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| author | Jakub Jelinek <jakub@redhat.com> | 2021-03-12 10:11:24 +0100 |
|---|---|---|
| committer | Jakub Jelinek <jakub@redhat.com> | 2021-03-12 10:11:24 +0100 |
| commit | 425afe1f0c907e6469cef1672160c9c95177e71a (patch) | |
| tree | a35dd0c983e635b77a6b1b09ddfac3ecb1eac044 /gcc | |
| parent | 0df3eb2622d80aed22b2c3814d51e1f455d5e5a1 (diff) | |
| download | gcc-425afe1f0c907e6469cef1672160c9c95177e71a.zip gcc-425afe1f0c907e6469cef1672160c9c95177e71a.tar.gz gcc-425afe1f0c907e6469cef1672160c9c95177e71a.tar.bz2 | |
c++: Fix up calls to immediate functions returning reference [PR99507]
build_cxx_call calls convert_from_reference at the end, so if an immediate
function returns a reference, we were constant evaluating not just that
call, but that call wrapped in an INDIRECT_REF. That unfortunately means
it can constant evaluate to something non-addressable, so if code later
needs to take its address it will fail.
The following patch fixes that by undoing the convert_from_reference
wrapping for the cxx_constant_value evaluation and readdding it ad the end.
2021-03-12 Jakub Jelinek <jakub@redhat.com>
PR c++/99507
* call.c (build_over_call): For immediate evaluation of functions
that return references, undo convert_from_reference effects before
calling cxx_constant_value and call convert_from_reference
afterwards.
* g++.dg/cpp2a/consteval19.C: New test.
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/cp/call.c | 4 | ||||
| -rw-r--r-- | gcc/testsuite/g++.dg/cpp2a/consteval19.C | 6 |
2 files changed, 10 insertions, 0 deletions
diff --git a/gcc/cp/call.c b/gcc/cp/call.c index 7d12fea..33278b5 100644 --- a/gcc/cp/call.c +++ b/gcc/cp/call.c @@ -9504,6 +9504,9 @@ build_over_call (struct z_candidate *cand, int flags, tsubst_flags_t complain) if (immediate_invocation_p (fndecl, nargs)) { tree obj_arg = NULL_TREE; + /* Undo convert_from_reference called by build_cxx_call. */ + if (REFERENCE_REF_P (call)) + call = TREE_OPERAND (call, 0); if (DECL_CONSTRUCTOR_P (fndecl)) obj_arg = cand->first_arg ? cand->first_arg : (*args)[0]; if (obj_arg && is_dummy_object (obj_arg)) @@ -9527,6 +9530,7 @@ build_over_call (struct z_candidate *cand, int flags, tsubst_flags_t complain) call = cxx_constant_value (call, obj_arg); if (obj_arg && !error_operand_p (call)) call = build2 (INIT_EXPR, void_type_node, obj_arg, call); + call = convert_from_reference (call); } } return call; diff --git a/gcc/testsuite/g++.dg/cpp2a/consteval19.C b/gcc/testsuite/g++.dg/cpp2a/consteval19.C new file mode 100644 index 0000000..d742f59 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/consteval19.C @@ -0,0 +1,6 @@ +// PR c++/99507 +// { dg-do compile { target c++20 } } + +constexpr int i{0}; +consteval const int &iref () { return i; } +const int *a{&iref ()}; |