On Thu, 2002-01-17 at 07:25, Torsten Weber wrote:
> On a RedHat 7.1 installation I compiled gawk (3.1.0), but gawk crashed
> (gawk couldn't run glibc-2.2.4/scripts/firstversions.awk, it resulted
> in:
> > (FILENAME=- FNR=1) fatal error: internal error
> > Aborted (core dumped)
> )
> The gawk problem disappeares if I compile without optimizing with -O2
> (i.e. optimizing with -O works).
>
> gcc version is 2.96 20000731 (Red Hat Linux 7.1 2.96-99.1)
>
> Is this problem already known, or where is my mistake?
>
Often compiling with -O2 reveals actual bugs in the code of the program,
not the compiler. For example, uninitialized variables can come out
differently depending on optimization level:
#include <stdlib.h>
#include <stdio.h>
int main()
{
int foo;
printf("Foo is %i\n", foo);
return 0;
}
[justinca@gs256 ~]$ gcc -O0 foo.c -o foo
[justinca@gs256 ~]$ ./foo
Foo is -1073743180
[justinca@gs256 ~]$ gcc -O2 foo.c -o foo
[justinca@gs256 ~]$ ./foo
Foo is 1075157696
-Justin
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