Hi Jakub,
I looked through your patch that looks good enough although it likely
must be improved to get better vectorization for AVX-2. One general
issue is that you introduced a new pass to undo if-conversion leading
to one restriction on if-conversion that prohibited to chain the
conditions:
/* Avoid creating mask loads/stores if we'd need to chain
conditions, to make it easier to undo them. */
I assume that you can do it without undo but simply creating a copy of
handled loop and restoring/deletion it in case of fail or success
(such approach is used by many compilers for software-pipelining loops
aka modulo scheduling). Is it difficult to implement in gcc framework
or you simply missed it. Also the current implementation is base on
if-conversion although predication is more preferable for it and can
allow us to vectorize more loop patterns. What is your opinion?
Best regards.
Yuri.
