On 07/31/2015 05:17 AM, Yuri Rumyantsev wrote:
Hi Richard,
I learned your updated patch for 23825 and it is more general in
comparison with my.
I'd like to propose you a compromise - let's consider my patch only
for force-vectorize outer loop only to allow outer-loop
vecctorization. Note that your approach will not hoist invariant
guards if loops contains something else except for inner-loop, i.e. it
won't be empty for taken branch.
I also would like to answer on your last question - CFG cleanup is
invoked to perform deletion of single-argument phi nodes from tail
block through substitution - such phi's prevent outer-loop
vectorization. But it is clear that such transformation can be done
other pass.
A single-argument PHI is a degenerate. phi-only-cprop might be your
friend :-)
jeff
