[Bug target/48743] -march=native mis-detects AMD K6-2+ / K6-3 as Athlon - compiled C fails with "illegal instruction"

[zuxy.meng at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48743

--- Comment #3 from Zuxy <zuxy.meng at gmail dot com> 2011-05-12 08:27:56 UTC ---
Created attachment 24233
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=24233
Proposed patch

For a brief time AMD produced K6-2+ and K6-3+ processors, targeting mobile
market. These processors support Extended 3DNow! but not CMOV or Extended MMX
(a subset of SSE) and are detected as Athlon by GCC so GCC will generate CMOV
for them, leading to #UD.

The patch solves the problem by differentiating K6 and Athlon by Extended MMX
rather than Extended 3DNow!.