------- Comment #4 from ubizjak at gmail dot com 2010-02-26 14:24 ------- (In reply to comment #3)
MMX arguments are passed via %mm registers when __builtin_apply_args is used. Touching %mm in any way will switch FP regstack to MMX mode, and since no emms is emitted, reading %st will always return NaN. [There were proposals to obsolete __bultin_apply, so who cares.] Your patch from comment #1 is OK. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37074
