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:
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
