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Still further adjust degree-based trig functions for more portability.

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Indeed, the non-static declaration foreseen in my previous commit message
is necessary.  Per Noah Misch.
This commit is contained in:
Tom Lane 2016-01-23 18:12:54 -05:00
parent 65abaab547
commit 360f67d31a
1 changed files with 10 additions and 1 deletions
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11
src/backend/utils/adt/float.c
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@ -83,6 +83,10 @@ static int float8_cmp_internal(float8 a, float8 b);
static double sind_q1(double x); static double sind_q1(double x);
static double cosd_q1(double x); static double cosd_q1(double x);
/* This is INTENTIONALLY NOT STATIC. Don't "fix" it. */
void init_degree_constants(float8 thirty, float8 forty_five, float8 sixty,
float8 one_half, float8 one);
#ifndef HAVE_CBRT #ifndef HAVE_CBRT
/* /*
* Some machines (in particular, some versions of AIX) have an extern * Some machines (in particular, some versions of AIX) have an extern
@ -1771,11 +1775,16 @@ dtan(PG_FUNCTION_ARGS)
* want exact results, we must ensure that none of the scaling constants used * want exact results, we must ensure that none of the scaling constants used
* in the degree-based trig functions are computed that way. * in the degree-based trig functions are computed that way.
* *
* The whole approach fails if init_degree_constants() gets inlined into the
* call sites, since then constant-folding can happen anyway. Currently it
* seems sufficient to declare it non-static to prevent that. We have no
* expectation that other files will call this, but don't tell gcc that.
*
* Other hazards we are trying to forestall with this kluge include the * Other hazards we are trying to forestall with this kluge include the
* possibility that compilers will rearrange the expressions, or compute * possibility that compilers will rearrange the expressions, or compute
* some intermediate results in registers wider than a standard double. * some intermediate results in registers wider than a standard double.
*/ */
static void void
init_degree_constants(float8 thirty, float8 forty_five, float8 sixty, init_degree_constants(float8 thirty, float8 forty_five, float8 sixty,
float8 one_half, float8 one) float8 one_half, float8 one)
{ {