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| author | Patrick Palka <ppalka@redhat.com> | 2023-11-16 09:32:07 -0500 |
|---|---|---|
| committer | Patrick Palka <ppalka@redhat.com> | 2023-11-16 09:32:07 -0500 |
| commit | 0077c0fb19981c108a01cd15af9b2d6d478c183b (patch) | |
| tree | d6ed5753cd394efc25fe7fbdee712634f1066939 | |
| parent | 4547c271c455dcf54ce9c4bb820acdd3b6193f6d (diff) | |
| download | gcc-0077c0fb19981c108a01cd15af9b2d6d478c183b.zip gcc-0077c0fb19981c108a01cd15af9b2d6d478c183b.tar.gz gcc-0077c0fb19981c108a01cd15af9b2d6d478c183b.tar.bz2 | |
c++: constantness of call to function pointer [PR111703]
potential_constant_expression for CALL_EXPR tests FUNCTION_POINTER_TYPE_P
on the callee rather than on the type of the callee, which means we
always pass want_rval=any when recursing and so may fail to identify a
non-constant function pointer callee as such. Fixing this turns out to
further work around PR111703.
PR c++/111703
PR c++/107939
gcc/cp/ChangeLog:
* constexpr.cc (potential_constant_expression_1) <case CALL_EXPR>:
Fix FUNCTION_POINTER_TYPE_P test.
gcc/testsuite/ChangeLog:
* g++.dg/cpp2a/concepts-fn8.C: Extend test.
* g++.dg/diagnostic/constexpr4.C: New test.
| -rw-r--r-- | gcc/cp/constexpr.cc | 7 | ||||
| -rw-r--r-- | gcc/testsuite/g++.dg/cpp2a/concepts-fn8.C | 2 | ||||
| -rw-r--r-- | gcc/testsuite/g++.dg/diagnostic/constexpr4.C | 9 |
3 files changed, 17 insertions, 1 deletions
diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc index 8a6b210..344107d 100644 --- a/gcc/cp/constexpr.cc +++ b/gcc/cp/constexpr.cc @@ -9547,7 +9547,12 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, } else if (fun) { - if (RECUR (fun, FUNCTION_POINTER_TYPE_P (fun) ? rval : any)) + if (TREE_TYPE (fun) + && FUNCTION_POINTER_TYPE_P (TREE_TYPE (fun))) + want_rval = rval; + else + want_rval = any; + if (RECUR (fun, want_rval)) /* Might end up being a constant function pointer. But it could also be a function object with constexpr op(), so we pass 'any' so that the underlying VAR_DECL is deemed diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-fn8.C b/gcc/testsuite/g++.dg/cpp2a/concepts-fn8.C index 3f63a5b..c63d26c 100644 --- a/gcc/testsuite/g++.dg/cpp2a/concepts-fn8.C +++ b/gcc/testsuite/g++.dg/cpp2a/concepts-fn8.C @@ -15,10 +15,12 @@ struct P { }; void (*f)(P); +P (*h)(P); template<class T> constexpr bool g() { P x; f(x); // { dg-bogus "from here" } + f(h(x)); // { dg-bogus "from here" } return true; } diff --git a/gcc/testsuite/g++.dg/diagnostic/constexpr4.C b/gcc/testsuite/g++.dg/diagnostic/constexpr4.C new file mode 100644 index 0000000..f37c01c --- /dev/null +++ b/gcc/testsuite/g++.dg/diagnostic/constexpr4.C @@ -0,0 +1,9 @@ +// Verify we diagnose a call to a non-constant function pointer ahead of time. +// { dg-do compile { target c++11 } } + +bool (*f)(int); + +template<int N> +void g() { + static_assert(f(N), ""); // { dg-error "non-constant|'f' is not usable" } +} |