{"id":26811,"url":"https://patchwork.libcamera.org/api/patches/26811/?format=json","web_url":"https://patchwork.libcamera.org/patch/26811/","project":{"id":1,"url":"https://patchwork.libcamera.org/api/projects/1/?format=json","name":"libcamera","link_name":"libcamera","list_id":"libcamera_core","list_email":"libcamera-devel@lists.libcamera.org","web_url":"","scm_url":"","webscm_url":""},"msgid":"<20260527171041.110173-1-simonparri@ganzeria.com>","date":"2026-05-27T17:10:37","name":"[RFC] meson: Make rpi/pisp pipeline build on GCC at low optimization","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"985fdda75915e796ccce718198888913ecb3176c","submitter":{"id":263,"url":"https://patchwork.libcamera.org/api/people/263/?format=json","name":"Simon Parri","email":"simonparri@ganzeria.com"},"delegate":null,"mbox":"https://patchwork.libcamera.org/patch/26811/mbox/","series":[{"id":5968,"url":"https://patchwork.libcamera.org/api/series/5968/?format=json","web_url":"https://patchwork.libcamera.org/project/libcamera/list/?series=5968","date":"2026-05-27T17:10:37","name":"[RFC] meson: Make rpi/pisp pipeline build on GCC at low optimization","version":1,"mbox":"https://patchwork.libcamera.org/series/5968/mbox/"}],"comments":"https://patchwork.libcamera.org/api/patches/26811/comments/","check":"pending","checks":"https://patchwork.libcamera.org/api/patches/26811/checks/","tags":{},"headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 93AE6BDCBC\n\tfor ;\n\tWed, 27 May 2026 17:10:52 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id BBC8C63024;\n\tWed, 27 May 2026 19:10:51 +0200 (CEST)","from omta002.uswest2.a.cloudfilter.net\n\t(omta002.uswest2.a.cloudfilter.net [35.164.127.225])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id CF5A162E6A\n\tfor ;\n\tWed, 27 May 2026 19:10:49 +0200 (CEST)","from mcc-obgw-6002b.ext.cloudfilter.net ([10.244.128.100])\n\tby cmsmtp with ESMTP\n\tid SFu5wmnMjk3IVSHmKwoXEF; Wed, 27 May 2026 17:10:48 +0000","from localhost ([173.16.167.196]) by cmsmtp with ESMTPS\n\tid SHmGw6kiQJ8IOSHmIwTDkN; Wed, 27 May 2026 17:10:47 +0000"],"X-Authority-Analysis":"v=2.4 cv=W9M4VQWk c=1 sm=1 tr=0 ts=6a172597\n\ta=VPmDnoH/21K0g3l4Zi3lTQ==:117 a=VPmDnoH/21K0g3l4Zi3lTQ==:17\n\ta=tGv0lvtu0_dalHgCflUA:9","From":"Simon Parri ","To":"libcamera-devel@lists.libcamera.org","Cc":"Simon Parri ","Subject":"[RFC PATCH] meson: Make rpi/pisp pipeline build on GCC at low\n\toptimization","Date":"Wed, 27 May 2026 19:10:37 +0200","Message-ID":"<20260527171041.110173-1-simonparri@ganzeria.com>","X-Mailer":"git-send-email 2.51.2","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit","X-CMAE-Envelope":"MS4xfIFnnazZiwn7i3au2Qfoc8AyM9zEVipUB0UGv1ZeC/WtY0q9rIIspPsWU+bPTTiL+5yvuceMTnH9KYVSZa9FLs+HaoJn3oIGRoHAkq5S72M7wNVFKMG+\n\tYJZDa8OZhA30WZ1iuYFYEhJlm4oJQTqFzTP5TQiBA+Hv6mx15B7QG+Rn09tnJwp/M+OBWt1BGvO/oEjZY3Pbxz12c8tpRrT8tJVd8XHLBKxTrp+iUQoGQbF/\n\tIfOEe3paP4I/Hg/KrTkWuw==","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "},"content":"The function PiSPCameraData::beOutputDequeue in pipelines/rpi/pisp.cpp\ncontains a variable \"index\" that is initialized in the loop along with the\nvariable \"stream\". When -ftree-vrp is not enabled, GCC cannot analyze the\ncode to determine that after \"ASSERT(stream)\", \"index\" will always be\ninitialized. Since it cannot determine that \"index\" will always be\ninitialized, it emits a warning, which is elevated to an error.\n\nIf the rpi/pisp pipeline is to be built, and the compiler is GCC, add\n-ftree-vrp to project arguments for C++.\n\nThis is not needed for Clang, since Clang always does the appropriate level of\ncode analysis (even at -O0).\n---\n\nNotes:\n I would like advice on whether using \"add_project_arguments\" is the correct\n thing to do here. It feels somewhat wrong to me because all the other\n flags (as far as I can tell) are set via common_arguments / c_arguments /\n cpp_arguments. However, since I need to check the enabled pipelines, I put the check\n after the code that sets the \"pipelines\" variable.\n \n Or is my approach wrong to begin with? Should I be adjusting the code itself\n instead of adding compiler flags? In my opinion, adding compiler flags is the\n correct approach, since the code already works as-is with Clang.\n \n Thank you for your attention.\n\n meson.build | 4 ++++\n 1 file changed, 4 insertions(+)","diff":"diff --git a/meson.build b/meson.build\nindex 9cd73462f..0344c55bb 100644\n--- a/meson.build\n+++ b/meson.build\n@@ -241,6 +241,10 @@ else\n pipelines = wanted_pipelines\n endif\n \n+if cc.get_id() == 'gcc' and pipelines.contains('rpi/pisp')\n+ add_project_arguments('-ftree-vrp', language : 'cpp')\n+endif\n+\n # Tests require the vimc pipeline handler, include it automatically when tests\n # are enabled.\n if get_option('test')\n","prefixes":["RFC"]}