Rework macro pgstat_is_ioop_tracked_in_bytes()

As written, it was triggering a compilation warning for old versions of
clang, as reported by buildfarm members ayu, batfish and demoiselle.
Forcing a cast with "unsigned int" should fix the warning.

While on it, the macro is moved to pgstat.h, closer to the declaration
of IOOp, per suggestion from Tom Lane.

Reported-by: Tom Lane
Reviewed-by: Bertrand Drouvot, Tom Lane, Nazir Bilal Yavuz
Discussion: https://postgr.es/m/1272824.1736961543@sss.pgh.pa.us

src/backend/utils/activity/pgstat_io.c

@@ -23,14 +23,6 @@
 static PgStat_PendingIO PendingIOStats;
 static bool have_iostats = false;
 
-/*
- * Check if an IOOp is tracked in bytes.  This relies on the ordering of IOOp
- * defined in pgstat.h, so make sure to update this check when changing its
- * elements.
- */
-#define pgstat_is_ioop_tracked_in_bytes(io_op) \
-	((io_op) < IOOP_NUM_TYPES && (io_op) >= IOOP_EXTEND)
-
 /*
  * Check that stats have not been counted for any combination of IOObject,
  * IOContext, and IOOp which are not tracked for the passed-in BackendType. If

src/include/pgstat.h

@@ -314,6 +314,10 @@ typedef enum IOOp
 
 #define IOOP_NUM_TYPES (IOOP_WRITE + 1)
 
+#define pgstat_is_ioop_tracked_in_bytes(io_op) \
+	(((unsigned int) (io_op)) < IOOP_NUM_TYPES && \
+	 ((unsigned int) (io_op)) >= IOOP_EXTEND)
+
 typedef struct PgStat_BktypeIO
 {
 	uint64		bytes[IOOBJECT_NUM_TYPES][IOCONTEXT_NUM_TYPES][IOOP_NUM_TYPES];