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

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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
This commit is contained in:
Tom Lane 2018-05-02 17:32:40 -04:00
parent 938c6f42d8
commit eab8d6312f
6 changed files with 1 additions and 170 deletions
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21
src/backend/utils/adt/float.c
View File

@ -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.

36
src/test/regress/expected/float8-exp-three-digits-win32.out
View File

@ -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

36
src/test/regress/expected/float8-small-is-zero.out
View File

@ -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

36
src/test/regress/expected/float8-small-is-zero_1.out
View File

@ -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

36
src/test/regress/expected/float8.out
View File

@ -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

6
src/test/regress/sql/float8.sql
View File

@ -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