[{"id":3683291,"web_url":"http://patchwork.ozlabs.org/comment/3683291/","msgid":"","list_archive_url":null,"date":"2026-04-28T09:24:58","subject":"Re: [GCC17-PATCH 1/2] phiopt: Set cfgchanged if cselim-limited\n happened","submitter":{"id":1765,"url":"http://patchwork.ozlabs.org/api/people/1765/","name":"Richard Biener","email":"richard.guenther@gmail.com"},"content":"On Fri, Apr 17, 2026 at 4:09 AM Andrew Pinski\n wrote:\n>\n> I noticed while improving cselim-limited that if\n> not creating a new phi, there are a few empty basic blocks.\n> So this sets cfgcleanup when cselim-limited does\n> something in phiopt. cselim-5.c shows the case I\n> was looking into.\n\nOK, though the name of cfg_changed is now a bit off, possibly\nrenaming it to cfg_cleanup_wanted or so might be an improvement.\n\n> gcc/ChangeLog:\n>\n> * tree-ssa-phiopt.cc (pass_phiopt::execute): Set cfgcleanup\n> if cselim_limited returns true.\n>\n> gcc/testsuite/ChangeLog:\n>\n> * gcc.dg/tree-ssa/cselim-5.c: New test.\n>\n> Signed-off-by: Andrew Pinski \n> ---\n> gcc/testsuite/gcc.dg/tree-ssa/cselim-5.c | 16 ++++++++++++++++\n> gcc/tree-ssa-phiopt.cc | 5 +++--\n> 2 files changed, 19 insertions(+), 2 deletions(-)\n> create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/cselim-5.c\n>\n> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/cselim-5.c b/gcc/testsuite/gcc.dg/tree-ssa/cselim-5.c\n> new file mode 100644\n> index 00000000000..8d1335f174a\n> --- /dev/null\n> +++ b/gcc/testsuite/gcc.dg/tree-ssa/cselim-5.c\n> @@ -0,0 +1,16 @@\n> +/* { dg-do compile } */\n> +/* { dg-options \"-O1 -fdump-tree-phiopt1\" } */\n> +\n> +int t;\n> +void f(int a, int b, int c, int d)\n> +{\n> + if (b)\n> + t = 0;\n> + else\n> + t = 0;\n> +}\n> +\n> +/* We should sink/merge the stores and end up with a single BB. */\n> +\n> +/* { dg-final { scan-tree-dump-times \"t = 0;\" 1 \"phiopt1\" } } */\n> +/* { dg-final { scan-tree-dump-times \" diff --git a/gcc/tree-ssa-phiopt.cc b/gcc/tree-ssa-phiopt.cc\n> index 0bf7e58b8f0..324559e6a7d 100644\n> --- a/gcc/tree-ssa-phiopt.cc\n> +++ b/gcc/tree-ssa-phiopt.cc\n> @@ -4048,10 +4048,11 @@ pass_phiopt::execute (function *)\n> hoist_adjacent_loads (bb, bb1, bb2, bb3);\n>\n> /* Try to see if there are only store in each side of the if\n> - and try to remove that; don't do this for -Og. */\n> + and try to remove that; don't do this for -Og.\n> + With sinking the stores we might end up with empty blocks. */\n> if (EDGE_COUNT (bb3->preds) == 2 && !optimize_debug)\n> while (cond_if_else_store_replacement_limited (bb1, bb2, bb3))\n> - ;\n> + cfgchanged = true;\n> }\n>\n> gimple_stmt_iterator gsi;\n> --\n> 2.43.0\n>","headers":{"Return-Path":"","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=IbLOLJq/;\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=IbLOLJq/","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=pass smtp.remote-ip=209.85.218.52"],"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 4g4ZmP6lDGz1xvV\n\tfor ; Tue, 28 Apr 2026 19:25:41 +1000 (AEST)","from vm01.sourceware.org (localhost [127.0.0.1])\n\tby sourceware.org (Postfix) with ESMTP id 20D2D4BB5899\n\tfor ; Tue, 28 Apr 2026 09:25:40 +0000 (GMT)","from mail-ej1-f52.google.com (mail-ej1-f52.google.com\n [209.85.218.52])\n by sourceware.org (Postfix) with ESMTPS id 8F5C04BB3BA2\n for ; Tue, 28 Apr 2026 09:25:12 +0000 (GMT)","by mail-ej1-f52.google.com with SMTP id\n a640c23a62f3a-b8f97c626aaso931568566b.2\n for ; Tue, 28 Apr 2026 02:25:12 -0700 (PDT)"],"DKIM-Filter":["OpenDKIM Filter v2.11.0 sourceware.org 20D2D4BB5899","OpenDKIM Filter v2.11.0 sourceware.org 8F5C04BB3BA2"],"DMARC-Filter":"OpenDMARC Filter v1.4.2 sourceware.org 8F5C04BB3BA2","ARC-Filter":"OpenARC Filter v1.0.0 sourceware.org 8F5C04BB3BA2","ARC-Seal":["i=2; a=rsa-sha256; d=sourceware.org; s=key; t=1777368312; cv=pass;\n b=ZlWu85JRXcbx4j6cHaoeNWOcqXrgrT23RTSb1ZgurpGLkdVGasHjQWH5fwyJNCg+K7YRgPTYeLLT0poz8mKO26/buzAmBvrtzX1BtRjtbWuYbwLj+tIEMHIqqWNS1fpMhy6BfQy8brM2BJej/XWdTuGLnKF9YHH3w7wnY/fOHOg=","i=1; a=rsa-sha256; t=1777368311; cv=none;\n d=google.com; s=arc-20240605;\n b=Wcn9ovUd9aZnEZAcJiFqTFjFjjn7XSOpBuQ2VaGnFeA0ojG9YCvrpan0+E1mdPwL5A\n iCrOVLXrLddMoIk+WrLUQ94QPMUBwEBFyZ775VyowfDxPzXhiA3zaFjrEx/SyXoTgFNo\n rZraTm9Wlyy85XjL7d4aiAMmLhBwQz+iczqksIdhHJ3YlpmPAaVax2RkJcdUt/7Wb0BP\n wXZYqEd4lX0IdyZqCo7vqxj0VlT9nPSjr4fW4TMiFov66+WCbJSXDlWmHuKrzk6oxpud\n YBuQon3OJ9gG/AQ4C2hQaDk0k7HiyAOKMJPupsVhIg6vAxhQdIfJl88GXH4tYWHX9V6X\n wzbg=="],"ARC-Message-Signature":["i=2; a=rsa-sha256; d=sourceware.org; s=key;\n t=1777368312; c=relaxed/simple;\n bh=rdEZYiAqG0GIhsonTApwKTSLQE63kGjuY2bHRMzSVdk=;\n h=DKIM-Signature:MIME-Version:From:Date:Message-ID:Subject:To;\n b=iaElKmD7jWTS0MnZZANXPAiQbAbQmxO2XQpYJpHV0pEQjkiQ5Uk2fCU7RqMqZ7lXzfSrufeNvrRIOiE/yBLYdQPOuasZEKdfVqSQlxTyNM/HAx+8fiM1W2zzgBCHYJ3MrScum6yWAAGanEW2yzLNXXA8DQiPPn9v9qci8iRZrIM=","i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com;\n s=arc-20240605;\n h=content-transfer-encoding:cc:to:subject:message-id:date:from\n :in-reply-to:references:mime-version:dkim-signature;\n bh=jkBLhtQNV3h3pGFyYLk2y1HraeriNw4hUDXsXFtwkrc=;\n fh=+uEDwx55CzEWtNA/tzpV1shOHaMh+Xh7AN17D33930Y=;\n b=PnsAwuZrYO2DTcMRVPlFnIUj5/6+GlnqAENJI1gRHP9BnmgQL6bvsAfjxk9Fkmw4AO\n SgEWus7sHWLq+d24ODYnhY/gP8QfSnZqj53OOEXtfcH52SAvOVJoFpScR/zqiokh/tF9\n nwOLqpx7PWEngq+y/e/tRjCoBg7fQnKXpCocIcHfYfycKxvLoQMvT7Mhj/8WADX+qLQK\n ZUV6LSLh4I74mpvItDo4JA+7gTZF7s7ISlOmnLlh6KV7/cb/0jTH4rI2gEfvdRg1yDSH\n EvyJn4FkZZLf+J2F9rNmKWzK95zq7iaqIgVxfvIJ0uua/fpd6aGFOizTdn3tuidOa+f8\n jXCg==; darn=gcc.gnu.org"],"ARC-Authentication-Results":["i=2; server2.sourceware.org","i=1; mx.google.com; arc=none"],"DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed;\n d=gmail.com; s=20251104; t=1777368311; x=1777973111; darn=gcc.gnu.org;\n h=content-transfer-encoding:cc:to:subject:message-id:date:from\n :in-reply-to:references:mime-version:from:to:cc:subject:date\n :message-id:reply-to;\n bh=jkBLhtQNV3h3pGFyYLk2y1HraeriNw4hUDXsXFtwkrc=;\n b=IbLOLJq/RiiID+bjHWwfv4DnaFfY4+JZuJs/SmHDYTxdnJYBg+dTKBxmYvxtTV0LZ8\n mBiUlgSkEI12UBSTRWtTzG06OYAl3zsG0TVUD7IwlbZIfLwe+b1O9Z4Q0NMRyHbkK6hm\n ATEK8HvbrZ4tgmDgBUY6d3d9lLNRVfARZlqt8DeE/0qnNkXriJ5m8Tfo7/Sl68dr46hV\n 2e69TpIy4WRa7p6PACZ+MQfq9+rdEa0pMEqBm3nxM9F/Y49LFeTNvGJARrdjo6gLE7jT\n wSsQIKtbDcKynfsWxkCJUjXPg/mVc+lZMKAsGbddPk/hk7KcpzYBodAljyfqN0s9UQV0\n N+4A==","X-Google-DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed;\n d=1e100.net; s=20251104; t=1777368311; x=1777973111;\n h=content-transfer-encoding:cc:to:subject:message-id:date:from\n :in-reply-to:references:mime-version:x-gm-gg:x-gm-message-state:from\n :to:cc:subject:date:message-id:reply-to;\n bh=jkBLhtQNV3h3pGFyYLk2y1HraeriNw4hUDXsXFtwkrc=;\n b=ShMhYzLhy8J2g1Rin9PM5ut6aNuF6YccLCraPOETv3wOzrqXXdbFFdRwvU7xEgCjmy\n bwdq4xjFTsQlOkPNcubMkUsF/NIbbxx0LaLZuEHMVCXgit57wd9q0WHbJiy7XGJ7kth3\n k8cCyRMk8O+vX7v5cNDRo84+QpXcZpKb4a0SkShNSElmm1wrdRwuAXwmKwZqRIuHwO7m\n bn0VnhA+DM6qanklUf1RmPAp6v3j9NJIQHVltTM/jE3NIhTuZIw9/jHsEgxEjj9oob74\n XZTaP+BrFL7m2zQW7Ki7GRSyFDNpksv+NpF8FYH6aifeGpBjJqSuLSK9iFItXiRulxM8\n PuqQ==","X-Gm-Message-State":"AOJu0YyoRDkh0vm+ZVV+zUFXe5mEaMx6zCwrphZhyzck1/nKGVt34RbE\n 6x8GU/LtrKJyzScMnhubkrB8hHJsRHxx+k0jWJqXvEgG0Gg1bI8dTvcm+ngVT9Mw56dsABwNqwJ\n iER6HdUTNU58qflruw6e4WDc03+zxvIiyPg==","X-Gm-Gg":"AeBDies1J2ZlB/FHyhnvb0Rt3pZleiXnFX0ZZ4AkuOJJSnGkOPHbSGkI85BlUrZK4Vc\n tyW3w70t0FLAtTxBQLPWk8+PHlcrN9HEfd43fJdD4a8Jr/HNl9ihm3hebNN9YTag5+qt1n9Qrv7\n q/BaLd2uNZF7JGm37mdD1JrPmw0UdrxCBOw1wcEYrAT2i+zOjsYLoVod76T6gtiRArIH+yrHgU4\n jFW2k69zw9Cg8Np2KHa+u7QHB3SL6uN2sx7ED+Uh1g3LCG7mN2jiQXcwtfMHPtFB8TjQ4zQE/Xk\n vYdAUEt4HrfTZVdp","X-Received":"by 2002:a17:907:8745:b0:ba7:670b:f076 with SMTP id\n a640c23a62f3a-bb8020c9f60mr142262366b.2.1777368310870; Tue, 28 Apr 2026\n 02:25:10 -0700 (PDT)","MIME-Version":"1.0","References":"<20260417020830.4154676-1-andrew.pinski@oss.qualcomm.com>","In-Reply-To":"<20260417020830.4154676-1-andrew.pinski@oss.qualcomm.com>","From":"Richard Biener ","Date":"Tue, 28 Apr 2026 11:24:58 +0200","X-Gm-Features":"AVHnY4Ie0WLQPjtK3Kinq2dk-4xyp_Fj4UrXvdykqhu1cJTANaObGY5nwawkJGI","Message-ID":"\n ","Subject":"Re: [GCC17-PATCH 1/2] phiopt: Set cfgchanged if cselim-limited\n happened","To":"Andrew Pinski ","Cc":"gcc-patches@gcc.gnu.org","Content-Type":"text/plain; charset=\"UTF-8\"","Content-Transfer-Encoding":"quoted-printable","X-BeenThere":"gcc-patches@gcc.gnu.org","X-Mailman-Version":"2.1.30","Precedence":"list","List-Id":"Gcc-patches mailing list ","List-Unsubscribe":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Errors-To":"gcc-patches-bounces~incoming=patchwork.ozlabs.org@gcc.gnu.org"}}]