[Bug c++/28642] ICE in layout_type, at stor-layout.c:1851

[apl at alum dot mit dot edu]

------- Comment #2 from apl at alum dot mit dot edu  2006-08-07 18:34 -------
Amending the "description"

    attribute ((may_alias)) in a union causes ICE.

I'm using the 7/15/2006 snapshot of 4.2

I realize that unions are implicitly 'aliased', but in fact this problem was
encountered while I was trying to debug a more complex situation.  I have a
template class that tries to deposit smaller addressable units into a larger
POD type.  The alias analysis code in gcc3.4 thru 4.2 optimizes this code in
ways that
produce "wrong results".  I've tried a number of workarounds, including use of
volatile asm instructions to deal with that without any success - and since I'm
in the realm of undefined behavior, I don't expect anything from GCC
developers.

But, regardless of the optimization issues, an ICE on what should be legal code
is something that needs fixing...


-- 

apl at alum dot mit dot edu changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to fail|                            |3.4.3 4.2.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28642