Revert back-branch changes in power()'s behavior for NaN inputs.

Per discussion, the value of fixing these bugs in the back branches
doesn't outweigh the downsides of changing corner-case behavior in
a minor release.  Hence, revert commits 217d8f3a1 and 4d864de48 in
the v10 branch and the corresponding commits in 9.3-9.6.

Discussion: https://postgr.es/m/75DB81BEEA95B445AE6D576A0A5C9E936A73E741@BPXM05GP.gisp.nec.co.jp

diff --git a/src/backend/utils/adt/float.c b/src/backend/utils/adt/float.c
index 45a62f261615d9c88e97b1a72f10b97ac5bb224e..18b3b949acbbaeafa3f02981d4d064bc2f4fa37c 100644 (file)
--- a/src/backend/utils/adt/float.c
+++ b/src/backend/utils/adt/float.c
@@ -1461,25 +1461,6 @@ dpow(PG_FUNCTION_ARGS)
        float8          arg2 = PG_GETARG_FLOAT8(1);
        float8          result;
 
-       /*
-        * The POSIX spec says that NaN ^ 0 = 1, and 1 ^ NaN = 1, while all other
-        * cases with NaN inputs yield NaN (with no error).  Many older platforms
-        * get one or more of these cases wrong, so deal with them via explicit
-        * logic rather than trusting pow(3).
-        */
-       if (isnan(arg1))
-       {
-               if (isnan(arg2) || arg2 != 0.0)
-                       PG_RETURN_FLOAT8(get_float8_nan());
-               PG_RETURN_FLOAT8(1.0);
-       }
-       if (isnan(arg2))
-       {
-               if (arg1 != 1.0)
-                       PG_RETURN_FLOAT8(get_float8_nan());
-               PG_RETURN_FLOAT8(1.0);
-       }
-
        /*
         * The SQL spec requires that we emit a particular SQLSTATE error code for
         * certain error conditions.  Specifically, we don't return a
@@ -1498,7 +1479,7 @@ dpow(PG_FUNCTION_ARGS)
         * pow() sets errno only on some platforms, depending on whether it
         * follows _IEEE_, _POSIX_, _XOPEN_, or _SVID_, so we try to avoid using
         * errno.  However, some platform/CPU combinations return errno == EDOM
-        * and result == NaN for negative arg1 and very large arg2 (they must be
+        * and result == Nan for negative arg1 and very large arg2 (they must be
         * using something different from our floor() test to decide it's
         * invalid).  Other platforms (HPPA) return errno == ERANGE and a large
         * (HUGE_VAL) but finite result to signal overflow.

diff --git a/src/test/regress/expected/float8-exp-three-digits-win32.out b/src/test/regress/expected/float8-exp-three-digits-win32.out
index 3896cdec7216296b19a796884f6242d8b6499219..7e1153308f55f4f374f1e80636ee16c195649b2b 100644 (file)
--- a/src/test/regress/expected/float8-exp-three-digits-win32.out
+++ b/src/test/regress/expected/float8-exp-three-digits-win32.out
@@ -340,42 +340,6 @@ SELECT power(float8 '144', float8 '0.5');
     12
 (1 row)
 
-SELECT power(float8 'NaN', float8 '0.5');
- power 
--------
-   NaN
-(1 row)
-
-SELECT power(float8 '144', float8 'NaN');
- power 
--------
-   NaN
-(1 row)
-
-SELECT power(float8 'NaN', float8 'NaN');
- power 
--------
-   NaN
-(1 row)
-
-SELECT power(float8 '-1', float8 'NaN');
- power 
--------
-   NaN
-(1 row)
-
-SELECT power(float8 '1', float8 'NaN');
- power 
--------
-     1
-(1 row)
-
-SELECT power(float8 'NaN', float8 '0');
- power 
--------
-     1
-(1 row)
-
 -- take exp of ln(f.f1)
 SELECT '' AS three, f.f1, exp(ln(f.f1)) AS exp_ln_f1
    FROM FLOAT8_TBL f

diff --git a/src/test/regress/expected/float8-small-is-zero.out b/src/test/regress/expected/float8-small-is-zero.out
index f8e09390f518c054569594db469e110788de2d6d..26b83781500c5b884096981a7bf74bdae30a6499 100644 (file)
--- a/src/test/regress/expected/float8-small-is-zero.out
+++ b/src/test/regress/expected/float8-small-is-zero.out
@@ -344,42 +344,6 @@ SELECT power(float8 '144', float8 '0.5');
     12
 (1 row)
 
-SELECT power(float8 'NaN', float8 '0.5');
- power 
--------
-   NaN
-(1 row)
-
-SELECT power(float8 '144', float8 'NaN');
- power 
--------
-   NaN
-(1 row)
-
-SELECT power(float8 'NaN', float8 'NaN');
- power 
--------
-   NaN
-(1 row)
-
-SELECT power(float8 '-1', float8 'NaN');
- power 
--------
-   NaN
-(1 row)
-
-SELECT power(float8 '1', float8 'NaN');
- power 
--------
-     1
-(1 row)
-
-SELECT power(float8 'NaN', float8 '0');
- power 
--------
-     1
-(1 row)
-
 -- take exp of ln(f.f1)
 SELECT '' AS three, f.f1, exp(ln(f.f1)) AS exp_ln_f1
    FROM FLOAT8_TBL f

diff --git a/src/test/regress/expected/float8-small-is-zero_1.out b/src/test/regress/expected/float8-small-is-zero_1.out
index ebfec4cdb6899ba5a53834751c014e999a5dafee..cea27908ebf1df102fa54d16d0212abc7c4a4d3f 100644 (file)
--- a/src/test/regress/expected/float8-small-is-zero_1.out
+++ b/src/test/regress/expected/float8-small-is-zero_1.out
@@ -344,42 +344,6 @@ SELECT power(float8 '144', float8 '0.5');
     12
 (1 row)
 
-SELECT power(float8 'NaN', float8 '0.5');
- power 
--------
-   NaN
-(1 row)
-
-SELECT power(float8 '144', float8 'NaN');
- power 
--------
-   NaN
-(1 row)
-
-SELECT power(float8 'NaN', float8 'NaN');
- power 
--------
-   NaN
-(1 row)
-
-SELECT power(float8 '-1', float8 'NaN');
- power 
--------
-   NaN
-(1 row)
-
-SELECT power(float8 '1', float8 'NaN');
- power 
--------
-     1
-(1 row)
-
-SELECT power(float8 'NaN', float8 '0');
- power 
--------
-     1
-(1 row)
-
 -- take exp of ln(f.f1)
 SELECT '' AS three, f.f1, exp(ln(f.f1)) AS exp_ln_f1
    FROM FLOAT8_TBL f

diff --git a/src/test/regress/expected/float8.out b/src/test/regress/expected/float8.out
index b05831d45c954918bc65f0f168fb6f711a6fd4d9..20c985e5df86ee6bcf603f45bec4df2947e1fad0 100644 (file)
--- a/src/test/regress/expected/float8.out
+++ b/src/test/regress/expected/float8.out
@@ -340,42 +340,6 @@ SELECT power(float8 '144', float8 '0.5');
     12
 (1 row)
 
-SELECT power(float8 'NaN', float8 '0.5');
- power 
--------
-   NaN
-(1 row)
-
-SELECT power(float8 '144', float8 'NaN');
- power 
--------
-   NaN
-(1 row)
-
-SELECT power(float8 'NaN', float8 'NaN');
- power 
--------
-   NaN
-(1 row)
-
-SELECT power(float8 '-1', float8 'NaN');
- power 
--------
-   NaN
-(1 row)
-
-SELECT power(float8 '1', float8 'NaN');
- power 
--------
-     1
-(1 row)
-
-SELECT power(float8 'NaN', float8 '0');
- power 
--------
-     1
-(1 row)
-
 -- take exp of ln(f.f1)
 SELECT '' AS three, f.f1, exp(ln(f.f1)) AS exp_ln_f1
    FROM FLOAT8_TBL f

diff --git a/src/test/regress/sql/float8.sql b/src/test/regress/sql/float8.sql
index eeebddd4b78d334ee73a777403b55060475c101a..215e7a478499a1cebb91c19f571dfbdbbb7a29f8 100644 (file)
--- a/src/test/regress/sql/float8.sql
+++ b/src/test/regress/sql/float8.sql
@@ -108,12 +108,6 @@ SELECT '' AS three, f.f1, |/f.f1 AS sqrt_f1
 
 -- power
 SELECT power(float8 '144', float8 '0.5');
-SELECT power(float8 'NaN', float8 '0.5');
-SELECT power(float8 '144', float8 'NaN');
-SELECT power(float8 'NaN', float8 'NaN');
-SELECT power(float8 '-1', float8 'NaN');
-SELECT power(float8 '1', float8 'NaN');
-SELECT power(float8 'NaN', float8 '0');
 
 -- take exp of ln(f.f1)
 SELECT '' AS three, f.f1, exp(ln(f.f1)) AS exp_ln_f1