https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91898
--- Comment #3 from Michael Matz <matz at gcc dot gnu.org> ---
For purposes of discussion, let's make a full example:
% cat ex.c
int get(int);
int foo (int a, int *ary)
{
//void *labelsy[] = {&&lab1, &&lab2, &&lab3, &&lab_end};
//int ary[] = {0, 1, 2, 3};
int i = 0;
int ret = 0;
for (;;)
switch (ary[i++]) {
case 0:
ret += get (1);
break;
case 1:
ret += get (2);
break;
case 2:
ret += get (3);
break;
case 3:
goto after_loop;
case 4:
ret += get (4);
break;
case 34:
ret += get (5);
break;
case 44:
ret += get (6);
break;
case 46:
ret += get (7);
break;
case 444:
ret += get (8);
break;
case 124:
ret += get (9);
break;
case 4321:
ret += get (10);
break;
}
after_loop:
return ret;
}
On at least x86-64 (with -O2) this is compiled to a table jump variant
for the switch. What Nathans wants, I think (please correct), is that the
table jump sequence (in particular the indirect jump) be duplicated.
