[Bug c++/22355] New: Multiple local static variables initialization: missed optimization opportunity

[Bug c++/22355] New: Multiple local static variables initialization: missed optimization opportunity

[yuri at tsoft dot com]

Following code (f()) if compiled with -fno-exceptions should
produce only one initialization boolean for all local
static variables, not one per variable. This is since
they always initialized together provided there are no exceptions.

If exceptions are allowed then it should be driven by
the flag in constructors saying if they allow exceptions or not.

Yuri

---------------------------
struct C {
  C();
  int get();
};


int f() {
  static C i;
  static C j;
  return (i.get() + j.get());
}

-- 
           Summary: Multiple local static variables initialization: missed
                    optimization opportunity
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: yuri at tsoft dot com
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22355

[Bug c++/22355] Multiple local static variables initialization: missed optimization opportunity

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-07-07 20:39 -------
Say we call f() again before finish initializing i. then we call the get statement, it just undefined?

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22355

[Bug c++/22355] Multiple local static variables initialization: missed optimization opportunity

[giovannibajo at libero dot it]

------- Additional Comments From giovannibajo at libero dot it  2005-07-07 20:52 -------
I think Andres is right: what if C's constructor calls f() (only the first time 
it is invoked)?

I believe this bug is invalid.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22355

[Bug c++/22355] Multiple local static variables initialization: missed optimization opportunity

[yuri at Magma-DA dot COM]

------- Additional Comments From yuri at Magma-DA dot COM  2005-07-07 21:21 -------
Subject: Re:  Multiple local static variables initialization:
 missed optimization opportunity

I agree, this situation is fuzzy and bug is probably invalid.
But there are actually local static initializations that are to blame.

Why should these be checked/initialized on entry into the function, not 
globally?
Any particular benefit of this ?
I think it would have been way cleaner if initializations were done 
globally when code is loaded.

Yuri


pinskia at gcc dot gnu dot org wrote:

>------- Additional Comments From pinskia at gcc dot gnu dot org  2005-07-07 20:39 -------
>Say we call f() again before finish initializing i. then we call the get statement, it just undefined?
>
>  
>



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22355

[Bug c++/22355] Multiple local static variables initialization: missed optimization opportunity

[bangerth at dealii dot org]

------- Additional Comments From bangerth at dealii dot org  2005-07-07 22:14 -------
That's just what the standard says: these variables are initialized when 
execution first passes their location of declaration. 
 
I guess this PR is indeed invalid, so I close it. 
 
W. 

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22355