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Literal zero slices should have the base be null.

--- a/6/simp.c

+++ b/6/simp.c

@@ -757,8 +757,8 @@

 	ty = tybase(exprtype(n));

 	switch (ty->type) {

 	case Typtr:	u = n;	break;

-	case Tyarray:	u = addr(s, n, base(exprtype(n)));	break;

 	case Tyslice:	u = load(addr(s, n, mktyptr(n->loc, base(exprtype(n)))));	break;

+	case Tyarray:	u = addr(s, n, base(exprtype(n)));	break;

 	default: die("Unslicable type %s", tystr(n->expr.type));

 	}

 	/* safe: all types we allow here have a sub[0] that we want to grab */

@@ -941,7 +941,7 @@

 static Node *simpslice(Simp *s, Node *n, Node *dst)

 {

 	Node *t;

-	Node *start, *end;

+	Node *start, *end, *arg;

 	Node *seq, *base, *sz, *len, *max;

 	Node *stbase, *stlen;

@@ -949,9 +949,16 @@

 		t = dst;

 	else

 		t = temp(s, n);

-	seq = rval(s, n->expr.args[0], NULL);

-	/* *(&slice) = (void*)base + off*sz */

-	base = slicebase(s, seq, n->expr.args[1]);

+	arg = n->expr.args[0];

+	if (exprop(arg) == Oarr && arg->expr.nargs == 0) {

+		seq = arg;

+		base = mkintlit(n->loc, 0);

+		base->expr.type = tyintptr;

+	} else {

+		/* *(&slice) = (void*)base + off*sz */

+		seq = rval(s, arg, NULL);

+		base = slicebase(s, seq, n->expr.args[1]);

+	}

 	start = ptrsized(s, rval(s, n->expr.args[1], NULL));

 	end = ptrsized(s, rval(s, n->expr.args[2], NULL));

 	len = sub(end, start);