diff --git a/go/vt/vtgate/evalengine/compiler_asm.go b/go/vt/vtgate/evalengine/compiler_asm.go
index 9099f8711c0..7dda215353f 100644
--- a/go/vt/vtgate/evalengine/compiler_asm.go
+++ b/go/vt/vtgate/evalengine/compiler_asm.go
@@ -5141,21 +5141,15 @@ func (asm *assembler) Introduce(offset int, t sqltypes.Type, col collations.Type
 
 func (asm *assembler) Fn_LAST_INSERT_ID() {
 	asm.emit(func(env *ExpressionEnv) int {
-		arg := env.vm.stack[env.vm.sp-1].(*evalUint64)
-		env.VCursor().SetLastInsertID(arg.u)
+		arg := env.vm.stack[env.vm.sp-1]
+		if arg == nil {
+			env.VCursor().SetLastInsertID(0)
+		} else {
+			iarg := evalToInt64(arg)
+			uarg := env.vm.arena.newEvalUint64(uint64(iarg.i))
+			env.vm.stack[env.vm.sp-1] = uarg
+			env.VCursor().SetLastInsertID(uarg.u)
+		}
 		return 1
 	}, "FN LAST_INSERT_ID UINT64(SP-1)")
 }
-
-func (asm *assembler) Fn_LAST_INSERT_ID_NULL() {
-	asm.emit(func(env *ExpressionEnv) int {
-		env.VCursor().SetLastInsertID(0)
-		return 1
-	}, "FN LAST_INSERT_ID NULL")
-}
-
-func (asm *assembler) addJump(end *jump) {
-	asm.emit(func(env *ExpressionEnv) int {
-		return end.offset()
-	}, "JUMP")
-}
diff --git a/go/vt/vtgate/evalengine/fn_misc.go b/go/vt/vtgate/evalengine/fn_misc.go
index cb17f8d6560..6f7d27c1101 100644
--- a/go/vt/vtgate/evalengine/fn_misc.go
+++ b/go/vt/vtgate/evalengine/fn_misc.go
@@ -219,19 +219,8 @@ func (call *builtinLastInsertID) compile(c *compiler) (ctype, error) {
 	if err != nil {
 		return ctype{}, err
 	}
-
-	setZero := c.compileNullCheck1(arg)
-	c.compileToUint64(arg, 1)
 	c.asm.Fn_LAST_INSERT_ID()
-	end := c.asm.jumpFrom()
-	c.asm.addJump(end)
-
-	c.asm.jumpDestination(setZero)
-	c.asm.Fn_LAST_INSERT_ID_NULL()
-
-	c.asm.jumpDestination(end)
-
-	return ctype{Type: sqltypes.Uint64, Flag: flagNullable, Col: collationNumeric}, nil
+	return ctype{Type: sqltypes.Uint64, Flag: arg.Flag & flagNullable, Col: collationNumeric}, nil
 }
 
 func printIPv6AsIPv4(addr netip.Addr) (netip.Addr, bool) {