From 2a9c631e88effc41d3e6432ab31767d311afad44 Mon Sep 17 00:00:00 2001
From: fuhsnn <66062782+fuhsnn@users.noreply.github.com>
Date: Sun, 29 Dec 2024 00:25:47 +0800
Subject: [PATCH] Handle pointer arithmetics with function operands

---
 parse.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/parse.c b/parse.c
index 16cdffb..3da1900 100644
--- a/parse.c
+++ b/parse.c
@@ -3383,6 +3383,11 @@ static Node *new_add(Node *lhs, Node *rhs, Token *tok) {
   if (is_numeric(lhs->ty) && is_numeric(rhs->ty))
     return new_binary(ND_ADD, lhs, rhs, tok);
 
+  if (lhs->ty->kind == TY_FUNC)
+    lhs = new_cast(lhs, pointer_to(lhs->ty));
+  if (rhs->ty->kind == TY_FUNC)
+    rhs = new_cast(rhs, pointer_to(rhs->ty));
+
   Node **ofs = is_integer(lhs->ty) ? &lhs : is_integer(rhs->ty) ? &rhs : NULL;
   Node *ptr = lhs->ty->base ? lhs : rhs->ty->base ? rhs : NULL;
 
@@ -3407,6 +3412,11 @@ static Node *new_sub(Node *lhs, Node *rhs, Token *tok) {
   if (is_numeric(lhs->ty) && is_numeric(rhs->ty))
     return new_binary(ND_SUB, lhs, rhs, tok);
 
+  if (lhs->ty->kind == TY_FUNC)
+    lhs = new_cast(lhs, pointer_to(lhs->ty));
+  if (rhs->ty->kind == TY_FUNC)
+    rhs = new_cast(rhs, pointer_to(rhs->ty));
+
   // ptr - num
   if (lhs->ty->base && is_integer(rhs->ty)) {
     if (lhs->ty->base->kind == TY_VLA)