From patchwork Wed Jun 20 22:19:01 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joseph Myers X-Patchwork-Id: 27957 Received: (qmail 23745 invoked by alias); 20 Jun 2018 22:19:09 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 23723 invoked by uid 89); 20 Jun 2018 22:19:08 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-24.5 required=5.0 tests=AWL, BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, RCVD_IN_DNSWL_NONE, SPF_PASS, URIBL_RED autolearn=ham version=3.3.2 spammy= X-HELO: relay1.mentorg.com Date: Wed, 20 Jun 2018 22:19:01 +0000 From: Joseph Myers To: Subject: Fix bug-strspn1.c, bug-strpbrk1.c build with GCC mainline [committed] Message-ID: User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 X-ClientProxiedBy: svr-ies-mbx-01.mgc.mentorg.com (139.181.222.1) To svr-ies-mbx-01.mgc.mentorg.com (139.181.222.1) Building the testsuite with GCC mainline fails with: bug-strspn1.c: In function 'main': bug-strspn1.c:14:3: error: right-hand operand of comma expression has no effect [-Werror=unused-value] strspn (b++, ""); ^~~~~~~~~~~~~~~~ and a similar error for bug-strpbrk1.c. I'm not sure what GCC change introduced this, and the wording of the message is a bit off (in the source it's not a comma expression, that must reflect GCC's IR). But the warning is correct (strspn is a pure function, the call is useless, and if there wasn't an argument with a side effect much older GCC would have warned); the point of the test is to verify that the side effect in an argument still occurs for this useless call that can otherwise be optimized to an (unused) constant (testing for a bug there once was in an old strspn macro). This patch duly arranges for the warning to be disabled for this code. Tested with build-many-glibcs.py for aarch64-linux-gnu. Committed. 2018-06-20 Joseph Myers * string/bug-strpbrk1.c: Include . (main): Disable -Wunused-value around call to strpbrk. * string/bug-strspn1.c: Include . (main): Disable -Wunused-value around call to strspn. diff --git a/string/bug-strpbrk1.c b/string/bug-strpbrk1.c index 28238b0..8e909a1 100644 --- a/string/bug-strpbrk1.c +++ b/string/bug-strpbrk1.c @@ -4,6 +4,7 @@ #include #include #include +#include int main (void) @@ -11,7 +12,14 @@ main (void) const char *a = "abc"; const char *b = a; + DIAG_PUSH_NEEDS_COMMENT; + /* GCC 9 correctly warns that this call to strpbrk is useless. That + is deliberate; this test is verifying that a side effect in an + argument still occurs when the call itself is useless and could + be optimized to return a constant. */ + DIAG_IGNORE_NEEDS_COMMENT (9, "-Wunused-value"); strpbrk (b++, ""); + DIAG_POP_NEEDS_COMMENT; if (b != a + 1) return 1; diff --git a/string/bug-strspn1.c b/string/bug-strspn1.c index a657baf..e3487ab 100644 --- a/string/bug-strspn1.c +++ b/string/bug-strspn1.c @@ -4,6 +4,7 @@ #include #include #include +#include int main (void) @@ -11,7 +12,14 @@ main (void) const char *a = "abc"; const char *b = a; + DIAG_PUSH_NEEDS_COMMENT; + /* GCC 9 correctly warns that this call to strspn is useless. That + is deliberate; this test is verifying that a side effect in an + argument still occurs when the call itself is useless and could + be optimized to return a constant. */ + DIAG_IGNORE_NEEDS_COMMENT (9, "-Wunused-value"); strspn (b++, ""); + DIAG_POP_NEEDS_COMMENT; if (b != a + 1) return 1;