diff --git a/c/sqlite/llgo_autogen.lla b/c/sqlite/llgo_autogen.lla
index 4672bbad..93b7c3ad 100644
Binary files a/c/sqlite/llgo_autogen.lla and b/c/sqlite/llgo_autogen.lla differ
diff --git a/cl/_testdata/print/out.ll b/cl/_testdata/print/out.ll
index 9fadd77e..1744b3f4 100644
--- a/cl/_testdata/print/out.ll
+++ b/cl/_testdata/print/out.ll
@@ -191,7 +191,7 @@ _llgo_1:                                          ; preds = %_llgo_3
   call void @main.println(%"github.com/goplus/llgo/internal/runtime.Slice" %47)
   br label %_llgo_2
 
-_llgo_2:                                          ; preds = %_llgo_3, %_llgo_1, %_llgo_0
+_llgo_2:                                          ; preds = %_llgo_1, %_llgo_3, %_llgo_0
   %48 = call ptr @"github.com/goplus/llgo/internal/runtime.AllocZ"(i64 48)
   %49 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.eface", ptr %48, i64 0
   %50 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
@@ -1451,7 +1451,7 @@ _llgo_1:                                          ; preds = %_llgo_3
   %7 = icmp ult i64 %9, 10
   br i1 %7, label %_llgo_2, label %_llgo_4
 
-_llgo_2:                                          ; preds = %_llgo_3, %_llgo_1
+_llgo_2:                                          ; preds = %_llgo_1, %_llgo_3
   %8 = call %"github.com/goplus/llgo/internal/runtime.Slice" @"github.com/goplus/llgo/internal/runtime.NewSlice3"(ptr %1, i64 1, i64 100, i64 %10, i64 100, i64 100)
   call void @main.gwrite(%"github.com/goplus/llgo/internal/runtime.Slice" %8)
   ret void
diff --git a/cl/_testdata/utf8/out.ll b/cl/_testdata/utf8/out.ll
index 964a3e9c..e24d991d 100644
--- a/cl/_testdata/utf8/out.ll
+++ b/cl/_testdata/utf8/out.ll
@@ -53,7 +53,7 @@ _llgo_0:
 _llgo_1:                                          ; preds = %_llgo_3
   %2 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
   %3 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %2, i32 0, i32 0
-  store ptr @0, ptr %3, align 8
+  store ptr @1, ptr %3, align 8
   %4 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %2, i32 0, i32 1
   store i64 7, ptr %4, align 4
   %5 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %2, align 8
@@ -79,7 +79,7 @@ _llgo_3:                                          ; preds = %_llgo_1, %_llgo_0
   %15 = phi i64 [ 0, %_llgo_0 ], [ %11, %_llgo_1 ]
   %16 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
   %17 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %16, i32 0, i32 0
-  store ptr @1, ptr %17, align 8
+  store ptr @0, ptr %17, align 8
   %18 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %16, i32 0, i32 1
   store i64 7, ptr %18, align 4
   %19 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %16, align 8
diff --git a/cl/_testdefer/loop/in.go b/cl/_testdefer/loop/in.go
new file mode 100644
index 00000000..ebd8938e
--- /dev/null
+++ b/cl/_testdefer/loop/in.go
@@ -0,0 +1,20 @@
+package main
+
+func f(s string) bool {
+	return len(s) > 2
+}
+
+func main() {
+	defer func() {
+		println("hi")
+	}()
+	for i := 0; i < 3; i++ {
+		if s := "hello"; f(s) {
+			defer println(s)
+		} else {
+			defer println("world")
+			return
+		}
+	}
+	defer println("bye")
+}
diff --git a/cl/_testdefer/loop/out.txt b/cl/_testdefer/loop/out.txt
new file mode 100644
index 00000000..ad86720d
--- /dev/null
+++ b/cl/_testdefer/loop/out.txt
@@ -0,0 +1,7 @@
+ 0: always
+ 1: cond
+ 4: loop
+ 2: loop
+ 5: loop
+ 3: cond
+ 6: cond
diff --git a/cl/_testdefer/multiret/in.go b/cl/_testdefer/multiret/in.go
new file mode 100644
index 00000000..82d34e31
--- /dev/null
+++ b/cl/_testdefer/multiret/in.go
@@ -0,0 +1,18 @@
+package main
+
+func f(s string) bool {
+	return len(s) > 2
+}
+
+func main() {
+	defer func() {
+		println("hi")
+	}()
+	if s := "hello"; f(s) {
+		defer println(s)
+	} else {
+		defer println("world")
+		return
+	}
+	defer println("bye")
+}
diff --git a/cl/_testdefer/multiret/out.txt b/cl/_testdefer/multiret/out.txt
new file mode 100644
index 00000000..c47bbe4c
--- /dev/null
+++ b/cl/_testdefer/multiret/out.txt
@@ -0,0 +1,4 @@
+ 0: always
+ 1: cond
+ 2: cond
+ 3: cond
diff --git a/cl/_testdefer/print/in.go b/cl/_testdefer/print/in.go
new file mode 100644
index 00000000..c9726adc
--- /dev/null
+++ b/cl/_testdefer/print/in.go
@@ -0,0 +1,52 @@
+package main
+
+func f() float64 {
+	return 1.0
+}
+
+func main() {
+	var v = f()
+	const n = 7 // digits printed
+	var buf [n + 7]byte
+	buf[0] = '+'
+	e := 0 // exp
+	if v == 0 {
+		if 1/v < 0 {
+			buf[0] = '-'
+		}
+	} else {
+		if v < 0 {
+			v = -v
+			buf[0] = '-'
+		}
+
+		// normalize
+		for v >= 10 {
+			e++
+			v /= 10
+		}
+		for v < 1 {
+			e--
+			v *= 10
+		}
+
+		// round
+		h := 5.0
+		for i := 0; i < n; i++ {
+			h /= 10
+		}
+		v += h
+		if v >= 10 {
+			e++
+			v /= 10
+		}
+	}
+
+	// format +d.dddd+edd
+	for i := 0; i < n; i++ {
+		s := int(v)
+		buf[i+2] = byte(s + '0')
+		v -= float64(s)
+		v *= 10
+	}
+}
diff --git a/cl/_testdefer/print/out.txt b/cl/_testdefer/print/out.txt
new file mode 100644
index 00000000..85787635
--- /dev/null
+++ b/cl/_testdefer/print/out.txt
@@ -0,0 +1,18 @@
+ 0: always
+ 1: cond
+ 3: cond
+ 4: cond
+ 5: cond
+ 7: loop
+ 6: loop
+10: loop
+ 8: loop
+ 9: cond
+13: loop
+11: loop
+12: cond
+14: cond
+ 2: cond
+17: loop
+15: loop
+16: always
diff --git a/cl/_testdefer/singleret/in.go b/cl/_testdefer/singleret/in.go
new file mode 100644
index 00000000..cd95da67
--- /dev/null
+++ b/cl/_testdefer/singleret/in.go
@@ -0,0 +1,17 @@
+package main
+
+func f(s string) bool {
+	return len(s) > 2
+}
+
+func main() {
+	defer func() {
+		println("hi")
+	}()
+	if s := "hello"; f(s) {
+		defer println(s)
+	} else {
+		defer println("world")
+	}
+	defer println("bye")
+}
diff --git a/cl/_testdefer/singleret/out.txt b/cl/_testdefer/singleret/out.txt
new file mode 100644
index 00000000..530763ee
--- /dev/null
+++ b/cl/_testdefer/singleret/out.txt
@@ -0,0 +1,5 @@
+ 0: always
+ 1: cond
+ 2: cond
+ 4: cond
+ 3: always
diff --git a/cl/_testgo/defer/out.ll b/cl/_testgo/defer/out.ll
index ebb35a1c..0a15d5ef 100644
--- a/cl/_testgo/defer/out.ll
+++ b/cl/_testgo/defer/out.ll
@@ -53,108 +53,97 @@ _llgo_0:
   call void @main.init()
   %9 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.Defer", ptr %4, i32 0, i32 1
   %10 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.Defer", ptr %4, i32 0, i32 3
-  %11 = load i64, ptr %9, align 4
-  %12 = or i64 %11, 1
-  store i64 %12, ptr %9, align 4
-  %13 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
-  %14 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %13, i32 0, i32 0
-  store ptr @0, ptr %14, align 8
-  %15 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %13, i32 0, i32 1
-  store i64 5, ptr %15, align 4
-  %16 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %13, align 8
-  %17 = call i1 @main.f(%"github.com/goplus/llgo/internal/runtime.String" %16)
-  br i1 %17, label %_llgo_2, label %_llgo_3
+  %11 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
+  %12 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %11, i32 0, i32 0
+  store ptr @0, ptr %12, align 8
+  %13 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %11, i32 0, i32 1
+  store i64 5, ptr %13, align 4
+  %14 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %11, align 8
+  %15 = call i1 @main.f(%"github.com/goplus/llgo/internal/runtime.String" %14)
+  br i1 %15, label %_llgo_2, label %_llgo_3
 
 _llgo_1:                                          ; No predecessors!
   ret i32 0
 
 _llgo_2:                                          ; preds = %_llgo_0
-  %18 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
-  %19 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %18, i32 0, i32 0
-  store ptr @1, ptr %19, align 8
-  %20 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %18, i32 0, i32 1
-  store i64 5, ptr %20, align 4
-  %21 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %18, align 8
-  %22 = load i64, ptr %9, align 4
-  %23 = or i64 %22, 2
-  store i64 %23, ptr %9, align 4
-  %24 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
-  %25 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %24, i32 0, i32 0
-  store ptr @2, ptr %25, align 8
-  %26 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %24, i32 0, i32 1
-  store i64 3, ptr %26, align 4
-  %27 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %24, align 8
-  %28 = load i64, ptr %9, align 4
-  %29 = or i64 %28, 4
-  store i64 %29, ptr %9, align 4
+  %16 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
+  %17 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %16, i32 0, i32 0
+  store ptr @1, ptr %17, align 8
+  %18 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %16, i32 0, i32 1
+  store i64 5, ptr %18, align 4
+  %19 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %16, align 8
+  %20 = load i64, ptr %9, align 4
+  %21 = or i64 %20, 1
+  store i64 %21, ptr %9, align 4
+  %22 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
+  %23 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %22, i32 0, i32 0
+  store ptr @2, ptr %23, align 8
+  %24 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %22, i32 0, i32 1
+  store i64 3, ptr %24, align 4
+  %25 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %22, align 8
+  %26 = load i64, ptr %9, align 4
+  %27 = or i64 %26, 2
+  store i64 %27, ptr %9, align 4
   store i64 0, ptr %10, align 4
   br label %_llgo_4
 
 _llgo_3:                                          ; preds = %_llgo_0
-  %30 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
-  %31 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %30, i32 0, i32 0
-  store ptr @3, ptr %31, align 8
-  %32 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %30, i32 0, i32 1
-  store i64 5, ptr %32, align 4
-  %33 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %30, align 8
-  %34 = load i64, ptr %9, align 4
-  %35 = or i64 %34, 8
-  store i64 %35, ptr %9, align 4
+  %28 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
+  %29 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %28, i32 0, i32 0
+  store ptr @3, ptr %29, align 8
+  %30 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %28, i32 0, i32 1
+  store i64 5, ptr %30, align 4
+  %31 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %28, align 8
+  %32 = load i64, ptr %9, align 4
+  %33 = or i64 %32, 4
+  store i64 %33, ptr %9, align 4
   store i64 1, ptr %10, align 4
   br label %_llgo_4
 
 _llgo_4:                                          ; preds = %_llgo_3, %_llgo_2
-  %36 = load i64, ptr %9, align 4
-  %37 = and i64 %36, 8
-  %38 = icmp ne i64 %37, 0
-  br i1 %38, label %_llgo_7, label %_llgo_8
+  %34 = load i64, ptr %9, align 4
+  %35 = and i64 %34, 4
+  %36 = icmp ne i64 %35, 0
+  br i1 %36, label %_llgo_7, label %_llgo_8
 
-_llgo_5:                                          ; preds = %_llgo_14
+_llgo_5:                                          ; preds = %_llgo_12
   ret i32 0
 
-_llgo_6:                                          ; preds = %_llgo_14
+_llgo_6:                                          ; preds = %_llgo_12
   ret i32 0
 
 _llgo_7:                                          ; preds = %_llgo_4
-  call void @"github.com/goplus/llgo/internal/runtime.PrintString"(%"github.com/goplus/llgo/internal/runtime.String" %33)
+  call void @"github.com/goplus/llgo/internal/runtime.PrintString"(%"github.com/goplus/llgo/internal/runtime.String" %31)
   call void @"github.com/goplus/llgo/internal/runtime.PrintByte"(i8 10)
   br label %_llgo_8
 
 _llgo_8:                                          ; preds = %_llgo_7, %_llgo_4
-  %39 = and i64 %36, 4
-  %40 = icmp ne i64 %39, 0
-  br i1 %40, label %_llgo_9, label %_llgo_10
+  %37 = and i64 %34, 2
+  %38 = icmp ne i64 %37, 0
+  br i1 %38, label %_llgo_9, label %_llgo_10
 
 _llgo_9:                                          ; preds = %_llgo_8
-  call void @"github.com/goplus/llgo/internal/runtime.PrintString"(%"github.com/goplus/llgo/internal/runtime.String" %27)
+  call void @"github.com/goplus/llgo/internal/runtime.PrintString"(%"github.com/goplus/llgo/internal/runtime.String" %25)
   call void @"github.com/goplus/llgo/internal/runtime.PrintByte"(i8 10)
   br label %_llgo_10
 
 _llgo_10:                                         ; preds = %_llgo_9, %_llgo_8
-  %41 = and i64 %36, 2
-  %42 = icmp ne i64 %41, 0
-  br i1 %42, label %_llgo_11, label %_llgo_12
+  %39 = and i64 %34, 1
+  %40 = icmp ne i64 %39, 0
+  br i1 %40, label %_llgo_11, label %_llgo_12
 
 _llgo_11:                                         ; preds = %_llgo_10
-  call void @"github.com/goplus/llgo/internal/runtime.PrintString"(%"github.com/goplus/llgo/internal/runtime.String" %21)
+  call void @"github.com/goplus/llgo/internal/runtime.PrintString"(%"github.com/goplus/llgo/internal/runtime.String" %19)
   call void @"github.com/goplus/llgo/internal/runtime.PrintByte"(i8 10)
   br label %_llgo_12
 
 _llgo_12:                                         ; preds = %_llgo_11, %_llgo_10
-  %43 = and i64 %36, 1
-  %44 = icmp ne i64 %43, 0
-  br i1 %44, label %_llgo_13, label %_llgo_14
-
-_llgo_13:                                         ; preds = %_llgo_12
   call void @"main.main$1"()
-  br label %_llgo_14
-
-_llgo_14:                                         ; preds = %_llgo_13, %_llgo_12
-  %45 = load %"github.com/goplus/llgo/internal/runtime.Defer", ptr %4, align 8
-  %46 = extractvalue %"github.com/goplus/llgo/internal/runtime.Defer" %45, 2
-  %47 = call i32 @pthread_setspecific(ptr %2, ptr %46)
-  %48 = load i64, ptr %10, align 4
-  switch i64 %48, label %_llgo_5 [
+  %41 = load %"github.com/goplus/llgo/internal/runtime.Defer", ptr %4, align 8
+  %42 = extractvalue %"github.com/goplus/llgo/internal/runtime.Defer" %41, 2
+  %43 = call i32 @pthread_setspecific(ptr %2, ptr %42)
+  %44 = load i64, ptr %10, align 4
+  switch i64 %44, label %_llgo_5 [
     i64 1, label %_llgo_6
   ]
 }
diff --git a/cl/_testgo/strucintf/out.ll b/cl/_testgo/strucintf/out.ll
index fada9257..131b5bb5 100644
--- a/cl/_testgo/strucintf/out.ll
+++ b/cl/_testgo/strucintf/out.ll
@@ -15,11 +15,11 @@ source_filename = "main"
 @2 = private unnamed_addr constant [5 x i8] c"main\00", align 1
 @__llgo_argc = global ptr null
 @__llgo_argv = global ptr null
+@3 = private unnamed_addr constant [12 x i8] c"Foo: not ok\00", align 1
 @"_llgo_struct$K-dZ9QotZfVPz2a0YdRa9vmZUuDXPTqZOlMShKEDJtk" = linkonce global ptr null
-@3 = private unnamed_addr constant [2 x i8] c"V\00", align 1
-@4 = private unnamed_addr constant [1 x i8] zeroinitializer, align 1
-@5 = private unnamed_addr constant [5 x i8] c"main\00", align 1
-@6 = private unnamed_addr constant [12 x i8] c"Foo: not ok\00", align 1
+@4 = private unnamed_addr constant [2 x i8] c"V\00", align 1
+@5 = private unnamed_addr constant [1 x i8] zeroinitializer, align 1
+@6 = private unnamed_addr constant [5 x i8] c"main\00", align 1
 @7 = private unnamed_addr constant [12 x i8] c"Bar: not ok\00", align 1
 @8 = private unnamed_addr constant [10 x i8] c"F: not ok\00", align 1
 
@@ -94,7 +94,7 @@ _llgo_2:                                          ; preds = %_llgo_3, %_llgo_1
 _llgo_3:                                          ; preds = %_llgo_12
   %16 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
   %17 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %16, i32 0, i32 0
-  store ptr @6, ptr %17, align 8
+  store ptr @3, ptr %17, align 8
   %18 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %16, i32 0, i32 1
   store i64 11, ptr %18, align 4
   %19 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %16, align 8
@@ -299,20 +299,20 @@ _llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
 _llgo_3:                                          ; preds = %_llgo_2
   %28 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
   %29 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %28, i32 0, i32 0
-  store ptr @3, ptr %29, align 8
+  store ptr @4, ptr %29, align 8
   %30 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %28, i32 0, i32 1
   store i64 1, ptr %30, align 4
   %31 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %28, align 8
   %32 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
   %33 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %32, i32 0, i32 0
-  store ptr @4, ptr %33, align 8
+  store ptr @5, ptr %33, align 8
   %34 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %32, i32 0, i32 1
   store i64 0, ptr %34, align 4
   %35 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %32, align 8
   %36 = call %"github.com/goplus/llgo/internal/abi.StructField" @"github.com/goplus/llgo/internal/runtime.StructField"(%"github.com/goplus/llgo/internal/runtime.String" %31, ptr %25, i64 0, %"github.com/goplus/llgo/internal/runtime.String" %35, i1 false)
   %37 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
   %38 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %37, i32 0, i32 0
-  store ptr @5, ptr %38, align 8
+  store ptr @6, ptr %38, align 8
   %39 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %37, i32 0, i32 1
   store i64 4, ptr %39, align 4
   %40 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %37, align 8
@@ -351,8 +351,8 @@ declare void @"github.com/goplus/llgo/internal/runtime.PrintInt"(i64)
 
 declare void @"github.com/goplus/llgo/internal/runtime.PrintByte"(i8)
 
-declare %"github.com/goplus/llgo/internal/runtime.eface" @"github.com/goplus/llgo/cl/internal/foo.Bar"()
-
 declare void @"github.com/goplus/llgo/internal/runtime.PrintString"(%"github.com/goplus/llgo/internal/runtime.String")
 
+declare %"github.com/goplus/llgo/internal/runtime.eface" @"github.com/goplus/llgo/cl/internal/foo.Bar"()
+
 declare %"github.com/goplus/llgo/internal/runtime.eface" @"github.com/goplus/llgo/cl/internal/foo.F"()
diff --git a/cl/blocks/block.go b/cl/blocks/block.go
new file mode 100644
index 00000000..21960751
--- /dev/null
+++ b/cl/blocks/block.go
@@ -0,0 +1,173 @@
+/*
+ * Copyright (c) 2024 The GoPlus Authors (goplus.org). All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package blocks
+
+import (
+	llssa "github.com/goplus/llgo/ssa"
+	"golang.org/x/tools/go/ssa"
+)
+
+type Info struct {
+	Kind llssa.DoAction
+	Next int
+}
+
+// -----------------------------------------------------------------------------
+
+type blockState struct {
+	self   *ssa.BasicBlock
+	preds  int
+	succs  []int
+	loop   bool
+	always bool
+	reach  bool
+	fdel   bool
+}
+
+func (p *blockState) kind() llssa.DoAction {
+	if p.loop {
+		return llssa.DeferInLoop
+	}
+	if p.always {
+		return llssa.DeferAlways
+	}
+	return llssa.DeferInCond
+}
+
+func newSuccs(succs []*ssa.BasicBlock) []int {
+	ret := make([]int, len(succs))
+	for i, blk := range succs {
+		ret[i] = blk.Index
+	}
+	return ret
+}
+
+func findLoop(states []*blockState, path []int, from, iblk int) []int {
+	path = append(path, iblk)
+	self := states[iblk]
+	for _, succ := range self.succs {
+		if states[succ].fdel {
+			continue
+		}
+		if pos := find(path, succ); pos >= 0 {
+			if pos > 0 {
+				continue
+			}
+			for _, i := range path {
+				s := states[i]
+				s.loop = true
+				s.fdel = true
+			}
+			return path
+		}
+		if ret := findLoop(states, path, from, succ); ret != nil {
+			return ret
+		}
+	}
+	return nil
+}
+
+// https://en.wikipedia.org/wiki/Topological_sorting
+func Infos(blks []*ssa.BasicBlock) []Info {
+	n := len(blks)
+	order := make([]int, 1, n+1)
+	order[0] = 0
+	end, iend := 0, 0
+	states := make([]*blockState, n)
+	for i, blk := range blks {
+		preds := len(blk.Preds)
+		if preds == 0 && i != 0 {
+			order = append(order, i)
+		}
+		if isEnd(blk) {
+			end++
+			iend = i
+		}
+		states[i] = &blockState{
+			self:  blk,
+			preds: preds,
+			succs: newSuccs(blk.Succs),
+		}
+	}
+
+	path := make([]int, 0, n)
+	if states[0].preds != 0 {
+		if loop := findLoop(states, path, 0, 0); len(loop) > 0 {
+			order = append(order, loop[1:]...)
+		}
+	} else {
+		states[0].always = true
+	}
+	if end == 1 {
+		states[iend].always = true
+	}
+	pos := 0
+
+retry:
+	for pos < len(order) {
+		iblk := order[pos]
+		pos++
+		state := states[iblk]
+		state.fdel = true
+		for _, succ := range state.succs {
+			s := states[succ]
+			if s.fdel {
+				continue
+			}
+			if s.preds--; s.preds == 0 {
+				order = append(order, succ)
+			} else {
+				s.reach = true
+			}
+		}
+	}
+	if pos < n {
+		for iblk, state := range states {
+			if state.fdel || !state.reach {
+				continue
+			}
+			if loop := findLoop(states, path, iblk, iblk); len(loop) > 0 {
+				order = append(order, loop...)
+				goto retry
+			}
+		}
+		panic("unreachable")
+	}
+	order = append(order, -1)
+	ret := make([]Info, n)
+	for i := 0; i < n; i++ {
+		iblk := order[i]
+		ret[iblk] = Info{states[iblk].kind(), order[i+1]}
+	}
+	return ret
+}
+
+func isEnd(blk *ssa.BasicBlock) bool {
+	// Note: skip recover block
+	return len(blk.Succs) == 0 && (len(blk.Preds) > 0 || blk.Index == 0)
+}
+
+func find(path []int, fv int) int {
+	for i, v := range path {
+		if v == fv {
+			return i
+		}
+	}
+	return -1
+}
+
+// -----------------------------------------------------------------------------
diff --git a/cl/blocks/block_test.go b/cl/blocks/block_test.go
new file mode 100644
index 00000000..2cad3c86
--- /dev/null
+++ b/cl/blocks/block_test.go
@@ -0,0 +1,140 @@
+/*
+ * Copyright (c) 2024 The GoPlus Authors (goplus.org). All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package blocks
+
+import (
+	"bytes"
+	"fmt"
+	"go/ast"
+	"go/parser"
+	"go/token"
+	"go/types"
+	"log"
+	"os"
+	"path"
+	"strings"
+	"testing"
+
+	"github.com/goplus/gogen/packages"
+	"golang.org/x/tools/go/ssa"
+	"golang.org/x/tools/go/ssa/ssautil"
+
+	llssa "github.com/goplus/llgo/ssa"
+)
+
+func TestTestdefer(t *testing.T) {
+	// debug = true
+	fromDir(t, "", "../_testdefer")
+}
+
+func TestFirstLoop(t *testing.T) {
+	blk := &ssa.BasicBlock{}
+	blk.Index = 0
+	blk.Preds = []*ssa.BasicBlock{blk}
+	blk.Succs = []*ssa.BasicBlock{blk}
+	infos := Infos([]*ssa.BasicBlock{blk})
+	if infos[0].Kind != llssa.DeferInLoop {
+		t.Fatal("TestFirstLoop")
+	}
+}
+
+func fromDir(t *testing.T, sel, relDir string) {
+	dir, err := os.Getwd()
+	if err != nil {
+		t.Fatal("Getwd failed:", err)
+	}
+	dir = path.Join(dir, relDir)
+	fis, err := os.ReadDir(dir)
+	if err != nil {
+		t.Fatal("ReadDir failed:", err)
+	}
+	for _, fi := range fis {
+		name := fi.Name()
+		if !fi.IsDir() || strings.HasPrefix(name, "_") {
+			continue
+		}
+		t.Run(name, func(t *testing.T) {
+			testFrom(t, dir+"/"+name, sel)
+		})
+	}
+}
+
+func testFrom(t *testing.T, pkgDir, sel string) {
+	if sel != "" && !strings.Contains(pkgDir, sel) {
+		return
+	}
+	log.Println("Parsing", pkgDir)
+	in := pkgDir + "/in.go"
+	out := pkgDir + "/out.txt"
+	b, err := os.ReadFile(out)
+	if err != nil {
+		t.Fatal("ReadFile failed:", err)
+	}
+	expected := string(b)
+	testBlockInfo(t, nil, in, expected)
+}
+
+func testBlockInfo(t *testing.T, src any, fname, expected string) {
+	t.Helper()
+	fset := token.NewFileSet()
+	f, err := parser.ParseFile(fset, fname, src, parser.ParseComments)
+	if err != nil {
+		t.Fatal("ParseFile failed:", err)
+	}
+	files := []*ast.File{f}
+	name := f.Name.Name
+	pkg := types.NewPackage(name, name)
+	imp := packages.NewImporter(fset)
+	foo, _, err := ssautil.BuildPackage(
+		&types.Config{Importer: imp}, fset, pkg, files, ssa.SanityCheckFunctions)
+	if err != nil {
+		t.Fatal("BuildPackage failed:", err)
+	}
+	foo.WriteTo(os.Stderr)
+
+	for _, member := range foo.Members {
+		switch f := member.(type) {
+		case *ssa.Function:
+			if f.Name() == "main" {
+				f.WriteTo(os.Stderr)
+				infos := Infos(f.Blocks)
+				if v := resultOf(infos); v != expected {
+					t.Fatalf("\n==> got:\n%s\n==> expected:\n%s\n", v, expected)
+				}
+				return
+			}
+		}
+	}
+}
+
+func resultOf(infos []Info) string {
+	var b bytes.Buffer
+	i := 0
+	for {
+		fmt.Fprintf(&b, "%2d: %s\n", i, kinds[infos[i].Kind])
+		if i = infos[i].Next; i < 0 {
+			break
+		}
+	}
+	return b.String()
+}
+
+var kinds = [...]string{
+	llssa.DeferAlways: "always",
+	llssa.DeferInCond: "cond",
+	llssa.DeferInLoop: "loop",
+}
diff --git a/cl/compile.go b/cl/compile.go
index 199e10ba..469cd296 100644
--- a/cl/compile.go
+++ b/cl/compile.go
@@ -27,6 +27,7 @@ import (
 	"sort"
 	"strings"
 
+	"github.com/goplus/llgo/cl/blocks"
 	llssa "github.com/goplus/llgo/ssa"
 	"golang.org/x/tools/go/ssa"
 )
@@ -149,7 +150,7 @@ type context struct {
 	bvals  map[ssa.Value]llssa.Expr    // block values
 	vargs  map[*ssa.Alloc][]llssa.Expr // varargs
 
-	blkInfos []blockInfo
+	blkInfos []blocks.Info
 
 	inits []func()
 	phis  []func()
@@ -280,14 +281,14 @@ func (p *context) compileFuncDecl(pkg llssa.Package, f *ssa.Function) (llssa.Fun
 			for i, block := range f.Blocks {
 				off[i] = p.compilePhis(b, block)
 			}
-			p.blkInfos = blockInfos(f.Blocks)
+			p.blkInfos = blocks.Infos(f.Blocks)
 			i := 0
 			for {
 				block := f.Blocks[i]
 				doMainInit := (i == 0 && name == "main")
 				doModInit := (i == 1 && f.Name() == "init" && sig.Recv() == nil)
 				p.compileBlock(b, block, off[i], doMainInit, doModInit)
-				if i = p.blkInfos[i].next; i < 0 {
+				if i = p.blkInfos[i].Next; i < 0 {
 					break
 				}
 			}
@@ -300,24 +301,6 @@ func (p *context) compileFuncDecl(pkg llssa.Package, f *ssa.Function) (llssa.Fun
 	return fn, nil, goFunc
 }
 
-type blockInfo struct {
-	kind llssa.DoAction
-	next int
-}
-
-func blockInfos(blks []*ssa.BasicBlock) []blockInfo {
-	n := len(blks)
-	infos := make([]blockInfo, n)
-	for i := range blks {
-		next := i + 1
-		if next >= n {
-			next = -1
-		}
-		infos[i] = blockInfo{kind: llssa.DeferInCond, next: next}
-	}
-	return infos
-}
-
 // funcOf returns a function by name and set ftype = goFunc, cFunc, etc.
 // or returns nil and set ftype = llgoCstr, llgoAlloca, llgoUnreachable, etc.
 func (p *context) funcOf(fn *ssa.Function) (aFn llssa.Function, pyFn llssa.PyObjRef, ftype int) {
@@ -829,7 +812,7 @@ func (p *context) compileInstr(b llssa.Builder, instr ssa.Instruction) {
 		val := p.compileValue(b, v.Value)
 		b.MapUpdate(m, key, val)
 	case *ssa.Defer:
-		p.call(b, p.blkInfos[v.Block().Index].kind, &v.Call)
+		p.call(b, p.blkInfos[v.Block().Index].Kind, &v.Call)
 	case *ssa.Go:
 		p.call(b, llssa.Go, &v.Call)
 	case *ssa.RunDefers:
diff --git a/internal/abi/llgo_autogen.lla b/internal/abi/llgo_autogen.lla
index eb0833a5..55b79262 100644
Binary files a/internal/abi/llgo_autogen.lla and b/internal/abi/llgo_autogen.lla differ
diff --git a/internal/runtime/llgo_autogen.lla b/internal/runtime/llgo_autogen.lla
index bd50b82b..f66c4e86 100644
Binary files a/internal/runtime/llgo_autogen.lla and b/internal/runtime/llgo_autogen.lla differ