From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 1734) id 24FD7385E019; Thu, 24 Mar 2022 22:44:14 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 24FD7385E019 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="utf-8" From: Marek Polacek To: gcc-cvs@gcc.gnu.org Subject: [gcc r12-7805] c++: ICE with template code in constexpr [PR104284] X-Act-Checkin: gcc X-Git-Author: Marek Polacek X-Git-Refname: refs/heads/trunk X-Git-Oldrev: 346ab5a54a831ad9c78afcbd8dfe98e0e07e3070 X-Git-Newrev: 9fdac7e16c940fb6264e6ddaf99c761f1a64a054 Message-Id: <20220324224414.24FD7385E019@sourceware.org> Date: Thu, 24 Mar 2022 22:44:14 +0000 (GMT) X-BeenThere: gcc-cvs@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-cvs mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 24 Mar 2022 22:44:14 -0000 https://gcc.gnu.org/g:9fdac7e16c940fb6264e6ddaf99c761f1a64a054 commit r12-7805-g9fdac7e16c940fb6264e6ddaf99c761f1a64a054 Author: Marek Polacek Date: Thu Mar 17 14:39:37 2022 -0400 c++: ICE with template code in constexpr [PR104284] Since r9-6073 cxx_eval_store_expression preevaluates the value to be stored, and that revealed a crash where a template code (here, code=IMPLICIT_CONV_EXPR) leaks into cxx_eval*. It happens because we're performing build_vec_init while processing a template, which calls get_temp_regvar which creates an INIT_EXPR. This INIT_EXPR's RHS contains an rvalue conversion so we create an IMPLICIT_CONV_EXPR. Its operand is not type-dependent and the whole INIT_EXPR is not type-dependent. So we call build_non_dependent_expr which, with -fchecking=2, calls fold_non_dependent_expr. At this point the expression still has an IMPLICIT_CONV_EXPR, which ought to be handled in instantiate_non_dependent_expr_internal. However, tsubst_copy_and_build doesn't handle INIT_EXPR; it will just call tsubst_copy which does nothing when args is null. So we fail to replace the IMPLICIT_CONV_EXPR and ICE. The problem is that we call build_vec_init in a template in the first place. We can avoid doing so by checking p_t_d before calling build_aggr_init in check_initializer. PR c++/104284 gcc/cp/ChangeLog: * decl.cc (check_initializer): Don't call build_aggr_init in a template. gcc/testsuite/ChangeLog: * g++.dg/cpp1y/constexpr-104284-1.C: New test. * g++.dg/cpp1y/constexpr-104284-2.C: New test. * g++.dg/cpp1y/constexpr-104284-3.C: New test. * g++.dg/cpp1y/constexpr-104284-4.C: New test. Diff: --- gcc/cp/decl.cc | 4 +++ gcc/testsuite/g++.dg/cpp1y/constexpr-104284-1.C | 34 ++++++++++++++++++++++++ gcc/testsuite/g++.dg/cpp1y/constexpr-104284-2.C | 33 +++++++++++++++++++++++ gcc/testsuite/g++.dg/cpp1y/constexpr-104284-3.C | 33 +++++++++++++++++++++++ gcc/testsuite/g++.dg/cpp1y/constexpr-104284-4.C | 35 +++++++++++++++++++++++++ 5 files changed, 139 insertions(+) diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc index 68741bbf5d2..69f60a6dc0f 100644 --- a/gcc/cp/decl.cc +++ b/gcc/cp/decl.cc @@ -7332,6 +7332,10 @@ check_initializer (tree decl, tree init, int flags, vec **cleanups) && !(init && BRACE_ENCLOSED_INITIALIZER_P (init) && CP_AGGREGATE_TYPE_P (type) && (CLASS_TYPE_P (type) + /* The call to build_aggr_init below could end up + calling build_vec_init, which may break when we + are processing a template. */ + || processing_template_decl || !TYPE_NEEDS_CONSTRUCTING (type) || type_has_extended_temps (type)))) || (DECL_DECOMPOSITION_P (decl) && TREE_CODE (type) == ARRAY_TYPE)) diff --git a/gcc/testsuite/g++.dg/cpp1y/constexpr-104284-1.C b/gcc/testsuite/g++.dg/cpp1y/constexpr-104284-1.C new file mode 100644 index 00000000000..809c26a6161 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp1y/constexpr-104284-1.C @@ -0,0 +1,34 @@ +// PR c++/104284 +// { dg-do compile { target c++14 } } +// { dg-additional-options "-fchecking=2" } + +struct S { + char c{}; +}; + +auto x1 = [](auto) { constexpr S s[]{{}}; }; +auto x2 = [](auto) { constexpr S s[]{{'a'}}; }; +#if __cpp_designated_initializers >= 201707L +auto x3 = [](auto) { constexpr S s[]{{.c = 'a'}}; }; +#endif +auto x4 = [](auto) { constexpr S s[]{'a'}; }; +auto x5 = [](auto) { constexpr S s[]{{{}}}; }; + +template +constexpr void g () +{ + constexpr S s1[]{{}}; + static_assert(s1[0].c == '\0', ""); + constexpr S s2[]{{'a'}}; + static_assert(s2[0].c == 'a', ""); +#if __cpp_designated_initializers >= 201707L + constexpr S s3[]{{.c = 'a'}}; + static_assert(s3[0].c == 'a', ""); +#endif + constexpr S s4[]{'a'}; + static_assert(s4[0].c == 'a', ""); + constexpr S s5[]{{{}}}; + static_assert(s5[0].c == '\0', ""); +} + +static_assert ((g(), true), ""); diff --git a/gcc/testsuite/g++.dg/cpp1y/constexpr-104284-2.C b/gcc/testsuite/g++.dg/cpp1y/constexpr-104284-2.C new file mode 100644 index 00000000000..704d37de129 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp1y/constexpr-104284-2.C @@ -0,0 +1,33 @@ +// PR c++/104284 +// { dg-do compile { target c++14 } } +// { dg-additional-options "-fchecking=2" } + +struct S { + char a; + constexpr S() : a{'a'} { } + constexpr S(char a_) : a{a_} { } +}; + +auto x1 = [](auto) { constexpr S s[]{{}}; }; +auto x2 = [](auto) { constexpr S s[]{{'a'}}; }; +auto x3 = [](auto) { constexpr S s[]{'a'}; }; +auto x4 = [](auto) { constexpr S s[]{{{}}}; }; + +template +constexpr void g() +{ + constexpr S s1[]{{}}; + static_assert(s1[0].a == 'a', ""); + constexpr S s2[]{{'a'}}; + static_assert(s2[0].a == 'a', ""); + constexpr S s3[]{'a'}; + static_assert(s3[0].a == 'a', ""); + constexpr S s4[]{{{}}}; + static_assert(s4[0].a == '\0', ""); +} + +void +f () +{ + g(); +} diff --git a/gcc/testsuite/g++.dg/cpp1y/constexpr-104284-3.C b/gcc/testsuite/g++.dg/cpp1y/constexpr-104284-3.C new file mode 100644 index 00000000000..6f23b255f9c --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp1y/constexpr-104284-3.C @@ -0,0 +1,33 @@ +// PR c++/104284 +// { dg-do compile { target c++14 } } +// { dg-additional-options "-fchecking=2" } +// Like constexpr-104284.C, but the function template is not +// constexpr. In that case, we were still calling build_vec_init +// in a template, just not crashing. + +struct S { + char c{}; +}; + +template +void g () +{ + constexpr S s1[]{{}}; + static_assert(s1[0].c == '\0', ""); + constexpr S s2[]{{'a'}}; + static_assert(s2[0].c == 'a', ""); +#if __cpp_designated_initializers >= 201707L + constexpr S s3[]{{.c = 'a'}}; + static_assert(s3[0].c == 'a', ""); +#endif + constexpr S s4[]{'a'}; + static_assert(s4[0].c == 'a', ""); + constexpr S s5[]{{{}}}; + static_assert(s5[0].c == '\0', ""); +} + +void +f () +{ + g(); +} diff --git a/gcc/testsuite/g++.dg/cpp1y/constexpr-104284-4.C b/gcc/testsuite/g++.dg/cpp1y/constexpr-104284-4.C new file mode 100644 index 00000000000..a99d3255a47 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp1y/constexpr-104284-4.C @@ -0,0 +1,35 @@ +// PR c++/104284 +// { dg-do run { target c++14 } } +// { dg-additional-options "-fchecking=2" } + +struct S { + char c{}; +}; + +template +constexpr void g () +{ + S s1[]{{}}; + if (s1[0].c != '\0') + __builtin_abort (); + S s2[]{{'a'}}; + if (s2[0].c != 'a') + __builtin_abort (); +#if __cpp_designated_initializers >= 201707L + S s3[]{{.c = 'a'}}; + if (s3[0].c != 'a') + __builtin_abort (); +#endif + S s4[]{'a'}; + if (s4[0].c != 'a') + __builtin_abort (); + S s5[]{{{}}}; + if (s5[0].c != '\0') + __builtin_abort (); +} + +int +main () +{ + g(); +}