diff --git a/Cargo.lock b/Cargo.lock
index 3c6f8016..02acb355 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -145,6 +145,12 @@ dependencies = [
  "yansi",
 ]
 
+[[package]]
+name = "atomic-maybe-uninit"
+version = "0.3.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e5a320ab39d3f29f95494ce06a1e5d86890eadb13e4438bfd3102b1f5566b299"
+
 [[package]]
 name = "atty"
 version = "0.2.14"
@@ -496,10 +502,10 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1137cd7e7fc0fb5d3c5a8678be38ec56e819125d8d7907411fe24ccb943faca8"
 dependencies = [
  "crossbeam-channel",
- "crossbeam-deque",
- "crossbeam-epoch",
+ "crossbeam-deque 0.8.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "crossbeam-epoch 0.9.18 (registry+https://github.com/rust-lang/crates.io-index)",
  "crossbeam-queue",
- "crossbeam-utils",
+ "crossbeam-utils 0.8.20 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -508,7 +514,7 @@ version = "0.5.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "33480d6946193aa8033910124896ca395333cae7e2d1113d1fef6c3272217df2"
 dependencies = [
- "crossbeam-utils",
+ "crossbeam-utils 0.8.20 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -517,8 +523,17 @@ version = "0.8.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "613f8cc01fe9cf1a3eb3d7f488fd2fa8388403e97039e2f73692932e291a770d"
 dependencies = [
- "crossbeam-epoch",
- "crossbeam-utils",
+ "crossbeam-epoch 0.9.18 (registry+https://github.com/rust-lang/crates.io-index)",
+ "crossbeam-utils 0.8.20 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "crossbeam-deque"
+version = "0.8.5"
+source = "git+https://github.com/Pivot-Studio/crossbeam.git#6925a93dbd6db8b13173252b159a9dc83febbe3a"
+dependencies = [
+ "crossbeam-epoch 0.9.18 (git+https://github.com/Pivot-Studio/crossbeam.git)",
+ "crossbeam-utils 0.8.20 (git+https://github.com/Pivot-Studio/crossbeam.git)",
 ]
 
 [[package]]
@@ -527,7 +542,15 @@ version = "0.9.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5b82ac4a3c2ca9c3460964f020e1402edd5753411d7737aa39c3714ad1b5420e"
 dependencies = [
- "crossbeam-utils",
+ "crossbeam-utils 0.8.20 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "crossbeam-epoch"
+version = "0.9.18"
+source = "git+https://github.com/Pivot-Studio/crossbeam.git#6925a93dbd6db8b13173252b159a9dc83febbe3a"
+dependencies = [
+ "crossbeam-utils 0.8.20 (git+https://github.com/Pivot-Studio/crossbeam.git)",
 ]
 
 [[package]]
@@ -536,7 +559,7 @@ version = "0.3.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "df0346b5d5e76ac2fe4e327c5fd1118d6be7c51dfb18f9b7922923f287471e35"
 dependencies = [
- "crossbeam-utils",
+ "crossbeam-utils 0.8.20 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -545,6 +568,14 @@ version = "0.8.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "22ec99545bb0ed0ea7bb9b8e1e9122ea386ff8a48c0922e43f36d45ab09e0e80"
 
+[[package]]
+name = "crossbeam-utils"
+version = "0.8.20"
+source = "git+https://github.com/Pivot-Studio/crossbeam.git#6925a93dbd6db8b13173252b159a9dc83febbe3a"
+dependencies = [
+ "atomic-maybe-uninit",
+]
+
 [[package]]
 name = "crunchy"
 version = "0.2.2"
@@ -558,7 +589,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "804c8821570c3f8b70230c2ba75ffa5c0f9a4189b9a432b6656c536712acae28"
 dependencies = [
  "cfg-if",
- "crossbeam-utils",
+ "crossbeam-utils 0.8.20 (registry+https://github.com/rust-lang/crates.io-index)",
  "hashbrown 0.14.5",
  "lock_api",
  "once_cell",
@@ -858,7 +889,7 @@ dependencies = [
  "backtrace",
  "cmake",
  "criterion",
- "crossbeam-deque",
+ "crossbeam-deque 0.8.5 (git+https://github.com/Pivot-Studio/crossbeam.git)",
  "int-enum",
  "lazy_static",
  "libc",
@@ -1617,8 +1648,8 @@ version = "1.12.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1465873a3dfdaa8ae7cb14b4383657caab0b3e8a0aa9ae8e04b044854c8dfce2"
 dependencies = [
- "crossbeam-deque",
- "crossbeam-utils",
+ "crossbeam-deque 0.8.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "crossbeam-utils 0.8.20 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
diff --git a/Cargo.toml b/Cargo.toml
index 8f1924a4..38ec8688 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -98,9 +98,9 @@ thread = ["threadpool"]
 members = ["internal_macro", "vm", "pl_linker", "immix", "kagari"]
 
 [profile.release]
-lto = "thin"
+lto = "fat"
 opt-level = 3
-debug = "line-tables-only"
+# debug = "line-tables-only"
 
 [profile.bench]
 opt-level = 3
@@ -127,3 +127,8 @@ vergen = { version = "8.3.1", features = [
     "rustc",
     "si",
 ] }
+
+
+[profile.dev]
+overflow-checks = false
+debug-assertions = false
\ No newline at end of file
diff --git a/alloc.ll b/alloc.ll
index e35b8e9f..19c0fa52 100644
--- a/alloc.ll
+++ b/alloc.ll
@@ -19,11 +19,19 @@ declare noalias void @DioGC__safepoint_ex(
 
 define noalias void @DioGC__safepoint(
     i64 %rsp) {
-    call void @DioGC__safepoint_ex(i64 %rsp, ptr @gc_handle)
+    %collector_ptr = load ptr, ptr @gc_handle, align 8, !invariant.load !0
+    call void @DioGC__safepoint_ex(i64 %rsp, ptr %collector_ptr)
     ret void
 }
 
 
+declare noalias void @gc_set_handle(ptr %handle)
+
+define void @gc_thread_init() {
+    call void @gc_set_handle(ptr @gc_handle)
+    ret void
+}
+
 declare void @llvm.memset.p0.i64(ptr nocapture, i8, i64, i1) nounwind
 
 
@@ -43,7 +51,7 @@ entry:
     br i1 %size_gt_7936, label %call_slowpath, label %check_collector
 check_collector:
     ; Load collector from gc_handle
-    %collector_ptr = load ptr, ptr @gc_handle, align 8
+    %collector_ptr = load ptr, ptr @gc_handle, align 8, !invariant.load !0
     
     ; Check if collector_ptr is null
     %is_null = icmp eq ptr %collector_ptr, null
@@ -158,3 +166,4 @@ finish_fast_path_2:
 
 
 attributes #0 = { nounwind allockind("alloc") "gc-leaf-function" }
+!0 = !{}
\ No newline at end of file
diff --git a/immix b/immix
index 54039556..e8ee732b 160000
--- a/immix
+++ b/immix
@@ -1 +1 @@
-Subproject commit 54039556ba4e99edb101a1a1cab6b0ddccecdbdf
+Subproject commit e8ee732bdfaeba9b122245573937fb27ab09f692
diff --git a/src/ast/ctx/cast.rs b/src/ast/ctx/cast.rs
index bd219df0..35e72991 100644
--- a/src/ast/ctx/cast.rs
+++ b/src/ast/ctx/cast.rs
@@ -288,7 +288,9 @@ impl<'a, 'ctx> Ctx<'a> {
         if let PLType::Union(u) = &*target_pltype.borrow() {
             let mut union_members = vec![];
             for tp in &u.sum_types {
-                let tp = tp.get_type(self, builder, true)?;
+                let tp = self.run_in_type_mod(u, |ctx,u|{
+                    tp.get_type(ctx, builder, true)
+                })?;
                 union_members.push(tp);
             }
             for (i, tp) in union_members.iter().enumerate() {