[Mesa-dev] [PATCH 08/19] i965/fs: Use a bitfield for fs_inst's bool fields.

[Matt Turner]

On Fri, Feb 21, 2014 at 1:40 PM, Kenneth Graunke <kenneth at whitecape.org> wrote:
> Please just do:
>
>    unsigned eot:1;

For

#include <stdint.h>

struct a {
unsigned a:1;
unsigned b:1;
unsigned c:1;
};

struct b {
uint8_t a:1;
uint8_t b:1;
uint8_t c:1;
};

void f(struct a a, struct b b) {}

pahole says:

struct a {
unsigned int               a:1;                  /*     0:31  4 */
unsigned int               b:1;                  /*     0:30  4 */
unsigned int               c:1;                  /*     0:29  4 */

/* size: 4, cachelines: 1, members: 3 */
/* bit_padding: 29 bits */
/* last cacheline: 4 bytes */
};
struct b {
uint8_t                    a:1;                  /*     0: 7  1 */
uint8_t                    b:1;                  /*     0: 6  1 */
uint8_t                    c:1;                  /*     0: 5  1 */

/* size: 1, cachelines: 1, members: 3 */
/* bit_padding: 5 bits */
/* last cacheline: 1 bytes */
};

I initially used unsigned, but I noticed this.