diff options
| author | Patrick Palka <ppalka@redhat.com> | 2022-09-16 11:10:43 -0400 |
|---|---|---|
| committer | Patrick Palka <ppalka@redhat.com> | 2022-09-16 11:10:43 -0400 |
| commit | 7107ea6fb933f1e928593c7e92edfd64ccf0df63 (patch) | |
| tree | 44af7a855317b9a75d2fd9d6aaf7436c1f88ea31 /gcc/cp/constexpr.cc | |
| parent | b6adc6255f527edd50c08c4aacb4ee21df1c349c (diff) | |
| download | gcc-7107ea6fb933f1e928593c7e92edfd64ccf0df63.zip gcc-7107ea6fb933f1e928593c7e92edfd64ccf0df63.tar.gz gcc-7107ea6fb933f1e928593c7e92edfd64ccf0df63.tar.bz2 | |
c++: 'mutable' member within constexpr [PR92505]
This patch permits accessing 'mutable' members of local objects during
constexpr evaluation, while continuing to reject it for global objects
(as in the last line of cpp0x/constexpr-mutable1.C). To distinguish
between the two cases, it looks like it suffices to just check
CONSTRUCTOR_MUTABLE_POSION in cxx_eval_component_reference before
deciding to reject a DECL_MUTABLE_P member access.
PR c++/92505
gcc/cp/ChangeLog:
* constexpr.cc (cxx_eval_component_reference): Check non_constant_p
sooner. In C++14 or later, reject a DECL_MUTABLE_P member access
only if CONSTRUCTOR_MUTABLE_POISION is also set.
gcc/testsuite/ChangeLog:
* g++.dg/cpp0x/constexpr-mutable3.C: New test.
* g++.dg/cpp1y/constexpr-mutable1.C: New test.
Diffstat (limited to 'gcc/cp/constexpr.cc')
| -rw-r--r-- | gcc/cp/constexpr.cc | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc index 57283ea..1063987 100644 --- a/gcc/cp/constexpr.cc +++ b/gcc/cp/constexpr.cc @@ -4088,6 +4088,8 @@ cxx_eval_component_reference (const constexpr_ctx *ctx, tree t, tree whole = cxx_eval_constant_expression (ctx, orig_whole, lval, non_constant_p, overflow_p); + if (*non_constant_p) + return t; if (INDIRECT_REF_P (whole) && integer_zerop (TREE_OPERAND (whole, 0))) { @@ -4108,20 +4110,21 @@ cxx_eval_component_reference (const constexpr_ctx *ctx, tree t, whole, part, NULL_TREE); /* Don't VERIFY_CONSTANT here; we only want to check that we got a CONSTRUCTOR. */ - if (!*non_constant_p && TREE_CODE (whole) != CONSTRUCTOR) + if (TREE_CODE (whole) != CONSTRUCTOR) { if (!ctx->quiet) error ("%qE is not a constant expression", orig_whole); *non_constant_p = true; + return t; } - if (DECL_MUTABLE_P (part)) + if ((cxx_dialect < cxx14 || CONSTRUCTOR_MUTABLE_POISON (whole)) + && DECL_MUTABLE_P (part)) { if (!ctx->quiet) error ("mutable %qD is not usable in a constant expression", part); *non_constant_p = true; + return t; } - if (*non_constant_p) - return t; bool pmf = TYPE_PTRMEMFUNC_P (TREE_TYPE (whole)); FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (whole), i, field, value) { |