[Ubuntu 15.10] gcc: Ensure -m[no-]crypto affects the correct subset of POWER8 instructions

[bugproxy]

gcc 4.8 introduces support for POWER8, which among other things adds support for cryptography instructions (section 5.11 of the 2.07 POWER ISA). Availability of cryptography instructions is specified with -m[no-]crypto. However, this switch incorrectly affects availability of ALL instructions in section 5.11, when in fact it should only control code generation of instructions flagged as "Category:Vector.AES" or "Category:Vector.SHA2". I have patches upstream to fix this, implemented with the following revisions:

GCC trunk (6.0): 222362, 222381
GCC 5.1: 222397
GCC 4.9: 222424
GCC 4.8: 222429

I would like to see the backported patch applied to the gcc shipped with the Ubuntu 15.10 release. We should also discuss applying it to the next available service pack for the 14.04 LTS release.

[Ubuntu Foundations Team Bug Bot (crichton)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. It seems that your bug report is not filed about a specific source package though, rather it is just filed against Ubuntu in general. It is important that bug reports be filed about source packages so that people interested in the package can find the bugs about it. You can find some hints about determining what package your bug might be about at https://wiki.ubuntu.com/Bugs/FindRightPackage. You might also ask for help in the #ubuntu-bugs irc channel on Freenode.

To change the source package that this bug is filed about visit https://bugs.launchpad.net/ubuntu/+bug/1449120/+editstatus and add the package name in the text box next to the word Package.

[This is an automated message. I apologize if it reached you inappropriately; please just reply to this message indicating so.]

[Steve Langasek (vorlon)]

It looks like this bug will be fixed as a matter of course when gcc 5.1 is included in the distro and becomes the default in Ubuntu 15.10. Assigning to Matthias for confirmation.

For 14.04, this appears to be addressed by the SRU of gcc-4.8 currently in trusty-proposed, which will bring us up to revision 222448.

[Steve Langasek (vorlon)]

gcc 5.2.1 is now the default in wily, so I believe this issue is resolved for 15.10.