Patch Detail
get:
Show a patch.
patch:
Update a patch.
put:
Update a patch.
GET /api/patches/2224143/?format=api
{ "id": 2224143, "url": "http://patchwork.ozlabs.org/api/patches/2224143/?format=api", "web_url": "http://patchwork.ozlabs.org/project/gcc/patch/20260416232619.1083145-1-elias.rosberg@hotmail.com/", "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": "<20260416232619.1083145-1-elias.rosberg@hotmail.com>", "list_archive_url": null, "date": "2026-04-16T23:26:18", "name": "riscv: Allow Zcmp push/pop when shrink-wrap-separate is inactive", "commit_ref": null, "pull_url": null, "state": "new", "archived": false, "hash": "43860ba5162d2842091739bc426d2205973ffa47", "submitter": { "id": 93172, "url": "http://patchwork.ozlabs.org/api/people/93172/?format=api", "name": "Elias Rosberg", "email": "elias.rosberg.dev@gmail.com" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/gcc/patch/20260416232619.1083145-1-elias.rosberg@hotmail.com/mbox/", "series": [ { "id": 500216, "url": "http://patchwork.ozlabs.org/api/series/500216/?format=api", "web_url": "http://patchwork.ozlabs.org/project/gcc/list/?series=500216", "date": "2026-04-16T23:26:18", "name": "riscv: Allow Zcmp push/pop when shrink-wrap-separate is inactive", "version": 1, "mbox": "http://patchwork.ozlabs.org/series/500216/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/2224143/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/2224143/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 (2048-bit key;\n unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256\n header.s=20251104 header.b=cnyaPCUZ;\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; helo=vm01.sourceware.org;\n envelope-from=gcc-patches-bounces~incoming=patchwork.ozlabs.org@gcc.gnu.org;\n receiver=patchwork.ozlabs.org)", "sourceware.org;\n\tdkim=pass (2048-bit key,\n unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256\n header.s=20251104 header.b=cnyaPCUZ", "sourceware.org;\n dmarc=pass (p=none dis=none) header.from=gmail.com", "sourceware.org; spf=pass smtp.mailfrom=gmail.com", "server2.sourceware.org;\n arc=none smtp.remote-ip=209.85.167.51" ], "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 4fxZ0w39yrz1yGt\n\tfor <incoming@patchwork.ozlabs.org>; Fri, 17 Apr 2026 09:27:10 +1000 (AEST)", "from vm01.sourceware.org (localhost [127.0.0.1])\n\tby sourceware.org (Postfix) with ESMTP id 03B4B4BB58C6\n\tfor <incoming@patchwork.ozlabs.org>; Thu, 16 Apr 2026 23:27:07 +0000 (GMT)", "from mail-lf1-f51.google.com (mail-lf1-f51.google.com\n [209.85.167.51])\n by sourceware.org (Postfix) with ESMTPS id 597324BB58C6\n for <gcc-patches@gcc.gnu.org>; Thu, 16 Apr 2026 23:26:39 +0000 (GMT)", "by mail-lf1-f51.google.com with SMTP id\n 2adb3069b0e04-5a4113ab355so65197e87.1\n for <gcc-patches@gcc.gnu.org>; Thu, 16 Apr 2026 16:26:39 -0700 (PDT)", "from localhost.localdomain (h-98-128-150-22.A1095.priv.bahnhof.se.\n [98.128.150.22]) by smtp.gmail.com with ESMTPSA id\n 2adb3069b0e04-5a4178d5d41sm42622e87.46.2026.04.16.16.26.35\n (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256);\n Thu, 16 Apr 2026 16:26:37 -0700 (PDT)" ], "DKIM-Filter": [ "OpenDKIM Filter v2.11.0 sourceware.org 03B4B4BB58C6", "OpenDKIM Filter v2.11.0 sourceware.org 597324BB58C6" ], "DMARC-Filter": "OpenDMARC Filter v1.4.2 sourceware.org 597324BB58C6", "ARC-Filter": "OpenARC Filter v1.0.0 sourceware.org 597324BB58C6", "ARC-Seal": "i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1776381999; cv=none;\n b=oiG/kVP03wCx96ghxs3VqKtEJh0FXK3pfeik0XAxcdQDqFFLl100CMtKd78SOfgmr0ABwQpyu3Zd84Qh8pMawr0mmWZ2qpnMItRovZtrBDH6860Rg11FIXcgDoQpO//i1xxjNv3PDzFS6gwYUB0wsBbyXHTK8LZvpG/4JTJ3P/Q=", "ARC-Message-Signature": "i=1; a=rsa-sha256; d=sourceware.org; s=key;\n t=1776381999; c=relaxed/simple;\n bh=G4Qv4SUjkzzYCAfAL0QPcGXaG1bQ0brKuE2X/YjYPRY=;\n h=DKIM-Signature:From:To:Subject:Date:Message-ID:MIME-Version;\n b=uW0gISYKKeQpDRP0oODtBhq5Q4pm3/Exh6Az1pLVIAj1tY46dY+gQ0KJIx9Tkicg3B0w10t2TeVXgy/VmNwW0Mg+fR/Nj4BbH1B9cA7/1PkKRqXY11sS+wPYf8kbNy908VztkTEnpvmJeS6tjqyPdlNb9c3/1q2YmUFzTbiELio=", "ARC-Authentication-Results": "i=1; server2.sourceware.org", "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/relaxed;\n d=gmail.com; s=20251104; t=1776381998; x=1776986798; darn=gcc.gnu.org;\n h=content-transfer-encoding:mime-version:message-id:date:subject:cc\n :to:from:from:to:cc:subject:date:message-id:reply-to;\n bh=lpR4BLAdoi6Mji5aM0+OPuXOWvMNqAZ8i5MwwhClkyE=;\n b=cnyaPCUZbJ+Lk8VldHSN0N0HKRWmwovtLYxYhMrn6spDu9I0IBso7O/n4X2aszJcvE\n RpxZzTzLKGD3ma2KkVUd2c/Nyx8X2Vj7v+TwLer/01oJdW72G71D6cV0T+Va9knLxT/J\n q2YAGEVU5xvykgfNvumlta7gsz4kRACnd2XPZUo0vkLyJwukgZDWxZuNmf6bx5RxkJY/\n RXJqmQgiNRcaZbmlP3wNC0oQgMVTLFRDvmA5JM9saQaxQJpdVd8NPGuUbimXKiyc9giu\n 1jzvoZiMyCtZg70MrfAgQqPFR/QL7fzBi45iYF0JvLbKuL6tP1F7yABzsg9L4UN5sUxL\n 64zg==", "X-Google-DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/relaxed;\n d=1e100.net; s=20251104; t=1776381998; x=1776986798;\n h=content-transfer-encoding:mime-version:message-id:date:subject:cc\n :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date\n :message-id:reply-to;\n bh=lpR4BLAdoi6Mji5aM0+OPuXOWvMNqAZ8i5MwwhClkyE=;\n b=MxLdpPbz9LqGwoqxwB8iGMScp+zlwOvDcCrhH5k5xjmBXvu3OLAd7dZU2iY5mh44oG\n TjZhs88gyZCRl9YD17h8aok4+/VEdpi31sIt4t5heK4HAkPgoabBP9l6DL0ZVDFmvhwH\n gW+/DVr5vLu+fS1T1xu8p2xvtxR1V/vYuTwMYW5+QsVSSwljhkoO5i9hY9GOfnQiBkRC\n /iLZHNV5dAJi4jyqzfRWOAWmV+CZEPvPaJaRHEfwagsE7ya46vsZQV+DQQ21XOUKNbaR\n +Fseu8JFPaBYrhF0vTBRRJrfowjE6DpfVCu+/XTaHKtX1GWznaI29K/UnN5dsbbYnS9/\n KdGw==", "X-Gm-Message-State": "AOJu0Yxa8OJH3r06i/IfO6fXARIQQ4AflkISZswGVtJQMlv5LGnJlcnN\n ag484bXPFp0zxb/wX/KhYmCtLdqENqYhOcrQfdOLpxnJDclNRdO4Z098EX0RdMXYedU=", "X-Gm-Gg": "AeBDietLPljdcsjJRwrIKgjhCAwAYbVfrRi5YgvHEQC0glRiffNX+EzQtiX0/ZjGKGu\n TSO/O0cZGKDBi7Ww5Af09H3xktDo8PLoBhFXQG6lov/XNILrE5VHc933C0GX1dm6L/P1HY0UBN1\n lG32t6GsCGUZUkBtnjN4E1AMkozCDsSdRG5Ii9cQJAHWQ0G+91ST8xFr5O1TtpmgSt0OkF3A/ib\n 6ftgpc+VyQacKKxU/SDqcWF2Smtlt+gW2mNgvhLGIDK3ulhXdHW+pfxk2aJ5VIh8MzPXfjUOc7K\n AuYAcYkqcFrvvBBOBBD3rybW1TS/gRZnB00XmQP/xOPB7aHlMU321BhtEH5Fd8hYY0mBlnK7Dh9\n Hx+UPRjE3bw8B1xOCtRZkYxbBwQVgO1ceb21To7ZP9PXhWqxdXRlqU1vBzuPwcUahNO2RioSYTK\n MihtpyEtYDmZPPrkRIG+LDUxiikO9eWtLerG9yDgy3WvuWDe+GLPh5Lnmgunhhc1eqZPyLQy273\n gURhAzIiZAp74nIDQ==", "X-Received": "by 2002:a05:6512:1387:b0:5a4:d21:de07 with SMTP id\n 2adb3069b0e04-5a4172ba69bmr83528e87.1.1776381997605;\n Thu, 16 Apr 2026 16:26:37 -0700 (PDT)", "From": "Elias Rosberg <elias.rosberg.dev@gmail.com>", "X-Google-Original-From": "Elias Rosberg <elias.rosberg@hotmail.com>", "To": "gcc-patches@gcc.gnu.org", "Cc": "kito.cheng@gmail.com,\n\tpalmer@dabbelt.com,\n\tjeffreyalaw@gmail.com", "Subject": "[PATCH] riscv: Allow Zcmp push/pop when shrink-wrap-separate is\n inactive", "Date": "Fri, 17 Apr 2026 01:26:18 +0200", "Message-ID": "<20260416232619.1083145-1-elias.rosberg@hotmail.com>", "X-Mailer": "git-send-email 2.47.3", "MIME-Version": "1.0", "Content-Transfer-Encoding": "8bit", "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": "This patch allows Zcmp push and pop instructions in functions where\nshrink-wrap-separate is not actually applied, leading to code size\nreductions. The previous heuristic was overly blunt, disabling Zcmp for\nany function where shrink-wrap-separate was enabled, without checking if\nthe optimization was utilized for that specific frame.\n\ngcc/\n\t* config/riscv/riscv.cc (riscv_avoid_multi_push): Check if\n\tshrink-wrap-separate was actually used for the current\n\tfunction.\n\ngcc/testsuite/\n\t* gcc.target/riscv/pr112478.c: Update scan-assembler patterns.\n\t* gcc.target/riscv/zcmp_shrink_wrap_separate.c: Likewise.\n\t* gcc.target/riscv/zcmp_no_shrink_wrap.c: New test.\n\t* gcc.target/riscv/zcmp_shrink_wrap.c: New test.\n\t* gcc.target/riscv/zcmp_shrink_wrap_sep.c: New test.\n\n2026-04-17 Elias Rosberg <elias.rosberg@hotmail.com>\n---\nHello,\n\nI am a student researcher and this is my first GCC patch. \nI identified a missed optimization where Zcmp cm.push/cm.pop \ninstructions were being suppressed at -O2 due to an overly blunt\ncheck for shrink-wrap-separate.\n\nEven when shrink-wrap-separate is enabled globally, it is not always applied to \nevery function. This patch adds a condition to allow Zcmp instructions in \nfunctions where shrink-wrap-separate did not actually trigger. \nThis makes cm.push/cm.pop generate for -O2 in:\n\n1. Functions that save callee saved registers, but have no shrink-wrapping \n2. Functions that save callee saved registers, and use standard monolithic\nshrink-wrapping.\n\nThe fix still suppresses generation of cm.push/cm.pop in:\n\n3. Functions that save callee saved registers, but use shrink-wrap-separate.\n\nIt has passed the full C-torture execute/compile and target RISC-V\nsuite with no regressions. Quick testing on SQLite3 shows a ~1.7% reduction \nin .text size for riscv32-unknown-elf at -O2.\n\nI do not have write access. So if this were to get approved, \nI will need help with the commit\n\n\n\n---\n gcc/config/riscv/riscv.cc | 3 ++-\n gcc/testsuite/gcc.target/riscv/pr112478.c | 2 +-\n .../gcc.target/riscv/zcmp_no_shrink_wrap.c | 18 ++++++++++++++++\n .../gcc.target/riscv/zcmp_shrink_wrap.c | 20 ++++++++++++++++++\n .../gcc.target/riscv/zcmp_shrink_wrap_sep.c | 21 +++++++++++++++++++\n .../riscv/zcmp_shrink_wrap_separate.c | 2 +-\n 6 files changed, 63 insertions(+), 3 deletions(-)\n create mode 100644 gcc/testsuite/gcc.target/riscv/zcmp_no_shrink_wrap.c\n create mode 100644 gcc/testsuite/gcc.target/riscv/zcmp_shrink_wrap.c\n create mode 100644 gcc/testsuite/gcc.target/riscv/zcmp_shrink_wrap_sep.c", "diff": "diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc\nindex 8a39c791c..e7d74128f 100644\n--- a/gcc/config/riscv/riscv.cc\n+++ b/gcc/config/riscv/riscv.cc\n@@ -8624,7 +8624,8 @@ riscv_avoid_multi_push (const struct riscv_frame_info *frame)\n || cfun->machine->interrupt_handler_p || cfun->machine->varargs_size != 0\n || crtl->args.pretend_args_size != 0\n || (use_shrink_wrapping_separate ()\n-\t && !riscv_avoid_shrink_wrapping_separate ())\n+\t && !riscv_avoid_shrink_wrapping_separate ()\n+\t && crtl->shrink_wrapped_separate)\n || (frame->mask & ~MULTI_PUSH_GPR_MASK))\n return true;\n \ndiff --git a/gcc/testsuite/gcc.target/riscv/pr112478.c b/gcc/testsuite/gcc.target/riscv/pr112478.c\nindex 0bbde20b7..771d7337f 100644\n--- a/gcc/testsuite/gcc.target/riscv/pr112478.c\n+++ b/gcc/testsuite/gcc.target/riscv/pr112478.c\n@@ -5,4 +5,4 @@ void foo() {\n asm volatile(\"# \" : ::\"ra\");\n }\n \n-/* { dg-final { scan-assembler \"s(w|d)\\[ \\t\\]*ra\" } } */\n+/* { dg-final { scan-assembler \"s(w|d)\\[ \\t\\]*ra|cm\\\\.push\\[ \\t\\]*\\\\{.*ra.*\\\\}\" } } */\ndiff --git a/gcc/testsuite/gcc.target/riscv/zcmp_no_shrink_wrap.c b/gcc/testsuite/gcc.target/riscv/zcmp_no_shrink_wrap.c\nnew file mode 100644\nindex 000000000..8d6703165\n--- /dev/null\n+++ b/gcc/testsuite/gcc.target/riscv/zcmp_no_shrink_wrap.c\n@@ -0,0 +1,18 @@\n+/* { dg-do compile } */ \n+/* { dg-options \"-O2 -march=rv32imac_zicsr_zifencei_zcmp -mabi=ilp32 -fshrink-wrap\" } */\n+/* { dg-skip-if \"\" { *-*-* } {\"-O0\" \"-O1\" \"-Os\" \"-Og\" \"-O3\" \"-Oz\" \"-flto\"} } */\n+\n+extern void\n+bar (int);\n+\n+/* Verify that Zcmp cm.push is used at -O2 when shrink-wrapping is \n+ active but no early return exists. */\n+void\n+foo (int a)\n+{\n+ bar (a);\n+ bar (a);\n+}\n+\n+/* { dg-final { scan-assembler \"cm\\\\.push\" } } */\n+/* { dg-final { scan-assembler \"cm\\\\.pop\" } } */\ndiff --git a/gcc/testsuite/gcc.target/riscv/zcmp_shrink_wrap.c b/gcc/testsuite/gcc.target/riscv/zcmp_shrink_wrap.c\nnew file mode 100644\nindex 000000000..aaa5881db\n--- /dev/null\n+++ b/gcc/testsuite/gcc.target/riscv/zcmp_shrink_wrap.c\n@@ -0,0 +1,20 @@\n+/* { dg-do compile } */\n+/* { dg-options \"-O2 -march=rv32imac_zicsr_zifencei_zcmp -mabi=ilp32 -fshrink-wrap\" } */\n+/* { dg-skip-if \"\" { *-*-* } { \"-O0\" \"-O1\" \"-Os\" \"-Og\" \"-O3\" \"-Oz\" \"-flto\" } } */\n+\n+extern void \n+bar (int);\n+\n+/* Verify that Zcmp cm.push is used at -O2 even when a simple \n+ shrink-wrap early return is present. */\n+void\n+foo (int a)\n+{\n+ if (a == 0)\n+ return;\n+ bar (a);\n+ bar (a);\n+}\n+\n+/* { dg-final { scan-assembler \"cm\\\\.push\" } } */\n+/* { dg-final { scan-assembler \"cm\\\\.pop\" } } */\ndiff --git a/gcc/testsuite/gcc.target/riscv/zcmp_shrink_wrap_sep.c b/gcc/testsuite/gcc.target/riscv/zcmp_shrink_wrap_sep.c\nnew file mode 100644\nindex 000000000..f4cd2e68c\n--- /dev/null\n+++ b/gcc/testsuite/gcc.target/riscv/zcmp_shrink_wrap_sep.c\n@@ -0,0 +1,21 @@\n+/* { dg-do compile } */\n+/* { dg-options \"-O2 -march=rv32imac_zicsr_zifencei_zcmp -mabi=ilp32 -fshrink-wrap-separate\" } */\n+/* { dg-skip-if \"\" { *-*-* } { \"-O0\" \"-O1\" \"-Os\" \"-Og\" \"-O3\" \"-Oz\" \"-flto\" } } */\n+\n+/* Verify that Zcmp cm.push is NOT used when shrink-wrap-separate is \n+ actively moving individual callee-saved registers. */\n+void\n+foo (int a)\n+{\n+ if (a == 1)\n+ {\n+ register int s0 asm (\"s0\") = 1;\n+ asm volatile (\"\" : : \"r\" (s0));\n+ return;\n+ }\n+ register int s1 asm (\"s1\") = 2;\n+ asm volatile (\"\" : : \"r\" (s1));\n+}\n+\n+/* { dg-final { scan-assembler-not \"cm\\\\.push\" } } */\n+/* { dg-final { scan-assembler-not \"cm\\\\.pop\" } } */\ndiff --git a/gcc/testsuite/gcc.target/riscv/zcmp_shrink_wrap_separate.c b/gcc/testsuite/gcc.target/riscv/zcmp_shrink_wrap_separate.c\nindex 035bc32ce..a5036712a 100644\n--- a/gcc/testsuite/gcc.target/riscv/zcmp_shrink_wrap_separate.c\n+++ b/gcc/testsuite/gcc.target/riscv/zcmp_shrink_wrap_separate.c\n@@ -90,4 +90,4 @@ calc_func (signed short *pdata, core_results *res)\n }\n }\n \n-/* { dg-final { scan-assembler-not \"cm\\.push\" } } */\n+/* { dg-final { scan-assembler \"cm\\\\.push\" } } */\n", "prefixes": [] }