From 5b3b05009830b29d1d3167bcd3321228535161dc Mon Sep 17 00:00:00 2001
From: Chapman Flack <chap@anastigmatix.net>
Date: Sun, 25 Feb 2018 22:52:22 -0500
Subject: [PATCH 1/2] Add regression test for cast float[48] to numeric.

At this stage, as expected, it fails.
---
 src/test/regress/expected/numeric.out | 34 ++++++++++++++++++++++++++++++++++
 src/test/regress/sql/numeric.sql      | 31 +++++++++++++++++++++++++++++++
 2 files changed, 65 insertions(+)

diff --git a/src/test/regress/expected/numeric.out b/src/test/regress/expected/numeric.out
index 17985e8..c186385 100644
--- a/src/test/regress/expected/numeric.out
+++ b/src/test/regress/expected/numeric.out
@@ -2063,3 +2063,37 @@ SELECT SUM((-9999)::numeric) FROM generate_series(1, 100000);
  -999900000
 (1 row)
 
+--
+-- Tests for cast from float4, float8
+--
+-- check precision of mantissa not lost
+WITH RECURSIVE
+  f4bit(place) AS (
+    VALUES (1::float4)
+    UNION
+    SELECT place/2::float4
+    FROM f4bit
+    WHERE 1::float4 + place/2::float4 > 1::float4
+  ),
+  f4(epsilon) AS (select min(place) FROM f4bit),
+  f8bit(place) AS (
+    VALUES (1::float8)
+    UNION
+    SELECT place/2::float8
+    FROM f8bit
+    WHERE 1::float8 + place/2::float8 > 1::float8
+  ),
+  f8(epsilon) AS (SELECT min(place) FROM f8bit),
+  testvalues(f4, f8) AS (
+    SELECT 1::float4+f4.epsilon, 1::float8+f8.epsilon
+    FROM f4, f8
+  )
+SELECT
+  f4::numeric > 1::numeric AS f4numericpreserved,
+  f8::numeric > 1::numeric AS f8numericpreserved
+FROM testvalues;
+ f4numericpreserved | f8numericpreserved 
+--------------------+--------------------
+ t                  | t
+(1 row)
+
diff --git a/src/test/regress/sql/numeric.sql b/src/test/regress/sql/numeric.sql
index d77504e..dab9ae2 100644
--- a/src/test/regress/sql/numeric.sql
+++ b/src/test/regress/sql/numeric.sql
@@ -1036,3 +1036,34 @@ select scale(-13.000000000000000);
 -- cases that need carry propagation
 SELECT SUM(9999::numeric) FROM generate_series(1, 100000);
 SELECT SUM((-9999)::numeric) FROM generate_series(1, 100000);
+
+--
+-- Tests for cast from float4, float8
+--
+
+-- check precision of mantissa not lost
+WITH RECURSIVE
+  f4bit(place) AS (
+    VALUES (1::float4)
+    UNION
+    SELECT place/2::float4
+    FROM f4bit
+    WHERE 1::float4 + place/2::float4 > 1::float4
+  ),
+  f4(epsilon) AS (select min(place) FROM f4bit),
+  f8bit(place) AS (
+    VALUES (1::float8)
+    UNION
+    SELECT place/2::float8
+    FROM f8bit
+    WHERE 1::float8 + place/2::float8 > 1::float8
+  ),
+  f8(epsilon) AS (SELECT min(place) FROM f8bit),
+  testvalues(f4, f8) AS (
+    SELECT 1::float4+f4.epsilon, 1::float8+f8.epsilon
+    FROM f4, f8
+  )
+SELECT
+  f4::numeric > 1::numeric AS f4numericpreserved,
+  f8::numeric > 1::numeric AS f8numericpreserved
+FROM testvalues;
-- 
2.7.3