code gen error for *(complex)++

includes array[i]++ and slice[i]++

R=rsc
CC=golang-dev
https://golang.org/cl/2614041

src/cmd/5g/ggen.c

@@ -458,13 +458,14 @@ cgen_asop(Node *n)
 		}
 		if(nr->ullman < UINF)
 		if(sudoaddable(a, nl, &addr, &w)) {
+			w = optoas(OAS, nl->type);
 			regalloc(&n2, nl->type, N);
-			p1 = gins(AMOVW, N, &n2);
+			p1 = gins(w, N, &n2);
 			p1->from = addr;
 			regalloc(&n3, nr->type, N);
 			cgen(nr, &n3);
 			gins(a, &n3, &n2);
-			p1 = gins(AMOVW, &n2, N);
+			p1 = gins(w, &n2, N);
 			p1->to = addr;
 			regfree(&n2);
 			regfree(&n3);

src/cmd/5g/gsubr.c

@@ -1835,14 +1835,20 @@ oindex:
 		gmove(&n2, reg);
 	}
 
-	if(*w == 1)
+	switch(*w) {
+	case 1:
 		gins(AADD, reg1, reg);
-	else if(*w == 2)
+		break;
+	case 2:
 		gshift(AADD, reg1, SHIFT_LL, 1, reg);
-	else if(*w == 4)
+		break;
+	case 4:
 		gshift(AADD, reg1, SHIFT_LL, 2, reg);
-	else if(*w == 8)
+		break;
+	case 8:
 		gshift(AADD, reg1, SHIFT_LL, 3, reg);
+		break;
+	}
 
 	naddr(reg1, a, 1);
 	a->type = D_OREG;