Bug 44682 - [4.6 Regression] warning: variable ‘x’ set but not used
Summary: [4.6 Regression] warning: variable ‘x’ set but not used
Status: RESOLVED FIXED
Alias: None
Product: gcc
Classification: Unclassified
Component: c++ (show other bugs)
Version: 4.6.0
: P3 normal
Target Milestone: 4.6.0
Assignee: Not yet assigned to anyone
URL:
Keywords: diagnostic
Depends on:
Blocks:
 
Reported: 2010-06-26 13:28 UTC by Wouter Vermaelen
Modified: 2010-06-29 15:24 UTC (History)
2 users (show)

See Also:
Host:
Target:
Build:
Known to work:
Known to fail:
Last reconfirmed: 2010-06-28 00:31:55

Attachments
gcc46-pr44682.patch (604 bytes, patch)
2010-06-28 08:54 UTC, Jakub Jelinek 		Details | Diff
View All Add an attachment (proposed patch, testcase, etc.)

Note You need to log in before you can comment on or make changes to this bug.
Description Wouter Vermaelen 2010-06-26 13:28:59 UTC 
> cat bug.ii
struct Base1 {
    virtual ~Base1() {}
};
struct Base2 {
    virtual ~Base2() {}
};
struct Foo : Base1, Base2 {};

void f(Foo&);

void g(void* v) {
    Base2* base = static_cast<Base2*>(v);
    Foo* foo = static_cast<Foo*>(base);
    f(*foo);
}


> g++ -Wall -c bug.ii
bug.ii: In function ‘void g(void*)’:
bug.ii:12:9: warning: variable ‘base’ set but not used [-Wunused-but-set-variable]


I'm using SVN revision trunk@161411 on linux x86_64.
Comment 1 Andrew Pinski 2010-06-28 00:31:55 UTC 
Confirmed.
Comment 2 Jakub Jelinek 2010-06-28 08:54:55 UTC 
Created attachment 21021 [details]
gcc46-pr44682.patch

Untested fix.
Comment 3 Jakub Jelinek 2010-06-28 20:13:00 UTC 
Subject: Bug 44682

Author: jakub
Date: Mon Jun 28 20:12:31 2010
New Revision: 161511

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=161511
Log:
	PR c++/44682
	* class.c (build_base_path): If want_pointer, call mark_rvalue_use
	on expr.

	* g++.dg/warn/Wunused-var-14.C: New test.

Added:
    trunk/gcc/testsuite/g++.dg/warn/Wunused-var-14.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/class.c
    trunk/gcc/testsuite/ChangeLog
Comment 4 Jakub Jelinek 2010-06-29 15:24:19 UTC 
Fixed.