[Bug target/54589] struct offset add should be folded into address calculation

[sgunderson at bigfoot dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54589

--- Comment #2 from sgunderson at bigfoot dot com 2012-09-17 09:18:16 UTC ---
FWIW, in my original code, func() is a part of a loop body (it keeps reading
values from src in a loop). It doesn't really change anything in the generated
code, though.