From: Tom Lane Date: Wed, 2 May 2018 21:32:40 +0000 (-0400) Subject: Revert back-branch changes in power()'s behavior for NaN inputs. X-Git-Tag: REL_10_4~15 X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=f74d83b3034f830bd68489b4aba99a4dee29c565;p=postgresql 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 45a62f2616..18b3b949ac 100644 --- 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 3896cdec72..7e1153308f 100644 --- 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 f8e09390f5..26b8378150 100644 --- 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 ebfec4cdb6..cea27908eb 100644 --- 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 b05831d45c..20c985e5df 100644 --- 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 eeebddd4b7..215e7a4784 100644 --- 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