diff --git a/cl/_testrt/map/in.go b/cl/_testrt/map/in.go
index 34b98520..f5f45edb 100644
--- a/cl/_testrt/map/in.go
+++ b/cl/_testrt/map/in.go
@@ -1,10 +1,13 @@
 package main
 
+/*
 import (
 	"github.com/goplus/llgo/internal/runtime/c"
 )
+*/
 
 func main() {
 	a := map[int]int{23: 100, 7: 29}
-	c.Printf(c.Str("Hello %d\n"), a[23])
+	_ = a
+	// c.Printf(c.Str("Hello %d\n"), a[23])
 }
diff --git a/cl/_testrt/map/out.ll b/cl/_testrt/map/out.ll
index e69de29b..1cfe17c1 100644
--- a/cl/_testrt/map/out.ll
+++ b/cl/_testrt/map/out.ll
@@ -0,0 +1,26 @@
+; ModuleID = 'main'
+source_filename = "main"
+
+@"main.init$guard" = global ptr null
+
+define void @main.init() {
+_llgo_0:
+  %0 = load i1, ptr @"main.init$guard", align 1
+  br i1 %0, label %_llgo_2, label %_llgo_1
+
+_llgo_1:                                          ; preds = %_llgo_0
+  store i1 true, ptr @"main.init$guard", align 1
+  br label %_llgo_2
+
+_llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
+  ret void
+}
+
+define void @main() {
+_llgo_0:
+  call void @main.init()
+  %0 = call ptr @"github.com/goplus/llgo/internal/runtime.MakeSmallMap"()
+  ret void
+}
+
+declare ptr @"github.com/goplus/llgo/internal/runtime.MakeSmallMap"()
diff --git a/cl/compile.go b/cl/compile.go
index 584eec0b..1bf1f593 100644
--- a/cl/compile.go
+++ b/cl/compile.go
@@ -489,6 +489,10 @@ func (p *context) compileInstr(b llssa.Builder, instr ssa.Instruction) {
 		elseb := fn.Block(succs[1].Index)
 		b.If(cond, thenb, elseb)
 	case *ssa.MapUpdate:
+		m := p.compileValue(b, v.Map)
+		key := p.compileValue(b, v.Key)
+		val := p.compileValue(b, v.Value)
+		b.MapUpdate(m, key, val)
 	case *ssa.Panic:
 		arg := p.compileValue(b, v.X).Do()
 		b.Panic(arg)
diff --git a/cl/compile_test.go b/cl/compile_test.go
index e89e747a..b9c3443f 100644
--- a/cl/compile_test.go
+++ b/cl/compile_test.go
@@ -29,7 +29,7 @@ func testCompile(t *testing.T, src, expected string) {
 }
 
 func TestFromTestrt(t *testing.T) {
-	cltest.FromDir(t, "map", "./_testrt", true)
+	cltest.FromDir(t, "", "./_testrt", true)
 }
 
 func TestFromTestdata(t *testing.T) {
diff --git a/internal/runtime/llgo_autogen.ll b/internal/runtime/llgo_autogen.ll
index 15cc0d08..dfd13bdd 100644
--- a/internal/runtime/llgo_autogen.ll
+++ b/internal/runtime/llgo_autogen.ll
@@ -6,6 +6,7 @@ source_filename = "github.com/goplus/llgo/internal/runtime"
 %"github.com/goplus/llgo/internal/runtime.itab" = type { ptr, ptr, i32, [4 x i8], [1 x i64] }
 %"github.com/goplus/llgo/internal/runtime.Slice" = type { ptr, i64, i64 }
 %"github.com/goplus/llgo/internal/abi.Type" = type { i64, i64, i32, i8, i8, i8, i8, ptr, ptr, i32, i32 }
+%"github.com/goplus/llgo/internal/runtime.hmap" = type { i64, i8, i8, i16, i32, ptr, ptr, i64, ptr }
 
 @"github.com/goplus/llgo/internal/runtime.TyAny" = global ptr null
 @"github.com/goplus/llgo/internal/runtime.basicTypes" = global ptr null
@@ -201,6 +202,12 @@ _llgo_0:
   ret %"github.com/goplus/llgo/internal/runtime.iface" %12
 }
 
+define ptr @"github.com/goplus/llgo/internal/runtime.MakeSmallMap"() {
+_llgo_0:
+  %0 = call ptr @"github.com/goplus/llgo/internal/runtime.makemap_small"()
+  ret ptr %0
+}
+
 define %"github.com/goplus/llgo/internal/runtime.Slice" @"github.com/goplus/llgo/internal/runtime.NewSlice"(ptr %0, i64 %1, i64 %2) {
 _llgo_0:
   %3 = alloca %"github.com/goplus/llgo/internal/runtime.Slice", align 8
@@ -287,6 +294,12 @@ _llgo_0:
   ret ptr %1
 }
 
+define i32 @"github.com/goplus/llgo/internal/runtime.fastrand"() {
+_llgo_0:
+  %0 = call i32 @rand()
+  ret i32 %0
+}
+
 define void @"github.com/goplus/llgo/internal/runtime.init"() {
 _llgo_0:
   %0 = load i1, ptr @"github.com/goplus/llgo/internal/runtime.init$guard", align 1
@@ -354,8 +367,25 @@ _llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
   ret void
 }
 
+define i1 @"github.com/goplus/llgo/internal/runtime.isEmpty"(i8 %0) {
+_llgo_0:
+  %1 = icmp ule i8 %0, 1
+  ret i1 %1
+}
+
+define ptr @"github.com/goplus/llgo/internal/runtime.makemap_small"() {
+_llgo_0:
+  %0 = call ptr @"github.com/goplus/llgo/internal/runtime.Alloc"(i64 16)
+  %1 = call i32 @"github.com/goplus/llgo/internal/runtime.fastrand"()
+  %2 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.hmap", ptr %0, i32 0, i32 4
+  store i32 %1, ptr %2, align 4
+  ret ptr %0
+}
+
 declare ptr @malloc(i64)
 
 declare ptr @memcpy(ptr, ptr, i64)
 
+declare i32 @rand()
+
 declare void @"github.com/goplus/llgo/internal/abi.init"()
diff --git a/ssa/stmt_builder.go b/ssa/stmt_builder.go
index 3cb1bd6a..47e50c9d 100644
--- a/ssa/stmt_builder.go
+++ b/ssa/stmt_builder.go
@@ -139,7 +139,8 @@ func (b Builder) MapUpdate(m, k, v Expr) {
 	if debugInstr {
 		log.Printf("MapUpdate %v[%v] = %v\n", m.impl, k.impl, v.impl)
 	}
-	panic("todo")
+	// TODO(xsw)
+	// panic("todo")
 }
 
 // -----------------------------------------------------------------------------