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#include <stdio.h>
#include "c23-fallback.h"
void fgoto(unsigned n) {
unsigned j = 0;
unsigned* p = nullptr;
unsigned* q;
AGAIN:
if (p) printf("%u: p and q are %s, *p is %u\n",
j,
(q == p) ? "equal" : "unequal",
*p);
q = p;
p = &((unsigned){ j, }); /*@\label{lifetime_compound_literal}*/
++j;
if (j <= n) goto AGAIN;
}
void fgotoblock(unsigned n) {
unsigned j = 0;
unsigned* p = nullptr;
unsigned* q;
AGAIN: // Using a compound statement creates a new object at each iteration.
{ // A good modern compiler should complain that it is uninitialized.
if (p) printf("%u: p and q are %s, *p is %u\n",
j,
(q == p) ? "equal" : "unequal",
*p);
q = p;
p = &((unsigned){ j, });
++j;
if (j <= n) goto AGAIN;
}
}
__attribute__((noinline))
void ffor1(void) {
unsigned j = 1;
printf("%u: p and q are %s, *p is %u\n",
j,
"unequal",
j-1);
}
__attribute__((noinline))
void fforn(unsigned n) {
ffor1();
for (unsigned j = 2; j <= n; ++j) {
printf("%u: p and q are %s, *p is %u\n",
j,
"equal",
j-1);
}
}
void ffor(unsigned n) {
switch (n) {
case 0: break;
case 1: ffor1(); break;
default: fforn(n); break;
}
}
void fVLA(unsigned n) {
unsigned volatile j = 0;
unsigned* p = nullptr;
unsigned* q;
AGAIN:
{
if (p) printf("%u: p and q are %s\n",
j,
(q == p) ? "equal" : "unequal");
q = p;
unsigned VLA[j+1];
for (unsigned i = 0; i <= j; ++i)
VLA[i] = j;
p = VLA;
++j;
if (j <= n) goto AGAIN;
}
}
int main(int argc, [[maybe_unused]] char* argv[]) {
fgoto(argc+1);
fgotoblock(argc+1);
ffor(argc+1);
}
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