blob: 9d248f4fc15e7365c8d625043107c7569ffed88f (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
|
#include "ir.h"
void
copyopt(struct function *fn)
{
struct block *blk = fn->entry;
FREQUIRE(FNUSE);
do {
for (int i = 0; i < blk->phi.n; ++i) {
/* simplify same-arg phi */
int phi = blk->phi.p[i];
union ref *arg = phitab.p[instrtab[phi].l.i];
for (int j = 1; j < blk->npred; ++j) {
if (arg[j].bits != arg->bits) goto Next;
}
/* being conservative here because phis could have circular dependencies? */
if (arg->t != RTMP || instrtab[arg->i].op != Ophi) {
replcuses(mkref(RTMP, phi), *arg);
delphi(blk, i--);
}
Next:;
}
for (int i = 0; i < blk->ins.n; ++i) {
union ref var = mkref(RTMP, blk->ins.p[i]);
struct instr *ins = &instrtab[var.i];
enum irclass k;
if (ins->op == Ocopy) {
union ref arg = ins->l;
if (arg.t == RTMP) k = insrescls(instrtab[arg.i]);
else if (arg.t == RICON) k = cls2siz[ins->cls] == 4 ? KI32 : KI64;
else if (arg.t == RXCON) k = isnumcon(arg) ? conht[arg.i].cls : KPTR;
else continue;
if (ins->cls != k) continue;
replcuses(var, arg);
*ins = mkinstr(Onop,0,);
deluses(var.i);
}
}
delnops(blk);
} while ((blk = blk->lnext) != fn->entry);
}
/* vim:set ts=3 sw=3 expandtab: */
|
