Re: port-powerpc/51366: kernel for powerpc/ibm4xx miscompiled by gcc >= 4.8.5

[Rin Okuyama <rokuyama%rk.phys.keio.ac.jp@localhost>]

The following reply was made to PR port-powerpc/51366; it has been noted by GNATS.

From: Rin Okuyama <rokuyama%rk.phys.keio.ac.jp@localhost>
To: gnats-bugs%NetBSD.org@localhost, port-powerpc-maintainer%netbsd.org@localhost,
 gnats-admin%netbsd.org@localhost, netbsd-bugs%netbsd.org@localhost
Cc: 
Subject: Re: port-powerpc/51366: kernel for powerpc/ibm4xx miscompiled by gcc
 >= 4.8.5
Date: Tue, 20 Sep 2016 21:24:16 +0900

 On 2016/09/18 6:10, coypu%SDF.ORG@localhost wrote:
 >  what you seem to be suggesting: set the default for RS6000 to ppc64, as
 >  the kernel is miscompiled when ppc is chosen.
 >  aside from seeming like a very dangerous change, it's very confusing to
 >  me. the documentation I have[1] says that ppc405 is 32bit.
 
 My patch does nothing for 64-bit machines. It merely stops gcc issuing a
 bogus pseudo-op for 32-bit machines. gcc >= 4.8.5 generates ".machine ppc"
 pseudo-op for 32-bit environment, which discards CPU type specified by
 -mcpu or -Wa,-m option. This results in miscompiling kernel codes for,
 at least, 405.