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* [Bug c++/54583] New: Spurious warning: value computed is not used with variable-size array @ 2012-09-14 20:17 stuff0002 at pobox dot com 2012-10-30 1:07 ` [Bug c++/54583] " paolo.carlini at oracle dot com ` (2 more replies) 0 siblings, 3 replies; 4+ messages in thread From: stuff0002 at pobox dot com @ 2012-09-14 20:17 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54583 Bug #: 54583 Summary: Spurious warning: value computed is not used with variable-size array Classification: Unclassified Product: gcc Version: 4.6.3 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ AssignedTo: unassigned@gcc.gnu.org ReportedBy: stuff0002@pobox.com When declaring a two-dimensional array with variable-length second dimension, there is a warning "value computed is not used". For example: $ cat warn1.cpp void fred(){ int n=10; double (*x)[n]; } $ g++ -c warn1.cpp -Wall warn1.cpp: In function ‘void fred()’: warn1.cpp:3:16: warning: value computed is not used [-Wunused-value] warn1.cpp:3:12: warning: unused variable ‘x’ [-Wunused-variable] The second warning ("unused variable") is to be expected of course, and is not the subject of this bug report. I don't believe the fact that x isn't used is relevant to the first warning, so code that uses x is omitted in the above example in the interests of constructing a minimal example. But to check, here is a longer example that uses x: $ cat warn2.cpp #include <stdio.h> #include <stdlib.h> #define M 10 void fred(){ int a,b,n; n=10; double (*x)[n]; x=(double(*)[n])malloc(M*n*sizeof(double)); for(a=0;a<M;a++)for(b=0;b<n;b++)x[a][b]=3; for(a=0;a<M;a++)for(b=0;b<n;b++)printf("%g\n",x[a][b]); } $ g++ -c warn2.cpp -Wall warn2.cpp: In function ‘void fred()’: warn2.cpp:8:16: warning: value computed is not used [-Wunused-value] g++ --version g++ (Ubuntu/Linaro 4.6.3-1ubuntu5) 4.6.3 ... ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug c++/54583] Spurious warning: value computed is not used with variable-size array 2012-09-14 20:17 [Bug c++/54583] New: Spurious warning: value computed is not used with variable-size array stuff0002 at pobox dot com @ 2012-10-30 1:07 ` paolo.carlini at oracle dot com 2012-10-31 19:15 ` paolo at gcc dot gnu.org 2012-10-31 19:17 ` paolo.carlini at oracle dot com 2 siblings, 0 replies; 4+ messages in thread From: paolo.carlini at oracle dot com @ 2012-10-30 1:07 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54583 Paolo Carlini <paolo.carlini at oracle dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |ASSIGNED Last reconfirmed| |2012-10-30 AssignedTo|unassigned at gcc dot |paolo.carlini at oracle dot |gnu.org |com Ever Confirmed|0 |1 --- Comment #1 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-10-30 01:07:27 UTC --- Mine. ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug c++/54583] Spurious warning: value computed is not used with variable-size array 2012-09-14 20:17 [Bug c++/54583] New: Spurious warning: value computed is not used with variable-size array stuff0002 at pobox dot com 2012-10-30 1:07 ` [Bug c++/54583] " paolo.carlini at oracle dot com @ 2012-10-31 19:15 ` paolo at gcc dot gnu.org 2012-10-31 19:17 ` paolo.carlini at oracle dot com 2 siblings, 0 replies; 4+ messages in thread From: paolo at gcc dot gnu.org @ 2012-10-31 19:15 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54583 --- Comment #2 from paolo at gcc dot gnu.org <paolo at gcc dot gnu.org> 2012-10-31 19:14:44 UTC --- Author: paolo Date: Wed Oct 31 19:14:39 2012 New Revision: 193043 URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=193043 Log: /cp 2012-10-31 Paolo Carlini <paolo.carlini@oracle.com> PR c++/54583 * tree.c (build_cplus_array_type): Set TREE_NO_WARNING on the TYPE_SIZE of VLAs. /testsuite 2012-10-31 Paolo Carlini <paolo.carlini@oracle.com> PR c++/54583 * g++.dg/ext/vla13.C: New. Added: trunk/gcc/testsuite/g++.dg/ext/vla13.C Modified: trunk/gcc/cp/ChangeLog trunk/gcc/cp/tree.c trunk/gcc/testsuite/ChangeLog ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug c++/54583] Spurious warning: value computed is not used with variable-size array 2012-09-14 20:17 [Bug c++/54583] New: Spurious warning: value computed is not used with variable-size array stuff0002 at pobox dot com 2012-10-30 1:07 ` [Bug c++/54583] " paolo.carlini at oracle dot com 2012-10-31 19:15 ` paolo at gcc dot gnu.org @ 2012-10-31 19:17 ` paolo.carlini at oracle dot com 2 siblings, 0 replies; 4+ messages in thread From: paolo.carlini at oracle dot com @ 2012-10-31 19:17 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54583 Paolo Carlini <paolo.carlini at oracle dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|ASSIGNED |RESOLVED Resolution| |FIXED Target Milestone|--- |4.8.0 --- Comment #3 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-10-31 19:16:40 UTC --- Fixed for 4.8.0. ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2012-10-31 19:17 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2012-09-14 20:17 [Bug c++/54583] New: Spurious warning: value computed is not used with variable-size array stuff0002 at pobox dot com 2012-10-30 1:07 ` [Bug c++/54583] " paolo.carlini at oracle dot com 2012-10-31 19:15 ` paolo at gcc dot gnu.org 2012-10-31 19:17 ` paolo.carlini at oracle dot com
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