From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by sourceware.org (Postfix) with ESMTPS id 6BF843858D20 for ; Mon, 9 Jan 2023 12:31:28 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 6BF843858D20 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=suse.de Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=suse.de Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 3E1C33ED66 for ; Mon, 9 Jan 2023 12:31:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1673267486; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc: mime-version:mime-version:content-type:content-type; bh=syGKrTYHWMqL58luvV4G91pathDEy+hMxQg8C8ROIBI=; b=XZib/BzcDO681X3HZhbZ8oVPZAG7/qUCyXkSImJxA3SHR2OYIi39En9suB0/wDDuZvbMtn zcHfFHy8VGaXPzitpZiY3e1W+kC/AT4BpqB5Fwg9n3hmWbre1InVA70bm9nsv/0lG5vBJJ ltdEv6lTdTWIV4l9PpTRG5q08KFZtlo= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1673267486; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc: mime-version:mime-version:content-type:content-type; bh=syGKrTYHWMqL58luvV4G91pathDEy+hMxQg8C8ROIBI=; b=U9qVgm5NZRT6mipvBkVYm5ggcM8Ft1FI0/8yK2xmc8idHLEdyzJoVqRXTV786Js7fD7Kd1 NT3/KOc5XwCf1YDg== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 2C9BA13583 for ; Mon, 9 Jan 2023 12:31:26 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id QyzgCR4JvGOcaQAAMHmgww (envelope-from ) for ; Mon, 09 Jan 2023 12:31:26 +0000 Date: Mon, 9 Jan 2023 13:31:25 +0100 (CET) From: Richard Biener To: gcc-patches@gcc.gnu.org Subject: [PATCH] middle-end/69482 - not preserving volatile accesses MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Message-Id: <20230109123126.2C9BA13583@imap2.suse-dmz.suse.de> X-Spam-Status: No, score=-11.8 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,GIT_PATCH_0,KAM_SHORT,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: The following addresses a long standing issue with not preserving accesses to non-volatile objects through volatile qualified pointers in the case that object gets expanded to a register. The fix is to treat accesses to an object with a volatile qualified access as forcing that object to memory. This issue got more exposed recently so it regressed more since GCC 11. Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed to trunk sofar. PR middle-end/69482 * cfgexpand.cc (discover_nonconstant_array_refs_r): Volatile qualified accesses also force objects to memory. * gcc.target/i386/pr69482-1.c: New testcase. * gcc.target/i386/pr69482-2.c: Likewise. --- gcc/cfgexpand.cc | 9 +++++++++ gcc/testsuite/gcc.target/i386/pr69482-1.c | 16 ++++++++++++++++ gcc/testsuite/gcc.target/i386/pr69482-2.c | 10 ++++++++++ 3 files changed, 35 insertions(+) create mode 100644 gcc/testsuite/gcc.target/i386/pr69482-1.c create mode 100644 gcc/testsuite/gcc.target/i386/pr69482-2.c diff --git a/gcc/cfgexpand.cc b/gcc/cfgexpand.cc index 86783a6b661..25b1558dcb9 100644 --- a/gcc/cfgexpand.cc +++ b/gcc/cfgexpand.cc @@ -6291,6 +6291,15 @@ discover_nonconstant_array_refs_r (tree * tp, int *walk_subtrees, if (IS_TYPE_OR_DECL_P (t)) *walk_subtrees = 0; + else if (REFERENCE_CLASS_P (t) && TREE_THIS_VOLATILE (t)) + { + t = get_base_address (t); + if (t && DECL_P (t) + && DECL_MODE (t) != BLKmode + && !TREE_ADDRESSABLE (t)) + bitmap_set_bit (forced_stack_vars, DECL_UID (t)); + *walk_subtrees = 0; + } else if (TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF) { while (((TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF) diff --git a/gcc/testsuite/gcc.target/i386/pr69482-1.c b/gcc/testsuite/gcc.target/i386/pr69482-1.c new file mode 100644 index 00000000000..f192261b104 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr69482-1.c @@ -0,0 +1,16 @@ +/* { dg-do compile } */ +/* { dg-options "-O3" } */ + +static inline void memset_s(void* s, int n) { + volatile unsigned char * p = s; + for(int i = 0; i < n; ++i) { + p[i] = 0; + } +} + +void test() { + unsigned char x[4]; + memset_s(x, sizeof x); +} + +/* { dg-final { scan-assembler-times "mov" 4 } } */ diff --git a/gcc/testsuite/gcc.target/i386/pr69482-2.c b/gcc/testsuite/gcc.target/i386/pr69482-2.c new file mode 100644 index 00000000000..58e89a79333 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr69482-2.c @@ -0,0 +1,10 @@ +/* { dg-do compile } */ +/* { dg-options "-O2" } */ + +void bar () +{ + int j; + *(volatile int *)&j = 0; +} + +/* { dg-final { scan-assembler-times "mov" 1 } } */ -- 2.35.3