[Bug tree-optimization/56211] New: gnulib yesno compiled incorrectly with -02 on x86_64

[allan at archlinux dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56211



             Bug #: 56211

           Summary: gnulib yesno compiled incorrectly with -02 on x86_64

    Classification: Unclassified

           Product: gcc

           Version: 4.7.2

            Status: UNCONFIRMED

          Severity: normal

          Priority: P3

         Component: tree-optimization

        AssignedTo: unassig...@gcc.gnu.org

        ReportedBy: al...@archlinux.org





Compiling gzip with optimization generates code that mangles the return value

of the gnulib yesno function on x86_64 Linux.  This bug is not present in i686.



This results in files being overwritten despite answering "n" to:

gzip: out.gz already exists; do you wish to overwrite (y or n)?



This is seen in both Arch Linux and Fedora 18 and is present in the latest 4.7

and 4.8 snapshots.



Git bisect implicates r173711:

http://gcc.gnu.org/git/?p=gcc.git;a=commit;h=4c7817e5



Downstream bug with relevant disassembly:

https://bugs.archlinux.org/task/33121