[Bug middle-end/28831] [4.6/4.7/4.8 Regression] Aggregate copy not elided when using a return value as a pass-by-value parameter

[chip at pobox dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28831

--- Comment #16 from Chip Salzenberg <chip at pobox dot com> 2012-08-06 00:57:13 UTC ---
Addendum: In cut down test cases where I only pass by value or only return by
value, but not both, I find no extra stores, which is good; but I still find a
lot of unnecessary frame allocation (either $24 or $40, depending), and tail
call is still missing.