[Bug tree-optimization/49768] [4.6/4.7 Regression] C99 style union initializations does not work as expected with optimizations

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49768

--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-07-18 
12:47:36 UTC ---
Created attachment 24787
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=24787
gcc47-pr49768.patch

The easier fix attached.  The more complicated would probably mean if we see
possible overlaps keeping recurding on all overlapping feelds and if the result
from them is INTEGER_CST, shift, mask and or them together.