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GET /api/patches/2226299/?format=api
{ "id": 2226299, "url": "http://patchwork.ozlabs.org/api/patches/2226299/?format=api", "web_url": "http://patchwork.ozlabs.org/project/gcc/patch/bmm.hhubwh7m90.gcc.gcc-TEST.pinskia.33.1.12@forge-stage.sourceware.org/", "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": "<bmm.hhubwh7m90.gcc.gcc-TEST.pinskia.33.1.12@forge-stage.sourceware.org>", "list_archive_url": null, "date": "2026-04-22T10:49:21", "name": "[v1,12/15] gimple-fold: Improve optimize_memcpy_to_memset by walking back until aliasing says the ref is a may clobber. [PR118947]", "commit_ref": null, "pull_url": null, "state": "new", "archived": false, "hash": "396b69430fbfd1798e0d6a4276255f0a068e5b65", "submitter": { "id": 93219, "url": "http://patchwork.ozlabs.org/api/people/93219/?format=api", "name": "Andrew Pinski via Sourceware Forge", "email": "forge-bot+pinskia@forge-stage.sourceware.org" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/gcc/patch/bmm.hhubwh7m90.gcc.gcc-TEST.pinskia.33.1.12@forge-stage.sourceware.org/mbox/", "series": [ { "id": 500990, "url": "http://patchwork.ozlabs.org/api/series/500990/?format=api", "web_url": "http://patchwork.ozlabs.org/project/gcc/list/?series=500990", "date": "2026-04-22T10:49:12", "name": "copy-prop-arg", "version": 1, "mbox": "http://patchwork.ozlabs.org/series/500990/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/2226299/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/2226299/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 spf=pass (sender SPF authorized) smtp.mailfrom=gcc.gnu.org\n (client-ip=2620:52:6:3111::32; helo=vm01.sourceware.org;\n envelope-from=gcc-patches-bounces~incoming=patchwork.ozlabs.org@gcc.gnu.org;\n receiver=patchwork.ozlabs.org)", "sourceware.org; dmarc=none (p=none dis=none)\n header.from=forge-stage.sourceware.org", "sourceware.org;\n spf=pass smtp.mailfrom=forge-stage.sourceware.org", "server2.sourceware.org;\n arc=none smtp.remote-ip=38.145.34.39" ], "Received": [ "from vm01.sourceware.org (vm01.sourceware.org\n [IPv6:2620:52:6:3111::32])\n\t(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n\t key-exchange x25519 server-signature ECDSA (secp384r1) server-digest SHA384)\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4g0xcB4k1pz1yD5\n\tfor <incoming@patchwork.ozlabs.org>; Wed, 22 Apr 2026 21:20:58 +1000 (AEST)", "from vm01.sourceware.org (localhost [127.0.0.1])\n\tby sourceware.org (Postfix) with ESMTP id 4EAF942898C9\n\tfor <incoming@patchwork.ozlabs.org>; Wed, 22 Apr 2026 11:20:56 +0000 (GMT)", "from forge-stage.sourceware.org (vm08.sourceware.org [38.145.34.39])\n by sourceware.org (Postfix) with ESMTPS id 9394641627F1\n for <gcc-patches@gcc.gnu.org>; Wed, 22 Apr 2026 10:50:34 +0000 (GMT)", "from forge-stage.sourceware.org (localhost [IPv6:::1])\n (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n key-exchange x25519 server-signature ECDSA (prime256v1) server-digest SHA256)\n (No client certificate requested)\n by forge-stage.sourceware.org (Postfix) with ESMTPS id EA9A642BE1\n for <gcc-patches@gcc.gnu.org>; Wed, 22 Apr 2026 10:50:31 +0000 (UTC)" ], "DKIM-Filter": [ "OpenDKIM Filter v2.11.0 sourceware.org 4EAF942898C9", "OpenDKIM Filter v2.11.0 sourceware.org 9394641627F1" ], "DMARC-Filter": "OpenDMARC Filter v1.4.2 sourceware.org 9394641627F1", "ARC-Filter": "OpenARC Filter v1.0.0 sourceware.org 9394641627F1", "ARC-Seal": "i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1776855034; cv=none;\n b=f2KVtkVwlacVaFoP82wJatbME/wwdMEZqvK+TAZ9rjyrAaC6ZYEYVC7Y+KfPE7WMuqhS6TQW7mAQrvk75g+sEJ89zpBo1E24gHMwwcCws1pjFMfxSvQXKbNgfyGkNxq5qRddJiLhfu7kUNW6Zyb2s1W+618xICOu/KvjpN66BUg=", "ARC-Message-Signature": "i=1; a=rsa-sha256; d=sourceware.org; s=key;\n t=1776855034; c=relaxed/simple;\n bh=+sHj46l4bDOo58W+WQjgDcYXav0dKSh4vFvDtapaDxM=;\n h=From:Date:Subject:To:Message-ID;\n b=t5tYmIEykxzYrXBgkpri2dpaTqP0XN9a3KPHebKaM1Km76A+YQZ9FyvLaGp0GwbB4V7OzhVX9Wa6uEY3FftGTXNhvA+c1JtjGYKgN2BgiktAvmpRIQqGa+ju/KA5QkR052Nar6IZWLeoczHY4Hdsu7icdL0Mgj+r3loeKbE3aJI=", "ARC-Authentication-Results": "i=1; server2.sourceware.org", "From": "Andrew Pinski via Sourceware Forge\n <forge-bot+pinskia@forge-stage.sourceware.org>", "Date": "Wed, 22 Apr 2026 10:49:21 +0000", "Subject": "[PATCH v1 12/15] gimple-fold: Improve optimize_memcpy_to_memset by\n walking back until aliasing says the ref is a may clobber. [PR118947]", "To": "gcc-patches mailing list <gcc-patches@gcc.gnu.org>", "Message-ID": "\n <bmm.hhubwh7m90.gcc.gcc-TEST.pinskia.33.1.12@forge-stage.sourceware.org>", "X-Mailer": "batrachomyomachia", "X-Pull-Request-Organization": "gcc", "X-Pull-Request-Repository": "gcc-TEST", "X-Pull-Request": "https://forge.sourceware.org/gcc/gcc-TEST/pulls/33", "References": "\n <bmm.hhubwh7m90.gcc.gcc-TEST.pinskia.33.1.0@forge-stage.sourceware.org>", "In-Reply-To": "\n <bmm.hhubwh7m90.gcc.gcc-TEST.pinskia.33.1.0@forge-stage.sourceware.org>", "X-Patch-URL": "\n https://forge.sourceware.org/pinskia/gcc-TEST/commit/09c4179c2cf8820b5bf97ccdeb9f311453451cf6", "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": "gcc-patches mailing list <gcc-patches@gcc.gnu.org>,\n pinskia@gcc.gnu.org", "Errors-To": "gcc-patches-bounces~incoming=patchwork.ozlabs.org@gcc.gnu.org" }, "content": "From: Andrew Pinski <quic_apinski@quicinc.com>\n\nThe case here is we have:\n```\n char buf[32] = {};\n void* ret = aaa();\n __builtin_memcpy(ret, buf, 32);\n```\n\nAnd buf does not escape. But we don't prop the zeroing from buf to the memcpy statement\nbecause optimize_memcpy_to_memset only looks back one statement. This can be fixed to look back\nuntil we get an statement that may clobber the reference. If we get a phi node, then we don't do\nanything.\n\nBootstrapped and tested on x86_64-linux-gnu.\n\n\tPR tree-optimization/118947\n\ngcc/ChangeLog:\n\n\t* gimple-fold.cc (optimize_memcpy_to_memset): Walk back until we get a\n\tstatement that may clobber the read.\n\ngcc/testsuite/ChangeLog:\n\n\t* gcc.dg/pr118947-1.c: New test.\n\nSigned-off-by: Andrew Pinski <quic_apinski@quicinc.com>\n---\n gcc/gimple-fold.cc | 39 ++++++++++++++++++++++---------\n gcc/testsuite/gcc.dg/pr118947-1.c | 15 ++++++++++++\n 2 files changed, 43 insertions(+), 11 deletions(-)\n create mode 100644 gcc/testsuite/gcc.dg/pr118947-1.c", "diff": "diff --git a/gcc/gimple-fold.cc b/gcc/gimple-fold.cc\nindex 1a48778da5a6..92276eb0bc29 100644\n--- a/gcc/gimple-fold.cc\n+++ b/gcc/gimple-fold.cc\n@@ -906,18 +906,41 @@ size_must_be_zero_p (tree size)\n static bool\n optimize_memcpy_to_memset (gimple_stmt_iterator *gsip, tree dest, tree src, tree len)\n {\n+ ao_ref read;\n gimple *stmt = gsi_stmt (*gsip);\n if (gimple_has_volatile_ops (stmt))\n return false;\n \n- tree vuse = gimple_vuse (stmt);\n- if (vuse == NULL || TREE_CODE (vuse) != SSA_NAME)\n- return false;\n \n- gimple *defstmt = SSA_NAME_DEF_STMT (vuse);\n tree src2 = NULL_TREE, len2 = NULL_TREE;\n poly_int64 offset, offset2;\n tree val = integer_zero_node;\n+ bool len_was_null = len == NULL_TREE;\n+ if (len == NULL_TREE)\n+ len = (TREE_CODE (src) == COMPONENT_REF\n+\t ? DECL_SIZE_UNIT (TREE_OPERAND (src, 1))\n+\t : TYPE_SIZE_UNIT (TREE_TYPE (src)));\n+ if (len == NULL_TREE\n+ || !poly_int_tree_p (len))\n+ return false;\n+\n+ ao_ref_init (&read, src);\n+ tree vuse = gimple_vuse (stmt);\n+ gimple *defstmt;\n+ do {\n+ if (vuse == NULL || TREE_CODE (vuse) != SSA_NAME)\n+ return false;\n+ defstmt = SSA_NAME_DEF_STMT (vuse);\n+ if (is_a <gphi*>(defstmt))\n+ return false;\n+\n+ /* If the len was null, then we can use TBBA. */\n+ if (stmt_may_clobber_ref_p_1 (defstmt, &read,\n+\t\t\t\t /* tbaa_p = */ len_was_null))\n+ break;\n+ vuse = gimple_vuse (defstmt);\n+ } while (true);\n+\n if (gimple_store_p (defstmt)\n && gimple_assign_single_p (defstmt)\n && TREE_CODE (gimple_assign_rhs1 (defstmt)) == STRING_CST\n@@ -956,17 +979,11 @@ optimize_memcpy_to_memset (gimple_stmt_iterator *gsip, tree dest, tree src, tree\n if (src2 == NULL_TREE)\n return false;\n \n- if (len == NULL_TREE)\n- len = (TREE_CODE (src) == COMPONENT_REF\n-\t ? DECL_SIZE_UNIT (TREE_OPERAND (src, 1))\n-\t : TYPE_SIZE_UNIT (TREE_TYPE (src)));\n if (len2 == NULL_TREE)\n len2 = (TREE_CODE (src2) == COMPONENT_REF\n \t ? DECL_SIZE_UNIT (TREE_OPERAND (src2, 1))\n \t : TYPE_SIZE_UNIT (TREE_TYPE (src2)));\n- if (len == NULL_TREE\n- || !poly_int_tree_p (len)\n- || len2 == NULL_TREE\n+ if (len2 == NULL_TREE\n || !poly_int_tree_p (len2))\n return false;\n \ndiff --git a/gcc/testsuite/gcc.dg/pr118947-1.c b/gcc/testsuite/gcc.dg/pr118947-1.c\nnew file mode 100644\nindex 000000000000..70b7f800065c\n--- /dev/null\n+++ b/gcc/testsuite/gcc.dg/pr118947-1.c\n@@ -0,0 +1,15 @@\n+/* PR tree-optimization/118947 */\n+/* { dg-do compile { target size32plus } } */\n+/* { dg-options \"-O2 -fdump-tree-forwprop1-details\" } */\n+/* { dg-final { scan-tree-dump-times \"after previous\" 1 \"forwprop1\" } } */\n+\n+void* aaa();\n+void* bbb()\n+{\n+ char buf[32] = {};\n+ /* Tha call to aaa should not matter and clobber buf. */\n+ void* ret = aaa();\n+ __builtin_memcpy(ret, buf, 32);\n+ return ret;\n+}\n+\n", "prefixes": [ "v1", "12/15" ] }