[Bug c++/20280] [4.0/4.1 regression] ICE in create_tmp_var, at gimplify.c:368
mark at codesourcery dot com
gcc-bugzilla@gcc.gnu.org
Fri Mar 4 01:37:00 GMT 2005
------- Additional Comments From mark at codesourcery dot com 2005-03-04 01:36 -------
Subject: Re: [PR c++/20280] hoist indirect_ref out of addressable cond_exprs
Alexandre Oliva wrote:
\
> I went ahead and verified that I didn't break bit-field lvalues in
> conditional expressions (my first attempt did), but I was surprised to
> find out that the calls to h() pass. I understand why they do (we
> create a temporary and bind to that), but I'm not sure this is correct
> behavior. Opinions?
> + // Hmm... I don't think these should be accepted. The conditional
> + // expressions are lvalues for sure, and 8.5.3/5 exempts lvalues
> + // that are bit-fields, but not lvalues that are conditional
> + // expressions involving bit-fields.
> + h (b ? x.i : x.j);
> + h (b ? x.i : x.k);
> + h (b ? x.j : x.k);
That's legal because "h" takes a "const &", which permits the compiler
to create a temporary. If it takes a non-const reference, you should
get an error.
And, I think these kinds of transformations (if necessary) should be
done in a langhook during gimplification, not at COND_EXPR-creation
time. We really want the C++ front-end's data structures to be an
accurate mirror of the input program for as long as possible.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20280
More information about the Gcc-bugs
mailing list