The following simple program produces some very unusual results in gcc 4.3.2:
#include <cstdio>
int n = 5;
int main ()
{
int m = 0;
for (int i = 0; i < n; i++)
{
m++;
m++;
}
printf ("m is %d.\n", m);
for (int i = 0; i < m; i++)
printf ("i is %d.\n", i);
printf ("where is the output?\n");
return 0;
}
When I run the program using "g++ -O2 a.cpp; ./a.out" I obtain the following
output:
m is 10.
where is the output?
Without "-O2" the output is as follows:
m is 10.
i is 0.
i is 1.
i is 2.
i is 3.
i is 4.
i is 5.
i is 6.
i is 7.
i is 8.
i is 9.
where is the output?
"gcc -v" gives the following:
Using built-in specs.
Target: i486-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 4.3.2-1ubuntu12'
--with-bugurl=file:///usr/share/doc/gcc-4.3/README.Bugs
--enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr --enable-shared
--with-system-zlib --libexecdir=/usr/lib --without-included-gettext
--enable-threads=posix --enable-nls --with-gxx-include-dir=/usr/include/c++/4.3
--program-suffix=-4.3 --enable-clocale=gnu --enable-libstdcxx-debug
--enable-objc-gc --enable-mpfr --enable-targets=all --enable-checking=release
--build=i486-linux-gnu --host=i486-linux-gnu --target=i486-linux-gnu
Thread model: posix
gcc version 4.3.2 (Ubuntu 4.3.2-1ubuntu12)
Lastly, here is a.ii:
# 1 "a.cpp"
# 1 "<built-in>"
# 1 "<command-line>"
# 1 "a.cpp"
# 1 "/usr/include/c++/4.3/cstdio" 1 3
# 46 "/usr/include/c++/4.3/cstdio" 3
# 47 "/usr/include/c++/4.3/cstdio" 3
# 1 "/usr/include/c++/4.3/i486-linux-gnu/bits/c++config.h" 1 3
# 40 "/usr/include/c++/4.3/i486-linux-gnu/bits/c++config.h" 3
# 1 "/usr/include/c++/4.3/i486-linux-gnu/bits/os_defines.h" 1 3
# 44 "/usr/include/c++/4.3/i486-linux-gnu/bits/os_defines.h" 3
# 1 "/usr/include/features.h" 1 3 4
# 330 "/usr/include/features.h" 3 4
# 1 "/usr/include/sys/cdefs.h" 1 3 4
# 348 "/usr/include/sys/cdefs.h" 3 4
# 1 "/usr/include/bits/wordsize.h" 1 3 4
# 349 "/usr/include/sys/cdefs.h" 2 3 4
# 331 "/usr/include/features.h" 2 3 4
# 354 "/usr/include/features.h" 3 4
# 1 "/usr/include/gnu/stubs.h" 1 3 4
# 1 "/usr/include/bits/wordsize.h" 1 3 4
# 5 "/usr/include/gnu/stubs.h" 2 3 4
# 1 "/usr/include/gnu/stubs-32.h" 1 3 4
# 8 "/usr/include/gnu/stubs.h" 2 3 4
# 355 "/usr/include/features.h" 2 3 4
# 45 "/usr/include/c++/4.3/i486-linux-gnu/bits/os_defines.h" 2 3
# 41 "/usr/include/c++/4.3/i486-linux-gnu/bits/c++config.h" 2 3
# 1 "/usr/include/c++/4.3/i486-linux-gnu/bits/cpu_defines.h" 1 3
# 44 "/usr/include/c++/4.3/i486-linux-gnu/bits/c++config.h" 2 3
# 233 "/usr/include/c++/4.3/i486-linux-gnu/bits/c++config.h" 3
namespace std __attribute__ ((__visibility__ ("default"))) {
# 245 "/usr/include/c++/4.3/i486-linux-gnu/bits/c++config.h" 3
}
# 49 "/usr/include/c++/4.3/cstdio" 2 3
# 1 "/usr/include/c++/4.3/cstddef" 1 3
# 45 "/usr/include/c++/4.3/cstddef" 3
# 46 "/usr/include/c++/4.3/cstddef" 3
# 1 "/usr/lib/gcc/i486-linux-gnu/4.3.2/include/stddef.h" 1 3 4
# 152 "/usr/lib/gcc/i486-linux-gnu/4.3.2/include/stddef.h" 3 4
typedef int ptrdiff_t;
# 214 "/usr/lib/gcc/i486-linux-gnu/4.3.2/include/stddef.h" 3 4
typedef unsigned int size_t;
# 49 "/usr/include/c++/4.3/cstddef" 2 3
namespace std __attribute__ ((__visibility__ ("default"))) {
using ::ptrdiff_t;
using ::size_t;
}
# 50 "/usr/include/c++/4.3/cstdio" 2 3
# 1 "/usr/include/stdio.h" 1 3 4
# 30 "/usr/include/stdio.h" 3 4
extern "C" {
# 1 "/usr/lib/gcc/i486-linux-gnu/4.3.2/include/stddef.h" 1 3 4
# 35 "/usr/include/stdio.h" 2 3 4
# 1 "/usr/include/bits/types.h" 1 3 4
# 28 "/usr/include/bits/types.h" 3 4
# 1 "/usr/include/bits/wordsize.h" 1 3 4
# 29 "/usr/include/bits/types.h" 2 3 4
typedef unsigned char __u_char;
typedef unsigned short int __u_short;
typedef unsigned int __u_int;
typedef unsigned long int __u_long;
typedef signed char __int8_t;
typedef unsigned char __uint8_t;
typedef signed short int __int16_t;
typedef unsigned short int __uint16_t;
typedef signed int __int32_t;
typedef unsigned int __uint32_t;
__extension__ typedef signed long long int __int64_t;
__extension__ typedef unsigned long long int __uint64_t;
__extension__ typedef long long int __quad_t;
__extension__ typedef unsigned long long int __u_quad_t;
# 131 "/usr/include/bits/types.h" 3 4
# 1 "/usr/include/bits/typesizes.h" 1 3 4
# 132 "/usr/include/bits/types.h" 2 3 4
__extension__ typedef __u_quad_t __dev_t;
__extension__ typedef unsigned int __uid_t;
__extension__ typedef unsigned int __gid_t;
__extension__ typedef unsigned long int __ino_t;
__extension__ typedef __u_quad_t __ino64_t;
__extension__ typedef unsigned int __mode_t;
__extension__ typedef unsigned int __nlink_t;
__extension__ typedef long int __off_t;
__extension__ typedef __quad_t __off64_t;
__extension__ typedef int __pid_t;
__extension__ typedef struct { int __val[2]; } __fsid_t;
__extension__ typedef long int __clock_t;
__extension__ typedef unsigned long int __rlim_t;
__extension__ typedef __u_quad_t __rlim64_t;
__extension__ typedef unsigned int __id_t;
__extension__ typedef long int __time_t;
__extension__ typedef unsigned int __useconds_t;
__extension__ typedef long int __suseconds_t;
__extension__ typedef int __daddr_t;
__extension__ typedef long int __swblk_t;
__extension__ typedef int __key_t;
__extension__ typedef int __clockid_t;
__extension__ typedef void * __timer_t;
__extension__ typedef long int __blksize_t;
__extension__ typedef long int __blkcnt_t;
__extension__ typedef __quad_t __blkcnt64_t;
__extension__ typedef unsigned long int __fsblkcnt_t;
__extension__ typedef __u_quad_t __fsblkcnt64_t;
__extension__ typedef unsigned long int __fsfilcnt_t;
__extension__ typedef __u_quad_t __fsfilcnt64_t;
__extension__ typedef int __ssize_t;
typedef __off64_t __loff_t;
typedef __quad_t *__qaddr_t;
typedef char *__caddr_t;
__extension__ typedef int __intptr_t;
__extension__ typedef unsigned int __socklen_t;
# 37 "/usr/include/stdio.h" 2 3 4
# 45 "/usr/include/stdio.h" 3 4
struct _IO_FILE;
typedef struct _IO_FILE FILE;
# 65 "/usr/include/stdio.h" 3 4
typedef struct _IO_FILE __FILE;
# 75 "/usr/include/stdio.h" 3 4
# 1 "/usr/include/libio.h" 1 3 4
# 32 "/usr/include/libio.h" 3 4
# 1 "/usr/include/_G_config.h" 1 3 4
# 15 "/usr/include/_G_config.h" 3 4
# 1 "/usr/lib/gcc/i486-linux-gnu/4.3.2/include/stddef.h" 1 3 4
# 16 "/usr/include/_G_config.h" 2 3 4
# 1 "/usr/include/wchar.h" 1 3 4
# 78 "/usr/include/wchar.h" 3 4
typedef struct
{
int __count;
union
{
unsigned int __wch;
char __wchb[4];
} __value;
} __mbstate_t;
# 21 "/usr/include/_G_config.h" 2 3 4
typedef struct
{
__off_t __pos;
__mbstate_t __state;
} _G_fpos_t;
typedef struct
{
__off64_t __pos;
__mbstate_t __state;
} _G_fpos64_t;
# 53 "/usr/include/_G_config.h" 3 4
typedef int _G_int16_t __attribute__ ((__mode__ (__HI__)));
typedef int _G_int32_t __attribute__ ((__mode__ (__SI__)));
typedef unsigned int _G_uint16_t __attribute__ ((__mode__ (__HI__)));
typedef unsigned int _G_uint32_t __attribute__ ((__mode__ (__SI__)));
# 33 "/usr/include/libio.h" 2 3 4
# 53 "/usr/include/libio.h" 3 4
# 1 "/usr/lib/gcc/i486-linux-gnu/4.3.2/include/stdarg.h" 1 3 4
# 43 "/usr/lib/gcc/i486-linux-gnu/4.3.2/include/stdarg.h" 3 4
typedef __builtin_va_list __gnuc_va_list;
# 54 "/usr/include/libio.h" 2 3 4
# 170 "/usr/include/libio.h" 3 4
struct _IO_jump_t; struct _IO_FILE;
# 180 "/usr/include/libio.h" 3 4
typedef void _IO_lock_t;
struct _IO_marker {
struct _IO_marker *_next;
struct _IO_FILE *_sbuf;
int _pos;
# 203 "/usr/include/libio.h" 3 4
};
enum __codecvt_result
{
__codecvt_ok,
__codecvt_partial,
__codecvt_error,
__codecvt_noconv
};
# 271 "/usr/include/libio.h" 3 4
struct _IO_FILE {
int _flags;
char* _IO_read_ptr;
char* _IO_read_end;
char* _IO_read_base;
char* _IO_write_base;
char* _IO_write_ptr;
char* _IO_write_end;
char* _IO_buf_base;
char* _IO_buf_end;
char *_IO_save_base;
char *_IO_backup_base;
char *_IO_save_end;
struct _IO_marker *_markers;
struct _IO_FILE *_chain;
int _fileno;
int _flags2;
__off_t _old_offset;
unsigned short _cur_column;
signed char _vtable_offset;
char _shortbuf[1];
_IO_lock_t *_lock;
# 319 "/usr/include/libio.h" 3 4
__off64_t _offset;
# 328 "/usr/include/libio.h" 3 4
void *__pad1;
void *__pad2;
void *__pad3;
void *__pad4;
size_t __pad5;
int _mode;
char _unused2[15 * sizeof (int) - 4 * sizeof (void *) - sizeof (size_t)];
};
struct _IO_FILE_plus;
extern struct _IO_FILE_plus _IO_2_1_stdin_;
extern struct _IO_FILE_plus _IO_2_1_stdout_;
extern struct _IO_FILE_plus _IO_2_1_stderr_;
# 364 "/usr/include/libio.h" 3 4
typedef __ssize_t __io_read_fn (void *__cookie, char *__buf, size_t __nbytes);
typedef __ssize_t __io_write_fn (void *__cookie, __const char *__buf,
size_t __n);
typedef int __io_seek_fn (void *__cookie, __off64_t *__pos, int __w);
typedef int __io_close_fn (void *__cookie);
typedef __io_read_fn cookie_read_function_t;
typedef __io_write_fn cookie_write_function_t;
typedef __io_seek_fn cookie_seek_function_t;
typedef __io_close_fn cookie_close_function_t;
typedef struct
{
__io_read_fn *read;
__io_write_fn *write;
__io_seek_fn *seek;
__io_close_fn *close;
} _IO_cookie_io_functions_t;
typedef _IO_cookie_io_functions_t cookie_io_functions_t;
struct _IO_cookie_file;
extern void _IO_cookie_init (struct _IO_cookie_file *__cfile, int __read_write,
void *__cookie, _IO_cookie_io_functions_t __fns);
extern "C" {
extern int __underflow (_IO_FILE *);
extern int __uflow (_IO_FILE *);
extern int __overflow (_IO_FILE *, int);
# 458 "/usr/include/libio.h" 3 4
extern int _IO_getc (_IO_FILE *__fp);
extern int _IO_putc (int __c, _IO_FILE *__fp);
extern int _IO_feof (_IO_FILE *__fp) throw ();
extern int _IO_ferror (_IO_FILE *__fp) throw ();
extern int _IO_peekc_locked (_IO_FILE *__fp);
extern void _IO_flockfile (_IO_FILE *) throw ();
extern void _IO_funlockfile (_IO_FILE *) throw ();
extern int _IO_ftrylockfile (_IO_FILE *) throw ();
# 488 "/usr/include/libio.h" 3 4
extern int _IO_vfscanf (_IO_FILE * __restrict, const char * __restrict,
__gnuc_va_list, int *__restrict);
extern int _IO_vfprintf (_IO_FILE *__restrict, const char *__restrict,
__gnuc_va_list);
extern __ssize_t _IO_padn (_IO_FILE *, int, __ssize_t);
extern size_t _IO_sgetn (_IO_FILE *, void *, size_t);
extern __off64_t _IO_seekoff (_IO_FILE *, __off64_t, int, int);
extern __off64_t _IO_seekpos (_IO_FILE *, __off64_t, int);
extern void _IO_free_backup_area (_IO_FILE *) throw ();
# 550 "/usr/include/libio.h" 3 4
}
# 76 "/usr/include/stdio.h" 2 3 4
typedef __gnuc_va_list va_list;
# 89 "/usr/include/stdio.h" 3 4
typedef _G_fpos_t fpos_t;
typedef _G_fpos64_t fpos64_t;
# 141 "/usr/include/stdio.h" 3 4
# 1 "/usr/include/bits/stdio_lim.h" 1 3 4
# 142 "/usr/include/stdio.h" 2 3 4
extern struct _IO_FILE *stdin;
extern struct _IO_FILE *stdout;
extern struct _IO_FILE *stderr;
extern int remove (__const char *__filename) throw ();
extern int rename (__const char *__old, __const char *__new) throw ();
extern int renameat (int __oldfd, __const char *__old, int __newfd,
__const char *__new) throw ();
extern FILE *tmpfile (void) __attribute__ ((__warn_unused_result__));
# 182 "/usr/include/stdio.h" 3 4
extern FILE *tmpfile64 (void) __attribute__ ((__warn_unused_result__));
extern char *tmpnam (char *__s) throw () __attribute__
((__warn_unused_result__));
extern char *tmpnam_r (char *__s) throw () __attribute__
((__warn_unused_result__));
# 204 "/usr/include/stdio.h" 3 4
extern char *tempnam (__const char *__dir, __const char *__pfx)
throw () __attribute__ ((__malloc__)) __attribute__
((__warn_unused_result__));
extern int fclose (FILE *__stream);
extern int fflush (FILE *__stream);
# 229 "/usr/include/stdio.h" 3 4
extern int fflush_unlocked (FILE *__stream);
# 239 "/usr/include/stdio.h" 3 4
extern int fcloseall (void);
extern FILE *fopen (__const char *__restrict __filename,
__const char *__restrict __modes) __attribute__
((__warn_unused_result__));
extern FILE *freopen (__const char *__restrict __filename,
__const char *__restrict __modes,
FILE *__restrict __stream) __attribute__ ((__warn_unused_result__));
# 272 "/usr/include/stdio.h" 3 4
extern FILE *fopen64 (__const char *__restrict __filename,
__const char *__restrict __modes) __attribute__
((__warn_unused_result__));
extern FILE *freopen64 (__const char *__restrict __filename,
__const char *__restrict __modes,
FILE *__restrict __stream) __attribute__ ((__warn_unused_result__));
extern FILE *fdopen (int __fd, __const char *__modes) throw () __attribute__
((__warn_unused_result__));
extern FILE *fopencookie (void *__restrict __magic_cookie,
__const char *__restrict __modes,
_IO_cookie_io_functions_t __io_funcs) throw () __attribute__
((__warn_unused_result__));
extern FILE *fmemopen (void *__s, size_t __len, __const char *__modes)
throw () __attribute__ ((__warn_unused_result__));
extern FILE *open_memstream (char **__bufloc, size_t *__sizeloc) throw ()
__attribute__ ((__warn_unused_result__));
extern void setbuf (FILE *__restrict __stream, char *__restrict __buf) throw
();
extern int setvbuf (FILE *__restrict __stream, char *__restrict __buf,
int __modes, size_t __n) throw ();
extern void setbuffer (FILE *__restrict __stream, char *__restrict __buf,
size_t __size) throw ();
extern void setlinebuf (FILE *__stream) throw ();
extern int fprintf (FILE *__restrict __stream,
__const char *__restrict __format, ...);
extern int printf (__const char *__restrict __format, ...);
extern int sprintf (char *__restrict __s,
__const char *__restrict __format, ...) throw ();
extern int vfprintf (FILE *__restrict __s, __const char *__restrict __format,
__gnuc_va_list __arg);
extern int vprintf (__const char *__restrict __format, __gnuc_va_list __arg);
extern int vsprintf (char *__restrict __s, __const char *__restrict __format,
__gnuc_va_list __arg) throw ();
extern int snprintf (char *__restrict __s, size_t __maxlen,
__const char *__restrict __format, ...)
throw () __attribute__ ((__format__ (__printf__, 3, 4)));
extern int vsnprintf (char *__restrict __s, size_t __maxlen,
__const char *__restrict __format, __gnuc_va_list __arg)
throw () __attribute__ ((__format__ (__printf__, 3, 0)));
extern int vasprintf (char **__restrict __ptr, __const char *__restrict __f,
__gnuc_va_list __arg)
throw () __attribute__ ((__format__ (__printf__, 2, 0))) __attribute__
((__warn_unused_result__));
extern int __asprintf (char **__restrict __ptr,
__const char *__restrict __fmt, ...)
throw () __attribute__ ((__format__ (__printf__, 2, 3))) __attribute__
((__warn_unused_result__));
extern int asprintf (char **__restrict __ptr,
__const char *__restrict __fmt, ...)
throw () __attribute__ ((__format__ (__printf__, 2, 3))) __attribute__
((__warn_unused_result__));
extern int vdprintf (int __fd, __const char *__restrict __fmt,
__gnuc_va_list __arg)
__attribute__ ((__format__ (__printf__, 2, 0)));
extern int dprintf (int __fd, __const char *__restrict __fmt, ...)
__attribute__ ((__format__ (__printf__, 2, 3)));
extern int fscanf (FILE *__restrict __stream,
__const char *__restrict __format, ...) __attribute__
((__warn_unused_result__));
extern int scanf (__const char *__restrict __format, ...) __attribute__
((__warn_unused_result__));
extern int sscanf (__const char *__restrict __s,
__const char *__restrict __format, ...) throw ();
# 441 "/usr/include/stdio.h" 3 4
extern int vfscanf (FILE *__restrict __s, __const char *__restrict __format,
__gnuc_va_list __arg)
__attribute__ ((__format__ (__scanf__, 2, 0))) __attribute__
((__warn_unused_result__));
extern int vscanf (__const char *__restrict __format, __gnuc_va_list __arg)
__attribute__ ((__format__ (__scanf__, 1, 0))) __attribute__
((__warn_unused_result__));
extern int vsscanf (__const char *__restrict __s,
__const char *__restrict __format, __gnuc_va_list __arg)
throw () __attribute__ ((__format__ (__scanf__, 2, 0)));
# 500 "/usr/include/stdio.h" 3 4
extern int fgetc (FILE *__stream);
extern int getc (FILE *__stream);
extern int getchar (void);
# 528 "/usr/include/stdio.h" 3 4
extern int getc_unlocked (FILE *__stream);
extern int getchar_unlocked (void);
# 539 "/usr/include/stdio.h" 3 4
extern int fgetc_unlocked (FILE *__stream);
extern int fputc (int __c, FILE *__stream);
extern int putc (int __c, FILE *__stream);
extern int putchar (int __c);
# 572 "/usr/include/stdio.h" 3 4
extern int fputc_unlocked (int __c, FILE *__stream);
extern int putc_unlocked (int __c, FILE *__stream);
extern int putchar_unlocked (int __c);
extern int getw (FILE *__stream);
extern int putw (int __w, FILE *__stream);
extern char *fgets (char *__restrict __s, int __n, FILE *__restrict __stream)
__attribute__ ((__warn_unused_result__));
extern char *gets (char *__s) __attribute__ ((__warn_unused_result__));
# 618 "/usr/include/stdio.h" 3 4
extern char *fgets_unlocked (char *__restrict __s, int __n,
FILE *__restrict __stream) __attribute__ ((__warn_unused_result__));
# 634 "/usr/include/stdio.h" 3 4
extern __ssize_t __getdelim (char **__restrict __lineptr,
size_t *__restrict __n, int __delimiter,
FILE *__restrict __stream) __attribute__ ((__warn_unused_result__));
extern __ssize_t getdelim (char **__restrict __lineptr,
size_t *__restrict __n, int __delimiter,
FILE *__restrict __stream) __attribute__ ((__warn_unused_result__));
extern __ssize_t getline (char **__restrict __lineptr,
size_t *__restrict __n,
FILE *__restrict __stream) __attribute__ ((__warn_unused_result__));
extern int fputs (__const char *__restrict __s, FILE *__restrict __stream);
extern int puts (__const char *__s);
extern int ungetc (int __c, FILE *__stream);
extern size_t fread (void *__restrict __ptr, size_t __size,
size_t __n, FILE *__restrict __stream) __attribute__
((__warn_unused_result__));
extern size_t fwrite (__const void *__restrict __ptr, size_t __size,
size_t __n, FILE *__restrict __s) __attribute__
((__warn_unused_result__));
# 695 "/usr/include/stdio.h" 3 4
extern int fputs_unlocked (__const char *__restrict __s,
FILE *__restrict __stream);
# 706 "/usr/include/stdio.h" 3 4
extern size_t fread_unlocked (void *__restrict __ptr, size_t __size,
size_t __n, FILE *__restrict __stream) __attribute__
((__warn_unused_result__));
extern size_t fwrite_unlocked (__const void *__restrict __ptr, size_t __size,
size_t __n, FILE *__restrict __stream) __attribute__
((__warn_unused_result__));
extern int fseek (FILE *__stream, long int __off, int __whence);
extern long int ftell (FILE *__stream) __attribute__
((__warn_unused_result__));
extern void rewind (FILE *__stream);
# 742 "/usr/include/stdio.h" 3 4
extern int fseeko (FILE *__stream, __off_t __off, int __whence);
extern __off_t ftello (FILE *__stream) __attribute__
((__warn_unused_result__));
# 761 "/usr/include/stdio.h" 3 4
extern int fgetpos (FILE *__restrict __stream, fpos_t *__restrict __pos);
extern int fsetpos (FILE *__stream, __const fpos_t *__pos);
# 784 "/usr/include/stdio.h" 3 4
extern int fseeko64 (FILE *__stream, __off64_t __off, int __whence);
extern __off64_t ftello64 (FILE *__stream) __attribute__
((__warn_unused_result__));
extern int fgetpos64 (FILE *__restrict __stream, fpos64_t *__restrict __pos);
extern int fsetpos64 (FILE *__stream, __const fpos64_t *__pos);
extern void clearerr (FILE *__stream) throw ();
extern int feof (FILE *__stream) throw () __attribute__
((__warn_unused_result__));
extern int ferror (FILE *__stream) throw () __attribute__
((__warn_unused_result__));
extern void clearerr_unlocked (FILE *__stream) throw ();
extern int feof_unlocked (FILE *__stream) throw () __attribute__
((__warn_unused_result__));
extern int ferror_unlocked (FILE *__stream) throw () __attribute__
((__warn_unused_result__));
extern void perror (__const char *__s);
# 1 "/usr/include/bits/sys_errlist.h" 1 3 4
# 27 "/usr/include/bits/sys_errlist.h" 3 4
extern int sys_nerr;
extern __const char *__const sys_errlist[];
extern int _sys_nerr;
extern __const char *__const _sys_errlist[];
# 823 "/usr/include/stdio.h" 2 3 4
extern int fileno (FILE *__stream) throw () __attribute__
((__warn_unused_result__));
extern int fileno_unlocked (FILE *__stream) throw () __attribute__
((__warn_unused_result__));
# 842 "/usr/include/stdio.h" 3 4
extern FILE *popen (__const char *__command, __const char *__modes)
__attribute__ ((__warn_unused_result__));
extern int pclose (FILE *__stream);
extern char *ctermid (char *__s) throw ();
extern char *cuserid (char *__s);
struct obstack;
extern int obstack_printf (struct obstack *__restrict __obstack,
__const char *__restrict __format, ...)
throw () __attribute__ ((__format__ (__printf__, 2, 3)));
extern int obstack_vprintf (struct obstack *__restrict __obstack,
__const char *__restrict __format,
__gnuc_va_list __args)
throw () __attribute__ ((__format__ (__printf__, 2, 0)));
extern void flockfile (FILE *__stream) throw ();
extern int ftrylockfile (FILE *__stream) throw () __attribute__
((__warn_unused_result__));
extern void funlockfile (FILE *__stream) throw ();
# 903 "/usr/include/stdio.h" 3 4
# 1 "/usr/include/bits/stdio.h" 1 3 4
# 44 "/usr/include/bits/stdio.h" 3 4
extern __inline __attribute__ ((__gnu_inline__)) int
getchar (void)
{
return _IO_getc (stdin);
}
extern __inline __attribute__ ((__gnu_inline__)) int
fgetc_unlocked (FILE *__fp)
{
return (__builtin_expect (((__fp)->_IO_read_ptr >= (__fp)->_IO_read_end), 0)
? __uflow (__fp) : *(unsigned char *) (__fp)->_IO_read_ptr++);
}
extern __inline __attribute__ ((__gnu_inline__)) int
getc_unlocked (FILE *__fp)
{
return (__builtin_expect (((__fp)->_IO_read_ptr >= (__fp)->_IO_read_end), 0)
? __uflow (__fp) : *(unsigned char *) (__fp)->_IO_read_ptr++);
}
extern __inline __attribute__ ((__gnu_inline__)) int
getchar_unlocked (void)
{
return (__builtin_expect (((stdin)->_IO_read_ptr >= (stdin)->_IO_read_end),
0) ? __uflow (stdin) : *(unsigned char *) (stdin)->_IO_read_ptr++);
}
extern __inline __attribute__ ((__gnu_inline__)) int
putchar (int __c)
{
return _IO_putc (__c, stdout);
}
extern __inline __attribute__ ((__gnu_inline__)) int
fputc_unlocked (int __c, FILE *__stream)
{
return (__builtin_expect (((__stream)->_IO_write_ptr >=
(__stream)->_IO_write_end), 0) ? __overflow (__stream, (unsigned char) (__c)) :
(unsigned char) (*(__stream)->_IO_write_ptr++ = (__c)));
}
extern __inline __attribute__ ((__gnu_inline__)) int
putc_unlocked (int __c, FILE *__stream)
{
return (__builtin_expect (((__stream)->_IO_write_ptr >=
(__stream)->_IO_write_end), 0) ? __overflow (__stream, (unsigned char) (__c)) :
(unsigned char) (*(__stream)->_IO_write_ptr++ = (__c)));
}
extern __inline __attribute__ ((__gnu_inline__)) int
putchar_unlocked (int __c)
{
return (__builtin_expect (((stdout)->_IO_write_ptr >=
(stdout)->_IO_write_end), 0) ? __overflow (stdout, (unsigned char) (__c)) :
(unsigned char) (*(stdout)->_IO_write_ptr++ = (__c)));
}
extern __inline __attribute__ ((__gnu_inline__)) __ssize_t
getline (char **__lineptr, size_t *__n, FILE *__stream)
{
return __getdelim (__lineptr, __n, '\n', __stream);
}
extern __inline __attribute__ ((__gnu_inline__)) int
feof_unlocked (FILE *__stream) throw ()
{
return (((__stream)->_flags & 0x10) != 0);
}
extern __inline __attribute__ ((__gnu_inline__)) int
ferror_unlocked (FILE *__stream) throw ()
{
return (((__stream)->_flags & 0x20) != 0);
}
# 904 "/usr/include/stdio.h" 2 3 4
# 1 "/usr/include/bits/stdio2.h" 1 3 4
# 24 "/usr/include/bits/stdio2.h" 3 4
extern int __sprintf_chk (char *__restrict __s, int __flag, size_t __slen,
__const char *__restrict __format, ...) throw ();
extern int __vsprintf_chk (char *__restrict __s, int __flag, size_t __slen,
__const char *__restrict __format,
__gnuc_va_list __ap) throw ();
extern __inline __attribute__ ((__always_inline__)) __attribute__
((__gnu_inline__, __artificial__)) int
sprintf (char *__restrict __s, __const char *__restrict __fmt, ...) throw ()
{
return __builtin___sprintf_chk (__s, 2 - 1,
__builtin_object_size (__s, 2 > 1), __fmt, __builtin_va_arg_pack ());
}
extern __inline __attribute__ ((__always_inline__)) __attribute__
((__gnu_inline__, __artificial__)) int
vsprintf (char *__restrict __s, __const char *__restrict __fmt, __gnuc_va_list
__ap) throw ()
{
return __builtin___vsprintf_chk (__s, 2 - 1,
__builtin_object_size (__s, 2 > 1), __fmt, __ap);
}
extern int __snprintf_chk (char *__restrict __s, size_t __n, int __flag,
size_t __slen, __const char *__restrict __format,
...) throw ();
extern int __vsnprintf_chk (char *__restrict __s, size_t __n, int __flag,
size_t __slen, __const char *__restrict __format,
__gnuc_va_list __ap) throw ();
extern __inline __attribute__ ((__always_inline__)) __attribute__
((__gnu_inline__, __artificial__)) int
snprintf (char *__restrict __s, size_t __n, __const char *__restrict __fmt,
...) throw ()
{
return __builtin___snprintf_chk (__s, __n, 2 - 1,
__builtin_object_size (__s, 2 > 1), __fmt, __builtin_va_arg_pack ());
}
extern __inline __attribute__ ((__always_inline__)) __attribute__
((__gnu_inline__, __artificial__)) int
vsnprintf (char *__restrict __s, size_t __n, __const char *__restrict __fmt,
__gnuc_va_list __ap) throw ()
{
return __builtin___vsnprintf_chk (__s, __n, 2 - 1,
__builtin_object_size (__s, 2 > 1), __fmt, __ap);
}
extern int __fprintf_chk (FILE *__restrict __stream, int __flag,
__const char *__restrict __format, ...);
extern int __printf_chk (int __flag, __const char *__restrict __format, ...);
extern int __vfprintf_chk (FILE *__restrict __stream, int __flag,
__const char *__restrict __format, __gnuc_va_list __ap);
extern int __vprintf_chk (int __flag, __const char *__restrict __format,
__gnuc_va_list __ap);
extern __inline __attribute__ ((__always_inline__)) __attribute__
((__gnu_inline__, __artificial__)) int
fprintf (FILE *__restrict __stream, __const char *__restrict __fmt, ...)
{
return __fprintf_chk (__stream, 2 - 1, __fmt,
__builtin_va_arg_pack ());
}
extern __inline __attribute__ ((__always_inline__)) __attribute__
((__gnu_inline__, __artificial__)) int
printf (__const char *__restrict __fmt, ...)
{
return __printf_chk (2 - 1, __fmt, __builtin_va_arg_pack ());
}
extern __inline __attribute__ ((__always_inline__)) __attribute__
((__gnu_inline__, __artificial__)) int
vprintf (__const char *__restrict __fmt, __gnuc_va_list __ap)
{
return __vfprintf_chk (stdout, 2 - 1, __fmt, __ap);
}
extern __inline __attribute__ ((__always_inline__)) __attribute__
((__gnu_inline__, __artificial__)) int
vfprintf (FILE *__restrict __stream,
__const char *__restrict __fmt, __gnuc_va_list __ap)
{
return __vfprintf_chk (__stream, 2 - 1, __fmt, __ap);
}
extern int __asprintf_chk (char **__restrict __ptr, int __flag,
__const char *__restrict __fmt, ...)
throw () __attribute__ ((__format__ (__printf__, 3, 4))) __attribute__
((__warn_unused_result__));
extern int __vasprintf_chk (char **__restrict __ptr, int __flag,
__const char *__restrict __fmt, __gnuc_va_list __arg)
throw () __attribute__ ((__format__ (__printf__, 3, 0))) __attribute__
((__warn_unused_result__));
extern int __dprintf_chk (int __fd, int __flag, __const char *__restrict __fmt,
...) __attribute__ ((__format__ (__printf__, 3, 4)));
extern int __vdprintf_chk (int __fd, int __flag,
__const char *__restrict __fmt, __gnuc_va_list __arg)
__attribute__ ((__format__ (__printf__, 3, 0)));
extern int __obstack_printf_chk (struct obstack *__restrict __obstack,
int __flag, __const char *__restrict __format,
...)
throw () __attribute__ ((__format__ (__printf__, 3, 4)));
extern int __obstack_vprintf_chk (struct obstack *__restrict __obstack,
int __flag,
__const char *__restrict __format,
__gnuc_va_list __args)
throw () __attribute__ ((__format__ (__printf__, 3, 0)));
extern __inline __attribute__ ((__always_inline__)) __attribute__
((__gnu_inline__, __artificial__)) int
asprintf (char **__restrict __ptr, __const char *__restrict __fmt, ...) throw
()
{
return __asprintf_chk (__ptr, 2 - 1, __fmt,
__builtin_va_arg_pack ());
}
extern __inline __attribute__ ((__always_inline__)) __attribute__
((__gnu_inline__, __artificial__)) int
__asprintf (char **__restrict __ptr, __const char *__restrict __fmt, ...) throw
()
{
return __asprintf_chk (__ptr, 2 - 1, __fmt,
__builtin_va_arg_pack ());
}
extern __inline __attribute__ ((__always_inline__)) __attribute__
((__gnu_inline__, __artificial__)) int
dprintf (int __fd, __const char *__restrict __fmt, ...)
{
return __dprintf_chk (__fd, 2 - 1, __fmt,
__builtin_va_arg_pack ());
}
extern __inline __attribute__ ((__always_inline__)) __attribute__
((__gnu_inline__, __artificial__)) int
obstack_printf (struct obstack *__restrict __obstack, __const char *__restrict
__fmt, ...) throw ()
{
return __obstack_printf_chk (__obstack, 2 - 1, __fmt,
__builtin_va_arg_pack ());
}
# 195 "/usr/include/bits/stdio2.h" 3 4
extern __inline __attribute__ ((__always_inline__)) __attribute__
((__gnu_inline__, __artificial__)) int
vasprintf (char **__restrict __ptr, __const char *__restrict __fmt,
__gnuc_va_list __ap) throw ()
{
return __vasprintf_chk (__ptr, 2 - 1, __fmt, __ap);
}
extern __inline __attribute__ ((__always_inline__)) __attribute__
((__gnu_inline__, __artificial__)) int
vdprintf (int __fd, __const char *__restrict __fmt, __gnuc_va_list __ap)
{
return __vdprintf_chk (__fd, 2 - 1, __fmt, __ap);
}
extern __inline __attribute__ ((__always_inline__)) __attribute__
((__gnu_inline__, __artificial__)) int
obstack_vprintf (struct obstack *__restrict __obstack, __const char *__restrict
__fmt, __gnuc_va_list __ap) throw ()
{
return __obstack_vprintf_chk (__obstack, 2 - 1, __fmt,
__ap);
}
extern char *__gets_chk (char *__str, size_t) __attribute__
((__warn_unused_result__));
extern char *__gets_warn (char *__str) __asm__ ("" "gets")
__attribute__ ((__warn_unused_result__)) __attribute__((__warning__
("please use fgets or getline instead, gets can't " "specify buffer size")));
extern __inline __attribute__ ((__always_inline__)) __attribute__
((__gnu_inline__, __artificial__)) __attribute__ ((__warn_unused_result__))
char *
gets (char *__str)
{
if (__builtin_object_size (__str, 2 > 1) != (size_t) -1)
return __gets_chk (__str, __builtin_object_size (__str, 2 > 1));
return __gets_warn (__str);
}
extern char *__fgets_chk (char *__restrict __s, size_t __size, int __n,
FILE *__restrict __stream) __attribute__ ((__warn_unused_result__));
extern char *__fgets_alias (char *__restrict __s, int __n, FILE *__restrict
__stream) __asm__ ("" "fgets") __attribute__ ((__warn_unused_result__));
extern char *__fgets_chk_warn (char *__restrict __s, size_t __size, int __n,
FILE *__restrict __stream) __asm__ ("" "__fgets_chk")
__attribute__ ((__warn_unused_result__)) __attribute__((__warning__
("fgets called with bigger size than length " "of destination buffer")));
extern __inline __attribute__ ((__always_inline__)) __attribute__
((__gnu_inline__, __artificial__)) __attribute__ ((__warn_unused_result__))
char *
fgets (char *__restrict __s, int __n, FILE *__restrict __stream)
{
if (__builtin_object_size (__s, 2 > 1) != (size_t) -1)
{
if (!__builtin_constant_p (__n) || __n <= 0)
return __fgets_chk (__s, __builtin_object_size (__s, 2 > 1), __n, __stream);
if ((size_t) __n > __builtin_object_size (__s, 2 > 1))
return __fgets_chk_warn (__s, __builtin_object_size (__s, 2 > 1), __n,
__stream);
}
return __fgets_alias (__s, __n, __stream);
}
extern size_t __fread_chk (void *__restrict __ptr, size_t __ptrlen,
size_t __size, size_t __n,
FILE *__restrict __stream) __attribute__ ((__warn_unused_result__));
extern size_t __fread_alias (void *__restrict __ptr, size_t __size, size_t __n,
FILE *__restrict __stream) __asm__ ("" "fread") __attribute__
((__warn_unused_result__));
extern size_t __fread_chk_warn (void *__restrict __ptr, size_t __ptrlen, size_t
__size, size_t __n, FILE *__restrict __stream) __asm__ ("" "__fread_chk")
__attribute__ ((__warn_unused_result__)) __attribute__((__warning__
("fread called with bigger size * nmemb than length " "of destination
buffer")));
extern __inline __attribute__ ((__always_inline__)) __attribute__
((__gnu_inline__, __artificial__)) __attribute__ ((__warn_unused_result__))
size_t
fread (void *__restrict __ptr, size_t __size, size_t __n,
FILE *__restrict __stream)
{
if (__builtin_object_size (__ptr, 0) != (size_t) -1)
{
if (!__builtin_constant_p (__size)
|| !__builtin_constant_p (__n)
|| (__size | __n) >= (((size_t) 1) << (8 * sizeof (size_t) / 2)))
return __fread_chk (__ptr, __builtin_object_size (__ptr, 0), __size, __n,
__stream);
if (__size * __n > __builtin_object_size (__ptr, 0))
return __fread_chk_warn (__ptr, __builtin_object_size (__ptr, 0), __size, __n,
__stream);
}
return __fread_alias (__ptr, __size, __n, __stream);
}
extern char *__fgets_unlocked_chk (char *__restrict __s, size_t __size,
int __n, FILE *__restrict __stream) __attribute__
((__warn_unused_result__));
extern char *__fgets_unlocked_alias (char *__restrict __s, int __n, FILE
*__restrict __stream) __asm__ ("" "fgets_unlocked") __attribute__
((__warn_unused_result__));
extern char *__fgets_unlocked_chk_warn (char *__restrict __s, size_t __size,
int __n, FILE *__restrict __stream) __asm__ ("" "__fgets_unlocked_chk")
__attribute__ ((__warn_unused_result__)) __attribute__((__warning__
("fgets_unlocked called with bigger size than length " "of destination
buffer")));
extern __inline __attribute__ ((__always_inline__)) __attribute__
((__gnu_inline__, __artificial__)) __attribute__ ((__warn_unused_result__))
char *
fgets_unlocked (char *__restrict __s, int __n, FILE *__restrict __stream)
{
if (__builtin_object_size (__s, 2 > 1) != (size_t) -1)
{
if (!__builtin_constant_p (__n) || __n <= 0)
return __fgets_unlocked_chk (__s, __builtin_object_size (__s, 2 > 1), __n,
__stream);
if ((size_t) __n > __builtin_object_size (__s, 2 > 1))
return __fgets_unlocked_chk_warn (__s, __builtin_object_size (__s, 2 > 1),
__n, __stream);
}
return __fgets_unlocked_alias (__s, __n, __stream);
}
extern size_t __fread_unlocked_chk (void *__restrict __ptr, size_t __ptrlen,
size_t __size, size_t __n,
FILE *__restrict __stream) __attribute__ ((__warn_unused_result__));
extern size_t __fread_unlocked_alias (void *__restrict __ptr, size_t __size,
size_t __n, FILE *__restrict __stream) __asm__ ("" "fread_unlocked")
__attribute__ ((__warn_unused_result__));
extern size_t __fread_unlocked_chk_warn (void *__restrict __ptr, size_t
__ptrlen, size_t __size, size_t __n, FILE *__restrict __stream) __asm__ (""
"__fread_unlocked_chk")
__attribute__ ((__warn_unused_result__)) __attribute__((__warning__
("fread_unlocked called with bigger size * nmemb than " "length of destination
buffer")));
extern __inline __attribute__ ((__always_inline__)) __attribute__
((__gnu_inline__, __artificial__)) __attribute__ ((__warn_unused_result__))
size_t
fread_unlocked (void *__restrict __ptr, size_t __size, size_t __n,
FILE *__restrict __stream)
{
if (__builtin_object_size (__ptr, 0) != (size_t) -1)
{
if (!__builtin_constant_p (__size)
|| !__builtin_constant_p (__n)
|| (__size | __n) >= (((size_t) 1) << (8 * sizeof (size_t) / 2)))
return __fread_unlocked_chk (__ptr, __builtin_object_size (__ptr, 0), __size,
__n,
__stream);
if (__size * __n > __builtin_object_size (__ptr, 0))
return __fread_unlocked_chk_warn (__ptr, __builtin_object_size (__ptr, 0),
__size, __n,
__stream);
}
if (__builtin_constant_p (__size)
&& __builtin_constant_p (__n)
&& (__size | __n) < (((size_t) 1) << (8 * sizeof (size_t) / 2))
&& __size * __n <= 8)
{
size_t __cnt = __size * __n;
char *__cptr = (char *) __ptr;
if (__cnt == 0)
return 0;
for (; __cnt > 0; --__cnt)
{
int __c = (__builtin_expect (((__stream)->_IO_read_ptr >=
(__stream)->_IO_read_end), 0) ? __uflow (__stream) : *(unsigned char *)
(__stream)->_IO_read_ptr++);
if (__c == (-1))
break;
*__cptr++ = __c;
}
return (__cptr - (char *) __ptr) / __size;
}
return __fread_unlocked_alias (__ptr, __size, __n, __stream);
}
# 907 "/usr/include/stdio.h" 2 3 4
}
# 51 "/usr/include/c++/4.3/cstdio" 2 3
# 98 "/usr/include/c++/4.3/cstdio" 3
namespace std __attribute__ ((__visibility__ ("default"))) {
using ::FILE;
using ::fpos_t;
using ::clearerr;
using ::fclose;
using ::feof;
using ::ferror;
using ::fflush;
using ::fgetc;
using ::fgetpos;
using ::fgets;
using ::fopen;
using ::fprintf;
using ::fputc;
using ::fputs;
using ::fread;
using ::freopen;
using ::fscanf;
using ::fseek;
using ::fsetpos;
using ::ftell;
using ::fwrite;
using ::getc;
using ::getchar;
using ::gets;
using ::perror;
using ::printf;
using ::putc;
using ::putchar;
using ::puts;
using ::remove;
using ::rename;
using ::rewind;
using ::scanf;
using ::setbuf;
using ::setvbuf;
using ::sprintf;
using ::sscanf;
using ::tmpfile;
using ::tmpnam;
using ::ungetc;
using ::vfprintf;
using ::vprintf;
using ::vsprintf;
}
# 155 "/usr/include/c++/4.3/cstdio" 3
namespace __gnu_cxx __attribute__ ((__visibility__ ("default"))) {
# 170 "/usr/include/c++/4.3/cstdio" 3
using ::snprintf;
using ::vfscanf;
using ::vscanf;
using ::vsnprintf;
using ::vsscanf;
}
namespace std __attribute__ ((__visibility__ ("default"))) {
using ::__gnu_cxx::snprintf;
using ::__gnu_cxx::vfscanf;
using ::__gnu_cxx::vscanf;
using ::__gnu_cxx::vsnprintf;
using ::__gnu_cxx::vsscanf;
}
# 2 "a.cpp" 2
int n = 5;
int main ()
{
int m = 0;
for (int i = 0; i < n; i++)
{
m++;
m++;
}
printf ("m is %d.\n", m);
for (int i = 0; i < m; i++)
printf ("i is %d.\n", i);
printf ("where is the output?\n");
return 0;
}
--
Summary: Loop is completely skipped
Product: gcc
Version: 4.3.2
Status: UNCONFIRMED
Severity: major
Priority: P3
Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: neal at mailinator dot com
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39904
