https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56049
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |missed-optimization
Target Milestone|7.0 |8.0
--- Comment #20 from Richard Biener <rguenth at gcc dot gnu.org> ---
Agreed. I've briefly looked into LIM and it's not easy to teach it this. LIM
uses its own "value numbering" and dependence analysis (ugh, well - it's
supposed
to be "cheaper" ...). The VN used for store-motion (store and load memory
location have to be detected as equal) is using operand_equal/hash_tree which
is too simplistic here.
There is the general issue of LIM dependence analysis that it doesn't handle
dependence distance <= 0 for read-write and > 0 for write-read dependences
more optimistically.
