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GET /api/1.1/patches/2225228/?format=api
{ "id": 2225228, "url": "http://patchwork.ozlabs.org/api/1.1/patches/2225228/?format=api", "web_url": "http://patchwork.ozlabs.org/project/gcc/patch/20260420164552.1598895-1-jason@redhat.com/", "project": { "id": 17, "url": "http://patchwork.ozlabs.org/api/1.1/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 }, "msgid": "<20260420164552.1598895-1-jason@redhat.com>", "date": "2026-04-20T16:45:36", "name": "[pushed] c++: std::optional reset and constexpr [PR124910]", "commit_ref": null, "pull_url": null, "state": "new", "archived": false, "hash": "0a79478e25b2ea4d283b2761b833c10d58c1d28b", "submitter": { "id": 4337, "url": "http://patchwork.ozlabs.org/api/1.1/people/4337/?format=api", "name": "Jason Merrill", "email": "jason@redhat.com" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/gcc/patch/20260420164552.1598895-1-jason@redhat.com/mbox/", "series": [ { "id": 500638, "url": "http://patchwork.ozlabs.org/api/1.1/series/500638/?format=api", "web_url": "http://patchwork.ozlabs.org/project/gcc/list/?series=500638", "date": "2026-04-20T16:45:36", "name": "[pushed] c++: std::optional reset and constexpr [PR124910]", "version": 1, "mbox": "http://patchwork.ozlabs.org/series/500638/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/2225228/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/2225228/checks/", "tags": {}, "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=GPn6shxv;\n\tdkim-atps=neutral", "legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=gcc.gnu.org\n (client-ip=2620:52:6:3111::32; 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Mon, 20 Apr 2026 16:45:53 +0000 (UTC)", "from jason-thinkpadp1gen4i.rmtusma.csb (unknown [10.22.65.102])\n by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP\n id 8AB2E180047F\n for <gcc-patches@gcc.gnu.org>; Mon, 20 Apr 2026 16:45:53 +0000 (UTC)" ], "DKIM-Filter": [ "OpenDKIM Filter v2.11.0 sourceware.org 847F34B7A1C5", "OpenDKIM Filter v2.11.0 sourceware.org 9B96E4BC0577" ], "DMARC-Filter": "OpenDMARC Filter v1.4.2 sourceware.org 9B96E4BC0577", "ARC-Filter": "OpenARC Filter v1.0.0 sourceware.org 9B96E4BC0577", "ARC-Seal": "i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1776703565; cv=none;\n b=AKiFSULgj0Q8PrGbGXPgMPTg94ereCxC2tMGD0OIUxM3S/lKFDQDR0vSmJHR6i2P04c6Dh5v3ua6idw5X0vdlZaR0nFrD6oKeT7PdWgAggtzdfD30JNZDDNwrD/rYYrvdUCYUPcHqPpTU/PYbvqmPU4MyFpzm6n6g5d3zBqgy0U=", "ARC-Message-Signature": "i=1; a=rsa-sha256; d=sourceware.org; s=key;\n t=1776703565; c=relaxed/simple;\n bh=iQhU2n5jr7nlBI1JDxS+aYtHmzIu+dbehF1aC2Vrsew=;\n h=DKIM-Signature:From:To:Subject:Date:Message-ID:MIME-Version;\n b=VM52ChykJbxHJiPUw8f+/UtJqb5qH0md8XeYTJ2Rg4srb5FZZt0mXdqx8IRnsFiEipWin4JcN/fT8RyoNSX4VT1F3PMBUtELHeSB48QT4OkMIuquFUv2yQvXn+6g5s1SSvFzwJ4bXSyCA7HQPdXcp5OJqrtisN0BOF0/kIveH8M=", "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=1776703565;\n h=from:from:reply-to:subject:subject:date:date:message-id:message-id:\n to:to:cc:mime-version:mime-version:content-type:content-type:\n content-transfer-encoding:content-transfer-encoding;\n bh=8Jf+HMVHf8dld6n71uA+QUMDzQLn1uJ/x79dD3Gan70=;\n b=GPn6shxvT517dw7i8IIgGb5wl3OQNrG/k/rl4GgMimhz6ZGQNZEn6qpSP0LYkJ9MVdBdvv\n MbRFz0562TYsSEAlU4ab6I+5hn213bLtlcjv6HuPZOwwjMEIWcuxnmJnDMuxbp1WL2DMGL\n NK2NFLVG7iyKmHiYh2Rmh05lsUBoj5I=", "X-MC-Unique": "SXp4UEM-OPOR2LUHYtAIVg-1", "X-Mimecast-MFC-AGG-ID": "SXp4UEM-OPOR2LUHYtAIVg_1776703554", "From": "Jason Merrill <jason@redhat.com>", "To": "gcc-patches@gcc.gnu.org", "Subject": "[pushed] c++: std::optional reset and constexpr [PR124910]", "Date": "Mon, 20 Apr 2026 12:45:36 -0400", "Message-ID": "<20260420164552.1598895-1-jason@redhat.com>", "MIME-Version": "1.0", "X-Scanned-By": "MIMEDefang 3.4.1 on 10.30.177.93", "X-Mimecast-Spam-Score": "0", "X-Mimecast-MFC-PROC-ID": "5y3H57iSPdSMYoeV8zm7xLgtnQUB9-68alb2PxxsvME_1776703554", "X-Mimecast-Originator": "redhat.com", "Content-Transfer-Encoding": "8bit", "content-type": "text/plain; charset=\"US-ASCII\"; x-default=true", "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>", "Errors-To": "gcc-patches-bounces~incoming=patchwork.ozlabs.org@gcc.gnu.org" }, "content": "Tested x86_64-pc-linux-gnu, applying to trunk.\n\n-- 8< --\n\nConstant evaluation didn't recognize that destroying _M_value made it no\nlonger the active member of the anonymous union, so we were treating the\nresult as containing an out-of-lifetime value. Instead we should treat the\nunion as no longer having an active member.\n\n\tPR c++/124910\n\ngcc/cp/ChangeLog:\n\n\t* constexpr.cc (cxx_eval_store_expression): Ending the\n\tlifetime of the active member means no active member.\n\ngcc/testsuite/ChangeLog:\n\n\t* g++.dg/cpp2a/constexpr-union11.C: New test.\n---\n gcc/cp/constexpr.cc | 10 +++++++\n .../g++.dg/cpp2a/constexpr-union11.C | 29 +++++++++++++++++++\n 2 files changed, 39 insertions(+)\n create mode 100644 gcc/testsuite/g++.dg/cpp2a/constexpr-union11.C\n\n\nbase-commit: b40bb34c3f5e9942d083efdee393c6e2d25e5981", "diff": "diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc\nindex 5b7d385fa97..a593b66dd41 100644\n--- a/gcc/cp/constexpr.cc\n+++ b/gcc/cp/constexpr.cc\n@@ -8207,6 +8207,16 @@ cxx_eval_store_expression (const constexpr_ctx *ctx, tree t,\n \t no_zero_init = true;\n \t}\n \n+ /* Ending the lifetime of the active union member means the union no\n+\t longer has an active member. */\n+ if (code == UNION_TYPE && refs->is_empty ()\n+\t && TREE_CLOBBER_P (init)\n+\t && CLOBBER_KIND (init) >= CLOBBER_OBJECT_END)\n+\t{\n+\t vec_safe_truncate (CONSTRUCTOR_ELTS (*valp), 0);\n+\t return void_node;\n+\t}\n+\n ctors.safe_push (valp);\n vec_safe_push (indexes, index);\n \ndiff --git a/gcc/testsuite/g++.dg/cpp2a/constexpr-union11.C b/gcc/testsuite/g++.dg/cpp2a/constexpr-union11.C\nnew file mode 100644\nindex 00000000000..56919715f55\n--- /dev/null\n+++ b/gcc/testsuite/g++.dg/cpp2a/constexpr-union11.C\n@@ -0,0 +1,29 @@\n+// PR c++/124910\n+// { dg-do compile { target c++20 } }\n+\n+struct nullopt_t { } nullopt;\n+using _Stored_type = int;\n+struct _Empty { };\n+struct _Optional_payload_base {\n+ union {\n+ int _M_value = 1;\n+ _Empty _M_empty;\n+ };\n+ constexpr void _M_reset() {\n+ _M_value.~_Stored_type();\n+ _M_empty = {};\n+ }\n+};\n+struct _Optional_payload : _Optional_payload_base {};\n+struct _Optional_base {\n+ _Optional_payload _M_payload;\n+};\n+struct optional : _Optional_base {\n+ constexpr void operator=(nullopt_t) { _M_payload._M_reset(); }\n+};\n+constexpr auto f() {\n+ optional result;\n+ result = nullopt;\n+ return result;\n+}\n+constexpr auto v = f();\n", "prefixes": [ "pushed" ] }