From: "Cristea Bogdan" <cristeab@gmail.com>
To: gcc-help@gcc.gnu.org
Subject: Floating point results change with different compilation options
Date: Tue, 23 Oct 2007 08:42:00 -0000 [thread overview]
Message-ID: <e7b7bbdc0710230104l55dcb060vef9233bc07922f12@mail.gmail.com> (raw)
Hi
I use gcc compiler in order to study the behavior of some iterative
maps (x_n=f(x_{n-1})) using single floating point precision (following
IEEE 754 standard). I have noticed that using different compiler
options, the output sequence could be very different. My programs are
written in C++ using 'float' type and I use 'gcc version 4.1.2
20061115 (prerelease) (Debian 4.1.1-21)'. Compilation options are:
'-Wall -O3 -march=pentium4' or '-Wall'. The same program compiled with
gcc 4.2.2 gives the same results regardless of the compilation options
(on an athlon64 processor).
Is this a bug of the compiler or the floating point representation
differs from one compiler version to the other?
--
Bogdan Cristea
next reply other threads:[~2007-10-23 8:04 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-23 8:42 Cristea Bogdan [this message]
2007-10-23 12:01 ` John Love-Jensen
2007-10-23 17:36 ` burlen
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