https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70873
H.J. Lu <hjl.tools at gmail dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2016-04-29
CC| |hjl.tools at gmail dot com
Ever confirmed|0 |1
--- Comment #3 from H.J. Lu <hjl.tools at gmail dot com> ---
(In reply to Bernd Schmidt from comment #2)
> Can you give me more information what exactly is causing the stall - which
> instructions are affected, and what needs to be done to avoid it?
xorpd %xmm6, %xmm6, %xmm6 <<< Clear %xmm6
vcvtss2sd (%esi,%eax,4), %xmm6, %xmm7
^^^^^^^ This cause SSE register stall.
It should generate
xorpd %xmm6, %xmm6, %xmm6
vcvtss2sd (%esi,%eax,4), %xmm6, %xmm6
