On Mon, Nov 15, 2010 at 11:43:22PM +0100, Andi Kleen wrote: > > testcase shows that in 4.1/4.2/4.3/4.4 this is miscompiled only when using > > -fno-ipa-reference, in 4.5 it is miscompiled always when optimizing > > unless -fno-ipa-pure-const (as 4.5 added local-pure-const pass which is run > > before ipa-reference) and in 4.6 this has been fixed by Honza when > > doing ipa cleanups. > > Maybe it would be better to simply change the kernel Makefiles to pass > -fno-ipa-pure-const instead of adding volatiles everywhere.
If you do this, please do it for 4.5.[012] only. If you disable all gcc passes that ever had any bugs in it, you'd need to disable most of them if not all. Jakub