These are needed to correctly distinguish pointer types in _Generic. They should also be used for type compatibility checks in other contexts, but currently are not.
This also fixes a couple small problems related to type qualifiers:
*restrict was not allowed to appear after * in type-names
*volatile status was not properly recorded in sym files
Here is an example of using _Generic to distinguish pointer types based on the qualifiers of the pointed-to type:
#include <stdio.h>
#define f(e) _Generic((e),\
int * restrict *: 1,\
int * volatile const *: 2,\
int **: 3,\
default: 0)
#define g(e) _Generic((e),\
int *: 1,\
const int *: 2,\
volatile int *: 3,\
default: 0)
int main(void) {
int * restrict * p1;
int * volatile const * p2;
int * const * p3;
// should print "1 2 0 1"
printf("%i %i %i %i\n", f(p1), f(p2), f(p3), f((int * restrict *)0));
int *q1;
const int *q2;
volatile int *q3;
const volatile int *q4;
// should print "1 2 3 0"
printf("%i %i %i %i\n", g(q1), g(q2), g(q3), g(q4));
}
Here is an example of a problem resulting from volatile not being recorded in sym files (if a sym file was present, the read of x was lifted out of the loop):
#pragma optimize -1
static volatile int x;
#include <stdio.h>
int main(void) {
int y;
for (unsigned i = 0; i < 100; i++) {
y = x*2 + 7;
}
}
