[Bug rtl-optimization/44194] struct returned by value generates useless stores

["jakub at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #2 from jakub at gcc dot gnu dot org  2010-05-19 10:13 -------
RTL DSE doesn't handle this because the call to bar, which isn't a const
function, is considered a wild read and thus makes all stores necessary in the
global as well as local algorithm.
RTL DSE doesn't consider whether a frame based address could have possibly
address taken or not and whether a call thus might read it or not.

For tail calls before reload, perhaps we could handle tail calls similarly to
const calls (be a read of all argument stores) with the addition that it would
act as a read for all constant address stores (basically wild read for anything
but frame based stores for the global algorithm, given that the stack is
unwound before the tail call).


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44194