diff --git a/mrbgems/mruby-compiler/core/codegen.c b/mrbgems/mruby-compiler/core/codegen.c
index c4868a81f..7a695cdc5 100644
--- a/mrbgems/mruby-compiler/core/codegen.c
+++ b/mrbgems/mruby-compiler/core/codegen.c
@@ -1457,19 +1457,13 @@ gen_addsub(codegen_scope *s, uint8_t op, uint16_t dst)
     struct mrb_insn_data data0 = mrb_decode_insn(mrb_prev_pc(s, data.addr));
     mrb_int n0;
     if (addr_pc(s, data.addr) == s->lastlabel || !get_int_operand(s, &data0, &n0)) {
-      /* OP_ADDI/OP_SUBI takes upto 8bits */
-      if (n > UINT8_MAX || n < -UINT8_MAX) goto normal;
+      /* Fold to OP_ADDI/OP_SUBI only for non-negative 8-bit n; flipping op
+         for negative n would change the method sent on user override (#2557). */
+      if (n < 0 || n > UINT8_MAX) goto normal;
       rewind_pc(s);
       if (n == 0) return;
-      if (n > 0) {
-        if (op == OP_ADD) genop_2(s, OP_ADDI, dst, (uint16_t)n);
-        else genop_2(s, OP_SUBI, dst, (uint16_t)n);
-      }
-      else {                    /* n < 0 */
-        n = -n;
-        if (op == OP_ADD) genop_2(s, OP_SUBI, dst, (uint16_t)n);
-        else genop_2(s, OP_ADDI, dst, (uint16_t)n);
-      }
+      if (op == OP_ADD) genop_2(s, OP_ADDI, dst, (uint16_t)n);
+      else genop_2(s, OP_SUBI, dst, (uint16_t)n);
       return;
     }
     if (op == OP_ADD) {
diff --git a/test/t/literals.rb b/test/t/literals.rb
index 03f0cb699..de30e816b 100644
--- a/test/t/literals.rb
+++ b/test/t/literals.rb
@@ -383,4 +383,20 @@ qwe]
   assert_equal :'{foo bar}', h
 end
 
+assert('operator override with negative integer literal', '#2557') do
+  cls = Class.new {
+    def +(x); ['add', x]; end
+    def -(x); ['sub', x]; end
+  }
+  q = cls.new
+  assert_equal ['add',  5], q +  5
+  assert_equal ['add', -5], q + -5
+  assert_equal ['sub',  5], q -  5
+  assert_equal ['sub', -5], q - -5
+  assert_equal ['add',  500], q +  500
+  assert_equal ['add', -500], q + -500
+  assert_equal ['sub',  500], q -  500
+  assert_equal ['sub', -500], q - -500
+end
+
 # Not Implemented ATM assert('Literals Regular expression', '8.7.6.5') do