Re: [Patch] LaTeX: export nested lists

On April 1, 2008 03:02:02 am Robert Staudinger wrote:
> On Sat, Mar 29, 2008 at 9:21 PM, Jose Da Silva <digital@joescat.com>
> wrote:
>
> [...]
>
> > In summary, the switch statement looks nicer from a source-code point
> > of view, but the if statement is a bit less code in a compiled sense.
>
> Unless you have data suggesting that it makes a big difference, the
> nicer source code should be preferred.

past experience with some other "older" compilers or cross compilers had
issues with creating tables of empty data if the values were far apart and
if you had a lot of switch statements, the amount of space would begin to
add up.

I tried gcc v4.2 and it appears it already does the conversion so therefore
not an issue with gcc v4.2 at least. Data in this example agrees with you.
-------------------------
#include <stdio.h>
int main(int argc, const char *argv[]) {
  int i;
  for (i = 0; i < 10; i++)
    switch (i) {
    case 3: putchar('a'); break;
    case 7: putchar('\n'); break;
    default: putchar('.'); break;
    }
// if (i == 3) putchar('a');
// else if (i == 7) putchar('\n');
// else putchar('.');

  return(0);
}
-------------------------
gcc -S -o file.asm file.c
shows this in the resulting output file
        cmpl $3, %eax
        jne .L13
etc.........

.L13:
        cmpl $7, %eax
        je .L11

or in other words, the switch example above is converted internally by gcc
to 2 if statements instead of using tables.
Received on Wed Apr 2 10:50:15 2008