http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38644
--- Comment #51 from rguenther at suse dot de <rguenther at suse dot de> 2011-09-26 08:04:37 UTC --- On Mon, 12 Sep 2011, rearnsha at arm dot com wrote: > http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38644 > > --- Comment #48 from Richard Earnshaw <rearnsha at arm dot com> 2011-09-12 > 15:31:51 UTC --- > On 12/09/11 16:18, law at redhat dot com wrote: > > > A much simpler way to fix this is to emit a barrier just prior to > > mucking around with stack pointer in the epilogue. That's how targets > > have dealt with this exact issue for a couple decades. > > Simpler, but wrong. The compiler should not be generating unsafe code > by default. The problem is in the mid-end and expecting every port to > get this right in order to work-around a mid-end bug is just stupid > stupid stupid. > > The mid end should not be scheduling around stack moves unless it has > been explicitly told it is safe to do this. I don't understand why > there is so much resistance to fixing the problem properly. The middle-end does not treat stack moves specially, they are just memory accesses. Extra dependences have to be modeled accordingly. It's a hack to treat stack moves specially, not a proper fix.
