Clean up some problems with redundant cross-type arithmetic operators. Add

int2-and-int8 implementations of the basic arithmetic operators +, -, *, /.
This doesn't really add any new functionality, but it avoids "operator is not
unique" failures that formerly occurred in these cases because the parser
couldn't decide whether to promote the int2 to int4 or int8.  We could
alternatively have removed the existing cross-type operators, but
experimentation shows that the cost of an additional type coercion expression
node is noticeable compared to such cheap operators; so let's not give up any
performance here.  On the other hand, I removed the int2-and-int4 modulo (%)
operators since they didn't seem as important from a performance standpoint.
Per a complaint last January from ykhuang.

1 files changed, 179 insertions, 1 deletions

diff --git a/src/backend/utils/adt/int8.c b/src/backend/utils/adt/int8.c
index 6f3f9e21055..dc56df4d186 100644
--- a/src/backend/utils/adt/int8.c
+++ b/src/backend/utils/adt/int8.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/int8.c,v 1.69 2008/04/21 00:26:45 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/int8.c,v 1.70 2008/06/17 19:10:56 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -922,6 +922,184 @@ int48div(PG_FUNCTION_ARGS)
 	PG_RETURN_INT64((int64) arg1 / arg2);
 }
 
+Datum
+int82pl(PG_FUNCTION_ARGS)
+{
+	int64		arg1 = PG_GETARG_INT64(0);
+	int16		arg2 = PG_GETARG_INT16(1);
+	int64		result;
+
+	result = arg1 + arg2;
+
+	/*
+	 * Overflow check.	If the inputs are of different signs then their sum
+	 * cannot overflow.  If the inputs are of the same sign, their sum had
+	 * better be that sign too.
+	 */
+	if (SAMESIGN(arg1, arg2) && !SAMESIGN(result, arg1))
+		ereport(ERROR,
+				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+				 errmsg("bigint out of range")));
+	PG_RETURN_INT64(result);
+}
+
+Datum
+int82mi(PG_FUNCTION_ARGS)
+{
+	int64		arg1 = PG_GETARG_INT64(0);
+	int16		arg2 = PG_GETARG_INT16(1);
+	int64		result;
+
+	result = arg1 - arg2;
+
+	/*
+	 * Overflow check.	If the inputs are of the same sign then their
+	 * difference cannot overflow.	If they are of different signs then the
+	 * result should be of the same sign as the first input.
+	 */
+	if (!SAMESIGN(arg1, arg2) && !SAMESIGN(result, arg1))
+		ereport(ERROR,
+				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+				 errmsg("bigint out of range")));
+	PG_RETURN_INT64(result);
+}
+
+Datum
+int82mul(PG_FUNCTION_ARGS)
+{
+	int64		arg1 = PG_GETARG_INT64(0);
+	int16		arg2 = PG_GETARG_INT16(1);
+	int64		result;
+
+	result = arg1 * arg2;
+
+	/*
+	 * Overflow check.	We basically check to see if result / arg1 gives arg2
+	 * again.  There is one case where this fails: arg1 = 0 (which cannot
+	 * overflow).
+	 *
+	 * Since the division is likely much more expensive than the actual
+	 * multiplication, we'd like to skip it where possible.  The best bang for
+	 * the buck seems to be to check whether both inputs are in the int32
+	 * range; if so, no overflow is possible.
+	 */
+	if (arg1 != (int64) ((int32) arg1) &&
+		result / arg1 != arg2)
+		ereport(ERROR,
+				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+				 errmsg("bigint out of range")));
+	PG_RETURN_INT64(result);
+}
+
+Datum
+int82div(PG_FUNCTION_ARGS)
+{
+	int64		arg1 = PG_GETARG_INT64(0);
+	int16		arg2 = PG_GETARG_INT16(1);
+	int64		result;
+
+	if (arg2 == 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_DIVISION_BY_ZERO),
+				 errmsg("division by zero")));
+
+	result = arg1 / arg2;
+
+	/*
+	 * Overflow check.	The only possible overflow case is for arg1 =
+	 * INT64_MIN, arg2 = -1, where the correct result is -INT64_MIN, which
+	 * can't be represented on a two's-complement machine.
+	 */
+	if (arg2 == -1 && arg1 < 0 && result < 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+				 errmsg("bigint out of range")));
+	PG_RETURN_INT64(result);
+}
+
+Datum
+int28pl(PG_FUNCTION_ARGS)
+{
+	int16		arg1 = PG_GETARG_INT16(0);
+	int64		arg2 = PG_GETARG_INT64(1);
+	int64		result;
+
+	result = arg1 + arg2;
+
+	/*
+	 * Overflow check.	If the inputs are of different signs then their sum
+	 * cannot overflow.  If the inputs are of the same sign, their sum had
+	 * better be that sign too.
+	 */
+	if (SAMESIGN(arg1, arg2) && !SAMESIGN(result, arg1))
+		ereport(ERROR,
+				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+				 errmsg("bigint out of range")));
+	PG_RETURN_INT64(result);
+}
+
+Datum
+int28mi(PG_FUNCTION_ARGS)
+{
+	int16		arg1 = PG_GETARG_INT16(0);
+	int64		arg2 = PG_GETARG_INT64(1);
+	int64		result;
+
+	result = arg1 - arg2;
+
+	/*
+	 * Overflow check.	If the inputs are of the same sign then their
+	 * difference cannot overflow.	If they are of different signs then the
+	 * result should be of the same sign as the first input.
+	 */
+	if (!SAMESIGN(arg1, arg2) && !SAMESIGN(result, arg1))
+		ereport(ERROR,
+				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+				 errmsg("bigint out of range")));
+	PG_RETURN_INT64(result);
+}
+
+Datum
+int28mul(PG_FUNCTION_ARGS)
+{
+	int16		arg1 = PG_GETARG_INT16(0);
+	int64		arg2 = PG_GETARG_INT64(1);
+	int64		result;
+
+	result = arg1 * arg2;
+
+	/*
+	 * Overflow check.	We basically check to see if result / arg2 gives arg1
+	 * again.  There is one case where this fails: arg2 = 0 (which cannot
+	 * overflow).
+	 *
+	 * Since the division is likely much more expensive than the actual
+	 * multiplication, we'd like to skip it where possible.  The best bang for
+	 * the buck seems to be to check whether both inputs are in the int32
+	 * range; if so, no overflow is possible.
+	 */
+	if (arg2 != (int64) ((int32) arg2) &&
+		result / arg2 != arg1)
+		ereport(ERROR,
+				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+				 errmsg("bigint out of range")));
+	PG_RETURN_INT64(result);
+}
+
+Datum
+int28div(PG_FUNCTION_ARGS)
+{
+	int16		arg1 = PG_GETARG_INT16(0);
+	int64		arg2 = PG_GETARG_INT64(1);
+
+	if (arg2 == 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_DIVISION_BY_ZERO),
+				 errmsg("division by zero")));
+	/* No overflow is possible */
+	PG_RETURN_INT64((int64) arg1 / arg2);
+}
+
 /* Binary arithmetics
  *
  *		int8and		- returns arg1 & arg2