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| author | Iain Sandoe <iain@sandoe.co.uk> | 2021-10-02 17:20:08 +0100 |
|---|---|---|
| committer | Iain Sandoe <iain@sandoe.co.uk> | 2021-12-17 16:57:47 +0000 |
| commit | 2466a8d0dd40d05cb4a239d7d4a21bbd9ffab698 (patch) | |
| tree | 52c549a73230b5b77b3da4bd2ba296f85af36860 /gcc/cp | |
| parent | 921942a8a106cb53994c21162922e4934eb3a3e0 (diff) | |
| download | gcc-2466a8d0dd40d05cb4a239d7d4a21bbd9ffab698.zip gcc-2466a8d0dd40d05cb4a239d7d4a21bbd9ffab698.tar.gz gcc-2466a8d0dd40d05cb4a239d7d4a21bbd9ffab698.tar.bz2 | |
coroutines: Handle initial awaiters with non-void returns [PR 100127].
The way in which a C++20 coroutine is specified discards any value
that might be returned from the initial or final await expressions.
This ICE was caused by an initial await expression with an
await_resume () returning a reference, the function rewrite code
was not set up to expect this.
Fixed by looking through any indirection present and by explicitly
discarding the value, if any, returned by await_resume().
It does not seem useful to make a diagnostic for this, since
the user could define a generic awaiter that usefully returns
values when used in a different position from the initial (or
final) await expressions.
Signed-off-by: Iain Sandoe <iain@sandoe.co.uk>
PR c++/100127
gcc/cp/ChangeLog:
* coroutines.cc (coro_rewrite_function_body): Handle initial
await expressions that try to produce a reference value.
gcc/testsuite/ChangeLog:
* g++.dg/coroutines/pr100127.C: New test.
Diffstat (limited to 'gcc/cp')
| -rw-r--r-- | gcc/cp/coroutines.cc | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/gcc/cp/coroutines.cc b/gcc/cp/coroutines.cc index bcc9173..25931c9 100644 --- a/gcc/cp/coroutines.cc +++ b/gcc/cp/coroutines.cc @@ -4211,9 +4211,15 @@ coro_rewrite_function_body (location_t fn_start, tree fnbody, tree orig, { /* Build a compound expression that sets the initial-await-resume-called variable true and then calls the - initial suspend expression await resume. */ + initial suspend expression await resume. + In the case that the user decides to make the initial await + await_resume() return a value, we need to discard it and, it is + a reference type, look past the indirection. */ + if (INDIRECT_REF_P (initial_await)) + initial_await = TREE_OPERAND (initial_await, 0); tree vec = TREE_OPERAND (initial_await, 3); tree aw_r = TREE_VEC_ELT (vec, 2); + aw_r = convert_to_void (aw_r, ICV_STATEMENT, tf_warning_or_error); tree update = build2 (MODIFY_EXPR, boolean_type_node, i_a_r_c, boolean_true_node); aw_r = cp_build_compound_expr (update, aw_r, tf_warning_or_error); |