https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62011
Travis Downs <travis.downs at gmail dot com> changed:
What |Removed |Added
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CC| |travis.downs at gmail dot com
--- Comment #15 from Travis Downs <travis.downs at gmail dot com> ---
For what it's worth and because Richard asked for it above, there is are Intel
erratum for this, at least as of Haswell, for example HSD146: "POPCNT
Instruction May Take Longer to Execute Than Expected".
It mentions only popcnt, and I found it for Haswell, Skylake (SKL029) and
Broadwell. The text is:
POPCNT Instruction May Take Longer to Execute Than Expected
Problem:
POPCNT instruction execution with a 32 or 64 bit operand may be delayed until
previous non-dependent instructions have executed.
Implication:
Software using the POPCNT instruction may experience lower performance than
expected.
Workaround:
None identified
