[Bug tree-optimization/78348] [7 REGRESSION] 15% performance drop for coremark-pro/nnet-test after r242038

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78348

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |rguenth at gcc dot gnu.org
   Target Milestone|---                         |7.0

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
Note that -O3 enables -floop-distribute-patterns which detects open-coded
memcpy/memmove/memset.  The idea is that canonicalizing leads to optimal
inline expansion or library code.

I'm not sure I would count this as two vs. three memory streams as usually
improving things on the store side helps (this is how the current heuristic
works).  CPUs are usually more store-bandwith limited.  But yes, some
sort of target specific parameter might help here (number of store streams
we can handle).