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-O2 -funroll-loops on LinuxPPC hangs gcc
- To: gcc-bugs at gcc dot gnu dot org
- Subject: -O2 -funroll-loops on LinuxPPC hangs gcc
- From: Andy Ritger <ritger at wolfram dot com>
- Date: Wed, 17 May 2000 15:49:01 -0500 (CDT)
The following bug was first noticed on a LinuxPPC installation on a
PowerPC 750 (G3) with egcs-2.91.66, and has been reproduced on a LinuxPPC
installation on an iMac with gcc-2.95.2.
Given the following source file:
agrippa.wolfram.com [35] linux-ppc> cat test.c
#include <stdio.h>
int main ()
{
long i = 1000000; // <--- number of loops
double c0, c1;
c0 = c1 = 1.0;
while (--i)
{
c0 += c0 * c0;
c1 += c1 * c1; // <--- this line
}
c0 = c0 + c1;
printf ("c0 = %f\n", c0);
return (0);
}
Compiled with:
gcc -funroll-loops -O2 test.c -o test
works fine.
But if you comment out the line labeled "// <--- this line" and compile
using the same command as above, then cc1 quickly consumes all system
memory and eventually crashes the machine.
Compiling with either (leaving the "// <--- this line" commented out):
gcc -funroll-loops test.c -o test
or
gcc -O2 test.c -o test
works fine.
Varying the number of loops (e.g. changing "long i = 1000000;" to
"long i = 10;") or changing "c0 += c0 * c0;" to "c0 += c0;" does allow the
program to compile, but cc1 still takes an unusually long time and
requires an unusually large amount of memory in the process.
I'ved included the preprocessor output "test.i" generated with the
original test.c with the line "// <--- this line" commented out and the
command line:
gcc -save-temps -funroll-loops -O2 test.c -o test
Using the -v option, I get:
agrippa.wolfram.com [63] linux-ppc> gcc -v -funroll-loops -O2 test.c -o
test
Reading specs from /usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/specs
gcc version egcs-2.91.66 19990314 (egcs-1.1.2 release)
/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/cpp -lang-c -v -undef
-D__GNUC__=2 -D__GNUC_MINOR__=91 -DPPC -D__ELF__ -Dunix -Dlinux -Dpowerpc
-D__PPC__ -D__ELF__ -D__unix__ -D__linux__ -D__powerpc__ -D__PPC -D__unix
-D__linux -D__powerpc -Asystem(unix) -Asystem(linux) -Acpu(powerpc)
-Amachine(powerpc) -D__CHAR_UNSIGNED__ -D__OPTIMIZE__ -D_CALL_SYSV
-D_BIG_ENDIAN -D__BIG_ENDIAN__ -Amachine(bigendian) -D_ARCH_PPC -D__unix__
-D__linux__ -Dunix -Dlinux -Asystem(unix) -Asystem(linux) test.c
/tmp/ccA13n20.i
GNU CPP version egcs-2.91.66 19990314 (egcs-1.1.2 release) (PowerPC
GNU/Linux)
#include "..." search starts here:
#include <...> search starts here:
/usr/ppc-redhat-linux/include
/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include
/usr/include
End of search list.
/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/cc1 /tmp/ccA13n20.i -quiet
-dumpbase test.c -O2 -version -funroll-loops -o /tmp/ccqeuyX7.s
GNU C version egcs-2.91.66 19990314 (egcs-1.1.2 release)
(ppc-redhat-linux) compiled by GNU C version egcs-2.91.66 19990314
(egcs-1.1.2 release).
and at cc1 is where compilation halts.
Please let me know if there is any other information I can provide.
Thank you for all your efforts.
- Andy Ritger
# 1 "test.c"
# 1 "/usr/include/stdio.h" 1 3
# 1 "/usr/include/features.h" 1 3
# 137 "/usr/include/features.h" 3
# 195 "/usr/include/features.h" 3
# 1 "/usr/include/sys/cdefs.h" 1 3
# 71 "/usr/include/sys/cdefs.h" 3
# 103 "/usr/include/sys/cdefs.h" 3
# 249 "/usr/include/features.h" 2 3
# 1 "/usr/include/gnu/stubs.h" 1 3
# 277 "/usr/include/features.h" 2 3
# 27 "/usr/include/stdio.h" 2 3
# 1 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/stddef.h" 1 3
# 19 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/stddef.h" 3
# 61 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/stddef.h" 3
# 131 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/stddef.h" 3
typedef unsigned int size_t;
# 271 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/stddef.h" 3
# 283 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/stddef.h" 3
# 317 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/stddef.h" 3
# 33 "/usr/include/stdio.h" 2 3
# 1 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/stdarg.h" 1 3
# 1 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/va-ppc.h" 1 3
typedef struct __va_list_tag {
char gpr;
char fpr;
char *overflow_arg_area;
char *reg_save_area;
} __va_list[1], __gnuc_va_list[1];
# 173 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/va-ppc.h" 3
# 229 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/va-ppc.h" 3
# 42 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/stdarg.h" 2 3
# 124 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/stdarg.h" 3
# 202 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/stdarg.h" 3
# 38 "/usr/include/stdio.h" 2 3
# 1 "/usr/include/bits/types.h" 1 3
# 1 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/stddef.h" 1 3
# 19 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/stddef.h" 3
# 61 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/stddef.h" 3
# 131 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/stddef.h" 3
# 188 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/stddef.h" 3
# 271 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/stddef.h" 3
# 283 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/stddef.h" 3
# 317 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/stddef.h" 3
# 29 "/usr/include/bits/types.h" 2 3
typedef unsigned char __u_char;
typedef unsigned short __u_short;
typedef unsigned int __u_int;
typedef unsigned long __u_long;
__extension__ typedef unsigned long long int __u_quad_t;
__extension__ typedef long long int __quad_t;
# 48 "/usr/include/bits/types.h" 3
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;
typedef __quad_t *__qaddr_t;
typedef __u_quad_t __dev_t;
typedef __u_int __uid_t;
typedef __u_int __gid_t;
typedef __u_long __ino_t;
typedef __u_int __mode_t;
typedef __u_int __nlink_t;
typedef long int __off_t;
typedef __quad_t __loff_t;
typedef int __pid_t;
typedef int __ssize_t;
typedef long int __rlim_t;
typedef __quad_t __rlim64_t;
typedef __u_int __id_t;
typedef struct
{
int __val[2];
} __fsid_t;
typedef int __daddr_t;
typedef char *__caddr_t;
typedef long int __time_t;
typedef long int __swblk_t;
typedef long int __clock_t;
typedef unsigned long int __fd_mask;
typedef struct
{
__fd_mask __fds_bits[1024 / (8 * sizeof (__fd_mask)) ];
} __fd_set;
typedef int __key_t;
typedef unsigned short int __ipc_pid_t;
typedef long int __blkcnt_t;
typedef __quad_t __blkcnt64_t;
typedef __u_long __fsblkcnt_t;
typedef __u_quad_t __fsblkcnt64_t;
typedef __u_long __fsfilcnt_t;
typedef __u_quad_t __fsfilcnt64_t;
typedef __u_long __ino64_t;
typedef __loff_t __off64_t;
typedef int __t_scalar_t;
typedef unsigned int __t_uscalar_t;
typedef int __intptr_t;
# 40 "/usr/include/stdio.h" 2 3
typedef struct _IO_FILE FILE;
# 1 "/usr/include/libio.h" 1 3
# 1 "/usr/include/_G_config.h" 1 3
# 1 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/stddef.h" 1 3
# 19 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/stddef.h" 3
# 61 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/stddef.h" 3
# 131 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/stddef.h" 3
# 188 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/stddef.h" 3
typedef long int wchar_t;
typedef unsigned int wint_t;
# 317 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/stddef.h" 3
# 14 "/usr/include/_G_config.h" 2 3
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__)));
# 30 "/usr/include/libio.h" 2 3
# 1 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/stdarg.h" 1 3
# 1 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/va-ppc.h" 1 3
# 37 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/va-ppc.h" 3
# 173 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/va-ppc.h" 3
# 229 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/va-ppc.h" 3
# 42 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/stdarg.h" 2 3
# 124 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/stdarg.h" 3
# 202 "/usr/lib/gcc-lib/ppc-redhat-linux/egcs-2.91.66/include/stdarg.h" 3
# 48 "/usr/include/libio.h" 2 3
# 67 "/usr/include/libio.h" 3
# 98 "/usr/include/libio.h" 3
struct _IO_jump_t; struct _IO_FILE;
typedef void _IO_lock_t;
struct _IO_marker {
struct _IO_marker *_next;
struct _IO_FILE *_sbuf;
int _pos;
# 186 "/usr/include/libio.h" 3
};
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 _blksize;
__off_t _old_offset;
unsigned short _cur_column;
signed char _vtable_offset;
char _shortbuf[1];
_IO_lock_t *_lock;
__off64_t _offset;
int _unused2[16];
};
typedef struct _IO_FILE _IO_FILE;
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_;
# 276 "/usr/include/libio.h" 3
extern int __underflow (_IO_FILE *) ;
extern int __uflow (_IO_FILE *) ;
extern int __overflow (_IO_FILE *, int) ;
extern int _IO_getc (_IO_FILE *__fp) ;
extern int _IO_putc (int __c, _IO_FILE *__fp) ;
extern int _IO_feof (_IO_FILE *__fp) ;
extern int _IO_ferror (_IO_FILE *__fp) ;
extern int _IO_peekc_locked (_IO_FILE *__fp) ;
extern void _IO_flockfile (_IO_FILE *) ;
extern void _IO_funlockfile (_IO_FILE *) ;
extern int _IO_ftrylockfile (_IO_FILE *) ;
extern int _IO_vfscanf (_IO_FILE * , const char * ,
__gnuc_va_list , int * ) ;
extern int _IO_vfprintf (_IO_FILE * , const char * ,
__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 *) ;
# 57 "/usr/include/stdio.h" 2 3
typedef __off_t fpos_t;
# 1 "/usr/include/bits/stdio_lim.h" 1 3
# 110 "/usr/include/stdio.h" 2 3
extern FILE *stdin;
extern FILE *stdout;
extern FILE *stderr;
extern int remove (__const char *__filename) ;
extern int rename (__const char *__old, __const char *__new) ;
extern FILE *tmpfile (void) ;
extern char *tmpnam (char *__s) ;
extern char *tmpnam_r (char *__s) ;
extern char *tempnam (__const char *__dir, __const char *__pfx) ;
extern int fclose (FILE *__stream) ;
extern int fflush (FILE *__stream) ;
extern int fflush_unlocked (FILE *__stream) ;
extern FILE *fopen (__const char * __filename,
__const char * __modes) ;
extern FILE *freopen (__const char * __filename,
__const char * __modes,
FILE * __stream) ;
# 197 "/usr/include/stdio.h" 3
extern FILE *fdopen (int __fd, __const char *__modes) ;
# 223 "/usr/include/stdio.h" 3
extern void setbuf (FILE * __stream, char * __buf) ;
extern int setvbuf (FILE * __stream, char * __buf,
int __modes, size_t __n) ;
extern void setbuffer (FILE * __stream, char * __buf,
size_t __size) ;
extern void setlinebuf (FILE *__stream) ;
extern int fprintf (FILE * __stream,
__const char * __format, ...) ;
extern int printf (__const char * __format, ...) ;
extern int sprintf (char * __s,
__const char * __format, ...) ;
extern int vfprintf (FILE * __s,
__const char * __format,
__gnuc_va_list __arg) ;
extern int vprintf (__const char * __format,
__gnuc_va_list __arg) ;
extern int vsprintf (char * __s,
__const char * __format,
__gnuc_va_list __arg) ;
extern int snprintf (char * __s, size_t __maxlen,
__const char * __format, ...)
__attribute__ ((__format__ (__printf__, 3, 4)));
extern int __vsnprintf (char * __s, size_t __maxlen,
__const char * __format,
__gnuc_va_list __arg)
__attribute__ ((__format__ (__printf__, 3, 0)));
extern int vsnprintf (char * __s, size_t __maxlen,
__const char * __format,
__gnuc_va_list __arg)
__attribute__ ((__format__ (__printf__, 3, 0)));
# 302 "/usr/include/stdio.h" 3
extern int fscanf (FILE * __stream,
__const char * __format, ...) ;
extern int scanf (__const char * __format, ...) ;
extern int sscanf (__const char * __s,
__const char * __format, ...) ;
# 330 "/usr/include/stdio.h" 3
extern int fgetc (FILE *__stream) ;
extern int getc (FILE *__stream) ;
extern int getchar (void) ;
extern int getc_unlocked (FILE *__stream) ;
extern int getchar_unlocked (void) ;
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) ;
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 * __s, int __n,
FILE * __stream) ;
extern char *gets (char *__s) ;
# 420 "/usr/include/stdio.h" 3
extern int fputs (__const char * __s,
FILE * __stream) ;
extern int puts (__const char *__s) ;
extern int ungetc (int __c, FILE *__stream) ;
extern size_t fread (void * __ptr, size_t __size,
size_t __n, FILE * __stream) ;
extern size_t fwrite (__const void * __ptr, size_t __size,
size_t __n, FILE * __s) ;
extern size_t fread_unlocked (void * __ptr, size_t __size,
size_t __n, FILE * __stream) ;
extern size_t fwrite_unlocked (__const void * __ptr,
size_t __size, size_t __n,
FILE * __stream) ;
extern int fseek (FILE *__stream, long int __off, int __whence) ;
extern long int ftell (FILE *__stream) ;
extern void rewind (FILE *__stream) ;
typedef __off_t off_t;
extern int fgetpos (FILE * __stream,
fpos_t * __pos) ;
extern int fsetpos (FILE *__stream, __const fpos_t *__pos) ;
# 519 "/usr/include/stdio.h" 3
# 529 "/usr/include/stdio.h" 3
extern void clearerr (FILE *__stream) ;
extern int feof (FILE *__stream) ;
extern int ferror (FILE *__stream) ;
extern void clearerr_unlocked (FILE *__stream) ;
extern int feof_unlocked (FILE *__stream) ;
extern int ferror_unlocked (FILE *__stream) ;
extern void perror (__const char *__s) ;
extern int sys_nerr;
extern __const char *__const sys_errlist[];
extern int fileno (FILE *__stream) ;
extern int fileno_unlocked (FILE *__stream) ;
extern FILE *popen (__const char *__command, __const char *__modes) ;
extern int pclose (FILE *__stream) ;
extern char *ctermid (char *__s) ;
# 603 "/usr/include/stdio.h" 3
extern void flockfile (FILE *__stream) ;
extern int ftrylockfile (FILE *__stream) ;
extern void funlockfile (FILE *__stream) ;
# 1 "/usr/include/bits/stdio.h" 1 3
extern __inline int
vprintf (__const char * __fmt, __gnuc_va_list __arg)
{
return vfprintf (stdout, __fmt, __arg);
}
extern __inline int
getchar (void)
{
return _IO_getc (stdin);
}
extern __inline int
getc_unlocked (FILE *__fp)
{
return (( __fp )->_IO_read_ptr >= ( __fp )->_IO_read_end ? __uflow ( __fp ) : *(unsigned char *) ( __fp )->_IO_read_ptr++) ;
}
extern __inline int
getchar_unlocked (void)
{
return (( stdin )->_IO_read_ptr >= ( stdin )->_IO_read_end ? __uflow ( stdin ) : *(unsigned char *) ( stdin )->_IO_read_ptr++) ;
}
extern __inline int
putchar (int __c)
{
return _IO_putc (__c, stdout);
}
extern __inline int
fputc_unlocked (int __c, FILE *__stream)
{
return ((( __stream )->_IO_write_ptr >= ( __stream )->_IO_write_end) ? __overflow ( __stream , (unsigned char) ( __c )) : (unsigned char) (*( __stream )->_IO_write_ptr++ = ( __c ))) ;
}
extern __inline int
putc_unlocked (int __c, FILE *__stream)
{
return ((( __stream )->_IO_write_ptr >= ( __stream )->_IO_write_end) ? __overflow ( __stream , (unsigned char) ( __c )) : (unsigned char) (*( __stream )->_IO_write_ptr++ = ( __c ))) ;
}
extern __inline int
putchar_unlocked (int __c)
{
return ((( stdout )->_IO_write_ptr >= ( stdout )->_IO_write_end) ? __overflow ( stdout , (unsigned char) ( __c )) : (unsigned char) (*( stdout )->_IO_write_ptr++ = ( __c ))) ;
}
extern __inline int
feof_unlocked (FILE *__stream)
{
return ((( __stream )->_flags & 0x10 ) != 0) ;
}
extern __inline int
ferror_unlocked (FILE *__stream)
{
return ((( __stream )->_flags & 0x20 ) != 0) ;
}
# 149 "/usr/include/bits/stdio.h" 3
# 165 "/usr/include/bits/stdio.h" 3
# 631 "/usr/include/stdio.h" 2 3
# 2 "test.c" 2
int main ()
{
long i = 10000000;
double c0, c1;
c0 = c1 = 1.0;
while (--i)
{
c0 += c0 * c0;
}
c0 = c0 + c1;
printf ("c0 = %f\n", c0);
return (0);
}