn smoke_nested_calls() {
+    smoke("function g(x) { return x + 1; } function f(x) { return g(x) + g(x + 1); } f(1)");
+}
+
+#[test]
+fn liveness_is_deterministic() {
+    let src = "function f(n) { var s = 0; for (var i = 0; i < n; i++) { s = s + i; } return s; } f(10)";
+    let (a, _, _) = run_liveness(src);
+    let (b, _, _) = run_liveness(src);
+    assert_eq!(a.block_live_in, b.block_live_in);
+    assert_eq!(a.block_live_out, b.block_live_out);
+    assert_eq!(a.inst_live_before, b.inst_live_before);
+    assert_eq!(a.inst_live_after, b.inst_live_after);
+}