Gentoo Archives: gentoo-amd64

From: Alex Schuster <wonko@×××××××××.org>
To: gentoo-amd64@l.g.o
Subject: Re: [gentoo-amd64] GCC-4.5.2 Has Serious Problems
Date: Thu, 30 Jun 2011 22:32:15
Message-Id: 4E0CF921.6040800@wonkology.org
In Reply to: [gentoo-amd64] GCC-4.5.2 Has Serious Problems by Frank Peters
1 Frank Peters writes:
2
3 > After banging my head for a while over some strange results, I began
4 > to suspect GCC-4.5.2, the latest version in portage, was creating
5 > faulty code.
6 >
7 > It seems to a correct suspicion.
8 [...]
9
10 > The problem can be fixed by compiling the program with "O1"
11 > optimization:
12
13 Or -O3.
14
15
16 > For anyone who wants to try to duplicate these results, please feel
17 > free to do so.
18 >
19 > So I will have to conclude that GCC-4.5.2 has serious problems.
20 > This kind of erroneous behavior could appear anywhere.
21
22 Oh dear, that's scary. I can confirm this. With -O0, -O1 and -O3, all is
23 fine. -O2 gives the result you see. And with -Os, I get yet another
24 result (0/0, 4/4, 8/8).
25
26 This is an AMD Athlon(tm) Dual Core Processor 4850e, gcc has been
27 copmpiled with these use flags: fortran gtk mudflap multilib nls nptl openmp
28
29 Who will file the bug report now?
30
31 Wonko

Replies

Subject Author
Re: [gentoo-amd64] GCC-4.5.2 Has Serious Problems Frank Peters <frank.peters@×××××××.net>