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| author | Patrick Palka <ppalka@redhat.com> | 2023-03-16 14:47:43 -0400 |
|---|---|---|
| committer | Patrick Palka <ppalka@redhat.com> | 2023-03-16 14:47:43 -0400 |
| commit | 31cdfdef04701e10cffcec4578b2337684f0e4bc (patch) | |
| tree | 81e471cb3f4b83772bfb63559f433e5908f3049e | |
| parent | c630157fd01140dbce120c1409c413a97dc17104 (diff) | |
| download | gcc-31cdfdef04701e10cffcec4578b2337684f0e4bc.zip gcc-31cdfdef04701e10cffcec4578b2337684f0e4bc.tar.gz gcc-31cdfdef04701e10cffcec4578b2337684f0e4bc.tar.bz2 | |
c++: maybe_constant_init and unevaluated operands [PR109030]
This testcase in this PR (already fixed by r13-6526-ge4692319fd5fc7)
demonstrates that maybe_constant_init can be called on an unevaluated
operand (e.g. from massage_init_elt) so this entry point should also
limit constant evaluation in that case, like maybe_constant_value does.
PR c++/109030
gcc/cp/ChangeLog:
* constexpr.cc (maybe_constant_init_1): For an unevaluated
non-manifestly-constant operand, don't constant evaluate
and instead call fold_to_constant as in maybe_constant_value.
gcc/testsuite/ChangeLog:
* g++.dg/cpp2a/constexpr-inst2.C: New test.
| -rw-r--r-- | gcc/cp/constexpr.cc | 4 | ||||
| -rw-r--r-- | gcc/testsuite/g++.dg/cpp2a/constexpr-inst2.C | 12 |
2 files changed, 16 insertions, 0 deletions
diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc index abf6ee5..3de60cf 100644 --- a/gcc/cp/constexpr.cc +++ b/gcc/cp/constexpr.cc @@ -8796,6 +8796,10 @@ maybe_constant_init_1 (tree t, tree decl, bool allow_non_constant, && (TREE_STATIC (decl) || DECL_EXTERNAL (decl))); if (is_static) manifestly_const_eval = true; + + if (cp_unevaluated_operand && !manifestly_const_eval) + return fold_to_constant (t); + t = cxx_eval_outermost_constant_expr (t, allow_non_constant, !is_static, mce_value (manifestly_const_eval), false, decl); diff --git a/gcc/testsuite/g++.dg/cpp2a/constexpr-inst2.C b/gcc/testsuite/g++.dg/cpp2a/constexpr-inst2.C new file mode 100644 index 0000000..7676b62 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/constexpr-inst2.C @@ -0,0 +1,12 @@ +// { dg-do compile { target c++11 } } + +struct __as_receiver { + int empty_env; +}; + +template<class T> +constexpr int f(T t) { + return t.fail; +}; + +using type = decltype(__as_receiver{f(0)}); // OK, f<int> not instantiated |