https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92130
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2019-10-17
CC| |rguenth at gcc dot gnu.org
Blocks| |53947
Ever confirmed|0 |1
--- Comment #8 from Richard Biener <rguenth at gcc dot gnu.org> ---
You can try -fno-tree-pre because for the original issue you mention the issue
is that PRE figures the first iteration computed values at compile-time which
then effectively rotates the loop which the vectorizer is not happy with.
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53947
[Bug 53947] [meta-bug] vectorizer missed-optimizations
