[Bug 591819] Re: compiled program segfault when -O0 is used to compile

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On 2011-08-30T16:29:35+00:00 eviom wrote:

Original thread: https://bugs.launchpad.net/ubuntu/+source/gcc-
defaults/+bug/591819

When I compile my code, if I compile it -O2, it compiles and runs fine.
if I compile it with -O0, it segfaults while rendering text with FTGL.
I've made no changes to anything in between compiles. Same FTGL code
works fine in win32 (vs2010).

Reply at: https://bugs.launchpad.net/gcc-defaults/+bug/591819/comments/5

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On 2011-08-30T16:38:22+00:00 Paolo-carlini wrote:

Please follow the normal bug reporting instructions:

  http://gcc.gnu.org/bugs/#report

Reply at: https://bugs.launchpad.net/gcc-defaults/+bug/591819/comments/7


** Changed in: gcc-defaults
       Status: Unknown => Incomplete

** Changed in: gcc-defaults
   Importance: Unknown => Medium

** Bug watch added: gcc.gnu.org/ #
   http://gcc.gnu.org/bugs/

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https://bugs.launchpad.net/bugs/591819

Title:
  compiled program segfault when -O0 is used to compile

Status in gcc-defaults:
  Incomplete
Status in “gcc-defaults” package in Ubuntu:
  Confirmed

Bug description:
  I don't know whether this is really a problem, or what not, but I'm
  attaching logs, and the program which causes it, along with every
  detail I can think of.  When I compile my code, if I compile it -O2,
  it compiles and runs fine.  if I compile it with -O0, it segfaults
  very early on in the execution.  I've made no changes to anything in
  between compiles.

  Compiling the code successfully requires the following libraries:
  opengl (mesa)
  glut (freeglut)
  curl
  FTGL (patched, see https://bugs.launchpad.net/ubuntu/+source/ftgl/+bug/485225 )

  procedure is as follows:

  ./configure
  make CFLAGS="-O0"
  src/altocumulus

  make clean
  make CFLAGS="-O2"
  src/altocumulus

  My code is pretty crappy, please ignore that, I'm still learning the basics of C.
  Regardless, the code shouldn't work with one level of optimization and fail with another.

  ProblemType: Bug
  DistroRelease: Ubuntu 10.04
  Package: gcc 4:4.4.3-1ubuntu1
  ProcVersionSignature: Ubuntu 2.6.32-22.36-generic 2.6.32.11+drm33.2
  Uname: Linux 2.6.32-22-generic x86_64
  NonfreeKernelModules: nvidia
  Architecture: amd64
  Date: Wed Jun  9 11:43:21 2010
  EcryptfsInUse: Yes
  InstallationMedia: Ubuntu 9.10 "Karmic Koala" - Release amd64 (20091027)
  ProcEnviron:
   PATH=(custom, user)
   LANG=en_US.utf8
   SHELL=/bin/bash
  SourcePackage: gcc-defaults

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