Revise overflow test in int84() to avoid codegen bug in some older

versions of gcc.  We don't really need to explicitly test the limits
anyway, just reverse-convert and see if we get the same answer.

Author: tglsfdc

src/backend/utils/adt/int8.c

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/int8.c,v 1.32 2001/08/24 14:07:49 petere Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/int8.c,v 1.33 2001/09/07 01:33:44 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -67,7 +67,7 @@ int8in(PG_FUNCTION_ARGS)
 	 * Do our own scan, rather than relying on sscanf which might be
 	 * broken for long long.
 	 */
-	while (*ptr && isspace((unsigned char) *ptr))		/* skip leading spaces */
+	while (*ptr && isspace((unsigned char) *ptr)) /* skip leading spaces */
 		ptr++;
 	if (*ptr == '-')			/* handle sign */
 		sign = -1, ptr++;
@@ -688,11 +688,12 @@ int84(PG_FUNCTION_ARGS)
 	int64		val = PG_GETARG_INT64(0);
 	int32		result;
 
-	if ((val < INT_MIN) || (val > INT_MAX))
-		elog(ERROR, "int8 conversion to int4 is out of range");
-
 	result = (int32) val;
 
+	/* Test for overflow by reverse-conversion. */
+	if ((int64) result != val)
+		elog(ERROR, "int8 conversion to int4 is out of range");
+
 	PG_RETURN_INT32(result);
 }