Launchpad has imported 1 comments from the remote bug at http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49169.
If you reply to an imported comment from within Launchpad, your comment will be sent to the remote bug automatically. Read more about Launchpad's inter-bugtracker facilities at https://help.launchpad.net/InterBugTracking. ------------------------------------------------------------------------ On 2011-05-26T02:13:27+00:00 Michael Hope wrote: ARM devices encode the instruction set mode in the LSB of the function address. Functions are word aligned on ARM. If you try to test the LSB of a function pointer then GCC assumes that the two least significant bits are zero and optimises away the test. This problem is seen in Mono and was originally reported at: https://bugs.launchpad.net/ubuntu/+source/gcc-4.5/+bug/721531 A reduced test case is: void main() { void *p = main; if ((int)p & 1) printf ("HIT!\n"); } When compiled with -march=armv7-a -mthumb -O0 then the word 'HIT!' will show. When compiled with -O2, the branch is not taken. The problem does not occur in 4.4.5. It does occur in 4.5.2, 4.6.0, and trunk r174044. Reply at: https://bugs.launchpad.net/gcc/+bug/721531/comments/18 ** Changed in: gcc Status: Unknown => New ** Changed in: gcc Importance: Unknown => Medium -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/721531 Title: [armel] gcc computes wrong address for main() at build time -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
