| Message ID | 20230501195902.1915703-1-ppalka@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | [1/2] c++: potentiality of templated memfn call [PR109480] | expand |
On 5/1/23 15:59, Patrick Palka wrote: > Here we're incorrectly deeming the templated call a.g() inside b's > initializer as potentially constant, despite g being non-constexpr, > which leads to us wastefully instantiating the initializer ahead of time > and triggering a bug in access checking deferral (which will get fixed > in the subsequent patch). > > This patch fixes this by calling get_fns earlier during potentiality > checking so that we also handle the templated form of a member function > call (whose overall callee is a COMPONENT_REF) when checking if the called > function is constexpr etc. > > PR c++/109480 > > gcc/cp/ChangeLog: > > * constexpr.cc (potential_constant_expression_1) <case CALL_EXPR>: > Reorganize to call get_fns sooner. Remove dead store to 'fun'. > > gcc/testsuite/ChangeLog: > > * g++.dg/cpp0x/noexcept59.C: Make e() constexpr so that the > expected "without object" diagnostic isn't replaced by a > "call to non-constexpr function" diagnostic. > * g++.dg/template/non-dependent25.C: New test. > --- > gcc/cp/constexpr.cc | 16 ++++++++-------- > gcc/testsuite/g++.dg/cpp0x/noexcept59.C | 2 +- > gcc/testsuite/g++.dg/template/non-dependent25.C | 14 ++++++++++++++ > 3 files changed, 23 insertions(+), 9 deletions(-) > create mode 100644 gcc/testsuite/g++.dg/template/non-dependent25.C > > diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc > index d1097764b10..29d872d0a5e 100644 > --- a/gcc/cp/constexpr.cc > +++ b/gcc/cp/constexpr.cc > @@ -9132,6 +9132,10 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, > > if (fun && is_overloaded_fn (fun)) > { > + if (!RECUR (fun, true)) > + return false; > + fun = get_fns (fun); > + > if (TREE_CODE (fun) == FUNCTION_DECL) > { > if (builtin_valid_in_constant_expr_p (fun)) > @@ -9167,7 +9171,8 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, > expression the address will be folded away, so look > through it now. */ > if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fun) > - && !DECL_CONSTRUCTOR_P (fun)) > + && !DECL_CONSTRUCTOR_P (fun) > + && !processing_template_decl) I don't see any rationale for this hunk? > { > tree x = get_nth_callarg (t, 0); > if (is_this_parameter (x)) > @@ -9182,16 +9187,11 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, > i = 1; > } > } > - else > - { > - if (!RECUR (fun, true)) > - return false; > - fun = get_first_fn (fun); > - } > + > + fun = OVL_FIRST (fun); > /* Skip initial arguments to base constructors. */ > if (DECL_BASE_CONSTRUCTOR_P (fun)) > i = num_artificial_parms_for (fun); > - fun = DECL_ORIGIN (fun); > } > else if (fun) > { > diff --git a/gcc/testsuite/g++.dg/cpp0x/noexcept59.C b/gcc/testsuite/g++.dg/cpp0x/noexcept59.C > index c752601ba09..1dc826d3111 100644 > --- a/gcc/testsuite/g++.dg/cpp0x/noexcept59.C > +++ b/gcc/testsuite/g++.dg/cpp0x/noexcept59.C > @@ -3,7 +3,7 @@ > > template <class ...Ts> class A > { > - void e (); > + constexpr bool e () { return true; }; > bool f (int() noexcept(this->e())); // { dg-error "this" } > bool g (int() noexcept(e())); // { dg-error "without object" } > }; > diff --git a/gcc/testsuite/g++.dg/template/non-dependent25.C b/gcc/testsuite/g++.dg/template/non-dependent25.C > new file mode 100644 > index 00000000000..a2f9801e11f > --- /dev/null > +++ b/gcc/testsuite/g++.dg/template/non-dependent25.C > @@ -0,0 +1,14 @@ > +// PR c++/109480 > + > +template<class T> > +struct A { > + void f() { > + A<int> a; > + const bool b = a.g(); > + } > + > +private: > + bool g() const; > +}; > + > +template struct A<int>;
On Tue, 2 May 2023, Jason Merrill wrote: > On 5/1/23 15:59, Patrick Palka wrote: > > Here we're incorrectly deeming the templated call a.g() inside b's > > initializer as potentially constant, despite g being non-constexpr, > > which leads to us wastefully instantiating the initializer ahead of time > > and triggering a bug in access checking deferral (which will get fixed > > in the subsequent patch). > > > > This patch fixes this by calling get_fns earlier during potentiality > > checking so that we also handle the templated form of a member function > > call (whose overall callee is a COMPONENT_REF) when checking if the called > > function is constexpr etc. > > > > PR c++/109480 > > > > gcc/cp/ChangeLog: > > > > * constexpr.cc (potential_constant_expression_1) <case CALL_EXPR>: > > Reorganize to call get_fns sooner. Remove dead store to 'fun'. > > > > gcc/testsuite/ChangeLog: > > > > * g++.dg/cpp0x/noexcept59.C: Make e() constexpr so that the > > expected "without object" diagnostic isn't replaced by a > > "call to non-constexpr function" diagnostic. > > * g++.dg/template/non-dependent25.C: New test. > > --- > > gcc/cp/constexpr.cc | 16 ++++++++-------- > > gcc/testsuite/g++.dg/cpp0x/noexcept59.C | 2 +- > > gcc/testsuite/g++.dg/template/non-dependent25.C | 14 ++++++++++++++ > > 3 files changed, 23 insertions(+), 9 deletions(-) > > create mode 100644 gcc/testsuite/g++.dg/template/non-dependent25.C > > > > diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc > > index d1097764b10..29d872d0a5e 100644 > > --- a/gcc/cp/constexpr.cc > > +++ b/gcc/cp/constexpr.cc > > @@ -9132,6 +9132,10 @@ potential_constant_expression_1 (tree t, bool > > want_rval, bool strict, bool now, > > if (fun && is_overloaded_fn (fun)) > > { > > + if (!RECUR (fun, true)) > > + return false; > > + fun = get_fns (fun); > > + > > if (TREE_CODE (fun) == FUNCTION_DECL) > > { > > if (builtin_valid_in_constant_expr_p (fun)) > > @@ -9167,7 +9171,8 @@ potential_constant_expression_1 (tree t, bool > > want_rval, bool strict, bool now, > > expression the address will be folded away, so look > > through it now. */ > > if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fun) > > - && !DECL_CONSTRUCTOR_P (fun)) > > + && !DECL_CONSTRUCTOR_P (fun) > > + && !processing_template_decl) > > I don't see any rationale for this hunk? Now that we call get_fns earlier, we can reach this code path with a templated non-static memfn call, but the code that follows assumes non-templated form. I tried teaching it to handle the templated form too, but there's apparently two different templated forms for non-static memfn calls, one with a COMPONENT_REF callee and one with an ordinary BASELINK callee (without a implicit object argument). In the former the implict object argument is inside the COMPONENT_REF (and is a reference instead of a pointer), and in the latter we don't even have an implicit object argument to inspect. FWIW I think which form we use depends on whether we know if the called function is a member of the current instantiation, e.g struct A { void f(); }; template<class T> struct B; template<class T> struct C : B<T> { void g(); void h() { A::f(); // templated form has BASELINK callee, no object arg C::g(); // templated form has COMPONENT_REF callee } }; So it seemed best to punt on templated non-static memfn calls here for now and treat that as a separate enhancement. > > > { > > tree x = get_nth_callarg (t, 0); > > if (is_this_parameter (x)) > > @@ -9182,16 +9187,11 @@ potential_constant_expression_1 (tree t, bool > > want_rval, bool strict, bool now, > > i = 1; > > } > > } > > - else > > - { > > - if (!RECUR (fun, true)) > > - return false; > > - fun = get_first_fn (fun); > > - } > > + > > + fun = OVL_FIRST (fun); > > /* Skip initial arguments to base constructors. */ > > if (DECL_BASE_CONSTRUCTOR_P (fun)) > > i = num_artificial_parms_for (fun); > > - fun = DECL_ORIGIN (fun); > > } > > else if (fun) > > { > > diff --git a/gcc/testsuite/g++.dg/cpp0x/noexcept59.C > > b/gcc/testsuite/g++.dg/cpp0x/noexcept59.C > > index c752601ba09..1dc826d3111 100644 > > --- a/gcc/testsuite/g++.dg/cpp0x/noexcept59.C > > +++ b/gcc/testsuite/g++.dg/cpp0x/noexcept59.C > > @@ -3,7 +3,7 @@ > > template <class ...Ts> class A > > { > > - void e (); > > + constexpr bool e () { return true; }; > > bool f (int() noexcept(this->e())); // { dg-error "this" } > > bool g (int() noexcept(e())); // { dg-error "without object" } > > }; > > diff --git a/gcc/testsuite/g++.dg/template/non-dependent25.C > > b/gcc/testsuite/g++.dg/template/non-dependent25.C > > new file mode 100644 > > index 00000000000..a2f9801e11f > > --- /dev/null > > +++ b/gcc/testsuite/g++.dg/template/non-dependent25.C > > @@ -0,0 +1,14 @@ > > +// PR c++/109480 > > + > > +template<class T> > > +struct A { > > + void f() { > > + A<int> a; > > + const bool b = a.g(); > > + } > > + > > +private: > > + bool g() const; > > +}; > > + > > +template struct A<int>; > >
on Tue, 2 May 2023, Patrick Palka wrote: > On Tue, 2 May 2023, Jason Merrill wrote: > > > On 5/1/23 15:59, Patrick Palka wrote: > > > Here we're incorrectly deeming the templated call a.g() inside b's > > > initializer as potentially constant, despite g being non-constexpr, > > > which leads to us wastefully instantiating the initializer ahead of time > > > and triggering a bug in access checking deferral (which will get fixed > > > in the subsequent patch). > > > > > > This patch fixes this by calling get_fns earlier during potentiality > > > checking so that we also handle the templated form of a member function > > > call (whose overall callee is a COMPONENT_REF) when checking if the called > > > function is constexpr etc. > > > > > > PR c++/109480 > > > > > > gcc/cp/ChangeLog: > > > > > > * constexpr.cc (potential_constant_expression_1) <case CALL_EXPR>: > > > Reorganize to call get_fns sooner. Remove dead store to 'fun'. > > > > > > gcc/testsuite/ChangeLog: > > > > > > * g++.dg/cpp0x/noexcept59.C: Make e() constexpr so that the > > > expected "without object" diagnostic isn't replaced by a > > > "call to non-constexpr function" diagnostic. > > > * g++.dg/template/non-dependent25.C: New test. > > > --- > > > gcc/cp/constexpr.cc | 16 ++++++++-------- > > > gcc/testsuite/g++.dg/cpp0x/noexcept59.C | 2 +- > > > gcc/testsuite/g++.dg/template/non-dependent25.C | 14 ++++++++++++++ > > > 3 files changed, 23 insertions(+), 9 deletions(-) > > > create mode 100644 gcc/testsuite/g++.dg/template/non-dependent25.C > > > > > > diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc > > > index d1097764b10..29d872d0a5e 100644 > > > --- a/gcc/cp/constexpr.cc > > > +++ b/gcc/cp/constexpr.cc > > > @@ -9132,6 +9132,10 @@ potential_constant_expression_1 (tree t, bool > > > want_rval, bool strict, bool now, > > > if (fun && is_overloaded_fn (fun)) > > > { > > > + if (!RECUR (fun, true)) > > > + return false; > > > + fun = get_fns (fun); > > > + > > > if (TREE_CODE (fun) == FUNCTION_DECL) > > > { > > > if (builtin_valid_in_constant_expr_p (fun)) > > > @@ -9167,7 +9171,8 @@ potential_constant_expression_1 (tree t, bool > > > want_rval, bool strict, bool now, > > > expression the address will be folded away, so look > > > through it now. */ > > > if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fun) > > > - && !DECL_CONSTRUCTOR_P (fun)) > > > + && !DECL_CONSTRUCTOR_P (fun) > > > + && !processing_template_decl) > > > > I don't see any rationale for this hunk? > > Now that we call get_fns earlier, we can reach this code path with a > templated non-static memfn call, but the code that follows assumes > non-templated form. > > I tried teaching it to handle the templated form too, but there's > apparently two different templated forms for non-static memfn calls, > one with a COMPONENT_REF callee and one with an ordinary BASELINK > callee (without a implicit object argument). In the former the implict > object argument is inside the COMPONENT_REF (and is a reference instead > of a pointer), and in the latter we don't even have an implicit object > argument to inspect. > > FWIW I think which form we use depends on whether we know if the called > function is a member of the current instantiation, e.g > > struct A { void f(); }; > > template<class T> struct B; > > template<class T> > struct C : B<T> { > void g(); > > void h() { > A::f(); // templated form has BASELINK callee, no object arg > C::g(); // templated form has COMPONENT_REF callee > } > }; > > So it seemed best to punt on templated non-static memfn calls here for > now and treat that as a separate enhancement. And I'm not even sure if the code path in question is necessary at all anymore: disabling it outright doesn't cause any regressions in the testsuite. It seems effectively equivalent to the body of the loop over the args a few lines later: for (; i < nargs; ++i) { tree x = get_nth_callarg (t, i); /* In a template, reference arguments haven't been converted to REFERENCE_TYPE and we might not even know if the parameter is a reference, so accept lvalue constants too. */ bool rv = processing_template_decl ? any : rval; /* Don't require an immediately constant value, as constexpr substitution might not use the value of the argument. */ bool sub_now = false; if (!potential_constant_expression_1 (x, rv, strict, sub_now, fundef_p, flags, jump_target)) return false; } > > > > > > { > > > tree x = get_nth_callarg (t, 0); > > > if (is_this_parameter (x)) > > > @@ -9182,16 +9187,11 @@ potential_constant_expression_1 (tree t, bool > > > want_rval, bool strict, bool now, > > > i = 1; > > > } > > > } > > > - else > > > - { > > > - if (!RECUR (fun, true)) > > > - return false; > > > - fun = get_first_fn (fun); > > > - } > > > + > > > + fun = OVL_FIRST (fun); > > > /* Skip initial arguments to base constructors. */ > > > if (DECL_BASE_CONSTRUCTOR_P (fun)) > > > i = num_artificial_parms_for (fun); > > > - fun = DECL_ORIGIN (fun); > > > } > > > else if (fun) > > > { > > > diff --git a/gcc/testsuite/g++.dg/cpp0x/noexcept59.C > > > b/gcc/testsuite/g++.dg/cpp0x/noexcept59.C > > > index c752601ba09..1dc826d3111 100644 > > > --- a/gcc/testsuite/g++.dg/cpp0x/noexcept59.C > > > +++ b/gcc/testsuite/g++.dg/cpp0x/noexcept59.C > > > @@ -3,7 +3,7 @@ > > > template <class ...Ts> class A > > > { > > > - void e (); > > > + constexpr bool e () { return true; }; > > > bool f (int() noexcept(this->e())); // { dg-error "this" } > > > bool g (int() noexcept(e())); // { dg-error "without object" } > > > }; > > > diff --git a/gcc/testsuite/g++.dg/template/non-dependent25.C > > > b/gcc/testsuite/g++.dg/template/non-dependent25.C > > > new file mode 100644 > > > index 00000000000..a2f9801e11f > > > --- /dev/null > > > +++ b/gcc/testsuite/g++.dg/template/non-dependent25.C > > > @@ -0,0 +1,14 @@ > > > +// PR c++/109480 > > > + > > > +template<class T> > > > +struct A { > > > + void f() { > > > + A<int> a; > > > + const bool b = a.g(); > > > + } > > > + > > > +private: > > > + bool g() const; > > > +}; > > > + > > > +template struct A<int>; > > > > >
On 5/2/23 15:53, Patrick Palka wrote: > on Tue, 2 May 2023, Patrick Palka wrote: > >> On Tue, 2 May 2023, Jason Merrill wrote: >> >>> On 5/1/23 15:59, Patrick Palka wrote: >>>> Here we're incorrectly deeming the templated call a.g() inside b's >>>> initializer as potentially constant, despite g being non-constexpr, >>>> which leads to us wastefully instantiating the initializer ahead of time >>>> and triggering a bug in access checking deferral (which will get fixed >>>> in the subsequent patch). >>>> >>>> This patch fixes this by calling get_fns earlier during potentiality >>>> checking so that we also handle the templated form of a member function >>>> call (whose overall callee is a COMPONENT_REF) when checking if the called >>>> function is constexpr etc. >>>> >>>> PR c++/109480 >>>> >>>> gcc/cp/ChangeLog: >>>> >>>> * constexpr.cc (potential_constant_expression_1) <case CALL_EXPR>: >>>> Reorganize to call get_fns sooner. Remove dead store to 'fun'. >>>> >>>> gcc/testsuite/ChangeLog: >>>> >>>> * g++.dg/cpp0x/noexcept59.C: Make e() constexpr so that the >>>> expected "without object" diagnostic isn't replaced by a >>>> "call to non-constexpr function" diagnostic. >>>> * g++.dg/template/non-dependent25.C: New test. >>>> --- >>>> gcc/cp/constexpr.cc | 16 ++++++++-------- >>>> gcc/testsuite/g++.dg/cpp0x/noexcept59.C | 2 +- >>>> gcc/testsuite/g++.dg/template/non-dependent25.C | 14 ++++++++++++++ >>>> 3 files changed, 23 insertions(+), 9 deletions(-) >>>> create mode 100644 gcc/testsuite/g++.dg/template/non-dependent25.C >>>> >>>> diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc >>>> index d1097764b10..29d872d0a5e 100644 >>>> --- a/gcc/cp/constexpr.cc >>>> +++ b/gcc/cp/constexpr.cc >>>> @@ -9132,6 +9132,10 @@ potential_constant_expression_1 (tree t, bool >>>> want_rval, bool strict, bool now, >>>> if (fun && is_overloaded_fn (fun)) >>>> { >>>> + if (!RECUR (fun, true)) >>>> + return false; >>>> + fun = get_fns (fun); >>>> + >>>> if (TREE_CODE (fun) == FUNCTION_DECL) >>>> { >>>> if (builtin_valid_in_constant_expr_p (fun)) >>>> @@ -9167,7 +9171,8 @@ potential_constant_expression_1 (tree t, bool >>>> want_rval, bool strict, bool now, >>>> expression the address will be folded away, so look >>>> through it now. */ >>>> if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fun) >>>> - && !DECL_CONSTRUCTOR_P (fun)) >>>> + && !DECL_CONSTRUCTOR_P (fun) >>>> + && !processing_template_decl) >>> >>> I don't see any rationale for this hunk? >> >> Now that we call get_fns earlier, we can reach this code path with a >> templated non-static memfn call, but the code that follows assumes >> non-templated form. >> >> I tried teaching it to handle the templated form too, but there's >> apparently two different templated forms for non-static memfn calls, >> one with a COMPONENT_REF callee and one with an ordinary BASELINK >> callee (without a implicit object argument). In the former the implict >> object argument is inside the COMPONENT_REF (and is a reference instead >> of a pointer), and in the latter we don't even have an implicit object >> argument to inspect. >> >> FWIW I think which form we use depends on whether we know if the called >> function is a member of the current instantiation, e.g >> >> struct A { void f(); }; >> >> template<class T> struct B; >> >> template<class T> >> struct C : B<T> { >> void g(); >> >> void h() { >> A::f(); // templated form has BASELINK callee, no object arg >> C::g(); // templated form has COMPONENT_REF callee >> } >> }; >> >> So it seemed best to punt on templated non-static memfn calls here for >> now and treat that as a separate enhancement. > > And I'm not even sure if the code path in question is necessary at all > anymore: disabling it outright doesn't cause any regressions in the testsuite. > It seems effectively equivalent to the body of the loop over the args a few > lines later: If removing that hunk doesn't regress anything, let's do it. Probably that should have happened in r13-55-ge9d2adc17d0dbe > for (; i < nargs; ++i) > { > tree x = get_nth_callarg (t, i); > /* In a template, reference arguments haven't been converted to > REFERENCE_TYPE and we might not even know if the parameter > is a reference, so accept lvalue constants too. */ > bool rv = processing_template_decl ? any : rval; > /* Don't require an immediately constant value, as constexpr > substitution might not use the value of the argument. */ > bool sub_now = false; > if (!potential_constant_expression_1 (x, rv, strict, > sub_now, fundef_p, flags, > jump_target)) > return false; > } > >> >>> >>>> { >>>> tree x = get_nth_callarg (t, 0); >>>> if (is_this_parameter (x)) >>>> @@ -9182,16 +9187,11 @@ potential_constant_expression_1 (tree t, bool >>>> want_rval, bool strict, bool now, >>>> i = 1; >>>> } >>>> } >>>> - else >>>> - { >>>> - if (!RECUR (fun, true)) >>>> - return false; >>>> - fun = get_first_fn (fun); >>>> - } >>>> + >>>> + fun = OVL_FIRST (fun); >>>> /* Skip initial arguments to base constructors. */ >>>> if (DECL_BASE_CONSTRUCTOR_P (fun)) >>>> i = num_artificial_parms_for (fun); >>>> - fun = DECL_ORIGIN (fun); >>>> } >>>> else if (fun) >>>> { >>>> diff --git a/gcc/testsuite/g++.dg/cpp0x/noexcept59.C >>>> b/gcc/testsuite/g++.dg/cpp0x/noexcept59.C >>>> index c752601ba09..1dc826d3111 100644 >>>> --- a/gcc/testsuite/g++.dg/cpp0x/noexcept59.C >>>> +++ b/gcc/testsuite/g++.dg/cpp0x/noexcept59.C >>>> @@ -3,7 +3,7 @@ >>>> template <class ...Ts> class A >>>> { >>>> - void e (); >>>> + constexpr bool e () { return true; }; >>>> bool f (int() noexcept(this->e())); // { dg-error "this" } >>>> bool g (int() noexcept(e())); // { dg-error "without object" } >>>> }; >>>> diff --git a/gcc/testsuite/g++.dg/template/non-dependent25.C >>>> b/gcc/testsuite/g++.dg/template/non-dependent25.C >>>> new file mode 100644 >>>> index 00000000000..a2f9801e11f >>>> --- /dev/null >>>> +++ b/gcc/testsuite/g++.dg/template/non-dependent25.C >>>> @@ -0,0 +1,14 @@ >>>> +// PR c++/109480 >>>> + >>>> +template<class T> >>>> +struct A { >>>> + void f() { >>>> + A<int> a; >>>> + const bool b = a.g(); >>>> + } >>>> + >>>> +private: >>>> + bool g() const; >>>> +}; >>>> + >>>> +template struct A<int>; >>> >>> >> >
On Wed, 3 May 2023, Jason Merrill wrote: > On 5/2/23 15:53, Patrick Palka wrote: > > on Tue, 2 May 2023, Patrick Palka wrote: > > > > > On Tue, 2 May 2023, Jason Merrill wrote: > > > > > > > On 5/1/23 15:59, Patrick Palka wrote: > > > > > Here we're incorrectly deeming the templated call a.g() inside b's > > > > > initializer as potentially constant, despite g being non-constexpr, > > > > > which leads to us wastefully instantiating the initializer ahead of > > > > > time > > > > > and triggering a bug in access checking deferral (which will get fixed > > > > > in the subsequent patch). > > > > > > > > > > This patch fixes this by calling get_fns earlier during potentiality > > > > > checking so that we also handle the templated form of a member > > > > > function > > > > > call (whose overall callee is a COMPONENT_REF) when checking if the > > > > > called > > > > > function is constexpr etc. > > > > > > > > > > PR c++/109480 > > > > > > > > > > gcc/cp/ChangeLog: > > > > > > > > > > * constexpr.cc (potential_constant_expression_1) <case > > > > > CALL_EXPR>: > > > > > Reorganize to call get_fns sooner. Remove dead store to > > > > > 'fun'. > > > > > > > > > > gcc/testsuite/ChangeLog: > > > > > > > > > > * g++.dg/cpp0x/noexcept59.C: Make e() constexpr so that the > > > > > expected "without object" diagnostic isn't replaced by a > > > > > "call to non-constexpr function" diagnostic. > > > > > * g++.dg/template/non-dependent25.C: New test. > > > > > --- > > > > > gcc/cp/constexpr.cc | 16 > > > > > ++++++++-------- > > > > > gcc/testsuite/g++.dg/cpp0x/noexcept59.C | 2 +- > > > > > gcc/testsuite/g++.dg/template/non-dependent25.C | 14 ++++++++++++++ > > > > > 3 files changed, 23 insertions(+), 9 deletions(-) > > > > > create mode 100644 gcc/testsuite/g++.dg/template/non-dependent25.C > > > > > > > > > > diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc > > > > > index d1097764b10..29d872d0a5e 100644 > > > > > --- a/gcc/cp/constexpr.cc > > > > > +++ b/gcc/cp/constexpr.cc > > > > > @@ -9132,6 +9132,10 @@ potential_constant_expression_1 (tree t, bool > > > > > want_rval, bool strict, bool now, > > > > > if (fun && is_overloaded_fn (fun)) > > > > > { > > > > > + if (!RECUR (fun, true)) > > > > > + return false; > > > > > + fun = get_fns (fun); > > > > > + > > > > > if (TREE_CODE (fun) == FUNCTION_DECL) > > > > > { > > > > > if (builtin_valid_in_constant_expr_p (fun)) > > > > > @@ -9167,7 +9171,8 @@ potential_constant_expression_1 (tree t, bool > > > > > want_rval, bool strict, bool now, > > > > > expression the address will be folded away, so look > > > > > through it now. */ > > > > > if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fun) > > > > > - && !DECL_CONSTRUCTOR_P (fun)) > > > > > + && !DECL_CONSTRUCTOR_P (fun) > > > > > + && !processing_template_decl) > > > > > > > > I don't see any rationale for this hunk? > > > > > > Now that we call get_fns earlier, we can reach this code path with a > > > templated non-static memfn call, but the code that follows assumes > > > non-templated form. > > > > > > I tried teaching it to handle the templated form too, but there's > > > apparently two different templated forms for non-static memfn calls, > > > one with a COMPONENT_REF callee and one with an ordinary BASELINK > > > callee (without a implicit object argument). In the former the implict > > > object argument is inside the COMPONENT_REF (and is a reference instead > > > of a pointer), and in the latter we don't even have an implicit object > > > argument to inspect. > > > > > > FWIW I think which form we use depends on whether we know if the called > > > function is a member of the current instantiation, e.g > > > > > > struct A { void f(); }; > > > > > > template<class T> struct B; > > > > > > template<class T> > > > struct C : B<T> { > > > void g(); > > > > > > void h() { > > > A::f(); // templated form has BASELINK callee, no object arg > > > C::g(); // templated form has COMPONENT_REF callee > > > } > > > }; > > > > > > So it seemed best to punt on templated non-static memfn calls here for > > > now and treat that as a separate enhancement. > > > > And I'm not even sure if the code path in question is necessary at all > > anymore: disabling it outright doesn't cause any regressions in the > > testsuite. > > It seems effectively equivalent to the body of the loop over the args a few > > lines later: > > If removing that hunk doesn't regress anything, let's do it. Probably that > should have happened in r13-55-ge9d2adc17d0dbe Sounds good, here's the combined patch which I'm bootstrapping for good measure. Does it look OK for trunk if bootstrap+regtest succeeds? -- >8 -- Subject: [PATCH] c++: potentiality of templated memfn call [PR109480] Here we're incorrectly deeming the templated call a.g() inside b's initializer as potentially constant, despite g being non-constexpr, which leads to us wastefully instantiating the initializer ahead of time, which incidentally tiggers a bug in access checking deferral (to be fixed by the subsequent patch). This patch fixes this by calling get_fns earlier during CALL_EXPR potentiality checking so that we're able to extract a FUNCTION_DECL out of a templated member function call (whose overall is typically a COMPONENT_REF) and to the usual checking if the called function is constexpr etc. In passing, I noticed potential_constant_expression_1's special handling of the object argument of a non-static member function call is effectively the same as the generic argument handling a few lines later. So this patch just gets rid of this special handling; otherwise we'd have to adapt it to handle templated versions of such calls. PR c++/109480 gcc/cp/ChangeLog: * constexpr.cc (potential_constant_expression_1) <case CALL_EXPR>: Reorganize to call get_fns sooner. Remove special handling of the object argument of a non-static member function call. Remove dead store to 'fun'. gcc/testsuite/ChangeLog: * g++.dg/cpp0x/noexcept59.C: Make e() constexpr so that the expected "without object" diagnostic isn't replaced by a "call to non-constexpr function" diagnostic. * g++.dg/template/non-dependent25.C: New test. --- gcc/cp/constexpr.cc | 32 ++++--------------- gcc/testsuite/g++.dg/cpp0x/noexcept59.C | 2 +- .../g++.dg/template/non-dependent25.C | 14 ++++++++ 3 files changed, 21 insertions(+), 27 deletions(-) create mode 100644 gcc/testsuite/g++.dg/template/non-dependent25.C diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc index d1097764b10..075339f7f62 100644 --- a/gcc/cp/constexpr.cc +++ b/gcc/cp/constexpr.cc @@ -9132,6 +9132,10 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, if (fun && is_overloaded_fn (fun)) { + if (!RECUR (fun, true)) + return false; + fun = get_fns (fun); + if (TREE_CODE (fun) == FUNCTION_DECL) { if (builtin_valid_in_constant_expr_p (fun)) @@ -9162,36 +9166,12 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, explain_invalid_constexpr_fn (fun); return false; } - /* A call to a non-static member function takes the address - of the object as the first argument. But in a constant - expression the address will be folded away, so look - through it now. */ - if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fun) - && !DECL_CONSTRUCTOR_P (fun)) - { - tree x = get_nth_callarg (t, 0); - if (is_this_parameter (x)) - return true; - /* Don't require an immediately constant value, as - constexpr substitution might not use the value. */ - bool sub_now = false; - if (!potential_constant_expression_1 (x, rval, strict, - sub_now, fundef_p, - flags, jump_target)) - return false; - i = 1; - } - } - else - { - if (!RECUR (fun, true)) - return false; - fun = get_first_fn (fun); } + + fun = OVL_FIRST (fun); /* Skip initial arguments to base constructors. */ if (DECL_BASE_CONSTRUCTOR_P (fun)) i = num_artificial_parms_for (fun); - fun = DECL_ORIGIN (fun); } else if (fun) { diff --git a/gcc/testsuite/g++.dg/cpp0x/noexcept59.C b/gcc/testsuite/g++.dg/cpp0x/noexcept59.C index c752601ba09..1dc826d3111 100644 --- a/gcc/testsuite/g++.dg/cpp0x/noexcept59.C +++ b/gcc/testsuite/g++.dg/cpp0x/noexcept59.C @@ -3,7 +3,7 @@ template <class ...Ts> class A { - void e (); + constexpr bool e () { return true; }; bool f (int() noexcept(this->e())); // { dg-error "this" } bool g (int() noexcept(e())); // { dg-error "without object" } }; diff --git a/gcc/testsuite/g++.dg/template/non-dependent25.C b/gcc/testsuite/g++.dg/template/non-dependent25.C new file mode 100644 index 00000000000..c00e44532b0 --- /dev/null +++ b/gcc/testsuite/g++.dg/template/non-dependent25.C @@ -0,0 +1,14 @@ +// PR c++/109480 + +template<class T> +struct A { + void f() { + A<int> a; + const bool b = a.g(); // { dg-bogus "private" } + } + +private: + bool g() const; +}; + +template struct A<int>;
On 5/3/23 16:50, Patrick Palka wrote: > On Wed, 3 May 2023, Jason Merrill wrote: > >> On 5/2/23 15:53, Patrick Palka wrote: >>> on Tue, 2 May 2023, Patrick Palka wrote: >>> >>>> On Tue, 2 May 2023, Jason Merrill wrote: >>>> >>>>> On 5/1/23 15:59, Patrick Palka wrote: >>>>>> Here we're incorrectly deeming the templated call a.g() inside b's >>>>>> initializer as potentially constant, despite g being non-constexpr, >>>>>> which leads to us wastefully instantiating the initializer ahead of >>>>>> time >>>>>> and triggering a bug in access checking deferral (which will get fixed >>>>>> in the subsequent patch). >>>>>> >>>>>> This patch fixes this by calling get_fns earlier during potentiality >>>>>> checking so that we also handle the templated form of a member >>>>>> function >>>>>> call (whose overall callee is a COMPONENT_REF) when checking if the >>>>>> called >>>>>> function is constexpr etc. >>>>>> >>>>>> PR c++/109480 >>>>>> >>>>>> gcc/cp/ChangeLog: >>>>>> >>>>>> * constexpr.cc (potential_constant_expression_1) <case >>>>>> CALL_EXPR>: >>>>>> Reorganize to call get_fns sooner. Remove dead store to >>>>>> 'fun'. >>>>>> >>>>>> gcc/testsuite/ChangeLog: >>>>>> >>>>>> * g++.dg/cpp0x/noexcept59.C: Make e() constexpr so that the >>>>>> expected "without object" diagnostic isn't replaced by a >>>>>> "call to non-constexpr function" diagnostic. >>>>>> * g++.dg/template/non-dependent25.C: New test. >>>>>> --- >>>>>> gcc/cp/constexpr.cc | 16 >>>>>> ++++++++-------- >>>>>> gcc/testsuite/g++.dg/cpp0x/noexcept59.C | 2 +- >>>>>> gcc/testsuite/g++.dg/template/non-dependent25.C | 14 ++++++++++++++ >>>>>> 3 files changed, 23 insertions(+), 9 deletions(-) >>>>>> create mode 100644 gcc/testsuite/g++.dg/template/non-dependent25.C >>>>>> >>>>>> diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc >>>>>> index d1097764b10..29d872d0a5e 100644 >>>>>> --- a/gcc/cp/constexpr.cc >>>>>> +++ b/gcc/cp/constexpr.cc >>>>>> @@ -9132,6 +9132,10 @@ potential_constant_expression_1 (tree t, bool >>>>>> want_rval, bool strict, bool now, >>>>>> if (fun && is_overloaded_fn (fun)) >>>>>> { >>>>>> + if (!RECUR (fun, true)) >>>>>> + return false; >>>>>> + fun = get_fns (fun); >>>>>> + >>>>>> if (TREE_CODE (fun) == FUNCTION_DECL) >>>>>> { >>>>>> if (builtin_valid_in_constant_expr_p (fun)) >>>>>> @@ -9167,7 +9171,8 @@ potential_constant_expression_1 (tree t, bool >>>>>> want_rval, bool strict, bool now, >>>>>> expression the address will be folded away, so look >>>>>> through it now. */ >>>>>> if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fun) >>>>>> - && !DECL_CONSTRUCTOR_P (fun)) >>>>>> + && !DECL_CONSTRUCTOR_P (fun) >>>>>> + && !processing_template_decl) >>>>> >>>>> I don't see any rationale for this hunk? >>>> >>>> Now that we call get_fns earlier, we can reach this code path with a >>>> templated non-static memfn call, but the code that follows assumes >>>> non-templated form. >>>> >>>> I tried teaching it to handle the templated form too, but there's >>>> apparently two different templated forms for non-static memfn calls, >>>> one with a COMPONENT_REF callee and one with an ordinary BASELINK >>>> callee (without a implicit object argument). In the former the implict >>>> object argument is inside the COMPONENT_REF (and is a reference instead >>>> of a pointer), and in the latter we don't even have an implicit object >>>> argument to inspect. >>>> >>>> FWIW I think which form we use depends on whether we know if the called >>>> function is a member of the current instantiation, e.g >>>> >>>> struct A { void f(); }; >>>> >>>> template<class T> struct B; >>>> >>>> template<class T> >>>> struct C : B<T> { >>>> void g(); >>>> >>>> void h() { >>>> A::f(); // templated form has BASELINK callee, no object arg >>>> C::g(); // templated form has COMPONENT_REF callee >>>> } >>>> }; >>>> >>>> So it seemed best to punt on templated non-static memfn calls here for >>>> now and treat that as a separate enhancement. >>> >>> And I'm not even sure if the code path in question is necessary at all >>> anymore: disabling it outright doesn't cause any regressions in the >>> testsuite. >>> It seems effectively equivalent to the body of the loop over the args a few >>> lines later: >> >> If removing that hunk doesn't regress anything, let's do it. Probably that >> should have happened in r13-55-ge9d2adc17d0dbe > > Sounds good, here's the combined patch which I'm bootstrapping for good > measure. Does it look OK for trunk if bootstrap+regtest succeeds? OK. > -- >8 -- > > Subject: [PATCH] c++: potentiality of templated memfn call [PR109480] > > Here we're incorrectly deeming the templated call a.g() inside b's > initializer as potentially constant, despite g being non-constexpr, > which leads to us wastefully instantiating the initializer ahead of time, > which incidentally tiggers a bug in access checking deferral (to be > fixed by the subsequent patch). > > This patch fixes this by calling get_fns earlier during CALL_EXPR > potentiality checking so that we're able to extract a FUNCTION_DECL out > of a templated member function call (whose overall is typically a > COMPONENT_REF) and to the usual checking if the called function is > constexpr etc. > > In passing, I noticed potential_constant_expression_1's special handling > of the object argument of a non-static member function call is effectively > the same as the generic argument handling a few lines later. So this > patch just gets rid of this special handling; otherwise we'd have to adapt > it to handle templated versions of such calls. > > PR c++/109480 > > gcc/cp/ChangeLog: > > * constexpr.cc (potential_constant_expression_1) <case CALL_EXPR>: > Reorganize to call get_fns sooner. Remove special handling of > the object argument of a non-static member function call. Remove > dead store to 'fun'. > > gcc/testsuite/ChangeLog: > > * g++.dg/cpp0x/noexcept59.C: Make e() constexpr so that the > expected "without object" diagnostic isn't replaced by a > "call to non-constexpr function" diagnostic. > * g++.dg/template/non-dependent25.C: New test. > --- > gcc/cp/constexpr.cc | 32 ++++--------------- > gcc/testsuite/g++.dg/cpp0x/noexcept59.C | 2 +- > .../g++.dg/template/non-dependent25.C | 14 ++++++++ > 3 files changed, 21 insertions(+), 27 deletions(-) > create mode 100644 gcc/testsuite/g++.dg/template/non-dependent25.C > > diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc > index d1097764b10..075339f7f62 100644 > --- a/gcc/cp/constexpr.cc > +++ b/gcc/cp/constexpr.cc > @@ -9132,6 +9132,10 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, > > if (fun && is_overloaded_fn (fun)) > { > + if (!RECUR (fun, true)) > + return false; > + fun = get_fns (fun); > + > if (TREE_CODE (fun) == FUNCTION_DECL) > { > if (builtin_valid_in_constant_expr_p (fun)) > @@ -9162,36 +9166,12 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, > explain_invalid_constexpr_fn (fun); > return false; > } > - /* A call to a non-static member function takes the address > - of the object as the first argument. But in a constant > - expression the address will be folded away, so look > - through it now. */ > - if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fun) > - && !DECL_CONSTRUCTOR_P (fun)) > - { > - tree x = get_nth_callarg (t, 0); > - if (is_this_parameter (x)) > - return true; > - /* Don't require an immediately constant value, as > - constexpr substitution might not use the value. */ > - bool sub_now = false; > - if (!potential_constant_expression_1 (x, rval, strict, > - sub_now, fundef_p, > - flags, jump_target)) > - return false; > - i = 1; > - } > - } > - else > - { > - if (!RECUR (fun, true)) > - return false; > - fun = get_first_fn (fun); > } > + > + fun = OVL_FIRST (fun); > /* Skip initial arguments to base constructors. */ > if (DECL_BASE_CONSTRUCTOR_P (fun)) > i = num_artificial_parms_for (fun); > - fun = DECL_ORIGIN (fun); > } > else if (fun) > { > diff --git a/gcc/testsuite/g++.dg/cpp0x/noexcept59.C b/gcc/testsuite/g++.dg/cpp0x/noexcept59.C > index c752601ba09..1dc826d3111 100644 > --- a/gcc/testsuite/g++.dg/cpp0x/noexcept59.C > +++ b/gcc/testsuite/g++.dg/cpp0x/noexcept59.C > @@ -3,7 +3,7 @@ > > template <class ...Ts> class A > { > - void e (); > + constexpr bool e () { return true; }; > bool f (int() noexcept(this->e())); // { dg-error "this" } > bool g (int() noexcept(e())); // { dg-error "without object" } > }; > diff --git a/gcc/testsuite/g++.dg/template/non-dependent25.C b/gcc/testsuite/g++.dg/template/non-dependent25.C > new file mode 100644 > index 00000000000..c00e44532b0 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/template/non-dependent25.C > @@ -0,0 +1,14 @@ > +// PR c++/109480 > + > +template<class T> > +struct A { > + void f() { > + A<int> a; > + const bool b = a.g(); // { dg-bogus "private" } > + } > + > +private: > + bool g() const; > +}; > + > +template struct A<int>;
Hello Patrick, On Wed, May 03 2023, Patrick Palka via Gcc-patches wrote: > [...] > > Subject: [PATCH] c++: potentiality of templated memfn call [PR109480] > > Here we're incorrectly deeming the templated call a.g() inside b's > initializer as potentially constant, despite g being non-constexpr, > which leads to us wastefully instantiating the initializer ahead of time, > which incidentally tiggers a bug in access checking deferral (to be > fixed by the subsequent patch). > > This patch fixes this by calling get_fns earlier during CALL_EXPR > potentiality checking so that we're able to extract a FUNCTION_DECL out > of a templated member function call (whose overall is typically a > COMPONENT_REF) and to the usual checking if the called function is > constexpr etc. > > In passing, I noticed potential_constant_expression_1's special handling > of the object argument of a non-static member function call is effectively > the same as the generic argument handling a few lines later. So this > patch just gets rid of this special handling; otherwise we'd have to adapt > it to handle templated versions of such calls. > > PR c++/109480 > > gcc/cp/ChangeLog: > > * constexpr.cc (potential_constant_expression_1) <case CALL_EXPR>: > Reorganize to call get_fns sooner. Remove special handling of > the object argument of a non-static member function call. Remove > dead store to 'fun'. > This patch makes g++ no longer accept the following, complaining that get_subsys is non-constexpr (with just -std=c++17 -S), which is of course auto-reduced from a much larger source file from Ceph: ----------------------------------- 8< ----------------------------------- struct { void get_subsys(); } PriorSet_dpp; struct PriorSet { template <typename> PriorSet(); }; template <typename> PriorSet::PriorSet() { [](auto cctX) { cctX.template should_gather<PriorSet_dpp.get_subsys()>; }; } ----------------------------------- 8< ----------------------------------- I assume that is intentional and am actually somewhat surprised it was accepted before, but can you please confirm? Thanks, Martin
Hi Martin, On Fri, May 12, 2023 at 12:13 PM Martin Jambor <mjambor@suse.cz> wrote: > > Hello Patrick, > > On Wed, May 03 2023, Patrick Palka via Gcc-patches wrote: > > > [...] > > > > Subject: [PATCH] c++: potentiality of templated memfn call [PR109480] > > > > Here we're incorrectly deeming the templated call a.g() inside b's > > initializer as potentially constant, despite g being non-constexpr, > > which leads to us wastefully instantiating the initializer ahead of time, > > which incidentally tiggers a bug in access checking deferral (to be > > fixed by the subsequent patch). > > > > This patch fixes this by calling get_fns earlier during CALL_EXPR > > potentiality checking so that we're able to extract a FUNCTION_DECL out > > of a templated member function call (whose overall is typically a > > COMPONENT_REF) and to the usual checking if the called function is > > constexpr etc. > > > > In passing, I noticed potential_constant_expression_1's special handling > > of the object argument of a non-static member function call is effectively > > the same as the generic argument handling a few lines later. So this > > patch just gets rid of this special handling; otherwise we'd have to adapt > > it to handle templated versions of such calls. > > > > PR c++/109480 > > > > gcc/cp/ChangeLog: > > > > * constexpr.cc (potential_constant_expression_1) <case CALL_EXPR>: > > Reorganize to call get_fns sooner. Remove special handling of > > the object argument of a non-static member function call. Remove > > dead store to 'fun'. > > > > This patch makes g++ no longer accept the following, complaining that > get_subsys is non-constexpr (with just -std=c++17 -S), which is of > course auto-reduced from a much larger source file from Ceph: > > ----------------------------------- 8< ----------------------------------- > struct { > void get_subsys(); > } PriorSet_dpp; > struct PriorSet { > template <typename> PriorSet(); > }; > template <typename> PriorSet::PriorSet() { > [](auto cctX) { cctX.template should_gather<PriorSet_dpp.get_subsys()>; }; > } > ----------------------------------- 8< ----------------------------------- > > I assume that is intentional and am actually somewhat surprised it was > accepted before, but can you please confirm? Yes, this seems correct/intentional to me-- no instantiation of the template would be valid because it's trying to use a non-constant expression (which we now correctly identify as such) as a template argument, so this snippet is IFNDR. I don't think we have testsuite coverage for this QoI diagnostic, I'll add one. > > Thanks, > > Martin >
On 5/12/23 13:02, Patrick Palka wrote: > Hi Martin, > > On Fri, May 12, 2023 at 12:13 PM Martin Jambor <mjambor@suse.cz> wrote: >> >> Hello Patrick, >> >> On Wed, May 03 2023, Patrick Palka via Gcc-patches wrote: >>> >> [...] >>> >>> Subject: [PATCH] c++: potentiality of templated memfn call [PR109480] >>> >>> Here we're incorrectly deeming the templated call a.g() inside b's >>> initializer as potentially constant, despite g being non-constexpr, >>> which leads to us wastefully instantiating the initializer ahead of time, >>> which incidentally tiggers a bug in access checking deferral (to be >>> fixed by the subsequent patch). >>> >>> This patch fixes this by calling get_fns earlier during CALL_EXPR >>> potentiality checking so that we're able to extract a FUNCTION_DECL out >>> of a templated member function call (whose overall is typically a >>> COMPONENT_REF) and to the usual checking if the called function is >>> constexpr etc. >>> >>> In passing, I noticed potential_constant_expression_1's special handling >>> of the object argument of a non-static member function call is effectively >>> the same as the generic argument handling a few lines later. So this >>> patch just gets rid of this special handling; otherwise we'd have to adapt >>> it to handle templated versions of such calls. >>> >>> PR c++/109480 >>> >>> gcc/cp/ChangeLog: >>> >>> * constexpr.cc (potential_constant_expression_1) <case CALL_EXPR>: >>> Reorganize to call get_fns sooner. Remove special handling of >>> the object argument of a non-static member function call. Remove >>> dead store to 'fun'. >>> >> >> This patch makes g++ no longer accept the following, complaining that >> get_subsys is non-constexpr (with just -std=c++17 -S), which is of >> course auto-reduced from a much larger source file from Ceph: >> >> ----------------------------------- 8< ----------------------------------- >> struct { >> void get_subsys(); >> } PriorSet_dpp; >> struct PriorSet { >> template <typename> PriorSet(); >> }; >> template <typename> PriorSet::PriorSet() { >> [](auto cctX) { cctX.template should_gather<PriorSet_dpp.get_subsys()>; }; >> } >> ----------------------------------- 8< ----------------------------------- >> >> I assume that is intentional and am actually somewhat surprised it was >> accepted before, but can you please confirm? > > Yes, this seems correct/intentional to me-- no instantiation of the > template would be valid because it's trying to use a non-constant > expression (which we now correctly identify as such) as a template > argument, so this snippet is IFNDR. > > I don't think we have testsuite coverage for this QoI diagnostic, I'll add one. Incidentally, I wonder about trying to make IFNDR diags in general permerrors or default-error pedwarns, but that doesn't need to happen now. Jason
diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc index d1097764b10..29d872d0a5e 100644 --- a/gcc/cp/constexpr.cc +++ b/gcc/cp/constexpr.cc @@ -9132,6 +9132,10 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, if (fun && is_overloaded_fn (fun)) { + if (!RECUR (fun, true)) + return false; + fun = get_fns (fun); + if (TREE_CODE (fun) == FUNCTION_DECL) { if (builtin_valid_in_constant_expr_p (fun)) @@ -9167,7 +9171,8 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, expression the address will be folded away, so look through it now. */ if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fun) - && !DECL_CONSTRUCTOR_P (fun)) + && !DECL_CONSTRUCTOR_P (fun) + && !processing_template_decl) { tree x = get_nth_callarg (t, 0); if (is_this_parameter (x)) @@ -9182,16 +9187,11 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, i = 1; } } - else - { - if (!RECUR (fun, true)) - return false; - fun = get_first_fn (fun); - } + + fun = OVL_FIRST (fun); /* Skip initial arguments to base constructors. */ if (DECL_BASE_CONSTRUCTOR_P (fun)) i = num_artificial_parms_for (fun); - fun = DECL_ORIGIN (fun); } else if (fun) { diff --git a/gcc/testsuite/g++.dg/cpp0x/noexcept59.C b/gcc/testsuite/g++.dg/cpp0x/noexcept59.C index c752601ba09..1dc826d3111 100644 --- a/gcc/testsuite/g++.dg/cpp0x/noexcept59.C +++ b/gcc/testsuite/g++.dg/cpp0x/noexcept59.C @@ -3,7 +3,7 @@ template <class ...Ts> class A { - void e (); + constexpr bool e () { return true; }; bool f (int() noexcept(this->e())); // { dg-error "this" } bool g (int() noexcept(e())); // { dg-error "without object" } }; diff --git a/gcc/testsuite/g++.dg/template/non-dependent25.C b/gcc/testsuite/g++.dg/template/non-dependent25.C new file mode 100644 index 00000000000..a2f9801e11f --- /dev/null +++ b/gcc/testsuite/g++.dg/template/non-dependent25.C @@ -0,0 +1,14 @@ +// PR c++/109480 + +template<class T> +struct A { + void f() { + A<int> a; + const bool b = a.g(); + } + +private: + bool g() const; +}; + +template struct A<int>;