minor cleanup, 64-bit /= and %= on 32-bit

R=ken
OCL=29806
CL=29808

src/cmd/6g/cgen.c

@@ -224,7 +224,7 @@ cgen(Node *n, Node *res)
 
 	case OLEN:
 		if(istype(nl->type, TMAP)) {
-			// map hsd len in the first 32-bit word.
+			// map has len in the first 32-bit word.
 			// a zero pointer means zero length
 			regalloc(&n1, types[tptr], res);
 			cgen(nl, &n1);
@@ -245,7 +245,7 @@ cgen(Node *n, Node *res)
 			break;
 		}
 		if(istype(nl->type, TSTRING) || isslice(nl->type)) {
-			// both slice and string have len in the first 32-bit word.
+			// both slice and string have len one pointer into the struct.
 			// a zero pointer means zero length
 			regalloc(&n1, types[tptr], res);
 			agen(nl, &n1);
@@ -835,7 +835,7 @@ stkof(Node *n)
 
 /*
  * block copy:
- *	memmove(&n, &ns, w);
+ *	memmove(&ns, &n, w);
  */
 void
 sgen(Node *n, Node *ns, int32 w)

src/cmd/6g/ggen.c

@@ -127,8 +127,11 @@ ginscall(Node *f, int proc)
 		gins(APUSHQ, &con, N);
 		if(proc == 1)
 			ginscall(newproc, 0);
-		else
+		else {
+			if(!hasdefer)
+				fatal("hasdefer=0 but has defer");
 			ginscall(deferproc, 0);
+		}
 		gins(APOPQ, N, &reg);
 		gins(APOPQ, N, &reg);
 		break;
@@ -176,7 +179,7 @@ cgen_callinter(Node *n, Node *res, int proc)
 	nodo.xoffset -= widthptr;
 	cgen(&nodo, &nodr);	// REG = 0(REG) -- i.m
 
-	nodo.xoffset = n->left->xoffset + 4*widthptr;
+	nodo.xoffset = n->left->xoffset + 3*widthptr + 8;
 	cgen(&nodo, &nodr);	// REG = 32+offset(REG) -- i.m->fun[f]
 
 	// BOTCH nodr.type = fntype;
@@ -852,10 +855,6 @@ lit:
 		p->from.scale = types[TINT32]->width;
 		p->from.offset += types[tptr]->width;
 //print("%P\n", p);
-
-		p = gins(ADATA, &nam, &nod1);
-		p->from.scale = types[TINT32]->width;
-		p->from.offset += types[tptr]->width+types[TINT32]->width;
 		break;
 	}
 

src/cmd/gc/go.h

@@ -755,6 +755,9 @@ void	tempname(Node*, Type*);
 Node*	staticname(Type*);
 int	iscomposite(Type*);
 Node*	callnew(Type*);
+Node*	saferef(Node*);
+int	is64(Type*);
+int	noconv(Type*, Type*);
 
 Type**	getthis(Type*);
 Type**	getoutarg(Type*);

src/cmd/gc/subr.c

@@ -1806,6 +1806,62 @@ loop:
 	return 1;
 }
 
+/*
+ * Is this a 64-bit type?
+ */
+int
+is64(Type *t)
+{
+	if(t == T)
+		return 0;
+	switch(simtype[t->etype]) {
+	case TINT64:
+	case TUINT64:
+	case TPTR64:
+		return 1;
+	}
+	return 0;
+}
+
+/*
+ * Is a conversion between t1 and t2 a no-op?
+ */
+int
+noconv(Type *t1, Type *t2)
+{
+	int e1, e2;
+
+	e1 = simtype[t1->etype];
+	e2 = simtype[t2->etype];
+
+	switch(e1) {
+	case TINT8:
+	case TUINT8:
+		return e2 == TINT8 || e2 == TUINT8;
+
+	case TINT16:
+	case TUINT16:
+		return e2 == TINT16 || e2 == TUINT16;
+
+	case TINT32:
+	case TUINT32:
+	case TPTR32:
+		return e2 == TINT32 || e2 == TUINT32 || e2 == TPTR32;
+
+	case TINT64:
+	case TUINT64:
+	case TPTR64:
+		return e2 == TINT64 || e2 == TUINT64 || e2 == TPTR64;
+
+	case TFLOAT32:
+		return e2 == TFLOAT32;
+
+	case TFLOAT64:
+		return e2 == TFLOAT64;
+	}
+	return 0;
+}
+
 void
 argtype(Node *on, Type *t)
 {
@@ -2417,6 +2473,42 @@ staticname(Type *t)
 	return n;
 }
 
+/*
+ * return side effect-free n, moving side effects to top.
+ */
+Node*
+saferef(Node *n)
+{
+	Node *l;
+	Node *r;
+
+	switch(n->op) {
+	case ONAME:
+		return n;
+	case ODOT:
+		l = saferef(n->left);
+		if(l == n->left)
+			return n;
+		r = nod(OXXX, N, N);
+		*r = *n;
+		r->left = l;
+		walktype(r, Elv);
+		return r;
+
+	case OINDEX:
+	case ODOTPTR:
+	case OIND:
+		l = nod(OXXX, N, N);
+		tempname(l, ptrto(n->type));
+		addtotop(nod(OAS, l, nod(OADDR, n, N)));
+		r = nod(OIND, l, N);
+		walktype(r, Elv);
+		return r;
+	}
+	fatal("saferef %N", n);
+	return N;
+}
+
 void
 setmaxarg(Type *t)
 {

src/cmd/gc/walk.c

@@ -1163,9 +1163,21 @@ loop:
 		n->right = nod(OCONV, n->right, N);
 		n->right->type = types[et];
 		r = nod(OCALL, l, list(n->left, n->right));
+		r = nod(OCONV, r, N);
+		r->type = n->left->left->type;
 		walktype(r, Erv);
 		indir(n, r);
 		goto ret;
+
+	case OASOP:
+		et = n->left->type->etype;
+		if(widthptr > 4 || (et != TUINT64 && et != TINT64))
+			break;
+		l = saferef(n->left);
+		r = nod(OAS, l, nod(n->etype, l, n->right));
+		walktype(r, Etop);
+		indir(n, r);
+		goto ret;
 	}
 
 	if(t == T)