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GET /api/patches/2216229/?format=api
{ "id": 2216229, "url": "http://patchwork.ozlabs.org/api/patches/2216229/?format=api", "web_url": "http://patchwork.ozlabs.org/project/gcc/patch/acTi9ApfgNjpz8TG@tucnak/", "project": { "id": 17, "url": "http://patchwork.ozlabs.org/api/projects/17/?format=api", "name": "GNU Compiler Collection", "link_name": "gcc", "list_id": "gcc-patches.gcc.gnu.org", "list_email": "gcc-patches@gcc.gnu.org", "web_url": null, "scm_url": null, "webscm_url": null, "list_archive_url": "", "list_archive_url_format": "", "commit_url_format": "" }, "msgid": "<acTi9ApfgNjpz8TG@tucnak>", "list_archive_url": null, "date": "2026-03-26T07:40:36", "name": "[RFC] c++, libstdc++: Attempt to implement P3842R1 - A conservative fix for constexpr uncaught_exceptions() and current_exception()", "commit_ref": null, "pull_url": null, "state": "new", "archived": false, "hash": "9e65b4091031d7a7de27a6779c18ceca3b5326dc", "submitter": { "id": 671, "url": "http://patchwork.ozlabs.org/api/people/671/?format=api", "name": "Jakub Jelinek", "email": "jakub@redhat.com" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/gcc/patch/acTi9ApfgNjpz8TG@tucnak/mbox/", "series": [ { "id": 497541, "url": "http://patchwork.ozlabs.org/api/series/497541/?format=api", "web_url": "http://patchwork.ozlabs.org/project/gcc/list/?series=497541", "date": "2026-03-26T07:40:36", "name": "[RFC] c++, libstdc++: Attempt to implement P3842R1 - A conservative fix for constexpr uncaught_exceptions() and current_exception()", "version": 1, "mbox": "http://patchwork.ozlabs.org/series/497541/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/2216229/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/2216229/checks/", "tags": {}, "related": [], "headers": { "Return-Path": "<gcc-patches-bounces~incoming=patchwork.ozlabs.org@gcc.gnu.org>", "X-Original-To": [ "incoming@patchwork.ozlabs.org", "gcc-patches@gcc.gnu.org" ], "Delivered-To": [ "patchwork-incoming@legolas.ozlabs.org", "gcc-patches@gcc.gnu.org" ], "Authentication-Results": [ "legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256\n header.s=mimecast20190719 header.b=GeRX50Ko;\n\tdkim-atps=neutral", "legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=gcc.gnu.org\n (client-ip=38.145.34.32; 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Thu, 26 Mar 2026 07:40:40 +0000 (UTC)", "from tucnak.zalov.cz (localhost [127.0.0.1])\n by tucnak.zalov.cz (8.18.1/8.18.1) with ESMTPS id 62Q7eaoD3900401\n (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT);\n Thu, 26 Mar 2026 08:40:36 +0100", "(from jakub@localhost)\n by tucnak.zalov.cz (8.18.1/8.18.1/Submit) id 62Q7eaP73900400;\n Thu, 26 Mar 2026 08:40:36 +0100" ], "DKIM-Filter": [ "OpenDKIM Filter v2.11.0 sourceware.org 4C54A4BA23C2", "OpenDKIM Filter v2.11.0 sourceware.org ECED34BA2E17" ], "DMARC-Filter": "OpenDMARC Filter v1.4.2 sourceware.org ECED34BA2E17", "ARC-Filter": "OpenARC Filter v1.0.0 sourceware.org ECED34BA2E17", "ARC-Seal": "i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1774510854; cv=none;\n b=xQBkVnkDhhgm5jJxkKZC65c9sc9lsqsfco+sGDz2U4FPxTXXlO6CmmxwWclv9vsjAbAM30/RxVZbo64U9t/s21/WogU/h/Ff4foYYIgvGjyRiV9bO0jCjzq98Nj2Fd2OUX29vYdKGhVOTF+uEDxCP97i5xnTa3JHKQvsijJnP/w=", "ARC-Message-Signature": "i=1; a=rsa-sha256; d=sourceware.org; s=key;\n t=1774510854; c=relaxed/simple;\n bh=mS+qVTt1FkrNkVQHENpjevPvCC5lcrlFWiVda4BEb8k=;\n h=DKIM-Signature:Date:From:To:Subject:Message-ID:MIME-Version;\n b=N1icSFIZFMHimzvTywwfFfbdCnHlvVC+W9NSsKwnePcaOfgLcKFU/SsI3Ch1gGu/vSc5Hm4aENBSDUrweGTHxGZzEgjOuBW2G2PfkxctGQRU4bPhJJcOS9n4McpTtZeuZIdjZp9oPbsXZKSasbsbHlGZUZJbLYKHuI3SKerr6aE=", "ARC-Authentication-Results": "i=1; server2.sourceware.org", "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com;\n s=mimecast20190719; t=1774510853;\n h=from:from:reply-to:reply-to:subject:subject:date:date:\n message-id:message-id:to:to:cc:cc:mime-version:mime-version:\n content-type:content-type; bh=A5a4Ofw/L9Fq9g54QcxomthwsHpKEHCNH5Z1bwa1t+E=;\n b=GeRX50KoCo4nDc7M3z0vEenhZVgEBYkP28On7B6vvVVbJrtw03dcE629j2M9gt6SQiZwB3\n G2u62Z3L66SumkyWAqP62XCPU4ilWiEWydSCcJFNFrVmmrl3/BMSev5X0V+E2pLcFnnv1E\n m86aLm5daqc9RW6c+LhIEw1oFYPix6I=", "X-MC-Unique": "Z7z7vA_yOn2g3Kr7Q4NsXA-1", "X-Mimecast-MFC-AGG-ID": "Z7z7vA_yOn2g3Kr7Q4NsXA_1774510841", "Date": "Thu, 26 Mar 2026 08:40:36 +0100", "From": "Jakub Jelinek <jakub@redhat.com>", "To": "Jason Merrill <jason@redhat.com>, Jonathan Wakely <jwakely@redhat.com>", "Cc": "gcc-patches@gcc.gnu.org, libstdc++@gcc.gnu.org,\n Ville Voutilainen <ville.voutilainen@gmail.com>, Hana =?iso-8859-1?q?Dus=ED?=\n\t=?iso-8859-1?q?kov=E1?= <hanicka@hanicka.net>", "Subject": "[RFC PATCH] c++, libstdc++: Attempt to implement P3842R1 - A\n conservative fix for constexpr uncaught_exceptions() and current_exception()", "Message-ID": "<acTi9ApfgNjpz8TG@tucnak>", "MIME-Version": "1.0", "X-Scanned-By": "MIMEDefang 3.0 on 10.30.177.12", "X-Mimecast-Spam-Score": "0", "X-Mimecast-MFC-PROC-ID": "lf6UK_xow-uuy9aTKKuIvG1fBhTgAD8iFDs1gDgq_EI_1774510841", "X-Mimecast-Originator": "redhat.com", "Content-Type": "text/plain; charset=us-ascii", "Content-Disposition": "inline", "X-BeenThere": "gcc-patches@gcc.gnu.org", "X-Mailman-Version": "2.1.30", "Precedence": "list", "List-Id": "Gcc-patches mailing list <gcc-patches.gcc.gnu.org>", "List-Unsubscribe": "<https://gcc.gnu.org/mailman/options/gcc-patches>,\n <mailto:gcc-patches-request@gcc.gnu.org?subject=unsubscribe>", "List-Archive": "<https://gcc.gnu.org/pipermail/gcc-patches/>", "List-Post": "<mailto:gcc-patches@gcc.gnu.org>", "List-Help": "<mailto:gcc-patches-request@gcc.gnu.org?subject=help>", "List-Subscribe": "<https://gcc.gnu.org/mailman/listinfo/gcc-patches>,\n <mailto:gcc-patches-request@gcc.gnu.org?subject=subscribe>", "Reply-To": "Jakub Jelinek <jakub@redhat.com>", "Errors-To": "gcc-patches-bounces~incoming=patchwork.ozlabs.org@gcc.gnu.org" }, "content": "Hi!\n\nThe following patch attempts to implement the\nP3842R1 - A conservative fix for constexpr uncaught_exceptions()\n\t and current_exception()\npaper. std::current_exception() and std::uncaught_exceptions() aren't\nconstexpr anymore (admittedly, they weren't declared that way in the\nheaders before either, but the FE magically treated them as such),\ninstead two new FE builtins are introduced so that one can get their\nbehavior before this patch when needed. So, at constant evaluation\ntime they are constant evaluated and if they are not folded away,\nthey are transformed into std::current_exception() or\nstd::uncaught_exceptions() runtime calls during gimplification.\n\nCompared to the paper, I had to also deal with nested_exception default\nctor which also calls current_exception.\n\nLightly tested on x86_64-linux so far.\n\n2026-03-26 Jakub Jelinek <jakub@redhat.com>\n\ngcc/cp/\n\t* cp-tree.h (enum cp_built_in_function): Add\n\tCP_BUILT_IN_CURRENT_EXCEPTION and CP_BUILT_IN_UNCAUGHT_EXCEPTIONS.\n\t* tree.cc (builtin_valid_in_constant_expr_p): Handle\n\tthose.\n\t* decl.cc (cxx_init_decl_processing): Build\n\tdecls for CP_BUILT_IN_CURRENT_EXCEPTION and\n\tCP_BUILT_IN_UNCAUGHT_EXCEPTIONS.\n\t(require_deduced_type): Deduce CP_BUILT_IN_CURRENT_EXCEPTION\n\treturn type.\n\t* cp-gimplify.cc (cp_gimplify_expr): Handle\n\tCP_BUILT_IN_CURRENT_EXCEPTION and CP_BUILT_IN_UNCAUGHT_EXCEPTIONS.\n\t* constexpr.cc (enum cxa_builtin): Remove STD_UNCAUGHT_EXCEPTIONS\n\tand STD_CURRENT_EXCEPTION, add BUILTIN_UNCAUGHT_EXCEPTIONS and\n\tBUILTIN_CURRENT_EXCEPTION, renumber some enumerators.\n\t(cxx_cxa_builtin_fn_p): Don't check for std::uncaught_exceptions\n\tnor std::current_exception.\n\t(cxx_eval_cxa_builtin_fn): Handle BUILTIN_UNCAUGHT_EXCEPTIONS\n\tand BUILTIN_CURRENT_EXCEPTION instead of STD_UNCAUGHT_EXCEPTIONS\n\tand STD_CURRENT_EXCEPTION.\n\t(cxx_eval_builtin_function_call): Handle\n\tCP_BUILT_IN_CURRENT_EXCEPTION and CP_BUILT_IN_UNCAUGHT_EXCEPTIONS.\n\tDo just one fndecl_builtin_p check for BUILT_IN_FRONTEND and\n\tswitch on DECL_FE_FUNCTION_CODE.\ngcc/testsuite/\n\t* g++.dg/cpp26/constexpr-eh3.C: Use __builtin_current_exception()\n\tinstead of std::current_exception() and\n\t__builttin_uncaught_exceptions() instead of\n\tstd::uncaught_exceptions().\n\t* g++.dg/cpp26/constexpr-eh8.C: Use __builtin_current_exception()\n\tinstead of std::current_exception().\nlibstdc++-v3/\n\t* libsupc++/exception_ptr.h (std::make_exception_ptr): Use\n\t__builtin_current_exception() instead of current_exception() if\n\tthe builtin exists.\n\t* libsupc++/nested_exception.h\n\t(std::nested_exception::nested_exception()): Likewise.\n\n\n\tJakub", "diff": "--- gcc/cp/cp-tree.h.jj\t2026-03-14 19:14:09.215002474 +0100\n+++ gcc/cp/cp-tree.h\t2026-03-26 07:13:41.876753432 +0100\n@@ -7135,6 +7135,8 @@ enum cp_built_in_function {\n CP_BUILT_IN_EH_PTR_ADJUST_REF,\n CP_BUILT_IN_IS_STRING_LITERAL,\n CP_BUILT_IN_CONSTEXPR_DIAG,\n+ CP_BUILT_IN_CURRENT_EXCEPTION,\n+ CP_BUILT_IN_UNCAUGHT_EXCEPTIONS,\n CP_BUILT_IN_LAST\n };\n \n--- gcc/cp/tree.cc.jj\t2026-03-17 10:13:37.458185984 +0100\n+++ gcc/cp/tree.cc\t2026-03-26 07:14:37.678808827 +0100\n@@ -570,6 +570,8 @@ builtin_valid_in_constant_expr_p (const_\n \t case CP_BUILT_IN_EH_PTR_ADJUST_REF:\n \t case CP_BUILT_IN_IS_STRING_LITERAL:\n \t case CP_BUILT_IN_CONSTEXPR_DIAG:\n+\t case CP_BUILT_IN_CURRENT_EXCEPTION:\n+\t case CP_BUILT_IN_UNCAUGHT_EXCEPTIONS:\n \t return true;\n \t default:\n \t break;\n--- gcc/cp/decl.cc.jj\t2026-03-14 20:48:22.203226599 +0100\n+++ gcc/cp/decl.cc\t2026-03-26 07:59:59.527656320 +0100\n@@ -5627,6 +5627,20 @@ cxx_init_decl_processing (void)\n \t\t\t\t CP_BUILT_IN_EH_PTR_ADJUST_REF,\n \t\t\t\t BUILT_IN_FRONTEND, NULL, NULL_TREE);\n set_call_expr_flags (decl, ECF_NOTHROW | ECF_LEAF);\n+\n+ /* Similar case to __builtin_source_locaiton above. The concrete\n+\t return type is std::exception_ptr, but we can't form the type\n+\t at this point, so it is deduced later. */\n+ decl = add_builtin_function (\"__builtin_current_exception\",\n+\t\t\t\t auto_ftype, CP_BUILT_IN_CURRENT_EXCEPTION,\n+\t\t\t\t BUILT_IN_FRONTEND, NULL, NULL_TREE);\n+ set_call_expr_flags (decl, ECF_NOTHROW | ECF_LEAF);\n+\n+ tree int_ftype = build_function_type_list (integer_type_node, NULL_TREE);\n+ decl = add_builtin_function (\"__builtin_uncaught_exceptions\",\n+\t\t\t\t int_ftype, CP_BUILT_IN_UNCAUGHT_EXCEPTIONS,\n+\t\t\t\t BUILT_IN_FRONTEND, NULL, NULL_TREE);\n+ set_call_expr_flags (decl, ECF_PURE | ECF_NOTHROW | ECF_LEAF);\n }\n \n decl\n@@ -21226,8 +21240,8 @@ require_deduced_type (tree decl, tsubst_\n if (undeduced_auto_decl (decl))\n {\n if (TREE_CODE (decl) == FUNCTION_DECL\n-\t && fndecl_built_in_p (decl, BUILT_IN_FRONTEND)\n-\t && DECL_FE_FUNCTION_CODE (decl) == CP_BUILT_IN_SOURCE_LOCATION)\n+\t && fndecl_built_in_p (decl, CP_BUILT_IN_SOURCE_LOCATION,\n+\t\t\t\tBUILT_IN_FRONTEND))\n \t{\n \t /* Set the return type of __builtin_source_location. */\n \t tree type = get_source_location_impl_type ();\n@@ -21242,6 +21256,33 @@ require_deduced_type (tree decl, tsubst_\n \t return true;\n \t}\n \n+ if (TREE_CODE (decl) == FUNCTION_DECL\n+\t && fndecl_built_in_p (decl, CP_BUILT_IN_CURRENT_EXCEPTION,\n+\t\t\t\tBUILT_IN_FRONTEND))\n+\t{\n+\t /* Set the return type of __builtin_current_exception. */\n+\t tree name = get_identifier (\"exception_ptr\");\n+\t tree eptr = lookup_qualified_name (std_node, name);\n+\t tree fld;\n+\t if (TREE_CODE (eptr) != TYPE_DECL\n+\t || !CLASS_TYPE_P (TREE_TYPE (eptr))\n+\t || !COMPLETE_TYPE_P (TREE_TYPE (eptr))\n+\t || !(fld = next_aggregate_field (TYPE_FIELDS (TREE_TYPE (eptr))))\n+\t || DECL_ARTIFICIAL (fld)\n+\t || TREE_CODE (TREE_TYPE (fld)) != POINTER_TYPE\n+\t || next_aggregate_field (DECL_CHAIN (fld))\n+\t || !tree_int_cst_equal (TYPE_SIZE (TREE_TYPE (eptr)),\n+\t\t\t\t TYPE_SIZE (TREE_TYPE (fld))))\n+\t {\n+\t error (\"%qs used without %qs declaration\",\n+\t\t \"__builtin_current_exception\", \"std::exception_ptr\");\n+\t return false;\n+\t }\n+\n+\t apply_deduced_return_type (decl, TREE_TYPE (eptr));\n+\t return true;\n+\t}\n+\n if (warning_suppressed_p (decl) && seen_error ())\n \t/* We probably already complained about deduction failure. */;\n else if (complain & tf_error)\n--- gcc/cp/cp-gimplify.cc.jj\t2026-02-17 15:56:52.069714036 +0100\n+++ gcc/cp/cp-gimplify.cc\t2026-03-26 07:59:10.326490311 +0100\n@@ -979,6 +979,32 @@ cp_gimplify_expr (tree *expr_p, gimple_s\n \t\t\t \"__builtin_eh_ptr_adjust_ref\");\n \t\t*expr_p = void_node;\n \t\tbreak;\n+\t case CP_BUILT_IN_CURRENT_EXCEPTION:\n+\t case CP_BUILT_IN_UNCAUGHT_EXCEPTIONS:\n+\t\t{\n+\t\t const char *name\n+\t\t = (DECL_FE_FUNCTION_CODE (decl)\n+\t\t == CP_BUILT_IN_CURRENT_EXCEPTION\n+\t\t ? \"current_exception\" : \"uncaught_exceptions\");\n+\t\t tree newdecl = lookup_qualified_name (std_node, name);\n+\t\t if (error_operand_p (newdecl))\n+\t\t *expr_p = build_zero_cst (TREE_TYPE (*expr_p));\n+\t\t else if (TREE_CODE (newdecl) != FUNCTION_DECL\n+\t\t\t || !same_type_p (TREE_TYPE (TREE_TYPE (newdecl)),\n+\t\t\t\t\t TREE_TYPE (TREE_TYPE (decl)))\n+\t\t\t || (TYPE_ARG_TYPES (TREE_TYPE (newdecl))\n+\t\t\t != void_list_node))\n+\t\t {\n+\t\t error_at (EXPR_LOCATION (*expr_p),\n+\t\t\t\t\"unexpected %<std::%s%> declaration\",\n+\t\t\t\tname);\n+\t\t *expr_p = build_zero_cst (TREE_TYPE (*expr_p));\n+\t\t }\n+\t\t else\n+\t\t *expr_p = build_call_expr_loc (EXPR_LOCATION (*expr_p),\n+\t\t\t\t\t\t newdecl, 0);\n+\t\t break;\n+\t\t}\n \t case CP_BUILT_IN_IS_STRING_LITERAL:\n \t\t*expr_p\n \t\t = fold_builtin_is_string_literal (EXPR_LOCATION (*expr_p),\n--- gcc/cp/constexpr.cc.jj\t2026-03-19 15:43:56.158342651 +0100\n+++ gcc/cp/constexpr.cc\t2026-03-26 07:35:40.946408082 +0100\n@@ -1804,10 +1804,10 @@ enum cxa_builtin {\n CXA_BAD_CAST = 8,\n CXA_BAD_TYPEID = 9,\n CXA_THROW_BAD_ARRAY_NEW_LENGTH = 10,\n- STD_UNCAUGHT_EXCEPTIONS = 11,\n- STD_CURRENT_EXCEPTION = 12,\n- STD_RETHROW_EXCEPTION = 13,\n- BUILTIN_EH_PTR_ADJUST_REF = 14\n+ STD_RETHROW_EXCEPTION = 11,\n+ BUILTIN_EH_PTR_ADJUST_REF = 12,\n+ BUILTIN_UNCAUGHT_EXCEPTIONS = 13,\n+ BUILTIN_CURRENT_EXCEPTION = 14\n };\n \n /* Return cxa_builtin if FNDECL is a __cxa_* function handled as\n@@ -1822,10 +1822,6 @@ cxx_cxa_builtin_fn_p (tree fndecl)\n {\n if (!decl_in_std_namespace_p (fndecl))\n \treturn CXA_NONE;\n- if (id_equal (DECL_NAME (fndecl), \"uncaught_exceptions\"))\n-\treturn STD_UNCAUGHT_EXCEPTIONS;\n- if (id_equal (DECL_NAME (fndecl), \"current_exception\"))\n-\treturn STD_CURRENT_EXCEPTION;\n if (id_equal (DECL_NAME (fndecl), \"rethrow_exception\"))\n \treturn STD_RETHROW_EXCEPTION;\n return CXA_NONE;\n@@ -2186,7 +2182,7 @@ cxx_eval_cxa_builtin_fn (const constexpr\n \t *jump_target = var;\n \t}\n return void_node;\n- case STD_UNCAUGHT_EXCEPTIONS:\n+ case BUILTIN_UNCAUGHT_EXCEPTIONS:\n if (nargs != 0)\n \tgoto invalid_nargs;\n /* Similarly to __builtin_is_constant_evaluated (), we don't\n@@ -2202,7 +2198,7 @@ cxx_eval_cxa_builtin_fn (const constexpr\n \t}\n return build_int_cst (integer_type_node,\n \t\t\t ctx->global->uncaught_exceptions);\n- case STD_CURRENT_EXCEPTION:\n+ case BUILTIN_CURRENT_EXCEPTION:\n if (nargs != 0)\n \tgoto invalid_nargs;\n else\n@@ -2489,40 +2485,53 @@ cxx_eval_builtin_function_call (const co\n return t;\n }\n \n- /* For __builtin_is_constant_evaluated, defer it if not\n- ctx->manifestly_const_eval (as sometimes we try to constant evaluate\n- without manifestly_const_eval even expressions or parts thereof which\n- will later be manifestly const_eval evaluated), otherwise fold it to\n- true. */\n- if (fndecl_built_in_p (fun, CP_BUILT_IN_IS_CONSTANT_EVALUATED,\n-\t\t\t BUILT_IN_FRONTEND))\n- {\n- if (ctx->manifestly_const_eval == mce_unknown)\n-\t{\n-\t *non_constant_p = true;\n-\t return t;\n-\t}\n- return constant_boolean_node (ctx->manifestly_const_eval == mce_true,\n-\t\t\t\t boolean_type_node);\n- }\n-\n- if (fndecl_built_in_p (fun, CP_BUILT_IN_SOURCE_LOCATION, BUILT_IN_FRONTEND))\n- {\n- temp_override<tree> ovr (current_function_decl);\n- if (ctx->call && ctx->call->fundef)\n-\tcurrent_function_decl = ctx->call->fundef->decl;\n- return fold_builtin_source_location (t);\n- }\n-\n- if (fndecl_built_in_p (fun, CP_BUILT_IN_EH_PTR_ADJUST_REF,\n-\t\t\t BUILT_IN_FRONTEND))\n- return cxx_eval_cxa_builtin_fn (ctx, t, BUILTIN_EH_PTR_ADJUST_REF,\n-\t\t\t\t fun, non_constant_p, overflow_p,\n-\t\t\t\t jump_target);\n+ if (fndecl_built_in_p (fun, BUILT_IN_FRONTEND))\n+ switch (DECL_FE_FUNCTION_CODE (fun))\n+ {\n+ case CP_BUILT_IN_IS_CONSTANT_EVALUATED:\n+\t/* For __builtin_is_constant_evaluated, defer it if not\n+\t ctx->manifestly_const_eval (as sometimes we try to constant evaluate\n+\t without manifestly_const_eval even expressions or parts thereof\n+\t which will later be manifestly const_eval evaluated), otherwise fold\n+\t it to true. */\n+\tif (ctx->manifestly_const_eval == mce_unknown)\n+\t {\n+\t *non_constant_p = true;\n+\t return t;\n+\t }\n+\treturn constant_boolean_node (ctx->manifestly_const_eval == mce_true,\n+\t\t\t\t boolean_type_node);\n \n- if (fndecl_built_in_p (fun, CP_BUILT_IN_CONSTEXPR_DIAG, BUILT_IN_FRONTEND))\n- return cxx_eval_constexpr_diag (ctx, t, non_constant_p, overflow_p,\n-\t\t\t\t jump_target);\n+ case CP_BUILT_IN_SOURCE_LOCATION:\n+\t{\n+\t temp_override<tree> ovr (current_function_decl);\n+\t if (ctx->call && ctx->call->fundef)\n+\t current_function_decl = ctx->call->fundef->decl;\n+\t return fold_builtin_source_location (t);\n+\t}\n+\n+ case CP_BUILT_IN_EH_PTR_ADJUST_REF:\n+\treturn cxx_eval_cxa_builtin_fn (ctx, t, BUILTIN_EH_PTR_ADJUST_REF,\n+\t\t\t\t\tfun, non_constant_p, overflow_p,\n+\t\t\t\t\tjump_target);\n+\n+ case CP_BUILT_IN_CURRENT_EXCEPTION:\n+\treturn cxx_eval_cxa_builtin_fn (ctx, t, BUILTIN_CURRENT_EXCEPTION,\n+\t\t\t\t\tfun, non_constant_p, overflow_p,\n+\t\t\t\t\tjump_target);\n+\n+ case CP_BUILT_IN_UNCAUGHT_EXCEPTIONS:\n+\treturn cxx_eval_cxa_builtin_fn (ctx, t, BUILTIN_UNCAUGHT_EXCEPTIONS,\n+\t\t\t\t\tfun, non_constant_p, overflow_p,\n+\t\t\t\t\tjump_target);\n+\n+ case CP_BUILT_IN_CONSTEXPR_DIAG:\n+\treturn cxx_eval_constexpr_diag (ctx, t, non_constant_p, overflow_p,\n+\t\t\t\t\tjump_target);\n+\n+ default:\n+\tbreak;\n+ }\n \n int strops = 0;\n int strret = 0;\n--- gcc/testsuite/g++.dg/cpp26/constexpr-eh3.C.jj\t2025-07-10 23:25:51.999281475 +0200\n+++ gcc/testsuite/g++.dg/cpp26/constexpr-eh3.C\t2026-03-26 07:47:22.816499223 +0100\n@@ -20,7 +20,7 @@ constexpr std::bad_typeid k;\n constexpr const char *l = k.what ();\n constexpr std::exception_ptr m = nullptr;\n static_assert (m == nullptr);\n-constexpr std::exception_ptr n = std::current_exception ();\n+constexpr std::exception_ptr n = __builtin_current_exception ();\n static_assert (n == nullptr);\n constexpr std::exception_ptr o;\n static_assert (o == nullptr);\n@@ -33,8 +33,8 @@ struct C { virtual void c (); };\n struct D : private B { virtual void d (); };\n struct E { virtual void e (); };\n struct F : D, E, private C { virtual void f (); };\n-struct G { constexpr G () { if (std::uncaught_exceptions () != 0) asm (\"\"); } };\n-struct H { constexpr H () : h (0) {} constexpr ~H () { if (std::uncaught_exceptions () != h) asm (\"\"); } int h; };\n+struct G { constexpr G () { if (__builtin_uncaught_exceptions () != 0) asm (\"\"); } };\n+struct H { constexpr H () : h (0) {} constexpr ~H () { if (__builtin_uncaught_exceptions () != h) asm (\"\"); } int h; };\n struct I : std::nested_exception { };\n struct J { virtual ~J () noexcept = default; };\n struct K final { };\n@@ -46,7 +46,7 @@ struct O : private std::nested_exception\n constexpr int\n foo (int x)\n {\n- if (std::uncaught_exceptions () != 0)\n+ if (__builtin_uncaught_exceptions () != 0)\n return -1;\n switch (x)\n {\n@@ -58,7 +58,7 @@ foo (int x)\n \t}\n catch (const std::bad_typeid &x)\n \t{\n-\t if (std::uncaught_exceptions () != 0)\n+\t if (__builtin_uncaught_exceptions () != 0)\n \t return -1;\n \t const char *p = x.what ();\n \t return 1;\n@@ -90,15 +90,15 @@ foo (int x)\n \t{\n \t H h;\n \t h.h = 1;\n-\t if (std::current_exception () != nullptr)\n+\t if (__builtin_current_exception () != nullptr)\n \t return -1;\n \t throw G ();\n \t}\n catch (const G &g)\n \t{\n-\t if (std::uncaught_exceptions () != 0)\n+\t if (__builtin_uncaught_exceptions () != 0)\n \t return -1;\n-\t if (std::current_exception () == nullptr)\n+\t if (__builtin_current_exception () == nullptr)\n \t return -1;\n \t return 3;\n \t}\n@@ -156,7 +156,7 @@ foo (int x)\n \t {\n \t if (a != 1)\n \t return -1;\n-\t b = std::current_exception ();\n+\t b = __builtin_current_exception ();\n \t if (b == nullptr)\n \t return -1;\n \t try\n@@ -167,14 +167,14 @@ foo (int x)\n \t {\n \t\tif (c != 2L)\n \t\t return -1;\n-\t\td = std::current_exception ();\n+\t\td = __builtin_current_exception ();\n \t\tif (d == nullptr || b == d)\n \t\t return -1;\n \t }\n-\t if (std::current_exception () != b)\n+\t if (__builtin_current_exception () != b)\n \t return -1;\n \t }\n-\tif (std::current_exception () != nullptr)\n+\tif (__builtin_current_exception () != nullptr)\n \t return -1;\n \ttry\n \t {\n@@ -281,7 +281,7 @@ foo (int x)\n \tcatch (...)\n \t {\n \t std::nested_exception c;\n-\t if (c.nested_ptr () != std::current_exception ())\n+\t if (c.nested_ptr () != __builtin_current_exception ())\n \t return -1;\n \t std::nested_exception d = c;\n \t if (d.nested_ptr () != c.nested_ptr ())\n@@ -439,4 +439,4 @@ static_assert (foo (12) == 13);\n static_assert (foo (13) == 14);\n static_assert (foo (14) == 15);\n static_assert (foo (15) == 16);\n-static_assert (std::uncaught_exceptions () == 0);\n+static_assert (__builtin_uncaught_exceptions () == 0);\n--- gcc/testsuite/g++.dg/cpp26/constexpr-eh8.C.jj\t2025-07-10 23:25:52.000281462 +0200\n+++ gcc/testsuite/g++.dg/cpp26/constexpr-eh8.C\t2026-03-26 07:47:38.627230789 +0100\n@@ -13,7 +13,7 @@ foo ()\n }\n catch (...)\n {\n- return std::current_exception ();\n+ return __builtin_current_exception ();\n }\n }\n \n--- libstdc++-v3/libsupc++/exception_ptr.h.jj\t2026-01-07 15:00:46.804265503 +0100\n+++ libstdc++-v3/libsupc++/exception_ptr.h\t2026-03-26 07:48:03.676805502 +0100\n@@ -342,7 +342,11 @@ namespace std _GLIBCXX_VISIBILITY(defaul\n \t}\n catch(...)\n \t{\n+#if __has_builtin(__builtin_current_exception)\n+\t return __builtin_current_exception();\n+#else\n \t return current_exception();\n+#endif\n \t}\n #endif\n return exception_ptr();\n--- libstdc++-v3/libsupc++/nested_exception.h.jj\t2026-01-07 15:00:46.804555760 +0100\n+++ libstdc++-v3/libsupc++/nested_exception.h\t2026-03-26 08:17:43.597623711 +0100\n@@ -62,8 +62,13 @@ namespace std _GLIBCXX_VISIBILITY(defaul\n \n public:\n /// The default constructor stores the current exception (if any).\n+#if __has_builtin(__builtin_current_exception)\n+ _GLIBCXX26_CONSTEXPR\n+ nested_exception() noexcept : _M_ptr(__builtin_current_exception()) { }\n+#else\n _GLIBCXX26_CONSTEXPR\n nested_exception() noexcept : _M_ptr(current_exception()) { }\n+#endif\n \n _GLIBCXX26_CONSTEXPR\n nested_exception(const nested_exception&) noexcept = default;\n", "prefixes": [ "RFC" ] }