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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 217d8f3 and 4d864de in the v10 branch and the corresponding commits in 9.3-9.6. Discussion: https://postgr.es/m/75DB81BEEA95B445AE6D576A0A5C9E936A73E741@BPXM05GP.gisp.nec.co.jp
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6 files changed

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-170
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6 files changed

+1
-170
lines changed

‎src/backend/utils/adt/float.c

Lines changed: 1 addition & 20 deletions
Original file line numberDiff line numberDiff line change
@@ -1455,25 +1455,6 @@ dpow(PG_FUNCTION_ARGS)
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float8 arg2 = PG_GETARG_FLOAT8(1);
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float8 result;
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/*
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* The POSIX spec says that NaN ^ 0 = 1, and 1 ^ NaN = 1, while all other
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* cases with NaN inputs yield NaN (with no error). Many older platforms
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* get one or more of these cases wrong, so deal with them via explicit
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* logic rather than trusting pow(3).
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*/
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if (isnan(arg1))
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{
1466-
if (isnan(arg2) || arg2 != 0.0)
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PG_RETURN_FLOAT8(get_float8_nan());
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PG_RETURN_FLOAT8(1.0);
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}
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if (isnan(arg2))
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{
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if (arg1 != 1.0)
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PG_RETURN_FLOAT8(get_float8_nan());
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PG_RETURN_FLOAT8(1.0);
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}
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/*
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* The SQL spec requires that we emit a particular SQLSTATE error code for
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* certain error conditions. Specifically, we don't return a
@@ -1492,7 +1473,7 @@ dpow(PG_FUNCTION_ARGS)
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* pow() sets errno only on some platforms, depending on whether it
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* follows _IEEE_, _POSIX_, _XOPEN_, or _SVID_, so we try to avoid using
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* errno. However, some platform/CPU combinations return errno == EDOM
1495-
* and result == NaN for negative arg1 and very large arg2 (they must be
1476+
* and result == Nan for negative arg1 and very large arg2 (they must be
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* using something different from our floor() test to decide it's
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* invalid). Other platforms (HPPA) return errno == ERANGE and a large
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* (HUGE_VAL) but finite result to signal overflow.

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

Lines changed: 0 additions & 36 deletions
Original file line numberDiff line numberDiff line change
@@ -340,42 +340,6 @@ SELECT power(float8 '144', float8 '0.5');
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12
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(1 row)
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343-
SELECT power(float8 'NaN', float8 '0.5');
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power
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-------
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NaN
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(1 row)
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SELECT power(float8 '144', float8 'NaN');
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power
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-------
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NaN
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(1 row)
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SELECT power(float8 'NaN', float8 'NaN');
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power
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-------
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NaN
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(1 row)
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SELECT power(float8 '-1', float8 'NaN');
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power
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-------
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NaN
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(1 row)
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SELECT power(float8 '1', float8 'NaN');
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power
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-------
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1
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(1 row)
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SELECT power(float8 'NaN', float8 '0');
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power
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-------
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1
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(1 row)
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379343
-- take exp of ln(f.f1)
380344
SELECT '' AS three, f.f1, exp(ln(f.f1)) AS exp_ln_f1
381345
FROM FLOAT8_TBL f

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

Lines changed: 0 additions & 36 deletions
Original file line numberDiff line numberDiff line change
@@ -344,42 +344,6 @@ SELECT power(float8 '144', float8 '0.5');
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12
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(1 row)
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SELECT power(float8 'NaN', float8 '0.5');
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power
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-------
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NaN
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(1 row)
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SELECT power(float8 '144', float8 'NaN');
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power
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-------
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NaN
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(1 row)
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SELECT power(float8 'NaN', float8 'NaN');
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power
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-------
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NaN
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(1 row)
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SELECT power(float8 '-1', float8 'NaN');
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power
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-------
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NaN
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(1 row)
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SELECT power(float8 '1', float8 'NaN');
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power
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-------
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1
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(1 row)
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SELECT power(float8 'NaN', float8 '0');
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power
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-------
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1
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(1 row)
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383347
-- take exp of ln(f.f1)
384348
SELECT '' AS three, f.f1, exp(ln(f.f1)) AS exp_ln_f1
385349
FROM FLOAT8_TBL f

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

Lines changed: 0 additions & 36 deletions
Original file line numberDiff line numberDiff line change
@@ -344,42 +344,6 @@ SELECT power(float8 '144', float8 '0.5');
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12
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(1 row)
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347-
SELECT power(float8 'NaN', float8 '0.5');
348-
power
349-
-------
350-
NaN
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(1 row)
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353-
SELECT power(float8 '144', float8 'NaN');
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power
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-------
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NaN
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(1 row)
358-
359-
SELECT power(float8 'NaN', float8 'NaN');
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power
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-------
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NaN
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(1 row)
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SELECT power(float8 '-1', float8 'NaN');
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power
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-------
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NaN
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(1 row)
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SELECT power(float8 '1', float8 'NaN');
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power
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-------
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1
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(1 row)
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SELECT power(float8 'NaN', float8 '0');
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power
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-------
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1
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(1 row)
382-
383347
-- take exp of ln(f.f1)
384348
SELECT '' AS three, f.f1, exp(ln(f.f1)) AS exp_ln_f1
385349
FROM FLOAT8_TBL f

‎src/test/regress/expected/float8.out

Lines changed: 0 additions & 36 deletions
Original file line numberDiff line numberDiff line change
@@ -340,42 +340,6 @@ SELECT power(float8 '144', float8 '0.5');
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12
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(1 row)
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343-
SELECT power(float8 'NaN', float8 '0.5');
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power
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-------
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NaN
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(1 row)
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SELECT power(float8 '144', float8 'NaN');
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power
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-------
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NaN
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(1 row)
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SELECT power(float8 'NaN', float8 'NaN');
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power
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-------
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NaN
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(1 row)
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361-
SELECT power(float8 '-1', float8 'NaN');
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power
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-------
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NaN
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(1 row)
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SELECT power(float8 '1', float8 'NaN');
368-
power
369-
-------
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1
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(1 row)
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373-
SELECT power(float8 'NaN', float8 '0');
374-
power
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-------
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1
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(1 row)
378-
379343
-- take exp of ln(f.f1)
380344
SELECT '' AS three, f.f1, exp(ln(f.f1)) AS exp_ln_f1
381345
FROM FLOAT8_TBL f

‎src/test/regress/sql/float8.sql

Lines changed: 0 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -108,12 +108,6 @@ SELECT '' AS three, f.f1, |/f.f1 AS sqrt_f1
108108

109109
-- power
110110
SELECT power(float8 '144', float8 '0.5');
111-
SELECT power(float8 'NaN', float8 '0.5');
112-
SELECT power(float8 '144', float8 'NaN');
113-
SELECT power(float8 'NaN', float8 'NaN');
114-
SELECT power(float8 '-1', float8 'NaN');
115-
SELECT power(float8 '1', float8 'NaN');
116-
SELECT power(float8 'NaN', float8 '0');
117111

118112
-- take exp of ln(f.f1)
119113
SELECT '' AS three, f.f1, exp(ln(f.f1)) AS exp_ln_f1

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