On Wed, 11 Jan 2017, Jakub Jelinek wrote:
> On Wed, Jan 11, 2017 at 09:31:38AM +0100, Richard Biener wrote:
> > > Or shall I add the function local address check into maybe_nonzero_address
> > > instead (return 1 for those)?
> >
> > Yes please, and cleanup the other user of maybe_nonzero_address then
> > (which contains the code you added).
>
> Ok, I'll bootstrap/regtest following patch then:
LGTM.
Richard.
> 2017-01-11 Jakub Jelinek <ja...@redhat.com>
>
> PR c++/71537
> * fold-const.c (maybe_nonzero_address): Return 1 for function
> local objects.
> (tree_single_nonzero_warnv_p): Don't handle function local objects
> here.
>
> * g++.dg/cpp1y/constexpr-71537.C: New test.
>
> --- gcc/fold-const.c.jj 2017-01-11 09:36:36.673864630 +0100
> +++ gcc/fold-const.c 2017-01-11 09:44:20.004660940 +0100
> @@ -8171,7 +8171,8 @@ pointer_may_wrap_p (tree base, tree offs
> /* Return a positive integer when the symbol DECL is known to have
> a nonzero address, zero when it's known not to (e.g., it's a weak
> symbol), and a negative integer when the symbol is not yet in the
> - symbol table and so whether or not its address is zero is unknown. */
> + symbol table and so whether or not its address is zero is unknown.
> + For function local objects always return positive integer. */
> static int
> maybe_nonzero_address (tree decl)
> {
> @@ -8179,6 +8180,13 @@ maybe_nonzero_address (tree decl)
> if (struct symtab_node *symbol = symtab_node::get_create (decl))
> return symbol->nonzero_address ();
>
> + /* Function local objects are never NULL. */
> + if (DECL_P (decl)
> + && (DECL_CONTEXT (decl)
> + && TREE_CODE (DECL_CONTEXT (decl)) == FUNCTION_DECL
> + && auto_var_in_fn_p (decl, DECL_CONTEXT (decl))))
> + return 1;
> +
> return -1;
> }
>
> @@ -13276,13 +13284,6 @@ tree_single_nonzero_warnv_p (tree t, boo
> if (nonzero_addr >= 0)
> return nonzero_addr;
>
> - /* Function local objects are never NULL. */
> - if (DECL_P (base)
> - && (DECL_CONTEXT (base)
> - && TREE_CODE (DECL_CONTEXT (base)) == FUNCTION_DECL
> - && auto_var_in_fn_p (base, DECL_CONTEXT (base))))
> - return true;
> -
> /* Constants are never weak. */
> if (CONSTANT_CLASS_P (base))
> return true;
> --- gcc/testsuite/g++.dg/cpp1y/constexpr-71537.C.jj 2017-01-11
> 09:41:32.103909019 +0100
> +++ gcc/testsuite/g++.dg/cpp1y/constexpr-71537.C 2017-01-11
> 09:41:32.103909019 +0100
> @@ -0,0 +1,14 @@
> +// PR c++/71537
> +// { dg-do compile { target c++14 } }
> +
> +constexpr bool
> +foo ()
> +{
> + constexpr int n[42] = { 1 };
> + constexpr int o = n ? 1 : 0;
> + constexpr int p = n + 1 ? 1 : 0;
> + constexpr int q = "abc" + 1 ? 1 : 0;
> + return p + p + q == 3;
> +}
> +
> +static_assert (foo (), "");
>
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB
21284 (AG Nuernberg)
