http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56028
Bug #: 56028
Summary: Splitting a 64-bit volatile store
Classification: Unclassified
Product: gcc
Version: 4.7.2
URL: http://gcc.gnu.org/ml/gcc-patches/2013-01/msg00870.htm
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Status: UNCONFIRMED
Keywords: wrong-code
Severity: normal
Priority: P3
Component: target
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: amona...@gcc.gnu.org
CC: eugeni.stepa...@gmail.com, khlebni...@openvz.org,
m...@pengutronix.de, paul...@linux.vnet.ibm.com,
ubiz...@gmail.com, valery.bickov+...@gmail.com
Target: i?86-*-* x86_64-*-*
Created attachment 29201
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=29201
test case
+++ This bug was initially created as a clone of Bug #55981 +++
As suggested in the parent bug, this is a separate report dealing specifically
with splitting of a 64-bit volatile (not necessarily atomic) store of an
immediate value into 32-bit accesses. Comment 10 of the original report says:
> > > Btw, the same happens if atomic is replaced with "volatile unsigned long
> > > y" -
> > > which does not violate the standard, but may be considered undesirable by
> > > some.
> > > I don't have a strong opinion about this.
> >
> > This really does need to be fixed in the "volatile unsigned long y" case, or
> > device drivers storing constants to device registers will break. So please
> > fix
> > this for volatiles as well as atomics.
>
> Please open a new PR for this.
It looks to me that volatiles should not be allowed as offsetable operands, but
let's discuss this in a separate PR.
