> On 28 Apr 2022, at 20:26, Jakub Jelinek <ja...@redhat.com> wrote:
>
> On Thu, Apr 28, 2022 at 08:17:04PM +0100, Iain Sandoe wrote:
>> Signed-off-by: Iain Sandoe <i...@sandoe.co.uk>
>>
>> PR c++/105426
>>
>> gcc/cp/ChangeLog:
>>
>> * coroutines.cc (register_local_var_uses): Allow promotion of unnamed
>> temporaries to coroutine frame copies.
>> ---
>> gcc/cp/coroutines.cc | 3 +++
>> 1 file changed, 3 insertions(+)
>>
>> diff --git a/gcc/cp/coroutines.cc b/gcc/cp/coroutines.cc
>> index 551ddc9cc41..2e393b2cddc 100644
>> --- a/gcc/cp/coroutines.cc
>> +++ b/gcc/cp/coroutines.cc
>> @@ -3973,6 +3973,9 @@ register_local_var_uses (tree *stmt, int *do_subtree,
>> void *d)
>> else if (lvname != NULL_TREE)
>> buf = xasprintf ("%s_%u_%u", IDENTIFIER_POINTER (lvname),
>> lvd->nest_depth, lvd->bind_indx);
>> + else
>> + buf = xasprintf ("_D%u_%u_%u", DECL_UID (lvar), lvd->nest_depth,
>> + lvd->bind_indx);
>> /* TODO: Figure out if we should build a local type that has any
>> excess alignment or size from the original decl. */
>> if (buf)
>
> This isn't going to play well with -fcompare-debug.
> We don't guarantee same DECL_UID values between -g and -g0, just that
> when two decls are created with both -g and -g0 they compare the same,
> but with -g the gap in between them could be larger.
> So names that include DECL_UID will be often different between -g and -g0.
that’s somewhat unfortunate (having the UIDs in the frame and the gimple is
quite
helpful to debugging). I guess I was not expecting a difference this early in
the FE
(we are before initial folding / constexpr stuff).
FWIW, I ran the coroutines and coroutines torture testsuites with
-fcompare-debug.
There are 5 fails, and those are unaffected by whether the field is made
nameless as
suggested below (so something else to investigate).
> Can't the FIELD_DECL be instead nameless? Say change coro_make_frame_entry
> to do
> tree id = name ? get_identifier (name) : NULL_TREE;
> instead of
> tree id = get_identifier (name);
Unfortunately, that does not work - although I cannot see anything in the
coroutines code
that would cause it to fail - perhaps something is not playing nicely with
DECL_VALUE_EXPRs on unnamed temps?
how about the following, which uniques the names by bind scope, scope nest and
then
sequence within that?
Iain
diff --git a/gcc/cp/coroutines.cc b/gcc/cp/coroutines.cc
index 2e393b2cddc..1d886b31c77 100644
--- a/gcc/cp/coroutines.cc
+++ b/gcc/cp/coroutines.cc
@@ -3913,6 +3913,7 @@ register_local_var_uses (tree *stmt, int *do_subtree,
void *d)
if (TREE_CODE (*stmt) == BIND_EXPR)
{
tree lvar;
+ unsigned serial = 0;
for (lvar = BIND_EXPR_VARS (*stmt); lvar != NULL;
lvar = DECL_CHAIN (lvar))
{
@@ -3974,16 +3975,14 @@ register_local_var_uses (tree *stmt, int *do_subtree,
void *d)
buf = xasprintf ("%s_%u_%u", IDENTIFIER_POINTER (lvname),
lvd->nest_depth, lvd->bind_indx);
else
- buf = xasprintf ("_D%u_%u_%u", DECL_UID (lvar), lvd->nest_depth,
- lvd->bind_indx);
+ buf = xasprintf ("_D%u_%u_%u", lvd->nest_depth, lvd->bind_indx,
+ serial++);
+
/* TODO: Figure out if we should build a local type that has any
excess alignment or size from the original decl. */
- if (buf)
- {
- local_var.field_id = coro_make_frame_entry (lvd->field_list, buf,
- lvtype, lvd->loc);
- free (buf);
- }
+ local_var.field_id = coro_make_frame_entry (lvd->field_list, buf,
+ lvtype, lvd->loc);
+ free (buf);
/* We don't walk any of the local var sub-trees, they won't contain
any bind exprs. */
}
