On Sun, 10 Feb 2019, Jan Hubicka wrote:
> > Hi,
> > this patch drops test for TYPE_NEEDS_CONSTRUCTING in tree.h and instead
> > sets TREE_READONLY to 0 for external vars of this type. For vars
> > declared locally we drop TREE_READONLY while expanding constructor.
> > Note that I have tried to drop TREE_READONLY always (not only for
> > DECL_EXTERNAL) and it breaks a testcase where constructor is constexpr.
> > So perhaps this is unnecesarily conservative for external vars having
> > constexpr cotr and perhaps it is better done by frontend.
> >
> > Curiously enough, this does not fix the actual testcase in PR88677.
> This turned out to be bug in my patch: I cleared the flag too late so
> free_lang_data caused very much same effect as the may_be_aliased flag.
> Here is updated patch, bootstrapped/regtested x86_64-linux. It also
> fixes the testcase though I am not quite sure how to add it to
> testsuite.
OK.
Richard.
> >
> > Bootstrapped/regtested x86_64-linux, makes sense?
> >
> PR lto/88777
> * cgraphunit.c (analyze_functions): Clear READONLY flag for external
> types that needs constructiong.
> * tree.h (may_be_aliased): Do not check TYPE_NEEDS_CONSTRUCTING.
> Index: cgraphunit.c
> ===================================================================
> --- cgraphunit.c (revision 268741)
> +++ cgraphunit.c (working copy)
> @@ -1226,6 +1226,15 @@ analyze_functions (bool first_time)
> && node != first_handled_var; node = next)
> {
> next = node->next;
> + /* For symbols declared locally we clear TREE_READONLY when emitting
> + the construtor (if one is needed). For external declarations we can
> + not safely assume that the type is readonly because we may be called
> + during its construction. */
> + if (TREE_CODE (node->decl) == VAR_DECL
> + && TYPE_P (TREE_TYPE (node->decl))
> + && TYPE_NEEDS_CONSTRUCTING (TREE_TYPE (node->decl))
> + && DECL_EXTERNAL (node->decl))
> + TREE_READONLY (node->decl) = 0;
> if (!node->aux && !node->referred_to_p ())
> {
> if (symtab->dump_file)
> Index: tree.h
> ===================================================================
> --- tree.h (revision 268741)
> +++ tree.h (working copy)
> @@ -5371,8 +5371,7 @@ may_be_aliased (const_tree var)
> || DECL_EXTERNAL (var)
> || TREE_ADDRESSABLE (var))
> && !((TREE_STATIC (var) || TREE_PUBLIC (var) || DECL_EXTERNAL (var))
> - && ((TREE_READONLY (var)
> - && !TYPE_NEEDS_CONSTRUCTING (TREE_TYPE (var)))
> + && (TREE_READONLY (var)
> || (TREE_CODE (var) == VAR_DECL
> && DECL_NONALIASED (var)))));
> }
>
>
--
Richard Biener <rguent...@suse.de>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB
21284 (AG Nuernberg)
