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[Bug rtl-optimization/40838] gcc shouldn't assume that the stack is aligned
- From: "mikulas at artax dot karlin dot mff dot cuni dot cz" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 17 Aug 2010 20:17:38 -0000
- Subject: [Bug rtl-optimization/40838] gcc shouldn't assume that the stack is aligned
- References: <bug-40838-1600@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #80 from mikulas at artax dot karlin dot mff dot cuni dot cz 2010-08-17 20:17 -------
Comment #79:
-mpreferred-stack-boundary=2 adheres to the sysv ABI but it doesn't adhere to
the Linux ABI (that requires 16-byte alignment), so if you compile anything
with -mpreferred-stack-boundary=2, it may crash when entering other dynamic
libraries.
-mstackrealign does the right thing, it realigns the stack when needed, but
keeps it 16-byte aligned on function output. It should be used.
I would be nice if gcc developers made -mstackrealign default (with an option
to turn it off for scientists who need maximum performance and don't care about
ABI) so that this ABI madness will finally end when distributions get
recompiled with it.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40838