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GET /api/patches/2217993/?format=api
{ "id": 2217993, "url": "http://patchwork.ozlabs.org/api/patches/2217993/?format=api", "web_url": "http://patchwork.ozlabs.org/project/gcc/patch/20260331080542.97649-1-garthlei@linux.alibaba.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": "<20260331080542.97649-1-garthlei@linux.alibaba.com>", "list_archive_url": null, "date": "2026-03-31T08:05:42", "name": "simplify-rtx: Simplify (eq/ne (and/ior x C1) C2) in special cases", "commit_ref": null, "pull_url": null, "state": "new", "archived": false, "hash": "4b6f60930adca9b2f53a44cb25c655c6f5fce22c", "submitter": { "id": 89310, "url": "http://patchwork.ozlabs.org/api/people/89310/?format=api", "name": "Bohan Lei", "email": "garthlei@linux.alibaba.com" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/gcc/patch/20260331080542.97649-1-garthlei@linux.alibaba.com/mbox/", "series": [ { "id": 498140, "url": "http://patchwork.ozlabs.org/api/series/498140/?format=api", "web_url": "http://patchwork.ozlabs.org/project/gcc/list/?series=498140", "date": "2026-03-31T08:05:42", "name": "simplify-rtx: Simplify (eq/ne (and/ior x C1) C2) in special cases", "version": 1, "mbox": "http://patchwork.ozlabs.org/series/498140/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/2217993/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/2217993/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=linux.alibaba.com header.i=@linux.alibaba.com\n header.a=rsa-sha256 header.s=default header.b=i1SabHfh;\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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s=key;\n t=1774944359; c=relaxed/simple;\n bh=XQHZYRCsBcw02PtoDjgaWymA5B8CKR7XETo6FEACTLY=;\n h=DKIM-Signature:From:To:Subject:Date:Message-Id:MIME-Version;\n b=dLeOiQsmbZeRKMYjykIXgXzCGfYRV5FcNmKxwTcx6yYsx0qyarSyqOELbpMZMKMMQCTK29CtVPUmq1iTlWFUmJJ1Bqp2iQCD4ZXn4yZzfDtQqeZjnACGA8mwuFGw+hBSEGk93g/K5Dg3sjiKcpYv+AoV1YVaAB4mMoJT5dwF4Zs=", "ARC-Authentication-Results": "i=1; server2.sourceware.org", "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/relaxed;\n d=linux.alibaba.com; s=default;\n t=1774944354; h=From:To:Subject:Date:Message-Id:MIME-Version;\n bh=rgNayV1X5j0fvRO56i4RWGbRW6/Yig/+L3gPugOM+h4=;\n b=i1SabHfhb64ctYO3GCyRAGkk/ppvQkHoiuds0W4C/aLQXQejBnid0xoJAr6bWrARNq4XLcmLw1p+uR0NCQBmMb0az9QKkeGeR7w9bCHeNw5adONDmTCcTi6/z6qfnlI24WSyrZTQhIIsGetJ1xhJSMUd1r+F4SF93dD22GRf9Tw=", "X-Alimail-AntiSpam": "AC=PASS; BC=-1|-1; BR=01201311R341e4; CH=green;\n DM=||false|;\n DS=||; FP=0|-1|-1|-1|0|-1|-1|-1; HT=maildocker-contentspam033037009110;\n MF=garthlei@linux.alibaba.com; NM=1; PH=DS; RN=4; SR=0;\n TI=SMTPD_---0X03ffoG_1774944345;", "From": "Bohan Lei <garthlei@linux.alibaba.com>", "To": "gcc-patches@gcc.gnu.org", "Cc": "jeffrey.law@oss.qualcomm.com, philipp.tomsich@vrull.eu,\n Bohan Lei <garthlei@linux.alibaba.com>", "Subject": "[PATCH] simplify-rtx: Simplify (eq/ne (and/ior x C1) C2) in special\n cases", "Date": "Tue, 31 Mar 2026 16:05:42 +0800", "Message-Id": "<20260331080542.97649-1-garthlei@linux.alibaba.com>", "X-Mailer": "git-send-email 2.39.3 (Apple Git-146)", "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 adds missing simplifications for (eq/ne (and/ior x C1) C2) in\nspecial cases. In the AND case, when (and C1 C2) is not equal to C1,\nsome bits set in C2 are not set in C1, and thus (eq (and x C1) C2) can\nnever be true. The OR case is similar when (and C1 C2) is not equal to\nC2.\n\nThe patch is meant to fix an ICE on RISC-V. In a former patch, I tried\nto change the insn condition directly, but Jeff pointed out that it was\nmore reasonable to optimize it out before the split. As was suggested\nby Jeff, this patch tries to simplify the expression in\nsimplify_relational_operation_1.\n\nThe URL for the former patch:\nhttps://patchwork.sourceware.org/project/gcc/patch/20251229024238.15044-1-garthlei@linux.alibaba.com/\n\ngcc/ChangeLog:\n\n\t* simplify-rtx.cc (simplify_context::simplify_relational_operation_1):\nAdd simplifications for (eq/ne (and/ior x C1) C2) in special cases.\n\ngcc/testsuite/ChangeLog:\n\n\t* gcc.target/riscv/zbs-if_then_else-02.c: New test.\n---\n gcc/simplify-rtx.cc | 30 +++++++++++++++++\n .../gcc.target/riscv/zbs-if_then_else-02.c | 32 +++++++++++++++++++\n 2 files changed, 62 insertions(+)\n create mode 100644 gcc/testsuite/gcc.target/riscv/zbs-if_then_else-02.c", "diff": "diff --git a/gcc/simplify-rtx.cc b/gcc/simplify-rtx.cc\nindex 50fc51152ca..e2d5abf394f 100644\n--- a/gcc/simplify-rtx.cc\n+++ b/gcc/simplify-rtx.cc\n@@ -6731,6 +6731,36 @@ simplify_context::simplify_relational_operation_1 (rtx_code code,\n \t}\n }\n \n+ /* (eq/ne (and x C1) C2) simplifies to 0/1 if (and C1 C2) is not equal\n+ to C1. Bits that are zero in C1 will be zero in the result, so if\n+ C1 has any bits set that C2 doesn't have, the comparison can never\n+ be true. */\n+ if ((code == EQ || code == NE)\n+ && op0code == AND\n+ && CONST_SCALAR_INT_P (op1)\n+ && CONST_SCALAR_INT_P (XEXP (op0, 1)))\n+ {\n+ HOST_WIDE_INT c1 = INTVAL (XEXP (op0, 1));\n+ HOST_WIDE_INT c2 = INTVAL (op1);\n+ if ((c1 & c2) != c1)\n+\treturn code == EQ ? const0_rtx : const_true_rtx;\n+ }\n+\n+ /* (eq/ne (ior x C1) C2) simplifies to 0/1 if (and C1 C2) is not equal\n+ to C2. Bits that are one in C1 will be one in the result, so if C2\n+ has any bits clear that C1 has set, the comparison can never be\n+ true. */\n+ if ((code == EQ || code == NE)\n+ && op0code == IOR\n+ && CONST_SCALAR_INT_P (op1)\n+ && CONST_SCALAR_INT_P (XEXP (op0, 1)))\n+ {\n+ HOST_WIDE_INT c1 = INTVAL (XEXP (op0, 1));\n+ HOST_WIDE_INT c2 = INTVAL (op1);\n+ if ((c1 & c2) != c2)\n+\treturn code == EQ ? const0_rtx : const_true_rtx;\n+ }\n+\n /* (eq/ne (bswap x) C1) simplifies to (eq/ne x C2) with C2 swapped. */\n if ((code == EQ || code == NE)\n && GET_CODE (op0) == BSWAP\ndiff --git a/gcc/testsuite/gcc.target/riscv/zbs-if_then_else-02.c b/gcc/testsuite/gcc.target/riscv/zbs-if_then_else-02.c\nnew file mode 100644\nindex 00000000000..3393bea8898\n--- /dev/null\n+++ b/gcc/testsuite/gcc.target/riscv/zbs-if_then_else-02.c\n@@ -0,0 +1,32 @@\n+/* { dg-do link { target { rv64 } } } */\n+/* { dg-options \"-march=rv64gc_zbb_zbs -mabi=lp64d -flto\" } */\n+/* { dg-skip-if \"\" { *-*-* } { \"-O0\" \"-Og\" \"-O1\" } } */\n+\n+struct S {\n+ int a;\n+ char b;\n+ int c;\n+} s;\n+\n+const signed char c = -37;\n+int d;\n+struct S v1[] = {{0, 8}, 0, 0, -108976}, v2[] = {{}, 0, 0, 2804};\n+int a;\n+struct S v3[3];\n+int *p = &a;\n+\n+void foo() {\n+ int a;\n+ if (a)\n+ ;\n+ else if (v1[0].b)\n+ s.a = 0;\n+ else\n+ d = 0;\n+ if (*p)\n+ if (v3[1].c)\n+ if (1 ^ (d & c & v2[1].c & ~v1[1].c | s.a))\n+ v3[2].c = 0;\n+}\n+\n+int main() { foo(); }\n", "prefixes": [] }