Add cross-type comparisons for integer types.

Extend the infrastructure in btree_gin.c to permit cross-type
operators, and add the code to support them for the int2, int4,
and int8 opclasses.  (To keep this patch digestible, I left
the other datatypes for later.)

Discussion: https://postgr.es/m/[email protected]

Author: tglsfdc

contrib/btree_gin/Makefile

@@ -7,7 +7,7 @@ OBJS = \
 
 EXTENSION = btree_gin
 DATA = btree_gin--1.0.sql btree_gin--1.0--1.1.sql btree_gin--1.1--1.2.sql \
-	 btree_gin--1.2--1.3.sql
+	 btree_gin--1.2--1.3.sql btree_gin--1.3--1.4.sql
 PGFILEDESC = "btree_gin - B-tree equivalent GIN operator classes"
 
 REGRESS = install_btree_gin int2 int4 int8 float4 float8 money oid \

contrib/btree_gin/btree_gin--1.3--1.4.sql

@@ -0,0 +1,63 @@
+/* contrib/btree_gin/btree_gin--1.3--1.4.sql */
+
+-- complain if script is sourced in psql, rather than via CREATE EXTENSION
+\echo Use "ALTER EXTENSION btree_gin UPDATE TO '1.4'" to load this file. \quit
+
+--
+-- Cross-type operator support is new in 1.4.  We only need to worry
+-- about this for cross-type operators that exist in core.
+--
+-- Because the opclass extractQuery and consistent methods don't directly
+-- get any information about the datatype of the RHS value, we have to
+-- encode that in the operator strategy numbers.  The strategy numbers
+-- are the operator's normal btree strategy (1-5) plus 8 times a code
+-- for the RHS datatype.
+--
+
+ALTER OPERATOR FAMILY int2_ops USING gin
+ADD
+    -- Code 1: RHS is int4
+    OPERATOR        9       < (int2, int4),
+    OPERATOR        10      <= (int2, int4),
+    OPERATOR        11      = (int2, int4),
+    OPERATOR        12      >= (int2, int4),
+    OPERATOR        13      > (int2, int4),
+    -- Code 2: RHS is int8
+    OPERATOR        17      < (int2, int8),
+    OPERATOR        18      <= (int2, int8),
+    OPERATOR        19      = (int2, int8),
+    OPERATOR        20      >= (int2, int8),
+    OPERATOR        21      > (int2, int8)
+;
+
+ALTER OPERATOR FAMILY int4_ops USING gin
+ADD
+    -- Code 1: RHS is int2
+    OPERATOR        9       < (int4, int2),
+    OPERATOR        10      <= (int4, int2),
+    OPERATOR        11      = (int4, int2),
+    OPERATOR        12      >= (int4, int2),
+    OPERATOR        13      > (int4, int2),
+    -- Code 2: RHS is int8
+    OPERATOR        17      < (int4, int8),
+    OPERATOR        18      <= (int4, int8),
+    OPERATOR        19      = (int4, int8),
+    OPERATOR        20      >= (int4, int8),
+    OPERATOR        21      > (int4, int8)
+;
+
+ALTER OPERATOR FAMILY int8_ops USING gin
+ADD
+    -- Code 1: RHS is int2
+    OPERATOR        9       < (int8, int2),
+    OPERATOR        10      <= (int8, int2),
+    OPERATOR        11      = (int8, int2),
+    OPERATOR        12      >= (int8, int2),
+    OPERATOR        13      > (int8, int2),
+    -- Code 2: RHS is int4
+    OPERATOR        17      < (int8, int4),
+    OPERATOR        18      <= (int8, int4),
+    OPERATOR        19      = (int8, int4),
+    OPERATOR        20      >= (int8, int4),
+    OPERATOR        21      > (int8, int4)
+;