[Bug c++/14199] New: [tree-ssa regression] Unjustified warning about unused variable

[Bug c++/14199] New: [tree-ssa regression] Unjustified warning about unused variable

[bangerth at dealii dot org]

Here is some recent regression I see on tree-ssa. I don't have a recent 
mainline checked out, so can't test whether this also happens on mainline, 
but here is what happens: 
----------------------------- 
struct X { 
    static void foo (); 
}; 
 
template <typename T> 
void foo (const T &t) { 
  t.foo(); 
} 
 
template void foo (const X &); 
------------------- 
 
deal.II/base> c++ -c -Wunused x.cc -W -Wall  
x.cc: In function `void foo(const T&) [with T = X]': 
x.cc:10:   instantiated from here 
x.cc:6: warning: unused parameter 't' 
 
This warning is clearly bogus! 
 
W.

-- 
           Summary: [tree-ssa regression] Unjustified warning about unused
                    variable
           Product: gcc
           Version: tree-ssa
            Status: UNCONFIRMED
          Keywords: diagnostic
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: bangerth at dealii dot org
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14199

[Bug c++/14199] [tree-ssa regression] Unjustified warning about unused variable

[bangerth at dealii dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |critical
   Target Milestone|---                         |tree-ssa


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14199

[Bug c++/14199] [tree-ssa regression] Unjustified warning about unused variable

[gerald at pfeifer dot com]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |gerald at pfeifer dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14199

[Bug c++/14199] [tree-ssa regression] Unjustified warning about unused variable

[bangerth at dealii dot org]

------- Additional Comments From bangerth at dealii dot org  2004-02-18 21:59 -------
I just checked that it indeed also fails on mainline. So tree-ssa 
only inherited this problem. 
 
W. 

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to fail|                            |tree-ssa 3.5.0
   Target Milestone|tree-ssa                    |3.5.0
            Version|tree-ssa                    |3.5.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14199

[Bug c++/14199] [tree-ssa regression] Unjustified warning about unused variable

[bangerth at dealii dot org]

------- Additional Comments From bangerth at dealii dot org  2004-02-18 22:04 -------
Actually, when I extracted this small snippet, I didn't even really think 
what it is about. The point is that the compiler really has some right 
to say that the object is unused: the function we call is static, so the 
object is really unused. It does make use to not issue the warning, though, 
since the template may as well be instantiated for classes for which this 
function is not static, and there is no good reason to show an warning message 
in one, but not the other case. So, in a sense, a patch will have to 
broaden the meaning of the word "unused"... 
 
W. 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14199

[Bug c++/14199] [3.4/3.5 regression] Unjustified warning about unused variable

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-02-18 22:09 -------
Confirmed.  It also happens in 3.4.0 and 3.5.0, the probelm is that the variable is really not used 
because the function is static.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|critical                    |normal
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
      Known to fail|tree-ssa 3.5.0              |3.4.0 3.5.0
      Known to work|                            |3.3.3
   Last reconfirmed|0000-00-00 00:00:00         |2004-02-18 22:09:49
               date|                            |
            Summary|[tree-ssa regression]       |[3.4/3.5 regression]
                   |Unjustified warning about   |Unjustified warning about
                   |unused variable             |unused variable
   Target Milestone|3.5.0                       |3.4.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14199

[Bug c++/14199] [3.4/3.5 regression] Unjustified warning about unused variable

[bangerth at dealii dot org]

------- Additional Comments From bangerth at dealii dot org  2004-02-19 00:37 -------
Looking at my logfiles: I believe this bug has been introduced in the last two to three 
days. Maybe someone can figure out which patch this was. 
 
W. 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14199

[Bug c++/14199] [3.4/3.5 regression] Unjustified warning about unused variable

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |minor


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14199

[Bug c++/14199] [3.4/3.5 regression] Unjustified warning about unused variable

[mmitchel at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |mark at codesourcery dot com
                   |dot org                     |
             Status|NEW                         |ASSIGNED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14199

[Bug c++/14199] [3.4/3.5 regression] Unjustified warning about unused variable

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2004-02-20 08:57 -------
Subject: Bug 14199

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	mmitchel@gcc.gnu.org	2004-02-20 08:57:33

Modified files:
	gcc/cp         : ChangeLog decl.c name-lookup.c pt.c semantics.c 
	gcc/testsuite  : ChangeLog 
	gcc/testsuite/g++.dg/other: error8.C 
Added files:
	gcc/testsuite/g++.dg/ext: packed5.C 
	gcc/testsuite/g++.dg/warn: Wunused-5.C 

Log message:
	PR c++/14199
	* pt.c (tsubst_copy): Call mark_used for a PARM_DECL.
	
	PR c++/14173
	* semantics.c (begin_class_definition): Set TYPE_PACKED correctly
	for all type variants.
	
	PR c++/14173
	* g++.dg/ext/packed5.C: New test.
	
	PR c++/14199
	* g++.dg/warn/Wunused-5.C: New test.
	
	PR c++/13927
	* decl.c (duplicate_decls): Return error_mark_node for invalid
	redeclarations.
	* name-lookup.c (push_namespace): Ignore the return value from
	pushdecl.
	* pt.c (push_template_decl_real): Robustify.
	
	PR c++/13927
	* g++.dg/other/error8.C: Remove XFAIL markers.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/cp/ChangeLog.diff?cvsroot=gcc&r1=1.3962&r2=1.3963
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/cp/decl.c.diff?cvsroot=gcc&r1=1.1187&r2=1.1188
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/cp/name-lookup.c.diff?cvsroot=gcc&r1=1.39&r2=1.40
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/cp/pt.c.diff?cvsroot=gcc&r1=1.830&r2=1.831
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/cp/semantics.c.diff?cvsroot=gcc&r1=1.388&r2=1.389
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/ChangeLog.diff?cvsroot=gcc&r1=1.3523&r2=1.3524
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/g++.dg/ext/packed5.C.diff?cvsroot=gcc&r1=NONE&r2=1.1
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/g++.dg/other/error8.C.diff?cvsroot=gcc&r1=1.1&r2=1.2
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/g++.dg/warn/Wunused-5.C.diff?cvsroot=gcc&r1=NONE&r2=1.1



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14199

[Bug c++/14199] [3.4/3.5 regression] Unjustified warning about unused variable

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2004-02-20 09:03 -------
Subject: Bug 14199

CVSROOT:	/cvs/gcc
Module name:	gcc
Branch: 	gcc-3_4-branch
Changes by:	mmitchel@gcc.gnu.org	2004-02-20 09:03:34

Modified files:
	gcc/cp         : ChangeLog pt.c semantics.c 
	gcc/testsuite  : ChangeLog 
Added files:
	gcc/testsuite/g++.dg/ext: packed5.C 
	gcc/testsuite/g++.dg/warn: Wunused-5.C 

Log message:
	PR c++/14199
	* pt.c (tsubst_copy): Call mark_used for a PARM_DECL.
	
	PR c++/14173
	* semantics.c (begin_class_definition): Set TYPE_PACKED correctly
	for all type variants.
	
	PR c++/14173
	* g++.dg/ext/packed5.C: New test.
	
	PR c++/14199
	* g++.dg/warn/Wunused-5.C: New test.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/cp/ChangeLog.diff?cvsroot=gcc&only_with_tag=gcc-3_4-branch&r1=1.3892.2.57&r2=1.3892.2.58
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/cp/pt.c.diff?cvsroot=gcc&only_with_tag=gcc-3_4-branch&r1=1.816.2.11&r2=1.816.2.12
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/cp/semantics.c.diff?cvsroot=gcc&only_with_tag=gcc-3_4-branch&r1=1.381.4.7&r2=1.381.4.8
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/ChangeLog.diff?cvsroot=gcc&only_with_tag=gcc-3_4-branch&r1=1.3389.2.95&r2=1.3389.2.96
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/g++.dg/ext/packed5.C.diff?cvsroot=gcc&only_with_tag=gcc-3_4-branch&r1=NONE&r2=1.1.2.1
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/g++.dg/warn/Wunused-5.C.diff?cvsroot=gcc&only_with_tag=gcc-3_4-branch&r1=NONE&r2=1.1.2.1



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14199

[Bug c++/14199] [3.4/3.5 regression] Unjustified warning about unused variable

[mmitchel at gcc dot gnu dot org]

------- Additional Comments From mmitchel at gcc dot gnu dot org  2004-02-20 09:05 -------
Fixed in GCC 3.4.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14199