From Lua 5.2: Allow mixed metamethods for ordered comparisons.

Needs -DLUAJIT_ENABLE_LUA52COMPAT.

src/lj_meta.c

@@ -386,7 +386,8 @@ TValue *lj_meta_comp(lua_State *L, cTValue *o1, cTValue *o2, int op)
     cTValue *mo = lj_meta_lookup(L, tviscdata(o1) ? o1 : o2, mm);
     if (LJ_UNLIKELY(tvisnil(mo))) goto err;
     return mmcall(L, cont, mo, o1, o2);
-  } else if (itype(o1) == itype(o2)) {  /* Never called with two numbers. */
+  } else if (LJ_52 || itype(o1) == itype(o2)) {
+    /* Never called with two numbers. */
     if (tvisstr(o1) && tvisstr(o2)) {
       int32_t res = lj_str_cmp(strV(o1), strV(o2));
       return (TValue *)(intptr_t)(((op&2) ? res <= 0 : res < 0) ^ (op&1));
@@ -396,8 +397,13 @@ TValue *lj_meta_comp(lua_State *L, cTValue *o1, cTValue *o2, int op)
 	ASMFunction cont = (op & 1) ? lj_cont_condf : lj_cont_condt;
 	MMS mm = (op & 2) ? MM_le : MM_lt;
 	cTValue *mo = lj_meta_lookup(L, o1, mm);
+#if LJ_52
+	if (tvisnil(mo) && tvisnil((mo = lj_meta_lookup(L, o2, mm))))
+#else
 	cTValue *mo2 = lj_meta_lookup(L, o2, mm);
-	if (tvisnil(mo) || !lj_obj_equal(mo, mo2)) {
+	if (tvisnil(mo) || !lj_obj_equal(mo, mo2))
+#endif
+	{
 	  if (op & 2) {  /* MM_le not found: retry with MM_lt. */
 	    cTValue *ot = o1; o1 = o2; o2 = ot;  /* Swap operands. */
 	    op ^= 3;  /* Use LT and flip condition. */

src/lj_record.c

@@ -969,6 +969,16 @@ static void rec_mm_comp(jit_State *J, RecordIndex *ix, int op)
   copyTV(J->L, &ix->tabv, &ix->valv);
   while (1) {
     MMS mm = (op & 2) ? MM_le : MM_lt;  /* Try __le + __lt or only __lt. */
+#if LJ_52
+    if (!lj_record_mm_lookup(J, ix, mm)) {  /* Lookup mm on 1st operand. */
+      ix->tab = ix->key;
+      copyTV(J->L, &ix->tabv, &ix->keyv);
+      if (!lj_record_mm_lookup(J, ix, mm))  /* Lookup mm on 2nd operand. */
+	goto nomatch;
+    }
+    rec_mm_callcomp(J, ix, op);
+    return;
+#else
     if (lj_record_mm_lookup(J, ix, mm)) {  /* Lookup mm on 1st operand. */
       cTValue *bv;
       TRef mo1 = ix->mobj;
@@ -992,8 +1002,9 @@ static void rec_mm_comp(jit_State *J, RecordIndex *ix, int op)
       rec_mm_callcomp(J, ix, op);
       return;
     }
+#endif
   nomatch:
-    /* First lookup failed. Retry with  __lt and swapped operands. */
+    /* Lookup failed. Retry with  __lt and swapped operands. */
     if (!(op & 2)) break;  /* Already at __lt. Interpreter will throw. */
     ix->tab = ix->key; ix->key = ix->val; ix->val = ix->tab;
     copyTV(J->L, &ix->tabv, &ix->keyv);
@@ -1742,6 +1753,8 @@ void lj_record_ins(jit_State *J)
 	  ta = IRT_NUM;
 	} else if (ta == IRT_NUM && tc == IRT_INT) {
 	  rc = emitir(IRTN(IR_CONV), rc, IRCONV_NUM_INT);
+	} else if (LJ_52) {
+	  ta = IRT_NIL;  /* Force metamethod for different types. */
 	} else if (!((ta == IRT_FALSE || ta == IRT_TRUE) &&
 		     (tc == IRT_FALSE || tc == IRT_TRUE))) {
 	  break;  /* Interpreter will throw for two different types. */