[arch-general] gcc 4.8 breaking libdrm for me

[Andreas Radke]

This is just a heads up notice. I've found gcc 4.8 breaking libdrm on my
nouveau nv44 device. When compiled with gcc 4.8 I'm faced with random
nouveau related error messages in dmesg. Using new google maps quickly
leads to Xorg hanging and finally to Xorg freezing or even crashing.
I've seen other Arch people also claiming about random X crashes.

Recompiling libdrm with -O0 or other new optimizaions disabled didn't
solve it for me so far. But recompiling with a local gcc 4.7.3 makes it
stable again.

I'm asking for help in tracking this down. We need to find out if a
certain part of libdrm has broken code that needs to be fixed. Please
everybody with random Xorg crashes try to downgrade to libdrm 2.4.43
(the last one that was built with gcc 4.7) and post your gfx card.

And this could also be a gcc 4.8 bug or regression. I've seen almost
the same behavior with kernel xfs file system code leading to fs
corruption under heavy load:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57436

Then we need to compare assembler code created by gcc 4.7 vs. 4.8.

Any suggestion and help is welcome.

-Andy
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