Miscompilation of tetex-1.0.6 by gcc-2.95

[Martin Kahlert]

Hi,
i simplified Ernst program quite a bit ;-)

Martin, -fstrict-aliasing has nothing to do with that.
It seems to be a more fundamental optimizer bug.

To show it, do this:
gcc -O1 -o test1 test.c
gcc -O2 -o test2 test.c

./test2
 hier is a bug: i=54
 Bad GF file: Unexpected 55 command between characters!

./test1
 hier is a bug: i=55
 Bad GF file: Unexpected 69 command between characters!

I append the shortest version which shows the tetex bug.

gcc -v:
Reading specs from /usr/local/lib/gcc-lib/i686-pc-linux-gnu/2.95/specs

gcc version 2.95 19990718 (prerelease)

#include <stdio.h>

int gfbyte ( void ) 
{
 static int i=0;
 static int x[]=
    {
     69, 55, 69, 69 
    };
 if (i<3) 
     i++;
 else
     i=0;
 return x[i];  
} 

int main( void ) 
{
 int pkloc,gfcom=249,i,j,k ;

 i = gfbyte ();

 do {
     if ( i == 0 ) 
	 j = 46 ;
     else 
	 j = gfbyte () ;
     i = i - 1 ;
 } while ( ! ( j != 32 ) ) ;

 i = i + 1 ;

 if ( i == 0 ) 
     k = -0 ;
 else
     k = i + 0 ;

 if ( k > 255 ) 
     pkloc = pkloc + 1 ;
 else
     pkloc = pkloc + 1 ;

 printf("hier is a bug: i=%d\n",i);

 k = 1 ;
 if ( k <= i)
     do 
	 j = gfbyte () ;
     while ( k++ < i ) ;

 do {
     gfcom = gfbyte () ;
     switch ( gfcom ) 
	{case 67 : 
	 case 68 : 
	     gfbyte () ;
	     gfbyte () ;
	     gfbyte () ;
	     i = gfbyte () ;

	     do 
		 gfcom = gfbyte () ;
	     while ( ! ( gfcom == 69 ) ) ;
	     break ;
	 default: 
	     fprintf( stderr , "%s%s%ld%s%c\n",  "Bad GF file: " , "Unexpected " , (long)gfcom ,         " command between characters" , '!' ) ;
	     exit ( 1 ) ;
	     break ;
	} 
 } while ( ! ( gfcom == 248 ) ) ;
} 

-- 
esa$ gcc -Wall -o ariane5 ariane5.c
ariane5.c: 666: warning: long float implicitly truncated to unsigned type
esa$ ariane5