From 400f16937328d50a7e8d7f0d158f7c92be1da45a Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Tue, 16 Jun 2020 11:09:42 -0400 Subject: [PATCH] In dpow(), remove redundant check for whether y is an integer. I failed to notice that we don't really need to check for y being an integer in the code path where x = -inf; we already did. Also make some further cosmetic rearrangements in that spot in hopes of dodging the seeming compiler bug that buildfarm member fossa is hitting. And be consistent about declaring variables as "float8" not "double", since the pre-existing variables in this function are like that. Discussion: https://postgr.es/m/E1jkyFX-0005RR-1Q@gemulon.postgresql.org --- src/backend/utils/adt/float.c | 21 ++++++++++----------- 1 file changed, 10 insertions(+), 11 deletions(-) diff --git a/src/backend/utils/adt/float.c b/src/backend/utils/adt/float.c index 086631dd19f..50ec3d3dde5 100644 --- a/src/backend/utils/adt/float.c +++ b/src/backend/utils/adt/float.c @@ -1546,7 +1546,7 @@ dpow(PG_FUNCTION_ARGS) */ if (isinf(arg2)) { - double absx = fabs(arg1); + float8 absx = fabs(arg1); if (absx == 1.0) result = 1.0; @@ -1578,16 +1578,15 @@ dpow(PG_FUNCTION_ARGS) } else /* x = -Inf */ { - bool yisoddinteger = false; + /* + * Per POSIX, the sign of the result depends on whether y is an + * odd integer. Since x < 0, we already know from the previous + * domain check that y is an integer. It is odd if y/2 is not + * also an integer. + */ + float8 halfy = arg2 / 2; /* should be computed exactly */ + bool yisoddinteger = (floor(halfy) != halfy); - if (arg2 == floor(arg2)) - { - /* y is integral; it's odd if y/2 is not integral */ - double halfy = arg2 / 2; /* should be computed exactly */ - - if (halfy != floor(halfy)) - yisoddinteger = true; - } if (arg2 > 0.0) result = yisoddinteger ? arg1 : -arg1; else @@ -1622,7 +1621,7 @@ dpow(PG_FUNCTION_ARGS) result = 0.0; /* we already verified y is positive */ else { - double absx = fabs(arg1); + float8 absx = fabs(arg1); if (absx == 1.0) result = 1.0;