[Bug tree-optimization/78869] [6/7/8 Regression] Strange __builtin_memcpy optimisations

[jamborm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78869
Bug 78869 depends on bug 80293, which changed state.

Bug 80293 Summary: [6/7 Regression] unnecessary code at -O2 (-O1 is fine)
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80293

           What    |Removed                     |Added
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             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED