Use C library functions instead of Abs() for int64

Instead of Abs() for int64, use the C standard functions labs() or
llabs() as appropriate.  Define a small wrapper around them that
matches our definition of int64.  (labs() is C90, llabs() is C99.)

Reviewed-by: Zhang Mingli <zmlpostgres@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/flat/4beb42b5-216b-bce8-d452-d924d5794c63%40enterprisedb.com

Author: petere

contrib/btree_gist/btree_cash.c

@@ -106,7 +106,7 @@ cash_dist(PG_FUNCTION_ARGS)
 				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
 				 errmsg("money out of range")));
 
-	ra = Abs(r);
+	ra = i64abs(r);
 
 	PG_RETURN_CASH(ra);
 }

contrib/btree_gist/btree_int8.c

@@ -106,7 +106,7 @@ int8_dist(PG_FUNCTION_ARGS)
 				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
 				 errmsg("bigint out of range")));
 
-	ra = Abs(r);
+	ra = i64abs(r);
 
 	PG_RETURN_INT64(ra);
 }

src/backend/utils/adt/datetime.c

@@ -4468,7 +4468,7 @@ AddVerboseIntPart(char *cp, int64 value, const char *units,
 	if (*is_zero)
 	{
 		*is_before = (value < 0);
-		value = Abs(value);
+		value = i64abs(value);
 	}
 	else if (*is_before)
 		value = -value;
@@ -4569,8 +4569,8 @@ EncodeInterval(struct pg_itm *itm, int style, char *str)
 
 					sprintf(cp, "%c%d-%d %c%lld %c%lld:%02d:",
 							year_sign, abs(year), abs(mon),
-							day_sign, (long long) Abs(mday),
-							sec_sign, (long long) Abs(hour), abs(min));
+							day_sign, (long long) i64abs(mday),
+							sec_sign, (long long) i64abs(hour), abs(min));
 					cp += strlen(cp);
 					cp = AppendSeconds(cp, sec, fsec, MAX_INTERVAL_PRECISION, true);
 					*cp = '\0';
@@ -4642,7 +4642,7 @@ EncodeInterval(struct pg_itm *itm, int style, char *str)
 				sprintf(cp, "%s%s%02lld:%02d:",
 						is_zero ? "" : " ",
 						(minus ? "-" : (is_before ? "+" : "")),
-						(long long) Abs(hour), abs(min));
+						(long long) i64abs(hour), abs(min));
 				cp += strlen(cp);
 				cp = AppendSeconds(cp, sec, fsec, MAX_INTERVAL_PRECISION, true);
 				*cp = '\0';

src/backend/utils/adt/dbsize.c

@@ -564,7 +564,7 @@ pg_size_pretty(PG_FUNCTION_ARGS)
 		uint8		bits;
 
 		/* use this unit if there are no more units or we're below the limit */
-		if (unit[1].name == NULL || Abs(size) < unit->limit)
+		if (unit[1].name == NULL || i64abs(size) < unit->limit)
 		{
 			if (unit->round)
 				size = half_rounded(size);

src/include/c.h

@@ -1282,6 +1282,15 @@ extern int	fdatasync(int fildes);
 #define strtou64(str, endptr, base) ((uint64) strtoull(str, endptr, base))
 #endif
 
+/*
+ * Similarly, wrappers around labs()/llabs() matching our int64.
+ */
+#ifdef HAVE_LONG_INT_64
+#define i64abs(i) labs(i)
+#else
+#define i64abs(i) llabs(i)
+#endif
+
 /*
  * Use "extern PGDLLIMPORT ..." to declare variables that are defined
  * in the core backend and need to be accessible by loadable modules.