Improve handling of INT_MIN / -1 and related cases.

Some platforms throw an exception for this division, rather than returning
a necessarily-overflowed result.  Since we were testing for overflow after
the fact, an exception isn't nice.  We can avoid the problem by treating
division by -1 as negation.

Add some regression tests so that we'll find out if any compilers try to
optimize away the overflow check conditions.

This ought to be back-patched, but I'm going to see what the buildfarm
reports about the regression tests first.

Per discussion with Xi Wang, though this is different from the patch he
submitted.

7 files changed, 118 insertions, 0 deletions

diff --git a/src/test/regress/expected/int2.out b/src/test/regress/expected/int2.out
index 021d476822c..53b484f718c 100644
--- a/src/test/regress/expected/int2.out
+++ b/src/test/regress/expected/int2.out
@@ -255,3 +255,14 @@ SELECT ((-1::int2<<15)+1::int2)::text;
  -32767
 (1 row)
 
+-- check sane handling of INT16_MIN overflow cases
+SELECT (-32768)::int2 * (-1)::int2;
+ERROR:  smallint out of range
+SELECT (-32768)::int2 / (-1)::int2;
+ERROR:  smallint out of range
+SELECT (-32768)::int2 % (-1)::int2;
+ ?column? 
+----------
+        0
+(1 row)
+
diff --git a/src/test/regress/expected/int4.out b/src/test/regress/expected/int4.out
index 8f780240ae7..fcb14e3855e 100644
--- a/src/test/regress/expected/int4.out
+++ b/src/test/regress/expected/int4.out
@@ -342,3 +342,24 @@ SELECT ((-1::int4<<31)+1)::text;
  -2147483647
 (1 row)
 
+-- check sane handling of INT_MIN overflow cases
+SELECT (-2147483648)::int4 * (-1)::int4;
+ERROR:  integer out of range
+SELECT (-2147483648)::int4 / (-1)::int4;
+ERROR:  integer out of range
+SELECT (-2147483648)::int4 % (-1)::int4;
+ ?column? 
+----------
+        0
+(1 row)
+
+SELECT (-2147483648)::int4 * (-1)::int2;
+ERROR:  integer out of range
+SELECT (-2147483648)::int4 / (-1)::int2;
+ERROR:  integer out of range
+SELECT (-2147483648)::int4 % (-1)::int2;
+ ?column? 
+----------
+        0
+(1 row)
+
diff --git a/src/test/regress/expected/int8-exp-three-digits.out b/src/test/regress/expected/int8-exp-three-digits.out
index b523bfcc01b..a1c70ed3e8d 100644
--- a/src/test/regress/expected/int8-exp-three-digits.out
+++ b/src/test/regress/expected/int8-exp-three-digits.out
@@ -815,3 +815,34 @@ SELECT ((-1::int8<<63)+1)::text;
  -9223372036854775807
 (1 row)
 
+-- check sane handling of INT64_MIN overflow cases
+SELECT (-9223372036854775808)::int8 * (-1)::int8;
+ERROR:  bigint out of range
+SELECT (-9223372036854775808)::int8 / (-1)::int8;
+ERROR:  bigint out of range
+SELECT (-9223372036854775808)::int8 % (-1)::int8;
+ ?column? 
+----------
+        0
+(1 row)
+
+SELECT (-9223372036854775808)::int8 * (-1)::int4;
+ERROR:  bigint out of range
+SELECT (-9223372036854775808)::int8 / (-1)::int4;
+ERROR:  bigint out of range
+SELECT (-9223372036854775808)::int8 % (-1)::int4;
+ ?column? 
+----------
+        0
+(1 row)
+
+SELECT (-9223372036854775808)::int8 * (-1)::int2;
+ERROR:  bigint out of range
+SELECT (-9223372036854775808)::int8 / (-1)::int2;
+ERROR:  bigint out of range
+SELECT (-9223372036854775808)::int8 % (-1)::int2;
+ ?column? 
+----------
+        0
+(1 row)
+
diff --git a/src/test/regress/expected/int8.out b/src/test/regress/expected/int8.out
index 811d6a55200..e79c3a8af95 100644
--- a/src/test/regress/expected/int8.out
+++ b/src/test/regress/expected/int8.out
@@ -815,3 +815,34 @@ SELECT ((-1::int8<<63)+1)::text;
  -9223372036854775807
 (1 row)
 
+-- check sane handling of INT64_MIN overflow cases
+SELECT (-9223372036854775808)::int8 * (-1)::int8;
+ERROR:  bigint out of range
+SELECT (-9223372036854775808)::int8 / (-1)::int8;
+ERROR:  bigint out of range
+SELECT (-9223372036854775808)::int8 % (-1)::int8;
+ ?column? 
+----------
+        0
+(1 row)
+
+SELECT (-9223372036854775808)::int8 * (-1)::int4;
+ERROR:  bigint out of range
+SELECT (-9223372036854775808)::int8 / (-1)::int4;
+ERROR:  bigint out of range
+SELECT (-9223372036854775808)::int8 % (-1)::int4;
+ ?column? 
+----------
+        0
+(1 row)
+
+SELECT (-9223372036854775808)::int8 * (-1)::int2;
+ERROR:  bigint out of range
+SELECT (-9223372036854775808)::int8 / (-1)::int2;
+ERROR:  bigint out of range
+SELECT (-9223372036854775808)::int8 % (-1)::int2;
+ ?column? 
+----------
+        0
+(1 row)
+
diff --git a/src/test/regress/sql/int2.sql b/src/test/regress/sql/int2.sql
index f11eb283c61..bacfbb24ac2 100644
--- a/src/test/regress/sql/int2.sql
+++ b/src/test/regress/sql/int2.sql
@@ -87,3 +87,8 @@ SELECT '' AS five, i.f1, i.f1 / int4 '2' AS x FROM INT2_TBL i;
 -- corner cases
 SELECT (-1::int2<<15)::text;
 SELECT ((-1::int2<<15)+1::int2)::text;
+
+-- check sane handling of INT16_MIN overflow cases
+SELECT (-32768)::int2 * (-1)::int2;
+SELECT (-32768)::int2 / (-1)::int2;
+SELECT (-32768)::int2 % (-1)::int2;
diff --git a/src/test/regress/sql/int4.sql b/src/test/regress/sql/int4.sql
index ffae7ce4cb4..1843a6d33bc 100644
--- a/src/test/regress/sql/int4.sql
+++ b/src/test/regress/sql/int4.sql
@@ -127,3 +127,11 @@ SELECT (2 + 2) / 2 AS two;
 -- corner case
 SELECT (-1::int4<<31)::text;
 SELECT ((-1::int4<<31)+1)::text;
+
+-- check sane handling of INT_MIN overflow cases
+SELECT (-2147483648)::int4 * (-1)::int4;
+SELECT (-2147483648)::int4 / (-1)::int4;
+SELECT (-2147483648)::int4 % (-1)::int4;
+SELECT (-2147483648)::int4 * (-1)::int2;
+SELECT (-2147483648)::int4 / (-1)::int2;
+SELECT (-2147483648)::int4 % (-1)::int2;
diff --git a/src/test/regress/sql/int8.sql b/src/test/regress/sql/int8.sql
index 27e0696b32f..2f7f30c91d3 100644
--- a/src/test/regress/sql/int8.sql
+++ b/src/test/regress/sql/int8.sql
@@ -194,3 +194,14 @@ SELECT * FROM generate_series('+4567890123456789'::int8, '+4567890123456799'::in
 -- corner case
 SELECT (-1::int8<<63)::text;
 SELECT ((-1::int8<<63)+1)::text;
+
+-- check sane handling of INT64_MIN overflow cases
+SELECT (-9223372036854775808)::int8 * (-1)::int8;
+SELECT (-9223372036854775808)::int8 / (-1)::int8;
+SELECT (-9223372036854775808)::int8 % (-1)::int8;
+SELECT (-9223372036854775808)::int8 * (-1)::int4;
+SELECT (-9223372036854775808)::int8 / (-1)::int4;
+SELECT (-9223372036854775808)::int8 % (-1)::int4;
+SELECT (-9223372036854775808)::int8 * (-1)::int2;
+SELECT (-9223372036854775808)::int8 / (-1)::int2;
+SELECT (-9223372036854775808)::int8 % (-1)::int2;