#41328 [NEW]: Weird results from floor after compiling with pentium4 optimizations

From: rgonzalez at gnt dot cc Operating system: Linux Slackware 10.2 PHP version: 5.2.2 PHP Bug Type: *Math Functions Bug description: Weird results from floor after compiling with pentium4 optimizations Description: ------------ I compiled PHP 5.2.2 with CFLAGS="-O2 -march=pentium4 -mcpu=pentium4", as usual (I've done so with all the 5.x.x series, and the proc is a Pentium 4, of course) and a customer complained about weird results in one of his scripts. I isolated the problem to be related to the floor function. The problem was that it returned weird results. Sample script: <?php $nt = 100; $promrow2['uni_gifts'] = 1; $promrow2['unidades'] = 10; $calc_cnt=floor(($nt*$promrow2['uni_gifts'])/$promrow2['unidades']); print $calc_cnt; ?> printed :.0000000001 I needed to cast (int)floor to get the right result. I recompiled with CFLAGS="-O2 -march=i686 -mcpu=i686" and the problem was solved. I've compiled 5.2.2 with nocona optimizations without problems in other machines. Software: PHP 5.2.2 GCC 3.2.2 Reproduce code: --------------- <?php $nt = 100; $promrow2['uni_gifts'] = 1; $promrow2['unidades'] = 10; $calc_cnt=floor(($nt*$promrow2['uni_gifts'])/$promrow2['unidades']); print $calc_cnt; ?> Expected result: ---------------- 10 Actual result: -------------- :.0000000001 -- Edit bug report at http://bugs.php.net/?id=41328&edit=1 -- Try a CVS snapshot (PHP 4.4): http://bugs.php.net/fix.php?id=41328&r=trysnapshot44 Try a CVS snapshot (PHP 5.2): http://bugs.php.net/fix.php?id=41328&r=trysnapshot52 Try a CVS snapshot (PHP 6.0): http://bugs.php.net/fix.php?id=41328&r=trysnapshot60 Fixed in CVS: http://bugs.php.net/fix.php?id=41328&r=fixedcvs Fixed in release: http://bugs.php.net/fix.php?id=41328&r=alreadyfixed Need backtrace: http://bugs.php.net/fix.php?id=41328&r=needtrace Need Reproduce Script: http://bugs.php.net/fix.php?id=41328&r=needscript Try newer version: http://bugs.php.net/fix.php?id=41328&r=oldversion Not developer issue: http://bugs.php.net/fix.php?id=41328&r=support Expected behavior: http://bugs.php.net/fix.php?id=41328&r=notwrong Not enough info: http://bugs.php.net/fix.php?id=41328&r=notenoughinfo Submitted twice: http://bugs.php.net/fix.php?id=41328&r=submittedtwice register_globals: http://bugs.php.net/fix.php?id=41328&r=globals PHP 3 support discontinued: http://bugs.php.net/fix.php?id=41328&r=php3 Daylight Savings: http://bugs.php.net/fix.php?id=41328&r=dst IIS Stability: http://bugs.php.net/fix.php?id=41328&r=isapi Install GNU Sed: http://bugs.php.net/fix.php?id=41328&r=gnused Floating point limitations: http://bugs.php.net/fix.php?id=41328&r=float No Zend Extensions: http://bugs.php.net/fix.php?id=41328&r=nozend MySQL Configuration Error: http://bugs.php.net/fix.php?id=41328&r=mysqlcfg