From 0465c23b3ee214ea3a117ab9d69a83cf85e7a82f Mon Sep 17 00:00:00 2001
From: Roberto I <roberto@inf.puc-rio.br>
Date: Thu, 28 May 2026 15:10:17 -0300
Subject: [PATCH] Cleaning 'luaP_isIT' and 'luaP_isOT'

- 'luaP_isOT' is only used for tests, so it is defined as a macro to avoid
wasting space with an unused function.
- 'luaP_isIT' must include OP_VARARGPREP.
---
 lcode.c    |  2 --
 lopcodes.c | 23 +++++++----------------
 lopcodes.h | 15 ++++++++++-----
 3 files changed, 17 insertions(+), 23 deletions(-)

diff --git a/lcode.c b/lcode.c
index e0024432..8b61d5de 100644
--- a/lcode.c
+++ b/lcode.c
@@ -1934,8 +1934,6 @@ void luaK_finish (FuncState *fs) {
     p->flag &= cast_byte(~PF_VAHID);  /* then it will not use hidden args. */
   for (i = 0; i < fs->pc; i++) {
     Instruction *pc = &p->code[i];
-    /* avoid "not used" warnings when assert is off (for 'onelua.c') */
-    (void)luaP_isOT; (void)luaP_isIT;
     lua_assert(i == 0 || luaP_isOT(*(pc - 1)) == luaP_isIT(*pc));
     switch (GET_OPCODE(*pc)) {
       case OP_RETURN0: case OP_RETURN1: {
diff --git a/lopcodes.c b/lopcodes.c
index da64ff18..bb1a4162 100644
--- a/lopcodes.c
+++ b/lopcodes.c
@@ -109,30 +109,21 @@ LUAI_DDEF const lu_byte luaP_opmodes[NUM_OPCODES] = {
 };
 
 
-
-/*
-** Check whether instruction sets top for next instruction, that is,
-** it results in multiple values.
-*/
-int luaP_isOT (Instruction i) {
-  OpCode op = GET_OPCODE(i);
-  switch (op) {
-    case OP_TAILCALL: return 1;
-    default:
-      return testOTMode(op) && GETARG_C(i) == 0;
-  }
-}
+#define testITMode(m)	(luaP_opmodes[m] & (1 << 5))
 
 
 /*
-** Check whether instruction uses top from previous instruction, that is,
-** it accepts multiple results.
+** Check whether instruction uses top. That happens for OP_VARARGPREP
+** and for instructions that use multiple values set by the previous
+** instruction.
 */
 int luaP_isIT (Instruction i) {
   OpCode op = GET_OPCODE(i);
   switch (op) {
     case OP_SETLIST:
-      return testITMode(GET_OPCODE(i)) && GETARG_vB(i) == 0;
+      return GETARG_vB(i) == 0;
+    case OP_VARARGPREP:
+      return 1;
     default:
       return testITMode(GET_OPCODE(i)) && GETARG_B(i) == 0;
   }
diff --git a/lopcodes.h b/lopcodes.h
index b6bd182e..86cff065 100644
--- a/lopcodes.h
+++ b/lopcodes.h
@@ -417,8 +417,8 @@ OP_EXTRAARG/*	Ax	extra (larger) argument for previous opcode	*/
 ** bits 0-2: op mode
 ** bit 3: instruction set register A
 ** bit 4: operator is a test (next instruction must be a jump)
-** bit 5: instruction uses 'L->top' set by previous instruction (when B == 0)
-** bit 6: instruction sets 'L->top' for next instruction (when C == 0)
+** bit 5: used by 'luaP_isIT'
+** bit 6: used by 'luaP_isOT'
 ** bit 7: instruction is an MM instruction (call a metamethod)
 */
 
@@ -427,12 +427,17 @@ LUAI_DDEC(const lu_byte luaP_opmodes[NUM_OPCODES];)
 #define getOpMode(m)	(cast(enum OpMode, luaP_opmodes[m] & 7))
 #define testAMode(m)	(luaP_opmodes[m] & (1 << 3))
 #define testTMode(m)	(luaP_opmodes[m] & (1 << 4))
-#define testITMode(m)	(luaP_opmodes[m] & (1 << 5))
-#define testOTMode(m)	(luaP_opmodes[m] & (1 << 6))
 #define testMMMode(m)	(luaP_opmodes[m] & (1 << 7))
 
 
-LUAI_FUNC int luaP_isOT (Instruction i);
+/* Check whether instruction sets top for next instruction, that is,
+** it results in multiple values. Used only for tests.
+*/
+#define luaP_isOT(i)  \
+	(GET_OPCODE(i) == OP_TAILCALL || \
+	 ((luaP_opmodes[GET_OPCODE(i)] & (1 << 6)) && GETARG_C(i) == 0))
+
+
 LUAI_FUNC int luaP_isIT (Instruction i);