🚀 go-pugleaf

gcc 2.1 misoptimizes the following program:

$ cat bug.c

main()
{
  signed char c = -1;
  printf("%d\n", c < 0);
  exit(0);
}
$ gcc -v -O bug.c
Reading specs from /usr/local/lib/gcc-lib/sparc-sun-sunos4.1/2.1/specs
gcc version 2.1
 /usr/local/lib/gcc-lib/sparc-sun-sunos4.1/2.1/cpp -lang-c -v -undef -D__GNUC__=2 -Dsparc -Dsun -Dunix -D__sparc__ -D__sun__ -D__unix__ -D__sparc -D__sun -D__unix -D__OPTIMIZE__ bug.c /usr/tmp/cca28545.i
GNU CPP version 2.1 (sparc)
 /usr/local/lib/gcc-lib/sparc-sun-sunos4.1/2.1/cc1 /usr/tmp/cca28545.i -quiet -dumpbase bug.c -O -version -o /usr/tmp/cca28545.s
GNU C version 2.1 (sparc) compiled by GNU C version 2.0.
 /usr/local/lib/gcc-lib/sparc-sun-sunos4.1/2.1/as -o bug.o /usr/tmp/cca28545.s
 /usr/local/lib/gcc-lib/sparc-sun-sunos4.1/2.1/ld -e start -dc -dp /lib/crt0.o -L/usr/local/lib/gcc-lib/sparc-sun-sunos4.1/2.1/ -L/usr/local/lib/ bug.o -lgcc -lc -lgcc
$ ./a.out
0
$ gcc bug.c
$ ./a.out
1
$ 

James Clark
jjc@jclark.com