diff --git a/CHANGES/12321.misc.rst b/CHANGES/12321.misc.rst
new file mode 100644
index 00000000000..71f9db77675
--- /dev/null
+++ b/CHANGES/12321.misc.rst
@@ -0,0 +1,2 @@
+Added ``cdef`` type declarations and inlined the upgrade check in the HTTP parser
+-- by :user:`bdraco`.
diff --git a/aiohttp/_http_parser.pyx b/aiohttp/_http_parser.pyx
index 9a444be66fc..932baa661f2 100644
--- a/aiohttp/_http_parser.pyx
+++ b/aiohttp/_http_parser.pyx
@@ -446,6 +446,9 @@ cdef class HttpParser:
         self._has_value = True
 
     cdef _on_headers_complete(self):
+        cdef str h_upg
+        cdef str enc
+
         self._process_header()
 
         should_close = not cparser.llhttp_should_keep_alive(self._cparser)
@@ -457,8 +460,7 @@ cdef class HttpParser:
 
         if self._cparser.type == cparser.HTTP_REQUEST:
             h_upg = headers.get("upgrade", "")
-            allowed = upgrade and h_upg.isascii() and h_upg.lower() in ALLOWED_UPGRADES
-            if allowed or self._cparser.method == cparser.HTTP_CONNECT:
+            if (upgrade and h_upg.isascii() and h_upg.lower() in ALLOWED_UPGRADES) or self._cparser.method == cparser.HTTP_CONNECT:
                 self._upgraded = True
         else:
             if upgrade and self._cparser.status_code == 101: