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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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40
lisc/emit.c
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@ -73,6 +73,20 @@ static char *ctoa[NCmp] = {
[Cne] = "ne",
};
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 void
eref(Ref r, Fn *fn, FILE *f)
{
@ -187,9 +201,9 @@ eins(Ins i, Fn *fn, FILE *f)
void
emitfn(Fn *fn, FILE *f)
{
char *js;
Blk *b, *s;
Ins *i;
int c;
fprintf(f,
".text\n"
@ -216,19 +230,19 @@ emitfn(Fn *fn, FILE *f)
if (b->s1 != b->link)
fprintf(f, "\tjmp .L%s\n", b->s1->name);
break;
case JJez:
if (b->s1 == b->link) {
js = "jne";
s = b->s2;
} else if (b->s2 == b->link) {
js = "je";
s = b->s1;
} else
diag("emit: unhandled jump (1)");
eop("cmp $0,", b->jmp.arg, R, fn, f);
fprintf(f, "\t%s .L%s\n", js, s->name);
break;
default:
c = b->jmp.type - JXJc;
if (0 <= c && c <= NCmp) {
if (b->link == b->s2) {
s = b->s1;
} else if (b->link == b->s1) {
c = cneg(c);
s = b->s2;
} else
diag("emit: unhandled jump (1)");
fprintf(f, "\tj%s .L%s\n", ctoa[c], s->name);
break;
}
diag("emit: unhandled jump (2)");
}
}