------- Comment #26 from rearnsha at gcc dot gnu dot org 2009-11-28 14:38 ------- (In reply to comment #25) > Further tests show that you're right about the non working kernel.
You should not use -march=iwmmxt (or -mcpu=<something equivalent>) when building the linux kernel. The kernel does not know how to save user-space context for iwmmxt on entry (it only saves co-processor state on context switches) so you will end up corrupting internal state. It's the same situation as trying to use floating-point hardware in the kernel -- basically, you can't, because the kernel is not set up to deal with it. > Should the iwmmxt arch be disabled by default on GCC 4.5? At least it would > make it clear that this arch is untested/not supported. > I can't reproduce the problem on trunk with the testcase provided. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40836
