[Bug tree-optimization/84859] [8 Regression] bogus -Warray-bounds on a memcpy in a loop

rguenth at gcc dot gnu.org gcc-bugzilla@gcc.gnu.org
Thu Mar 15 15:19:00 GMT 2018


https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84859

--- Comment #9 from Richard Biener <rguenth at gcc dot gnu.org> ---
Like moving over a const call after the stores might cause us to spill across
the call.  Moving over any stmt could enlarge lifetimes enough to do that. 
Register
lifetime could be so that we cannot coalesce the copies in the PHI (but that
probably is offset by removing one of the stores -- but maybe the fast path
is slowed down then).

value_replacement has /* Allow up to 2 cheap preparation statements that
prepare argument ... */ for example.  But I guess preparation stmts are never
of a concern?


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