[Bug tree-optimization/21531] New: 4.0/4.1 Regression __builtin_expect

[Bug tree-optimization/21531] New: 4.0/4.1 Regression __builtin_expect

[alexander_herrmann at yahoo dot com dot au]

GNU C - maybe related to my bugreport 21513 but different.

Error:
src/aie_sql_meta.c: In Funktion aie_sql_meta_create_index:
src/aie_sql_meta.c:258: Warnung: tableid koennte in dieser Funktion
uninitialisiert verwendet werden
src/aie_sql_meta.c:259: Warnung: index_typ koennte in dieser Funktion
uninitialisiert verwendet werden
make: *** [obj/aie_sql_meta.o] Fehler 1

       int tableid;
       int index_typ;
could be unitilized in this function. It can but if not it's not used.
Difference to GCC 3.4.3. It is set but within another function. The function
itself resides in the same sourcefile so imo gcc would be able to figure out
that they are either initilized or not used. Especially when compiled with the
compiler switch -funit-at-a-time . btw if the initialisation would be in another
C sourcefile then the warning is ok imo because the compiler cannot know the
content - as tody - of two sourcefiles at the same time.

The function is to create a SQL Index out of a predefined structure. The two
variables are set within the function aie_sql_meta_get_index_def_from_id - see
below. 

The function it is as follows:

bool aie_sql_meta_create_index(int indexid, struct aie_sql_meta_db
                                                   *aie_sql_meta_db)
{
   bool rc = true;
   const char *index_name = aie_sql_meta_get_index_name_from_id(indexid, 
                                                            aie_sql_meta_db); 
    if (__builtin_expect((index_name != NULL),true))
    {
       unsigned int size_index_def = 0;
       int tableid;
       int index_typ;
       struct aie_sql_index_def *index_def =
	    aie_sql_meta_get_index_def_from_id(indexid, &tableid, &index_typ,
		                               &size_index_def,
                                               aie_sql_meta_db); 
       if (__builtin_expect(((index_def == NULL) ||
		             (size_index_def <= 0) ||
			     (tableid <= 0)),false))
       {
          sys_log("%s(%d):Fehler Meta SQL Table Def Create index "
	                             "IndexID[%d] index [%s] TableID[%d]!", 
                                                                  __FILE__,
								  __LINE__,
								  indexid,
								  index_name,
								  tableid);
	  rc = false;
       }
       else
       {
          const char *table_name = aie_sql_meta_get_table_name_from_id(tableid, 
                                                              aie_sql_meta_db); 
	  if (__builtin_expect((table_name != NULL),true))
	  {
             if (__builtin_expect(
		   (!aie_sql_create_index(aie_sql_meta_db->aie_sql_data,
					  table_name, 
					  index_name, 
					  index_typ,
		                          true,
                                           index_def,
                                           size_index_def)),false))
	     {
                sys_log("%s(%d):Fehler Meta SQL Create index "
		        "IndexID[%d] index [%s] Tableid[%d]!", 
                                                                  __FILE__,
								  __LINE__,
								  indexid,
								  index_name,
								  tableid);
	        rc = false;
	     }
	  }
	  else
	  {
             sys_log("%s(%d):Fehler Meta SQL Create index Table nicht gefunden "
	                     "IndexID[%d] index [%s] Tableid[%d]!", 
                                                                  __FILE__,
								  __LINE__,
								  indexid,
								  index_name,
								  tableid);
	     rc = false;
	  }
       }
    }
    else
    {
       sys_log("%s(%d): Create Table ID[%d] Table ID nicht gefunden!",
	                                                          __FILE__,
								  __LINE__,
								  indexid);
       rc = false;
    }
    return(rc);
}


struct aie_sql_index_def *aie_sql_meta_get_index_def_from_id(int indexid,
                                                         int *tableid, 
                                                         int *index_typ, 
                                                unsigned int *size_index_def, 
                                                struct aie_sql_meta_db 
						       *aie_sql_meta_db)
{
   struct aie_sql_index_def *aie_index_def = NULL;
   if (__builtin_expect((aie_sql_meta_db != NULL), true))
   {
      struct aie_sql_db *sql_db = aie_sql_meta_db->sql_db;
      unsigned int size_sql_db = aie_sql_meta_db->size_sql_db;
      if (__builtin_expect(((sql_db != NULL)  && (size_sql_db > 0)), true))
      {
	 register unsigned int z = 0;
	 for(z = 0;z < size_sql_db;z++)
	 {
            struct aie_sql_index *tbl_index;
            if (__builtin_expect(((tbl_index = sql_db->index) != NULL),true))
            {
                unsigned int size_index = sql_db->size_index;
		if (__builtin_expect((size_index > 0),true))
		{
		   register unsigned int y = 0;
		   for(y = 0; y < size_index; y++)
		   {
		      if (__builtin_expect((tbl_index->indexid == indexid), 
			                                                false))
		      {
			 if (__builtin_expect((tableid != NULL),true))
			 {
			    *tableid = tbl_index->tableid;
			 }
			 if (__builtin_expect((index_typ != NULL),true))
			 {
			    *index_typ = tbl_index->index_typ;
			 }
			 if (__builtin_expect((size_index_def != NULL),true))
			 {
			    *size_index_def = tbl_index->size_index_def;
			 }
			 aie_index_def = tbl_index->index_def;
			 break;
		      }
		      tbl_index++;
		   }

		}
		else
		{
	          sys_log("%s(%d): Warnung DB %d Indizies == 0", __FILE__, 
		                                                 __LINE__,
							         sql_db->dbid);
		}
            }
	    else
	    {
	       //sys_log("%s(%d): Warnung DB %d keine Indizies!", __FILE__, 
		//                                                __LINE__,
		//						sql_db->dbid);
	    }
	    sql_db++;
	 }
      }
      else
      {
         sys_log("%s(%d): Mata Date - Keine DB Info", __FILE__, __LINE__);
      }
   }
   else
   {
      sys_log("%s(%d): Mata Date Ptr == NULL!", __FILE__, __LINE__);
   }
   return(aie_index_def);
}

Solution: Waste a byte and maybe a CPU cycle and initilize it when defined.

-- 
           Summary: 4.0/4.1 Regression __builtin_expect
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: alexander_herrmann at yahoo dot com dot au
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: i686-pc-linux-gnu
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21531

[Bug tree-optimization/21531] 4.0/4.1 Regression __builtin_expect

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-05-12 12:12 -------
Can you attached the preprocessed source code (The only reason why I did not ask for PR 21513 is 
because I figured out to compile it and reproduce it without it).

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21531

[Bug tree-optimization/21531] 4.0/4.1 Regression __builtin_expect

[alexander_herrmann at yahoo dot com dot au]

------- Additional Comments From alexander_herrmann at yahoo dot com dot au  2005-05-13 09:53 -------
Subject: Re:  4.0/4.1 Regression __builtin_expect

Hi there,
> ------- Additional Comments From pinskia at gcc dot
> gnu dot org  2005-05-12 12:12 -------
> Can you attached the preprocessed source code (The
> only reason why I did not ask for PR 21513 is 
> because I figured out to compile it and reproduce it
> without it).
Ok, I will do so. I also make a testcase for it - till
tommorow. Sorry for the delay but I have some paid
work higher in my priority. 
Alexander

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-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21531

[Bug tree-optimization/21531] 4.0/4.1 Regression __builtin_expect

[alexander_herrmann at yahoo dot com dot au]

------- Additional Comments From alexander_herrmann at yahoo dot com dot au  2005-05-13 11:16 -------
Subject: Re:  4.0/4.1 Regression __builtin_expect

The promised Testcase. Earlier than expected :) 

aie_sql_meta.c: In Funktion
ปaie_sql_meta_create_indexซ:
aie_sql_meta.c:32: Warnung: ปindex_typซ
k๖nnte in dieser Funktion uninitialisiert
verwendet werden
aie_sql_meta.c:31: Warnung: ปtableidซ
k๖nnte in dieser Funktion uninitialisiert
verwendet werden

It only seems to happen with the compilerswitches
-Wall -O3 
It's kinda complete program so I guess the (very
large) precompiled isn't needed. Thanks for the fast
response and btw. GCC 4.0.0 seems to be a good work.
Finds more undefined prototypes than 3.4.3. What is
kind of missing is a error and a warning number as the
messages may be in strange languages these days which
makes it hard for english only to figure out what the
message means. Just a suggestion which came to my mind
producing the testcase. Maybe I should work on that :)
in my spare time.
#include <stdlib.h>
#include <stdio.h>

// reduced Testcase
// compiled with 
// gcc  -Wall -O3 aie_sql_meta.c 
// Alexander J. Herrmann 13.05.2005 
webmaster@aiengine.org

typedef int 	bool;

struct aie_sql_index_def
{
   char *something;
};

bool aie_sql_meta_create_index(int indexid);
struct aie_sql_index_def
*aie_sql_meta_get_index_def_from_id(int indexid,
                                                      
  int *tableid, 
                                                      
  int *index_typ);

int main(void)
{
   aie_sql_meta_create_index(1); // the good case
   aie_sql_meta_create_index(0); // the never should
happen case
   return(0);
}

bool aie_sql_meta_create_index(int indexid)
{
   bool rc = 1;
   int tableid;   // These are the two variables
complained about
   int index_typ;
   struct aie_sql_index_def *index_def =
	    aie_sql_meta_get_index_def_from_id(indexid,
&tableid, &index_typ);
   if (__builtin_expect(((index_def == NULL) ||
			     (tableid <= 0)),0))
   {
	  // error variables not set but also not used
	  rc = 0;
   }
   else
   {
       // Ok, variables set and used
       printf("%d %d\n", tableid, index_typ);
   }
   return(rc);
}

struct aie_sql_index_def
*aie_sql_meta_get_index_def_from_id(int indexid,
                                                      
  int *tableid, 
                                                      
  int *index_typ)
{
   static struct aie_sql_index_def aie_index_def;
   if (indexid == 1)
   {
      // the Good case
      *tableid = 1;
      *index_typ = 1;
   }
   else
   {
      // The what never should happen case
      return(NULL);
   }
   return(&aie_index_def);
}


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-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21531

[Bug tree-optimization/21531] 4.0/4.1 Regression __builtin_expect

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-05-13 11:42 -------
The warning is correct for tableid and index_typ as this is an "or" expression.

So this is invalid.

If I change it to && then that is just PR 21513.

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21531

[Bug tree-optimization/21531] 4.0/4.1 Regression __builtin_expect

[alexander_herrmann at yahoo dot com dot au]

------- Additional Comments From alexander_herrmann at yahoo dot com dot au  2005-05-13 11:55 -------
Subject: Re:  4.0/4.1 Regression __builtin_expect

> The warning is correct for tableid and index_typ as
> this is an "or" expression.
  if (__builtin_expect(((index_def == NULL) ||
			     (tableid <= 0)),0))
I didn't look at it this way. True but on the other
hand to my knowledge the || for tableid should only be
used when index_def is != NULL and if this is the case
then tableid has been set. 



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-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21531

[Bug tree-optimization/21531] 4.0/4.1 Regression __builtin_expect

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-05-13 12:00 -------
Then it is a dup of bug 21513.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21531

[Bug tree-optimization/21531] 4.0/4.1 Regression __builtin_expect

[alexander_herrmann at yahoo dot com dot au]

------- Additional Comments From alexander_herrmann at yahoo dot com dot au  2005-05-13 13:06 -------
Subject: Re:  4.0/4.1 Regression __builtin_expect

Ok, than we move it into another catagory. Compiler
crashes with segmentation fault. 
After 20 years of C programing it is like felling
feeling a bug. Trying to produce a testcase with || I
seem to have triggered it. The compiler get's a
segmentation fault on this one :)

aie_sql_meta.c: In Funktion aie_sql_meta_create_index:

aie_sql_meta.c:23: interner Compiler-Fehler:
Segmentation fault

#include <stdlib.h>
#include <stdio.h>
#include <time.h>

// reduced Testcase
// compiled with 
// gcc  -Wall -O3 aie_sql_meta.c 
// Alexander J. Herrmann 13.05.2005 
webmaster@aiengine.org

typedef int 	bool;

bool aie_sql_meta_create_index(void);
void aie_sql_meta_get_index_def_from_id(int indexid,
int *tableid, 
                                                      
  int *index_typ);

int main(void)
{
   aie_sql_meta_create_index(); 
   return(0);
}

bool aie_sql_meta_create_index(void)
{
   bool rc = 1;
   int tableid;   // Never gets initialized 
   int index_typ = 1;
   int indexid = 0;
   aie_sql_meta_get_index_def_from_id(indexid,
&tableid, &index_typ);
   if (__builtin_expect(((index_typ) || (tableid <=
0)),0))
   {
	  // error variables not set but also not used
	  rc = 0;
   }
   else
   {
       // tableid was never initialized
       printf("%d %d\n", tableid, index_typ);
   }
   return(rc);
}

void aie_sql_meta_get_index_def_from_id(int indexid,
int *tableid, 
                                                      
  int *index_typ)
{
   if (indexid == 1)
   {
      // the Good case
      *tableid = 1;
      *index_typ = 0;
   }
   else
   {
      *index_typ = 0;
   }
}





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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21531