[Bug tree-optimization/84969] [8 Regression] Wrong code with -ftree-loop-distribute-patterns

[amker at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84969

--- Comment #2 from amker at gcc dot gnu.org ---
I see, there are two issues here.
 - wrong code issue: fuse_memset_builtins breaks dependence between two
intersect memset call;
 - efficiency issue: The loop should not be distributed into two memset calls
by some model.

I will fix the first one now and check if the second should be fixed at this
point or not.