------- Additional Comments From aoliva at gcc dot gnu dot org 2005-03-11 19:29 ------- Subject: Re: [PR c++/20103] failure to gimplify constructors for addressable types
On Mar 11, 2005, Richard Henderson <[EMAIL PROTECTED]> wrote: > On Tue, Mar 08, 2005 at 05:42:57PM -0300, Alexandre Oliva wrote: >> The change to the gimplify.c is needed to avoid having >> gimple_add_tmp_var twice for the variable, once while expanding the >> declaration/initialization, once while expanding the clean-ups. > Can you say more about how this comes to be? It doesn't make > sense to me... Just a matter of misinterpreting observed behavior :-( Here's the correct sequence of events without the change: gimplify_compound_literal_expr calls gimple_add_tmp_var, and then gimplify_and_add for the statement list containing the decl of the temporary variable gimplify_and_add calls gimplify_stmt for the stmt list, that calls calls gimplify_expr, that calls gimplify_decl_expr, that calls gimple_add_tmp_var again. I should now try to figure out why it is that in C it doesn't get called twice, in but in C++ it does. I remember I tried to remove the first call from gimplify_compound_literal_expr, but that didn't work because the presence of the initializer would cause gimplify_decl_expr to build a modify_expr referencing the decl, and this fails if the decl isn't, erhm, bound yet. Perhaps I should move the call to gimple_add_tmp_var in gimplify_decl_expr before the init stmt; this even makes sense to me. Incidentally, we don't actually generate cleanups for these temps, unlike the target_expr case, so we fail to call dtors for them. Ugh. Fixing this will take some more work. Patch withdrawn for the time being. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20103
