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jez becomes jnz, complete cmp+jmp contraction

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This commit is contained in:
Quentin Carbonneaux 2015-08-07 16:01:07 -04:00
parent ad012e9d55
commit e65a615c90
12 changed files with 77 additions and 75 deletions
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72
lisc/isel.c
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@ -39,20 +39,6 @@ newtmp(int type, Fn *fn)
return t;
}
static int
cneg(int cmp)
{
switch (cmp) {
default: diag("cneg: unhandled comparison");
case Ceq: return Cne;
case Csle: return Csgt;
case Cslt: return Csge;
case Csgt: return Csle;
case Csge: return Cslt;
case Cne: return Ceq;
}
}
static int
islong(Ref r, Fn *fn)
{
@ -131,6 +117,8 @@ sel(Ins i, Fn *fn)
case OCopy:
emit(i.op, i.to, i.arg[0], i.arg[1]);
break;
case ONop:
break;
default:
if (OCmp <= i.op && i.op <= OCmp1) {
c = i.op - OCmp;
@ -150,6 +138,9 @@ flagi(Ins *i0, Ins *i)
while (i>i0)
switch ((--i)->op) {
default:
return 0;
case OAdd: /* <arch> */
case OSub:
return i;
case OCopy:
case OStore:
@ -158,51 +149,48 @@ flagi(Ins *i0, Ins *i)
return 0;
}
static Ins *
static void
seljmp(Blk *b, Fn *fn)
{
Ref r;
int c;
Ins *fi;
fi = &b->ins[b->nins];
if (b->jmp.type != JJez)
return fi;
if (b->jmp.type != JJnz)
return;
r = b->jmp.arg;
b->jmp.arg = R;
assert(!req(r, R));
if (rtype(r) == RCon) {
b->jmp.type = JJmp;
if (!req(r, CON_Z))
if (req(r, CON_Z))
b->s1 = b->s2;
b->s2 = 0;
return fi;
return;
}
fi = flagi(b->ins, fi);
fi = flagi(b->ins, &b->ins[b->nins]);
if (fi && req(fi->to, r)) {
assert(1 == fn->tmp[r.val].nuse);
if (fn->tmp[r.val].nuse == 1
&& OCmp <= fi->op && fi->op <= OCmp1) {
if (OCmp <= fi->op && fi->op <= OCmp1) {
c = fi->op - OCmp;
if (rtype(fi->arg[0]) == RCon)
c = COP(c);
b->jmp.type = JXJc + cneg(c);
selcmp(fi->arg, fn);
return fi;
}
/* what if it is a comparison
* that is used more than once?
* !!!
*/
b->jmp.type = JXJc + Ceq;
return fi+1;
b->jmp.type = JXJc + c;
if (fn->tmp[r.val].nuse == 1) {
assert(fn->tmp[r.val].ndef==1);
selcmp(fi->arg, fn);
*fi = (Ins){ONop, R, {R, R}};
/* !!! use counts are invalid after that !!! */
return;
}
} else
b->jmp.type = JXJc + Cne;
} else {
if (islong(r, fn))
emit(OXCmpl, R, CON_Z, r);
else
emit(OXCmpw, R, CON_Z, r);
b->jmp.type = JXJc + Cne;
}
if (islong(r, fn))
emit(OXCmpl, R, CON_Z, r);
else
emit(OXCmpw, R, CON_Z, r);
b->jmp.type = JXJc + Ceq;
return &b->ins[b->nins];
}
/* instruction selection
@ -217,8 +205,8 @@ isel(Fn *fn)
for (b=fn->start; b; b=b->link) {
curi = &insb[NIns];
i = seljmp(b, fn);
while (i>b->ins) {
seljmp(b, fn);
for (i=&b->ins[b->nins]; i>b->ins;) {
sel(*--i, fn);
}
nins = &insb[NIns] - curi;