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From: "vincent-gcc at vinc17 dot net" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c/52106] New: missing -Wunused-but-set-variable warning with the a = b = ... construct Date: Fri, 03 Feb 2012 12:34:00 -0000 [thread overview] Message-ID: <bug-52106-4@http.gcc.gnu.org/bugzilla/> (raw) http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52106 Bug #: 52106 Summary: missing -Wunused-but-set-variable warning with the a = b = ... construct Classification: Unclassified Product: gcc Version: unknown Status: UNCONFIRMED Severity: enhancement Priority: P3 Component: c AssignedTo: unassigned@gcc.gnu.org ReportedBy: vincent-gcc@vinc17.net The following code int foo (void) { int a, b, c, d; a = b = 0; c = d = 0; return a + d; } gives: $ gcc-snapshot -Wall -c tst.c tst.c: In function 'foo': tst.c:3:13: warning: variable 'c' set but not used [-Wunused-but-set-variable] One would expect the same warning for variable 'b'. Even though it appears to be used to assign variable 'a', it shouldn't count in such a construct. Indeed a variable assignment is useless if the variable isn't used in a later expression (if the goal is to convert the value, then a cast would be more readable). Tested with: gcc (Debian 20120128-1) 4.7.0 20120128 (experimental) [trunk revision 183664]
next reply other threads:[~2012-02-03 12:34 UTC|newest] Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top 2012-02-03 12:34 vincent-gcc at vinc17 dot net [this message] 2012-02-03 12:54 ` [Bug c/52106] " jakub at gcc dot gnu.org 2012-02-03 13:29 ` [Bug c/52106] warning for useless assignments vincent-gcc at vinc17 dot net 2012-02-03 13:33 ` rguenth at gcc dot gnu.org 2012-02-03 17:18 ` [Bug c/52106] [C11] missing -Wunused-but-set-variable warning with the a = b = ... construct pinskia at gcc dot gnu.org
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