From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oo1-xc34.google.com (mail-oo1-xc34.google.com [IPv6:2607:f8b0:4864:20::c34]) by sourceware.org (Postfix) with ESMTPS id 54F9638582A1 for ; Wed, 11 Jan 2023 21:27:34 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 54F9638582A1 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=linaro.org Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=linaro.org Received: by mail-oo1-xc34.google.com with SMTP id 187-20020a4a09c4000000b004d8f3cb09f5so4365370ooa.6 for ; Wed, 11 Jan 2023 13:27:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=content-transfer-encoding:mime-version:message-id:date:subject:to :from:from:to:cc:subject:date:message-id:reply-to; bh=uBRIqpWsi78Krkwr9uTrtJqyVft6XsjluL0OopVS3MY=; b=DDsedWc2+lA6WDuxJxcEZMxWWUwO8RI1DOnTzNTpAJNBYsP9t5RYAQ2EbOUkF1Mq+T p8dUTrIGHkIy3ELXzOVL02/kVBz0/gxWStzAEgD8qOJo9DmI5nGmlAF9ESRxZd3aNImI vEmYTaKMjL/LLbuYhltRllvhPk/JS7+auc90m3gtHLAPskvo5fvv7ZoEpEkh1FS6drFh z4tYfb1SuLpM1H5kKr3ltne9YNyf5lqqZQWfL15XYE3gTOIxKGu4rYeNCdYJZzr7jcd8 U7KatQoD4u0BHuFbGgLy8jrXwT0X2ys0vgmcxuB4jnJ89Jweo2NyjfnTDC71NNcAHriS 0IKg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:to :from:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=uBRIqpWsi78Krkwr9uTrtJqyVft6XsjluL0OopVS3MY=; b=hR7ZO7HTmLwFmmNQGHTBne8boG1PK8IuMkgzFFqMYTf40PcXo4Ho8dD7VB7CCke/y5 vg/Xwy4nBTtwaW3R0OkI34qRJ8icWdfHBpOLyZ2dPyHmitGptKm9LKgI9FnhTsiCjZt6 eAkCW2NOISiQLPo3X6Yzp9GTtuzu8xueCE6VKlZsdX4FsRzC232nl83canxuL9D0UDgY QcbLDT007aREctM/8DXLoHdwsQ6mez9CMlf1SK/eiMcnIzQV6/BUKlWqighMEB7r9yxQ wtiJ2jt67BmBx3HLHdPVC7iVq6RJWY7Q2o7uCYTyKnEI/fn9DcOJwyIsWtVEwx5XsXSP Lwhg== X-Gm-Message-State: AFqh2kqvW8rCXwArgM2epwTQW6g9H8p4yTVpVycK6MQkGWMenekjmUkB 28MtetS3yxswSNkMqIwjO8gq4jQSIFmVfTdOiOw= X-Google-Smtp-Source: AMrXdXuMHPdzAdqshGphCW4g0jfa4RDfnykDTaqqyFf3zIfrI9QfPrX0cyRExtvRNLaDwtZI7M1/ig== X-Received: by 2002:a4a:5892:0:b0:4f2:6881:dbd5 with SMTP id f140-20020a4a5892000000b004f26881dbd5mr25000oob.6.1673472453088; Wed, 11 Jan 2023 13:27:33 -0800 (PST) Received: from mandiga.. ([2804:1b3:a7c0:a93a:a504:f3f6:dd7b:801]) by smtp.gmail.com with ESMTPSA id bc31-20020a056820169f00b0049f8b4b2095sm7584550oob.44.2023.01.11.13.27.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 11 Jan 2023 13:27:32 -0800 (PST) From: Adhemerval Zanella To: libc-alpha@sourceware.org, Carlos O'Donell Subject: [PATCH v2] string: Suppress -Wmaybe-unitialized for wordcopy [BZ #19444] Date: Wed, 11 Jan 2023 18:27:29 -0300 Message-Id: <20230111212729.4109942-1-adhemerval.zanella@linaro.org> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-12.9 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,GIT_PATCH_0,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: When compiling with GCC 6+ the sparc build warns that some variables might be used uninitialized. However it does not seem the fact, since the variables are really initialized (and also other targets that use the same code, like powerpc, do not warn about it). So suppress the warning for now. Changes from v1: * Update patch description and the explanation for the suppresion. --- string/wordcopy.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/string/wordcopy.c b/string/wordcopy.c index ae5ccd793c..a8a40c9f01 100644 --- a/string/wordcopy.c +++ b/string/wordcopy.c @@ -19,7 +19,19 @@ /* BE VERY CAREFUL IF YOU CHANGE THIS CODE...! */ #include +#include +/* Compiling with -O1 might warn that 'a2' and 'a3' may be used + uninitialized. There are only two ways to arrive at labels 'do4', 'do3' + or 'do1', all of which use 'a2' or 'a3' in the MERGE macro: either from + the earlier switch case statement or via a loop iteration. In all cases + the switch statement or previous loop sets both 'a2' and 'a3'. + + Since the usage is within the MERGE macro we disable the + warning in the definition, but only in this file. */ +DIAG_PUSH_NEEDS_COMMENT; +DIAG_IGNORE_NEEDS_COMMENT (6, "-Wmaybe-uninitialized"); #include +DIAG_POP_NEEDS_COMMENT; /* _wordcopy_fwd_aligned -- Copy block beginning at SRCP to block beginning at DSTP with LEN `op_t' words (not LEN bytes!). @@ -94,7 +106,15 @@ WORDCOPY_FWD_ALIGNED (long int dstp, long int srcp, size_t len) { do8: a0 = ((op_t *) srcp)[0]; + /* Compiling with -O1 may warn that 'a1' may be used uninitialized. + There are only two ways to arrive at label 'do8' and they are via a + do-while loop iteration or directly via the earlier switch 'case 1:' + case. The switch case always sets 'a1' and all previous loop + iterations will also have set 'a1' before the use. */ + DIAG_PUSH_NEEDS_COMMENT; + DIAG_IGNORE_NEEDS_COMMENT (6, "-Wmaybe-uninitialized"); ((op_t *) dstp)[0] = a1; + DIAG_POP_NEEDS_COMMENT; do7: a1 = ((op_t *) srcp)[1]; ((op_t *) dstp)[1] = a0; @@ -291,7 +311,11 @@ WORDCOPY_BWD_ALIGNED (long int dstp, long int srcp, size_t len) { do8: a0 = ((op_t *) srcp)[7]; + /* Check the comment on WORDCOPY_FWD_ALIGNED. */ + DIAG_PUSH_NEEDS_COMMENT; + DIAG_IGNORE_NEEDS_COMMENT (6, "-Wmaybe-uninitialized"); ((op_t *) dstp)[7] = a1; + DIAG_POP_NEEDS_COMMENT; do7: a1 = ((op_t *) srcp)[6]; ((op_t *) dstp)[6] = a0; -- 2.34.1