* [PATCH] c++: fix ICE with is_really_empty_class [PR110106] @ 2023-07-18 21:14 Marek Polacek 2023-07-19 14:11 ` Patrick Palka 0 siblings, 1 reply; 12+ messages in thread From: Marek Polacek @ 2023-07-18 21:14 UTC (permalink / raw) To: GCC Patches, Jason Merrill Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk and branches? -- >8 -- is_really_empty_class is liable to crash when it gets an incomplete or dependent type. Since r11-557, we pass the yet-uninstantiated class type S<0> of the PARM_DECL s to is_really_empty_class -- because of the potential_rvalue_constant_expression -> is_rvalue_constant_expression change in cp_parser_constant_expression. Here we're not parsing a template so we did not check COMPLETE_TYPE_P as we should. PR c++/110106 gcc/cp/ChangeLog: * constexpr.cc (potential_constant_expression_1): Check COMPLETE_TYPE_P even when !processing_template_decl. gcc/testsuite/ChangeLog: * g++.dg/cpp0x/noexcept80.C: New test. --- gcc/cp/constexpr.cc | 2 +- gcc/testsuite/g++.dg/cpp0x/noexcept80.C | 12 ++++++++++++ 2 files changed, 13 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/g++.dg/cpp0x/noexcept80.C diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc index 6e8f1c2b61e..1f59c5472fb 100644 --- a/gcc/cp/constexpr.cc +++ b/gcc/cp/constexpr.cc @@ -9116,7 +9116,7 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, if (now && want_rval) { tree type = TREE_TYPE (t); - if ((processing_template_decl && !COMPLETE_TYPE_P (type)) + if (!COMPLETE_TYPE_P (type) || dependent_type_p (type) || is_really_empty_class (type, /*ignore_vptr*/false)) /* An empty class has no data to read. */ diff --git a/gcc/testsuite/g++.dg/cpp0x/noexcept80.C b/gcc/testsuite/g++.dg/cpp0x/noexcept80.C new file mode 100644 index 00000000000..3e90af747e2 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp0x/noexcept80.C @@ -0,0 +1,12 @@ +// PR c++/110106 +// { dg-do compile { target c++11 } } + +template<int> struct S +{ +}; + +struct G { + G(S<0>); +}; + +void y(S<0> s) noexcept(noexcept(G{s})); base-commit: fca089e8a47314a40ad93527ba9f9d0d374b3afb -- 2.41.0 ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH] c++: fix ICE with is_really_empty_class [PR110106] 2023-07-18 21:14 [PATCH] c++: fix ICE with is_really_empty_class [PR110106] Marek Polacek @ 2023-07-19 14:11 ` Patrick Palka 2023-07-20 18:13 ` Marek Polacek 0 siblings, 1 reply; 12+ messages in thread From: Patrick Palka @ 2023-07-19 14:11 UTC (permalink / raw) To: Marek Polacek; +Cc: GCC Patches, Jason Merrill On Tue, 18 Jul 2023, Marek Polacek via Gcc-patches wrote: > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk and branches? Looks reasonable to me. Though I wonder if we could also fix this by not checking potentiality at all in this case? The problematic call to is_rvalue_constant_expression happens from cp_parser_constant_expression with 'allow_non_constant' != 0 and with 'non_constant_p' being a dummy out argument that comes from cp_parser_functional_cast, so the result of is_rvalue_constant_expression is effectively unused in this case, and we should be able to safely elide it when 'allow_non_constant && non_constant_p == nullptr'. Relatedly, ISTM the member cp_parser::non_integral_constant_expression_p is also effectively unused and could be removed? > > -- >8 -- > > is_really_empty_class is liable to crash when it gets an incomplete > or dependent type. Since r11-557, we pass the yet-uninstantiated > class type S<0> of the PARM_DECL s to is_really_empty_class -- because > of the potential_rvalue_constant_expression -> is_rvalue_constant_expression > change in cp_parser_constant_expression. Here we're not parsing > a template so we did not check COMPLETE_TYPE_P as we should. > > PR c++/110106 > > gcc/cp/ChangeLog: > > * constexpr.cc (potential_constant_expression_1): Check COMPLETE_TYPE_P > even when !processing_template_decl. > > gcc/testsuite/ChangeLog: > > * g++.dg/cpp0x/noexcept80.C: New test. > --- > gcc/cp/constexpr.cc | 2 +- > gcc/testsuite/g++.dg/cpp0x/noexcept80.C | 12 ++++++++++++ > 2 files changed, 13 insertions(+), 1 deletion(-) > create mode 100644 gcc/testsuite/g++.dg/cpp0x/noexcept80.C > > diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc > index 6e8f1c2b61e..1f59c5472fb 100644 > --- a/gcc/cp/constexpr.cc > +++ b/gcc/cp/constexpr.cc > @@ -9116,7 +9116,7 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, > if (now && want_rval) > { > tree type = TREE_TYPE (t); > - if ((processing_template_decl && !COMPLETE_TYPE_P (type)) > + if (!COMPLETE_TYPE_P (type) > || dependent_type_p (type) > || is_really_empty_class (type, /*ignore_vptr*/false)) > /* An empty class has no data to read. */ > diff --git a/gcc/testsuite/g++.dg/cpp0x/noexcept80.C b/gcc/testsuite/g++.dg/cpp0x/noexcept80.C > new file mode 100644 > index 00000000000..3e90af747e2 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/cpp0x/noexcept80.C > @@ -0,0 +1,12 @@ > +// PR c++/110106 > +// { dg-do compile { target c++11 } } > + > +template<int> struct S > +{ > +}; > + > +struct G { > + G(S<0>); > +}; > + > +void y(S<0> s) noexcept(noexcept(G{s})); > > base-commit: fca089e8a47314a40ad93527ba9f9d0d374b3afb > -- > 2.41.0 > > ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH] c++: fix ICE with is_really_empty_class [PR110106] 2023-07-19 14:11 ` Patrick Palka @ 2023-07-20 18:13 ` Marek Polacek 2023-07-20 18:37 ` Jason Merrill 0 siblings, 1 reply; 12+ messages in thread From: Marek Polacek @ 2023-07-20 18:13 UTC (permalink / raw) To: Patrick Palka; +Cc: GCC Patches, Jason Merrill On Wed, Jul 19, 2023 at 10:11:27AM -0400, Patrick Palka wrote: > On Tue, 18 Jul 2023, Marek Polacek via Gcc-patches wrote: > > > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk and branches? > > Looks reasonable to me. Thanks. > Though I wonder if we could also fix this by not checking potentiality > at all in this case? The problematic call to is_rvalue_constant_expression > happens from cp_parser_constant_expression with 'allow_non_constant' != 0 > and with 'non_constant_p' being a dummy out argument that comes from > cp_parser_functional_cast, so the result of is_rvalue_constant_expression > is effectively unused in this case, and we should be able to safely elide > it when 'allow_non_constant && non_constant_p == nullptr'. Sounds plausible. I think my patch could be applied first since it removes a tiny bit of code, then I can hopefully remove the flag below, then maybe go back and optimize the call to is_rvalue_constant_expression. Does that sound sensible? > Relatedly, ISTM the member cp_parser::non_integral_constant_expression_p > is also effectively unused and could be removed? It looks that way. Seems it's only used in cp_parser_constant_expression: 10806 if (allow_non_constant_p) 10807 *non_constant_p = parser->non_integral_constant_expression_p; but that could be easily replaced by a local var. I'd be happy to see if we can actually do away with it. (I wonder why it was introduced and when it actually stopped being useful.) Thanks, > > > > -- >8 -- > > > > is_really_empty_class is liable to crash when it gets an incomplete > > or dependent type. Since r11-557, we pass the yet-uninstantiated > > class type S<0> of the PARM_DECL s to is_really_empty_class -- because > > of the potential_rvalue_constant_expression -> is_rvalue_constant_expression > > change in cp_parser_constant_expression. Here we're not parsing > > a template so we did not check COMPLETE_TYPE_P as we should. > > > > PR c++/110106 > > > > gcc/cp/ChangeLog: > > > > * constexpr.cc (potential_constant_expression_1): Check COMPLETE_TYPE_P > > even when !processing_template_decl. > > > > gcc/testsuite/ChangeLog: > > > > * g++.dg/cpp0x/noexcept80.C: New test. > > --- > > gcc/cp/constexpr.cc | 2 +- > > gcc/testsuite/g++.dg/cpp0x/noexcept80.C | 12 ++++++++++++ > > 2 files changed, 13 insertions(+), 1 deletion(-) > > create mode 100644 gcc/testsuite/g++.dg/cpp0x/noexcept80.C > > > > diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc > > index 6e8f1c2b61e..1f59c5472fb 100644 > > --- a/gcc/cp/constexpr.cc > > +++ b/gcc/cp/constexpr.cc > > @@ -9116,7 +9116,7 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, > > if (now && want_rval) > > { > > tree type = TREE_TYPE (t); > > - if ((processing_template_decl && !COMPLETE_TYPE_P (type)) > > + if (!COMPLETE_TYPE_P (type) > > || dependent_type_p (type) > > || is_really_empty_class (type, /*ignore_vptr*/false)) > > /* An empty class has no data to read. */ > > diff --git a/gcc/testsuite/g++.dg/cpp0x/noexcept80.C b/gcc/testsuite/g++.dg/cpp0x/noexcept80.C > > new file mode 100644 > > index 00000000000..3e90af747e2 > > --- /dev/null > > +++ b/gcc/testsuite/g++.dg/cpp0x/noexcept80.C > > @@ -0,0 +1,12 @@ > > +// PR c++/110106 > > +// { dg-do compile { target c++11 } } > > + > > +template<int> struct S > > +{ > > +}; > > + > > +struct G { > > + G(S<0>); > > +}; > > + > > +void y(S<0> s) noexcept(noexcept(G{s})); > > > > base-commit: fca089e8a47314a40ad93527ba9f9d0d374b3afb > > -- > > 2.41.0 > > > > > Marek ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH] c++: fix ICE with is_really_empty_class [PR110106] 2023-07-20 18:13 ` Marek Polacek @ 2023-07-20 18:37 ` Jason Merrill 2023-07-20 19:51 ` Marek Polacek 0 siblings, 1 reply; 12+ messages in thread From: Jason Merrill @ 2023-07-20 18:37 UTC (permalink / raw) To: Marek Polacek, Patrick Palka; +Cc: GCC Patches On 7/20/23 14:13, Marek Polacek wrote: > On Wed, Jul 19, 2023 at 10:11:27AM -0400, Patrick Palka wrote: >> On Tue, 18 Jul 2023, Marek Polacek via Gcc-patches wrote: >> >>> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk and branches? >> >> Looks reasonable to me. > > Thanks. > >> Though I wonder if we could also fix this by not checking potentiality >> at all in this case? The problematic call to is_rvalue_constant_expression >> happens from cp_parser_constant_expression with 'allow_non_constant' != 0 >> and with 'non_constant_p' being a dummy out argument that comes from >> cp_parser_functional_cast, so the result of is_rvalue_constant_expression >> is effectively unused in this case, and we should be able to safely elide >> it when 'allow_non_constant && non_constant_p == nullptr'. > > Sounds plausible. I think my patch could be applied first since it > removes a tiny bit of code, then I can hopefully remove the flag below, > then maybe go back and optimize the call to is_rvalue_constant_expression. > Does that sound sensible? > >> Relatedly, ISTM the member cp_parser::non_integral_constant_expression_p >> is also effectively unused and could be removed? > > It looks that way. Seems it's only used in cp_parser_constant_expression: > 10806 if (allow_non_constant_p) > 10807 *non_constant_p = parser->non_integral_constant_expression_p; > but that could be easily replaced by a local var. I'd be happy to see if > we can actually do away with it. (I wonder why it was introduced and when > it actually stopped being useful.) It was for the C++98 notion of constant-expression, which was more of a parser-level notion, and has been supplanted by the C++11 version. I'm happy to remove it, and therefore remove the is_rvalue_constant_expression call. >>> -- >8 -- >>> >>> is_really_empty_class is liable to crash when it gets an incomplete >>> or dependent type. Since r11-557, we pass the yet-uninstantiated >>> class type S<0> of the PARM_DECL s to is_really_empty_class -- because >>> of the potential_rvalue_constant_expression -> is_rvalue_constant_expression >>> change in cp_parser_constant_expression. Here we're not parsing >>> a template so we did not check COMPLETE_TYPE_P as we should. >>> >>> PR c++/110106 >>> >>> gcc/cp/ChangeLog: >>> >>> * constexpr.cc (potential_constant_expression_1): Check COMPLETE_TYPE_P >>> even when !processing_template_decl. >>> >>> gcc/testsuite/ChangeLog: >>> >>> * g++.dg/cpp0x/noexcept80.C: New test. >>> --- >>> gcc/cp/constexpr.cc | 2 +- >>> gcc/testsuite/g++.dg/cpp0x/noexcept80.C | 12 ++++++++++++ >>> 2 files changed, 13 insertions(+), 1 deletion(-) >>> create mode 100644 gcc/testsuite/g++.dg/cpp0x/noexcept80.C >>> >>> diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc >>> index 6e8f1c2b61e..1f59c5472fb 100644 >>> --- a/gcc/cp/constexpr.cc >>> +++ b/gcc/cp/constexpr.cc >>> @@ -9116,7 +9116,7 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, >>> if (now && want_rval) >>> { >>> tree type = TREE_TYPE (t); >>> - if ((processing_template_decl && !COMPLETE_TYPE_P (type)) >>> + if (!COMPLETE_TYPE_P (type) >>> || dependent_type_p (type) There shouldn't be a problem completing the type here, so it seems to me that we're missing a call to complete_type_p, at least when !processing_template_decl. Probably need to move the dependent_type_p check up as a result. Jason ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH] c++: fix ICE with is_really_empty_class [PR110106] 2023-07-20 18:37 ` Jason Merrill @ 2023-07-20 19:51 ` Marek Polacek 2023-07-20 21:58 ` Marek Polacek 2023-07-21 17:44 ` Jason Merrill 0 siblings, 2 replies; 12+ messages in thread From: Marek Polacek @ 2023-07-20 19:51 UTC (permalink / raw) To: Jason Merrill; +Cc: Patrick Palka, GCC Patches On Thu, Jul 20, 2023 at 02:37:07PM -0400, Jason Merrill wrote: > On 7/20/23 14:13, Marek Polacek wrote: > > On Wed, Jul 19, 2023 at 10:11:27AM -0400, Patrick Palka wrote: > > > On Tue, 18 Jul 2023, Marek Polacek via Gcc-patches wrote: > > > > > > > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk and branches? > > > > > > Looks reasonable to me. > > > > Thanks. > > > Though I wonder if we could also fix this by not checking potentiality > > > at all in this case? The problematic call to is_rvalue_constant_expression > > > happens from cp_parser_constant_expression with 'allow_non_constant' != 0 > > > and with 'non_constant_p' being a dummy out argument that comes from > > > cp_parser_functional_cast, so the result of is_rvalue_constant_expression > > > is effectively unused in this case, and we should be able to safely elide > > > it when 'allow_non_constant && non_constant_p == nullptr'. > > > > Sounds plausible. I think my patch could be applied first since it > > removes a tiny bit of code, then I can hopefully remove the flag below, > > then maybe go back and optimize the call to is_rvalue_constant_expression. > > Does that sound sensible? > > > > > Relatedly, ISTM the member cp_parser::non_integral_constant_expression_p > > > is also effectively unused and could be removed? > > > > It looks that way. Seems it's only used in cp_parser_constant_expression: > > 10806 if (allow_non_constant_p) > > 10807 *non_constant_p = parser->non_integral_constant_expression_p; > > but that could be easily replaced by a local var. I'd be happy to see if > > we can actually do away with it. (I wonder why it was introduced and when > > it actually stopped being useful.) > > It was for the C++98 notion of constant-expression, which was more of a > parser-level notion, and has been supplanted by the C++11 version. I'm > happy to remove it, and therefore remove the is_rvalue_constant_expression > call. Wonderful. I'll do that next. > > > > -- >8 -- > > > > > > > > is_really_empty_class is liable to crash when it gets an incomplete > > > > or dependent type. Since r11-557, we pass the yet-uninstantiated > > > > class type S<0> of the PARM_DECL s to is_really_empty_class -- because > > > > of the potential_rvalue_constant_expression -> is_rvalue_constant_expression > > > > change in cp_parser_constant_expression. Here we're not parsing > > > > a template so we did not check COMPLETE_TYPE_P as we should. > > > > > > > > PR c++/110106 > > > > > > > > gcc/cp/ChangeLog: > > > > > > > > * constexpr.cc (potential_constant_expression_1): Check COMPLETE_TYPE_P > > > > even when !processing_template_decl. > > > > > > > > gcc/testsuite/ChangeLog: > > > > > > > > * g++.dg/cpp0x/noexcept80.C: New test. > > > > --- > > > > gcc/cp/constexpr.cc | 2 +- > > > > gcc/testsuite/g++.dg/cpp0x/noexcept80.C | 12 ++++++++++++ > > > > 2 files changed, 13 insertions(+), 1 deletion(-) > > > > create mode 100644 gcc/testsuite/g++.dg/cpp0x/noexcept80.C > > > > > > > > diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc > > > > index 6e8f1c2b61e..1f59c5472fb 100644 > > > > --- a/gcc/cp/constexpr.cc > > > > +++ b/gcc/cp/constexpr.cc > > > > @@ -9116,7 +9116,7 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, > > > > if (now && want_rval) > > > > { > > > > tree type = TREE_TYPE (t); > > > > - if ((processing_template_decl && !COMPLETE_TYPE_P (type)) > > > > + if (!COMPLETE_TYPE_P (type) > > > > || dependent_type_p (type) > > There shouldn't be a problem completing the type here, so it seems to me > that we're missing a call to complete_type_p, at least when > !processing_template_decl. Probably need to move the dependent_type_p check > up as a result. Like so? Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk? -- >8 -- is_really_empty_class is liable to crash when it gets an incomplete or dependent type. Since r11-557, we pass the yet-uninstantiated class type S<0> of the PARM_DECL s to is_really_empty_class -- because of the potential_rvalue_constant_expression -> is_rvalue_constant_expression change in cp_parser_constant_expression. Here we're not parsing a template so we did not check COMPLETE_TYPE_P as we should. It should work to complete the type before checking COMPLETE_TYPE_P. PR c++/110106 gcc/cp/ChangeLog: * constexpr.cc (potential_constant_expression_1): Try to complete the type when !processing_template_decl. gcc/testsuite/ChangeLog: * g++.dg/cpp0x/noexcept80.C: New test. --- gcc/cp/constexpr.cc | 5 +++-- gcc/testsuite/g++.dg/cpp0x/noexcept80.C | 12 ++++++++++++ 2 files changed, 15 insertions(+), 2 deletions(-) create mode 100644 gcc/testsuite/g++.dg/cpp0x/noexcept80.C diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc index 6e8f1c2b61e..fb94f3cefcb 100644 --- a/gcc/cp/constexpr.cc +++ b/gcc/cp/constexpr.cc @@ -9116,8 +9116,9 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, if (now && want_rval) { tree type = TREE_TYPE (t); - if ((processing_template_decl && !COMPLETE_TYPE_P (type)) - || dependent_type_p (type) + if (dependent_type_p (type) + || !COMPLETE_TYPE_P (processing_template_decl + ? type : complete_type (type)) || is_really_empty_class (type, /*ignore_vptr*/false)) /* An empty class has no data to read. */ return true; diff --git a/gcc/testsuite/g++.dg/cpp0x/noexcept80.C b/gcc/testsuite/g++.dg/cpp0x/noexcept80.C new file mode 100644 index 00000000000..3e90af747e2 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp0x/noexcept80.C @@ -0,0 +1,12 @@ +// PR c++/110106 +// { dg-do compile { target c++11 } } + +template<int> struct S +{ +}; + +struct G { + G(S<0>); +}; + +void y(S<0> s) noexcept(noexcept(G{s})); base-commit: 4b8878fbf7b74ea5c3405c9f558df0517036f131 -- 2.41.0 ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH] c++: fix ICE with is_really_empty_class [PR110106] 2023-07-20 19:51 ` Marek Polacek @ 2023-07-20 21:58 ` Marek Polacek 2023-07-21 17:44 ` Jason Merrill 2023-07-21 17:44 ` Jason Merrill 1 sibling, 1 reply; 12+ messages in thread From: Marek Polacek @ 2023-07-20 21:58 UTC (permalink / raw) To: Jason Merrill; +Cc: Patrick Palka, GCC Patches On Thu, Jul 20, 2023 at 03:51:32PM -0400, Marek Polacek wrote: > On Thu, Jul 20, 2023 at 02:37:07PM -0400, Jason Merrill wrote: > > On 7/20/23 14:13, Marek Polacek wrote: > > > On Wed, Jul 19, 2023 at 10:11:27AM -0400, Patrick Palka wrote: > > > > On Tue, 18 Jul 2023, Marek Polacek via Gcc-patches wrote: > > > > > > > > > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk and branches? > > > > > > > > Looks reasonable to me. > > > > > > Thanks. > > > > Though I wonder if we could also fix this by not checking potentiality > > > > at all in this case? The problematic call to is_rvalue_constant_expression > > > > happens from cp_parser_constant_expression with 'allow_non_constant' != 0 > > > > and with 'non_constant_p' being a dummy out argument that comes from > > > > cp_parser_functional_cast, so the result of is_rvalue_constant_expression > > > > is effectively unused in this case, and we should be able to safely elide > > > > it when 'allow_non_constant && non_constant_p == nullptr'. > > > > > > Sounds plausible. I think my patch could be applied first since it > > > removes a tiny bit of code, then I can hopefully remove the flag below, > > > then maybe go back and optimize the call to is_rvalue_constant_expression. > > > Does that sound sensible? > > > > > > > Relatedly, ISTM the member cp_parser::non_integral_constant_expression_p > > > > is also effectively unused and could be removed? > > > > > > It looks that way. Seems it's only used in cp_parser_constant_expression: > > > 10806 if (allow_non_constant_p) > > > 10807 *non_constant_p = parser->non_integral_constant_expression_p; > > > but that could be easily replaced by a local var. I'd be happy to see if > > > we can actually do away with it. (I wonder why it was introduced and when > > > it actually stopped being useful.) > > > > It was for the C++98 notion of constant-expression, which was more of a > > parser-level notion, and has been supplanted by the C++11 version. I'm > > happy to remove it, and therefore remove the is_rvalue_constant_expression > > call. > > Wonderful. I'll do that next. I found a use of parser->non_integral_constant_expression_p: finish_id_expression_1 can set it to true which then makes a difference in cp_parser_constant_expression in C++98. In cp_parser_constant_expression we set n_i_c_e_p to false, call cp_parser_assignment_expression in which finish_id_expression_1 sets n_i_c_e_p to true, then back in cp_parser_constant_expression we skip the cxx11 block, and set *non_constant_p to true. If I remove n_i_c_e_p, we lose that. This can be seen in init/array60.C. Marek ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH] c++: fix ICE with is_really_empty_class [PR110106] 2023-07-20 21:58 ` Marek Polacek @ 2023-07-21 17:44 ` Jason Merrill 2023-07-25 19:59 ` Marek Polacek 0 siblings, 1 reply; 12+ messages in thread From: Jason Merrill @ 2023-07-21 17:44 UTC (permalink / raw) To: Marek Polacek; +Cc: Patrick Palka, GCC Patches On 7/20/23 17:58, Marek Polacek wrote: > On Thu, Jul 20, 2023 at 03:51:32PM -0400, Marek Polacek wrote: >> On Thu, Jul 20, 2023 at 02:37:07PM -0400, Jason Merrill wrote: >>> On 7/20/23 14:13, Marek Polacek wrote: >>>> On Wed, Jul 19, 2023 at 10:11:27AM -0400, Patrick Palka wrote: >>>>> On Tue, 18 Jul 2023, Marek Polacek via Gcc-patches wrote: >>>>> >>>>>> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk and branches? >>>>> >>>>> Looks reasonable to me. >>>> >>>> Thanks. >>>>> Though I wonder if we could also fix this by not checking potentiality >>>>> at all in this case? The problematic call to is_rvalue_constant_expression >>>>> happens from cp_parser_constant_expression with 'allow_non_constant' != 0 >>>>> and with 'non_constant_p' being a dummy out argument that comes from >>>>> cp_parser_functional_cast, so the result of is_rvalue_constant_expression >>>>> is effectively unused in this case, and we should be able to safely elide >>>>> it when 'allow_non_constant && non_constant_p == nullptr'. >>>> >>>> Sounds plausible. I think my patch could be applied first since it >>>> removes a tiny bit of code, then I can hopefully remove the flag below, >>>> then maybe go back and optimize the call to is_rvalue_constant_expression. >>>> Does that sound sensible? >>>> >>>>> Relatedly, ISTM the member cp_parser::non_integral_constant_expression_p >>>>> is also effectively unused and could be removed? >>>> >>>> It looks that way. Seems it's only used in cp_parser_constant_expression: >>>> 10806 if (allow_non_constant_p) >>>> 10807 *non_constant_p = parser->non_integral_constant_expression_p; >>>> but that could be easily replaced by a local var. I'd be happy to see if >>>> we can actually do away with it. (I wonder why it was introduced and when >>>> it actually stopped being useful.) >>> >>> It was for the C++98 notion of constant-expression, which was more of a >>> parser-level notion, and has been supplanted by the C++11 version. I'm >>> happy to remove it, and therefore remove the is_rvalue_constant_expression >>> call. >> >> Wonderful. I'll do that next. > > I found a use of parser->non_integral_constant_expression_p: > finish_id_expression_1 can set it to true which then makes > a difference in cp_parser_constant_expression in C++98. In > cp_parser_constant_expression we set n_i_c_e_p to false, call > cp_parser_assignment_expression in which finish_id_expression_1 > sets n_i_c_e_p to true, then back in cp_parser_constant_expression > we skip the cxx11 block, and set *non_constant_p to true. If I > remove n_i_c_e_p, we lose that. This can be seen in init/array60.C. Sure, we would need to use the C++11 code for C++98 mode, which is likely fine but is more uncertain. It's probably simpler to just ignore n_i_c_e_p for C++11 and up, along with Patrick's suggestion of allowing null non_constant_p with true allow_non_constant_p. Jason ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH] c++: fix ICE with is_really_empty_class [PR110106] 2023-07-21 17:44 ` Jason Merrill @ 2023-07-25 19:59 ` Marek Polacek 2023-07-25 20:24 ` Jason Merrill 0 siblings, 1 reply; 12+ messages in thread From: Marek Polacek @ 2023-07-25 19:59 UTC (permalink / raw) To: Jason Merrill; +Cc: Patrick Palka, GCC Patches On Fri, Jul 21, 2023 at 01:44:17PM -0400, Jason Merrill wrote: > On 7/20/23 17:58, Marek Polacek wrote: > > On Thu, Jul 20, 2023 at 03:51:32PM -0400, Marek Polacek wrote: > > > On Thu, Jul 20, 2023 at 02:37:07PM -0400, Jason Merrill wrote: > > > > On 7/20/23 14:13, Marek Polacek wrote: > > > > > On Wed, Jul 19, 2023 at 10:11:27AM -0400, Patrick Palka wrote: > > > > > > On Tue, 18 Jul 2023, Marek Polacek via Gcc-patches wrote: > > > > > > > > > > > > > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk and branches? > > > > > > > > > > > > Looks reasonable to me. > > > > > > > > > > Thanks. > > > > > > Though I wonder if we could also fix this by not checking potentiality > > > > > > at all in this case? The problematic call to is_rvalue_constant_expression > > > > > > happens from cp_parser_constant_expression with 'allow_non_constant' != 0 > > > > > > and with 'non_constant_p' being a dummy out argument that comes from > > > > > > cp_parser_functional_cast, so the result of is_rvalue_constant_expression > > > > > > is effectively unused in this case, and we should be able to safely elide > > > > > > it when 'allow_non_constant && non_constant_p == nullptr'. > > > > > > > > > > Sounds plausible. I think my patch could be applied first since it > > > > > removes a tiny bit of code, then I can hopefully remove the flag below, > > > > > then maybe go back and optimize the call to is_rvalue_constant_expression. > > > > > Does that sound sensible? > > > > > > > > > > > Relatedly, ISTM the member cp_parser::non_integral_constant_expression_p > > > > > > is also effectively unused and could be removed? > > > > > > > > > > It looks that way. Seems it's only used in cp_parser_constant_expression: > > > > > 10806 if (allow_non_constant_p) > > > > > 10807 *non_constant_p = parser->non_integral_constant_expression_p; > > > > > but that could be easily replaced by a local var. I'd be happy to see if > > > > > we can actually do away with it. (I wonder why it was introduced and when > > > > > it actually stopped being useful.) > > > > > > > > It was for the C++98 notion of constant-expression, which was more of a > > > > parser-level notion, and has been supplanted by the C++11 version. I'm > > > > happy to remove it, and therefore remove the is_rvalue_constant_expression > > > > call. > > > > > > Wonderful. I'll do that next. > > > > I found a use of parser->non_integral_constant_expression_p: > > finish_id_expression_1 can set it to true which then makes > > a difference in cp_parser_constant_expression in C++98. In > > cp_parser_constant_expression we set n_i_c_e_p to false, call > > cp_parser_assignment_expression in which finish_id_expression_1 > > sets n_i_c_e_p to true, then back in cp_parser_constant_expression > > we skip the cxx11 block, and set *non_constant_p to true. If I > > remove n_i_c_e_p, we lose that. This can be seen in init/array60.C. > > Sure, we would need to use the C++11 code for C++98 mode, which is likely > fine but is more uncertain. > > It's probably simpler to just ignore n_i_c_e_p for C++11 and up, along with > Patrick's suggestion of allowing null non_constant_p with true > allow_non_constant_p. Something like this, then? I see that cp_parser_initializer_clause et al offer further opportunities (because they sometimes use a dummy too) but this should be a good start. Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk? -- >8 -- It's pointless to call *_rvalue_constant_expression when we're not using the result. Also apply some drive-by cleanups. gcc/cp/ChangeLog: * parser.cc (cp_parser_constant_expression): Allow non_constant_p to be nullptr even when allow_non_constant_p is true. Don't call _rvalue_constant_expression when not necessary. Move local variable declarations closer to their first use. (cp_parser_static_assert): Don't pass a dummy down to cp_parser_constant_expression. --- gcc/cp/parser.cc | 24 +++++++++++------------- 1 file changed, 11 insertions(+), 13 deletions(-) diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc index 5e2b5cba57e..efaa806f107 100644 --- a/gcc/cp/parser.cc +++ b/gcc/cp/parser.cc @@ -10734,11 +10734,6 @@ cp_parser_constant_expression (cp_parser* parser, bool *non_constant_p /* = NULL */, bool strict_p /* = false */) { - bool saved_integral_constant_expression_p; - bool saved_allow_non_integral_constant_expression_p; - bool saved_non_integral_constant_expression_p; - cp_expr expression; - /* It might seem that we could simply parse the conditional-expression, and then check to see if it were TREE_CONSTANT. However, an expression that is TREE_CONSTANT is @@ -10757,10 +10752,12 @@ cp_parser_constant_expression (cp_parser* parser, will fold this operation to an INTEGER_CST for `3'. */ /* Save the old settings. */ - saved_integral_constant_expression_p = parser->integral_constant_expression_p; - saved_allow_non_integral_constant_expression_p + bool saved_integral_constant_expression_p + = parser->integral_constant_expression_p; + bool saved_allow_non_integral_constant_expression_p = parser->allow_non_integral_constant_expression_p; - saved_non_integral_constant_expression_p = parser->non_integral_constant_expression_p; + bool saved_non_integral_constant_expression_p + = parser->non_integral_constant_expression_p; /* We are now parsing a constant-expression. */ parser->integral_constant_expression_p = true; parser->allow_non_integral_constant_expression_p @@ -10780,6 +10777,7 @@ cp_parser_constant_expression (cp_parser* parser, For example, cp_parser_initializer_clauses uses this function to determine whether a particular assignment-expression is in fact constant. */ + cp_expr expression; if (strict_p) expression = cp_parser_conditional_expression (parser); else @@ -10789,7 +10787,8 @@ cp_parser_constant_expression (cp_parser* parser, = saved_integral_constant_expression_p; parser->allow_non_integral_constant_expression_p = saved_allow_non_integral_constant_expression_p; - if (cxx_dialect >= cxx11) + if (cxx_dialect >= cxx11 + && (!allow_non_constant_p || non_constant_p)) { /* Require an rvalue constant expression here; that's what our callers expect. Reference constant expressions are handled @@ -10803,7 +10802,7 @@ cp_parser_constant_expression (cp_parser* parser, if (!is_const && !allow_non_constant_p) require_rvalue_constant_expression (decay); } - if (allow_non_constant_p) + if (allow_non_constant_p && non_constant_p) *non_constant_p = parser->non_integral_constant_expression_p; parser->non_integral_constant_expression_p = saved_non_integral_constant_expression_p; @@ -16400,12 +16399,11 @@ cp_parser_linkage_specification (cp_parser* parser, tree prefix_attr) If MEMBER_P, this static_assert is a class member. */ static void -cp_parser_static_assert(cp_parser *parser, bool member_p) +cp_parser_static_assert (cp_parser *parser, bool member_p) { cp_expr condition; location_t token_loc; tree message; - bool dummy; /* Peek at the `static_assert' token so we can keep track of exactly where the static assertion started. */ @@ -16430,7 +16428,7 @@ cp_parser_static_assert(cp_parser *parser, bool member_p) condition = cp_parser_constant_expression (parser, /*allow_non_constant_p=*/true, - /*non_constant_p=*/&dummy); + /*non_constant_p=*/nullptr); if (cp_lexer_peek_token (parser->lexer)->type == CPP_CLOSE_PAREN) { base-commit: 6e424febfbcb27c21a7fe3a137e614765f9cf9d2 -- 2.41.0 ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH] c++: fix ICE with is_really_empty_class [PR110106] 2023-07-25 19:59 ` Marek Polacek @ 2023-07-25 20:24 ` Jason Merrill 2023-07-25 20:30 ` Marek Polacek 0 siblings, 1 reply; 12+ messages in thread From: Jason Merrill @ 2023-07-25 20:24 UTC (permalink / raw) To: Marek Polacek; +Cc: Patrick Palka, GCC Patches On 7/25/23 15:59, Marek Polacek wrote: > On Fri, Jul 21, 2023 at 01:44:17PM -0400, Jason Merrill wrote: >> On 7/20/23 17:58, Marek Polacek wrote: >>> On Thu, Jul 20, 2023 at 03:51:32PM -0400, Marek Polacek wrote: >>>> On Thu, Jul 20, 2023 at 02:37:07PM -0400, Jason Merrill wrote: >>>>> On 7/20/23 14:13, Marek Polacek wrote: >>>>>> On Wed, Jul 19, 2023 at 10:11:27AM -0400, Patrick Palka wrote: >>>>>>> On Tue, 18 Jul 2023, Marek Polacek via Gcc-patches wrote: >>>>>>> >>>>>>>> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk and branches? >>>>>>> >>>>>>> Looks reasonable to me. >>>>>> >>>>>> Thanks. >>>>>>> Though I wonder if we could also fix this by not checking potentiality >>>>>>> at all in this case? The problematic call to is_rvalue_constant_expression >>>>>>> happens from cp_parser_constant_expression with 'allow_non_constant' != 0 >>>>>>> and with 'non_constant_p' being a dummy out argument that comes from >>>>>>> cp_parser_functional_cast, so the result of is_rvalue_constant_expression >>>>>>> is effectively unused in this case, and we should be able to safely elide >>>>>>> it when 'allow_non_constant && non_constant_p == nullptr'. >>>>>> >>>>>> Sounds plausible. I think my patch could be applied first since it >>>>>> removes a tiny bit of code, then I can hopefully remove the flag below, >>>>>> then maybe go back and optimize the call to is_rvalue_constant_expression. >>>>>> Does that sound sensible? >>>>>> >>>>>>> Relatedly, ISTM the member cp_parser::non_integral_constant_expression_p >>>>>>> is also effectively unused and could be removed? >>>>>> >>>>>> It looks that way. Seems it's only used in cp_parser_constant_expression: >>>>>> 10806 if (allow_non_constant_p) >>>>>> 10807 *non_constant_p = parser->non_integral_constant_expression_p; >>>>>> but that could be easily replaced by a local var. I'd be happy to see if >>>>>> we can actually do away with it. (I wonder why it was introduced and when >>>>>> it actually stopped being useful.) >>>>> >>>>> It was for the C++98 notion of constant-expression, which was more of a >>>>> parser-level notion, and has been supplanted by the C++11 version. I'm >>>>> happy to remove it, and therefore remove the is_rvalue_constant_expression >>>>> call. >>>> >>>> Wonderful. I'll do that next. >>> >>> I found a use of parser->non_integral_constant_expression_p: >>> finish_id_expression_1 can set it to true which then makes >>> a difference in cp_parser_constant_expression in C++98. In >>> cp_parser_constant_expression we set n_i_c_e_p to false, call >>> cp_parser_assignment_expression in which finish_id_expression_1 >>> sets n_i_c_e_p to true, then back in cp_parser_constant_expression >>> we skip the cxx11 block, and set *non_constant_p to true. If I >>> remove n_i_c_e_p, we lose that. This can be seen in init/array60.C. >> >> Sure, we would need to use the C++11 code for C++98 mode, which is likely >> fine but is more uncertain. >> >> It's probably simpler to just ignore n_i_c_e_p for C++11 and up, along with >> Patrick's suggestion of allowing null non_constant_p with true >> allow_non_constant_p. > > Something like this, then? I see that cp_parser_initializer_clause et al > offer further opportunities (because they sometimes use a dummy too) but > this should be a good start. Looks good. Please do update the other callers as well, while you're looking at this. > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk? > > -- >8 -- > It's pointless to call *_rvalue_constant_expression when we're not using > the result. Also apply some drive-by cleanups. > > gcc/cp/ChangeLog: > > * parser.cc (cp_parser_constant_expression): Allow non_constant_p to be > nullptr even when allow_non_constant_p is true. Don't call > _rvalue_constant_expression when not necessary. Move local variable > declarations closer to their first use. > (cp_parser_static_assert): Don't pass a dummy down to > cp_parser_constant_expression. > --- > gcc/cp/parser.cc | 24 +++++++++++------------- > 1 file changed, 11 insertions(+), 13 deletions(-) > > diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc > index 5e2b5cba57e..efaa806f107 100644 > --- a/gcc/cp/parser.cc > +++ b/gcc/cp/parser.cc > @@ -10734,11 +10734,6 @@ cp_parser_constant_expression (cp_parser* parser, > bool *non_constant_p /* = NULL */, > bool strict_p /* = false */) > { > - bool saved_integral_constant_expression_p; > - bool saved_allow_non_integral_constant_expression_p; > - bool saved_non_integral_constant_expression_p; > - cp_expr expression; > - > /* It might seem that we could simply parse the > conditional-expression, and then check to see if it were > TREE_CONSTANT. However, an expression that is TREE_CONSTANT is > @@ -10757,10 +10752,12 @@ cp_parser_constant_expression (cp_parser* parser, > will fold this operation to an INTEGER_CST for `3'. */ > > /* Save the old settings. */ > - saved_integral_constant_expression_p = parser->integral_constant_expression_p; > - saved_allow_non_integral_constant_expression_p > + bool saved_integral_constant_expression_p > + = parser->integral_constant_expression_p; > + bool saved_allow_non_integral_constant_expression_p > = parser->allow_non_integral_constant_expression_p; > - saved_non_integral_constant_expression_p = parser->non_integral_constant_expression_p; > + bool saved_non_integral_constant_expression_p > + = parser->non_integral_constant_expression_p; > /* We are now parsing a constant-expression. */ > parser->integral_constant_expression_p = true; > parser->allow_non_integral_constant_expression_p > @@ -10780,6 +10777,7 @@ cp_parser_constant_expression (cp_parser* parser, > For example, cp_parser_initializer_clauses uses this function to > determine whether a particular assignment-expression is in fact > constant. */ > + cp_expr expression; > if (strict_p) > expression = cp_parser_conditional_expression (parser); > else > @@ -10789,7 +10787,8 @@ cp_parser_constant_expression (cp_parser* parser, > = saved_integral_constant_expression_p; > parser->allow_non_integral_constant_expression_p > = saved_allow_non_integral_constant_expression_p; > - if (cxx_dialect >= cxx11) > + if (cxx_dialect >= cxx11 > + && (!allow_non_constant_p || non_constant_p)) > { > /* Require an rvalue constant expression here; that's what our > callers expect. Reference constant expressions are handled > @@ -10803,7 +10802,7 @@ cp_parser_constant_expression (cp_parser* parser, > if (!is_const && !allow_non_constant_p) > require_rvalue_constant_expression (decay); > } > - if (allow_non_constant_p) > + if (allow_non_constant_p && non_constant_p) > *non_constant_p = parser->non_integral_constant_expression_p; > parser->non_integral_constant_expression_p > = saved_non_integral_constant_expression_p; > @@ -16400,12 +16399,11 @@ cp_parser_linkage_specification (cp_parser* parser, tree prefix_attr) > If MEMBER_P, this static_assert is a class member. */ > > static void > -cp_parser_static_assert(cp_parser *parser, bool member_p) > +cp_parser_static_assert (cp_parser *parser, bool member_p) > { > cp_expr condition; > location_t token_loc; > tree message; > - bool dummy; > > /* Peek at the `static_assert' token so we can keep track of exactly > where the static assertion started. */ > @@ -16430,7 +16428,7 @@ cp_parser_static_assert(cp_parser *parser, bool member_p) > condition = > cp_parser_constant_expression (parser, > /*allow_non_constant_p=*/true, > - /*non_constant_p=*/&dummy); > + /*non_constant_p=*/nullptr); > > if (cp_lexer_peek_token (parser->lexer)->type == CPP_CLOSE_PAREN) > { > > base-commit: 6e424febfbcb27c21a7fe3a137e614765f9cf9d2 ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH] c++: fix ICE with is_really_empty_class [PR110106] 2023-07-25 20:24 ` Jason Merrill @ 2023-07-25 20:30 ` Marek Polacek 2023-07-26 2:03 ` Jason Merrill 0 siblings, 1 reply; 12+ messages in thread From: Marek Polacek @ 2023-07-25 20:30 UTC (permalink / raw) To: Jason Merrill; +Cc: Patrick Palka, GCC Patches On Tue, Jul 25, 2023 at 04:24:39PM -0400, Jason Merrill wrote: > On 7/25/23 15:59, Marek Polacek wrote: > > Something like this, then? I see that cp_parser_initializer_clause et al > > offer further opportunities (because they sometimes use a dummy too) but > > this should be a good start. > > Looks good. Please do update the other callers as well, while you're > looking at this. Thanks. Can I push this part first? ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH] c++: fix ICE with is_really_empty_class [PR110106] 2023-07-25 20:30 ` Marek Polacek @ 2023-07-26 2:03 ` Jason Merrill 0 siblings, 0 replies; 12+ messages in thread From: Jason Merrill @ 2023-07-26 2:03 UTC (permalink / raw) To: Marek Polacek; +Cc: Patrick Palka, GCC Patches On 7/25/23 16:30, Marek Polacek wrote: > On Tue, Jul 25, 2023 at 04:24:39PM -0400, Jason Merrill wrote: >> On 7/25/23 15:59, Marek Polacek wrote: >>> Something like this, then? I see that cp_parser_initializer_clause et al >>> offer further opportunities (because they sometimes use a dummy too) but >>> this should be a good start. >> >> Looks good. Please do update the other callers as well, while you're >> looking at this. > > Thanks. Can I push this part first? Ah, sure. I had thought the other callers would be trivial to add. Jason ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH] c++: fix ICE with is_really_empty_class [PR110106] 2023-07-20 19:51 ` Marek Polacek 2023-07-20 21:58 ` Marek Polacek @ 2023-07-21 17:44 ` Jason Merrill 1 sibling, 0 replies; 12+ messages in thread From: Jason Merrill @ 2023-07-21 17:44 UTC (permalink / raw) To: Marek Polacek; +Cc: Patrick Palka, GCC Patches On 7/20/23 15:51, Marek Polacek wrote: > On Thu, Jul 20, 2023 at 02:37:07PM -0400, Jason Merrill wrote: >> On 7/20/23 14:13, Marek Polacek wrote: >>> On Wed, Jul 19, 2023 at 10:11:27AM -0400, Patrick Palka wrote: >>>> On Tue, 18 Jul 2023, Marek Polacek via Gcc-patches wrote: >>>> >>>>> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk and branches? >>>> >>>> Looks reasonable to me. >>> >>> Thanks. >>>> Though I wonder if we could also fix this by not checking potentiality >>>> at all in this case? The problematic call to is_rvalue_constant_expression >>>> happens from cp_parser_constant_expression with 'allow_non_constant' != 0 >>>> and with 'non_constant_p' being a dummy out argument that comes from >>>> cp_parser_functional_cast, so the result of is_rvalue_constant_expression >>>> is effectively unused in this case, and we should be able to safely elide >>>> it when 'allow_non_constant && non_constant_p == nullptr'. >>> >>> Sounds plausible. I think my patch could be applied first since it >>> removes a tiny bit of code, then I can hopefully remove the flag below, >>> then maybe go back and optimize the call to is_rvalue_constant_expression. >>> Does that sound sensible? >>> >>>> Relatedly, ISTM the member cp_parser::non_integral_constant_expression_p >>>> is also effectively unused and could be removed? >>> >>> It looks that way. Seems it's only used in cp_parser_constant_expression: >>> 10806 if (allow_non_constant_p) >>> 10807 *non_constant_p = parser->non_integral_constant_expression_p; >>> but that could be easily replaced by a local var. I'd be happy to see if >>> we can actually do away with it. (I wonder why it was introduced and when >>> it actually stopped being useful.) >> >> It was for the C++98 notion of constant-expression, which was more of a >> parser-level notion, and has been supplanted by the C++11 version. I'm >> happy to remove it, and therefore remove the is_rvalue_constant_expression >> call. > > Wonderful. I'll do that next. > >>>>> -- >8 -- >>>>> >>>>> is_really_empty_class is liable to crash when it gets an incomplete >>>>> or dependent type. Since r11-557, we pass the yet-uninstantiated >>>>> class type S<0> of the PARM_DECL s to is_really_empty_class -- because >>>>> of the potential_rvalue_constant_expression -> is_rvalue_constant_expression >>>>> change in cp_parser_constant_expression. Here we're not parsing >>>>> a template so we did not check COMPLETE_TYPE_P as we should. >>>>> >>>>> PR c++/110106 >>>>> >>>>> gcc/cp/ChangeLog: >>>>> >>>>> * constexpr.cc (potential_constant_expression_1): Check COMPLETE_TYPE_P >>>>> even when !processing_template_decl. >>>>> >>>>> gcc/testsuite/ChangeLog: >>>>> >>>>> * g++.dg/cpp0x/noexcept80.C: New test. >>>>> --- >>>>> gcc/cp/constexpr.cc | 2 +- >>>>> gcc/testsuite/g++.dg/cpp0x/noexcept80.C | 12 ++++++++++++ >>>>> 2 files changed, 13 insertions(+), 1 deletion(-) >>>>> create mode 100644 gcc/testsuite/g++.dg/cpp0x/noexcept80.C >>>>> >>>>> diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc >>>>> index 6e8f1c2b61e..1f59c5472fb 100644 >>>>> --- a/gcc/cp/constexpr.cc >>>>> +++ b/gcc/cp/constexpr.cc >>>>> @@ -9116,7 +9116,7 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, >>>>> if (now && want_rval) >>>>> { >>>>> tree type = TREE_TYPE (t); >>>>> - if ((processing_template_decl && !COMPLETE_TYPE_P (type)) >>>>> + if (!COMPLETE_TYPE_P (type) >>>>> || dependent_type_p (type) >> >> There shouldn't be a problem completing the type here, so it seems to me >> that we're missing a call to complete_type_p, at least when >> !processing_template_decl. Probably need to move the dependent_type_p check >> up as a result. > > Like so? > > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk? OK. > -- >8 -- > is_really_empty_class is liable to crash when it gets an incomplete > or dependent type. Since r11-557, we pass the yet-uninstantiated > class type S<0> of the PARM_DECL s to is_really_empty_class -- because > of the potential_rvalue_constant_expression -> is_rvalue_constant_expression > change in cp_parser_constant_expression. Here we're not parsing > a template so we did not check COMPLETE_TYPE_P as we should. > > It should work to complete the type before checking COMPLETE_TYPE_P. > > PR c++/110106 > > gcc/cp/ChangeLog: > > * constexpr.cc (potential_constant_expression_1): Try to complete the > type when !processing_template_decl. > > gcc/testsuite/ChangeLog: > > * g++.dg/cpp0x/noexcept80.C: New test. > --- > gcc/cp/constexpr.cc | 5 +++-- > gcc/testsuite/g++.dg/cpp0x/noexcept80.C | 12 ++++++++++++ > 2 files changed, 15 insertions(+), 2 deletions(-) > create mode 100644 gcc/testsuite/g++.dg/cpp0x/noexcept80.C > > diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc > index 6e8f1c2b61e..fb94f3cefcb 100644 > --- a/gcc/cp/constexpr.cc > +++ b/gcc/cp/constexpr.cc > @@ -9116,8 +9116,9 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, > if (now && want_rval) > { > tree type = TREE_TYPE (t); > - if ((processing_template_decl && !COMPLETE_TYPE_P (type)) > - || dependent_type_p (type) > + if (dependent_type_p (type) > + || !COMPLETE_TYPE_P (processing_template_decl > + ? type : complete_type (type)) > || is_really_empty_class (type, /*ignore_vptr*/false)) > /* An empty class has no data to read. */ > return true; > diff --git a/gcc/testsuite/g++.dg/cpp0x/noexcept80.C b/gcc/testsuite/g++.dg/cpp0x/noexcept80.C > new file mode 100644 > index 00000000000..3e90af747e2 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/cpp0x/noexcept80.C > @@ -0,0 +1,12 @@ > +// PR c++/110106 > +// { dg-do compile { target c++11 } } > + > +template<int> struct S > +{ > +}; > + > +struct G { > + G(S<0>); > +}; > + > +void y(S<0> s) noexcept(noexcept(G{s})); > > base-commit: 4b8878fbf7b74ea5c3405c9f558df0517036f131 ^ permalink raw reply [flat|nested] 12+ messages in thread
end of thread, other threads:[~2023-07-26 2:03 UTC | newest] Thread overview: 12+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2023-07-18 21:14 [PATCH] c++: fix ICE with is_really_empty_class [PR110106] Marek Polacek 2023-07-19 14:11 ` Patrick Palka 2023-07-20 18:13 ` Marek Polacek 2023-07-20 18:37 ` Jason Merrill 2023-07-20 19:51 ` Marek Polacek 2023-07-20 21:58 ` Marek Polacek 2023-07-21 17:44 ` Jason Merrill 2023-07-25 19:59 ` Marek Polacek 2023-07-25 20:24 ` Jason Merrill 2023-07-25 20:30 ` Marek Polacek 2023-07-26 2:03 ` Jason Merrill 2023-07-21 17:44 ` Jason Merrill
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