[Bug c/48685] [4.5/4.6/4.7 regression] ICE in gimplify_expr, at gimplify.c:7034

[joseph at codesourcery dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48685

--- Comment #4 from joseph at codesourcery dot com <joseph at codesourcery dot com> 2011-04-21 15:36:26 UTC ---
The C front end should not depend on fold creating NON_LVALUE_EXPRs 
anywhere, but I don't know if C++ has such dependencies.  Where does the 
NON_LVALUE_EXPR come from?  In any case, I don't think NON_LVALUE_EXPR 
should be used for type conversions; a NON_LVALUE_EXPR with void type 
should only ever be used if the contained expression has void type (with 
the same qualifiers), and under those conditions STRIP_TYPE_NOPS should 
remove it.

c_fully_fold_internal needs to preserve the type of the expression, so 
can't just remove a NON_LVALUE_EXPR that changes the type without adding 
some other conversion to the new type - but as noted above, if a 
NON_LVALUE_EXPR is changing the type I think the creation of that 
NON_LVALUE_EXPR is what's wrong.