Re: com php-src: Fix for failing tests. gcc 4.8.3 would optimize away the assigment.: ext/mysqlnd/mysqlnd_ps_codec.c

On Sat, Dec 27, 2014 at 2:17 AM, Keyur Govande <kgovande@gmail.com> wrote: > > > On Fri, Dec 26, 2014 at 9:52 PM, Dmitry Stogov <dmitry@zend.com> wrote: > >> This patch increases the binary size on 2MB (20%) :( >> >> # without patch >> >> $ size sapi/cli/php >> text data bss dec hex filename >> 11243874 55868 134140 11433882 ae779a sapi/cli/php >> >> # with patch >> >> $ size sapi/cli/php >> text data bss dec hex filename >> 13398084 55888 134148 13588120 cf5698 sapi/cli/php >> >> It's probably better not to use dec32. >> > > Ahh :( > > dec32 is 3 orders of magnitude faster than the alternative (convert float > to a string via fcvt or gcvt, and then to double via strtod). > > That said though, I will make dec32 optional via a configure option > defaulted to off and make the slow path the default. This will bring the > Mysqli implementation in-line with what PDO-libmysqlclient does and fix the > slight discrepancy in precision that arises due to that. > > dec32 is more precise, for example 3.141593 vs. 3.14159 with > PDO-libmysqlclient when pi is stored in a Mysql 4 byte float column. > > I should have a pull request on Github in a day or two. > Sorry for the delay, the holidays intruded on my plans. The pull request is up here: https://github.com/php/php-src/pull/983 and all tests pass on Windows and Linux (with gcc 4.8.3). I'll merge it in in a few days if no concerns are raised. Thanks and Happy New Year! Keyur. > >> Thanks. Dmitry. >> >> On Fri, Dec 26, 2014 at 11:36 PM, Keyur Govande <keyur@php.net> wrote: >> >>> Commit: aa192f57c9d867ab3d7be69c7f269cfd7a10d14f >>> Author: Keyur Govande <keyur@php.net> Fri, 26 Dec 2014 >>> 20:36:19 +0000 >>> Parents: 80260bcfa667bf25c65264b129f08a35059436a0 >>> Branches: PHP-5.5 PHP-5.6 master >>> >>> Link: >>> îÓ±+¤Íà²_Í >>> òŽ·>Jhttp://git.php.net/?p=php-src.git;a=commitdiff;h=aa192f57c9d867ab3d7be69c7f269cfd7a10d14f >>> >>> Log: >>> Fix for failing tests. gcc 4.8.3 would optimize away the assigment. >>> >>> Changed paths: >>> M ext/mysqlnd/mysqlnd_ps_codec.c >>> >>> >>> Diff: >>> diff --git a/ext/mysqlnd/mysqlnd_ps_codec.c >>> b/ext/mysqlnd/mysqlnd_ps_codec.c >>> index d960912..a57ff5d 100644 >>> --- a/ext/mysqlnd/mysqlnd_ps_codec.c >>> +++ b/ext/mysqlnd/mysqlnd_ps_codec.c >>> @@ -195,7 +195,8 @@ ps_fetch_float(zval * zv, const MYSQLND_FIELD * >>> const field, unsigned int pack_l >>> #ifdef HAVE_DECIMAL_FP_SUPPORT >>> { >>> typedef float dec32 __attribute__((mode(SD))); >>> - dec32 d32val = fval; >>> + /* volatile so the compiler will not optimize away the >>> conversion */ >>> + volatile dec32 d32val = fval; >>> >>> /* The following cast is guaranteed to do the right >>> thing */ >>> dval = (double) d32val; >>> >>> >>> -- >>> PHP CVS Mailing List (http://www.php.net/) >>> To unsubscribe, visit: http://www.php.net/unsub.php >>> >>> >> >