Bug#512050: gcc-4.3: pessimizes function without SSE intrinsics

[Martin Michlmayr <tbm@cyrius.com>]

Brian,

Upstream closed this bug report as invalid:

"That is because the early complete unrolling comes and unrolls the
loop so the autovectorizer does not have a loop to work on anymore.
If I increase it to be 16 instead of 4, the loop is vectorizer.

So the original testcase is invalid as two things: aliasing and
alignment.  Aliasing because out could overlap with in1/in2, restrict
fixes that.  And then the alignment comes into play because there is
no way to say the incoming arguments are 16 byte aligned."

"t.c:11: note: cost model: Adding cost of checks for loop versioning
to treat misalignment.

t.c:11: note: cost model: Adding cost of checks for loop versioning
aliasing."

-- 
Martin Michlmayr
http://www.cyrius.com/