libmach: correct handling of .5 files with D_REGREG addresses

undo workaround in gc

Fixes #943.

R=kaib
CC=golang-dev
https://golang.org/cl/1889041

src/cmd/gc/range.c

@@ -115,9 +115,7 @@ walkrange(Node *n)
 		v2 = n->list->next->n;
 	hv2 = N;
 
-	// TODO(kaib): re-enable this optimization on arm once we are on par with 6g/8g
-	// see http://code.google.com/p/go/issues/detail?id=943
-	if(v2 == N && t->etype == TARRAY && thechar != '5') {
+	if(v2 == N && t->etype == TARRAY) {
 		// will have just one reference to argument.
 		// no need to make a potentially expensive copy.
 		ha = a;

src/libmach/5obj.c

@@ -123,6 +123,9 @@ addr(Biobuf *bp)
 	case D_PSR:
 	case D_FPCR:
 		break;
+	case D_REGREG:
+		Bgetc(bp);
+		break;
 	case D_CONST2:
 		Bgetc(bp);
 		Bgetc(bp);