On 8/28/24 11:21 AM, Marek Polacek wrote:
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
OK for trunk/13/14.
-- >8 -- Here we crash on a cp_gimplify_expr/TARGET_EXPR assert: gcc_checking_assert (!TARGET_EXPR_ELIDING_P (*expr_p) || !TREE_ADDRESSABLE (TREE_TYPE (*expr_p))); We cannot elide the TARGET_EXPR because we're taking its address. It is set as eliding in massage_init_elt. I've tried to not set TARGET_EXPR_ELIDING_P when the context is not direct-initialization. That didn't work: even when it's not direct-initialization now, it can become one later, for instance, after split_nonconstant_init. One problem is that replace_placeholders_for_class_temp_r will replace placeholders in non-eliding TARGET_EXPRs with the slot, but if we then elide the TARGET_EXPR, we end up with a "stray" VAR_DECL and crash. (Only some TARGET_EXPRs are handled by replace_decl.) I thought I'd have to go back to <https://gcc.gnu.org/pipermail/gcc-patches/2024-May/651163.html> but then I realized that this problem occurrs only with ()-init but not {}-init. With {}-init, there is no problem, because we are clearing TARGET_EXPR_ELIDING_P in process_init_constructor_record: /* We can't actually elide the temporary when initializing a potentially-overlapping field from a function that returns by value. */ if (ce->index && TREE_CODE (next) == TARGET_EXPR && unsafe_copy_elision_p (ce->index, next)) TARGET_EXPR_ELIDING_P (next) = false; But that does not happen for ()-init because we have no ce->index. ()-init doesn't allow brace elision so we don't really reshape them. But I can just move the clearing a few lines down and then it handles both ()-init and {}-init. PR c++/116424 gcc/cp/ChangeLog: * typeck2.cc (process_init_constructor_record): Move the clearing of TARGET_EXPR_ELIDING_P down. gcc/testsuite/ChangeLog: * g++.dg/cpp2a/paren-init38.C: New test. --- gcc/cp/typeck2.cc | 14 +++++++------- gcc/testsuite/g++.dg/cpp2a/paren-init38.C | 20 ++++++++++++++++++++ 2 files changed, 27 insertions(+), 7 deletions(-) create mode 100644 gcc/testsuite/g++.dg/cpp2a/paren-init38.C diff --git a/gcc/cp/typeck2.cc b/gcc/cp/typeck2.cc index 30a6fbe95c9..a0c8f833ac1 100644 --- a/gcc/cp/typeck2.cc +++ b/gcc/cp/typeck2.cc @@ -1774,13 +1774,6 @@ process_init_constructor_record (tree type, tree init, int nested, int flags, { gcc_assert (ce->value); next = massage_init_elt (fldtype, next, nested, flags, complain); - /* We can't actually elide the temporary when initializing a - potentially-overlapping field from a function that returns by - value. */ - if (ce->index - && TREE_CODE (next) == TARGET_EXPR - && unsafe_copy_elision_p (ce->index, next)) - TARGET_EXPR_ELIDING_P (next) = false; ++idx; } } @@ -1873,6 +1866,13 @@ process_init_constructor_record (tree type, tree init, int nested, int flags, } }+ /* We can't actually elide the temporary when initializing a+ potentially-overlapping field from a function that returns by + value. */ + if (TREE_CODE (next) == TARGET_EXPR + && unsafe_copy_elision_p (field, next)) + TARGET_EXPR_ELIDING_P (next) = false; + if (is_empty_field (field) && !TREE_SIDE_EFFECTS (next)) /* Don't add trivial initialization of an empty base/field to the diff --git a/gcc/testsuite/g++.dg/cpp2a/paren-init38.C b/gcc/testsuite/g++.dg/cpp2a/paren-init38.C new file mode 100644 index 00000000000..58743e051da --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/paren-init38.C @@ -0,0 +1,20 @@ +// PR c++/116424 +// { dg-do compile { target c++20 } } + +struct dd { + char *ptr; + dd(); + dd(dd &&__str); +}; +struct v { + dd n{}; + int f = -1; + v operator|(const v &other) const; +}; +struct cc : v {}; +static const cc a; +static const cc b; +static const cc c1(a | b); +static const cc c2{a | b}; +static const cc c3 = cc(a | b); +static const cc c4 = cc{a | b}; base-commit: bdcd30e4711943cae70a1b47f8a63e96a94c02a0
