Launchpad has imported 5 comments from the remote bug at https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80533.
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 2017-04-26T19:07:20+00:00 3-sje wrote: Created attachment 41274 Test case GCC should treat zero length arrays like C99 flexible arrays when they are at the end of a structure. I.e. recognize that accesses to that array may go beyond the end of the structure. GCC has been treating zero length arrays and flexible arrays differently since at least 5.0. This was found on aarch64 but the bug is not platform specific. A test case is attached, it cannot be run but if compiled for aarch64 with -O2 -fno-strict-aliasing and either -UFLEX or -DFLEX you can see the different code. In the -UFLEX case it generates a load/load/store/store sequence and in the -DFLEX case it generates load/store/load/store for the code in the main loop. See also: https://gcc.gnu.org/ml/gcc/2017-04/msg00118.html https://gcc.gnu.org/ml/gcc-patches/2017-04/msg01257.html Reply at: https://bugs.launchpad.net/ubuntu/+source/gcc-6/+bug/1685385/comments/2 ------------------------------------------------------------------------ On 2017-04-27T07:55:09+00:00 Rguenth wrote: Mine. Reply at: https://bugs.launchpad.net/ubuntu/+source/gcc-6/+bug/1685385/comments/3 ------------------------------------------------------------------------ On 2017-04-27T12:35:16+00:00 Rguenth wrote: Author: rguenth Date: Thu Apr 27 12:34:45 2017 New Revision: 247327 URL: https://gcc.gnu.org/viewcvs?rev=247327&root=gcc&view=rev Log: 2017-04-27 Richard Biener <[email protected]> PR middle-end/80533 * emit-rtl.c (set_mem_attributes_minus_bitpos): When stripping ARRAY_REFs from MEM_EXPR make sure we're not keeping a reference to a trailing array. Modified: trunk/gcc/ChangeLog trunk/gcc/emit-rtl.c Reply at: https://bugs.launchpad.net/ubuntu/+source/gcc-6/+bug/1685385/comments/4 ------------------------------------------------------------------------ On 2017-04-27T12:59:11+00:00 Rguenth wrote: Fixed on trunk sofar. Reply at: https://bugs.launchpad.net/ubuntu/+source/gcc-6/+bug/1685385/comments/5 ------------------------------------------------------------------------ On 2020-02-14T09:48:33+00:00 Rguenth wrote: Fixed on all still maintained branches. Reply at: https://bugs.launchpad.net/ubuntu/+source/gcc-6/+bug/1685385/comments/8 ** Changed in: gcc Status: In Progress => Fix Released -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1685385 Title: GCC generates bad code with zero length array and -O3 To manage notifications about this bug go to: https://bugs.launchpad.net/gcc/+bug/1685385/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
