Re: c/7857: Different behaviour if compiled with optimization!

["Pop Sébastian" <pop@gauvain.u-strasbg.fr>]

The following reply was made to PR c/7857; it has been noted by GNATS.

From: =?iso-8859-1?Q?Pop_S=E9bastian?= <pop@gauvain.u-strasbg.fr>
To: jcas@netcabo.pt
Cc: gcc-gnats@gcc.gnu.org, austern@apple.com
Subject: Re: c/7857: Different behaviour if compiled with optimization!
Date: Wed, 9 Oct 2002 19:15:06 +0200

 On Sun, Sep 08, 2002 at 02:36:46PM -0000, jcas@netcabo.pt wrote:
 > /*
 > Compile with -O3 and runs fine
 > without there's a precision error.
 > SQ's value has the correct value with -O3 (+1 than without -O3 for n==46611179)
 > 
 
 Reproduced with 
 gcc version 2.95.4 20011002 (Debian prerelease)
 version gcc 3.3 20021007 (experimental)
 
 
 Compiling the bug report without -O3 gives an error: "Undefined reference to 'sqrt'".
 For completing the link we have to specify the -lm.
 Thus with no optimization, the 'sqrt' function is the one defined in the math library,
 whereas with -O3 the 'sqrt' function is the one defined by GCC... (I think)
 
 I hope that this helps,
 Sebastian.
 
 
 pop@gauvain:~/gcc/main/test$ ../usr/bin/gcc -o pr7857 ./pr7857.c -O3
 pop@gauvain:~/gcc/main/test$ ../usr/bin/gcc -o pr7857 ./pr7857.c
 /tmp/emacs-09607/cc4vzVim.o: dans la fonction `main':
 /tmp/emacs-09607/cc4vzVim.o(.text+0xaf): r\351f\351rence ind\351finie vers `sqrt'
 collect2: ld a retourn\351 1 code d'\351tat d'ex\351cution
 pop@gauvain:~/gcc/main/test$ ../usr/bin/gcc -o pr7857 ./pr7857.c -lm
 pop@gauvain:~/gcc/main/test$