[release-branch.go1] cmd/[568]g: correct freeing of allocated Regs.

««« backport f1028a23b059
cmd/[568]g: correct freeing of allocated Regs.

R=golang-dev, rsc
CC=golang-dev, remy
https://golang.org/cl/6281050

»»»

src/cmd/5g/reg.c

@@ -695,8 +695,8 @@ brk:
 			}
 		}
 	}
-	if(r1 != R) {
-		r1->link = freer;
+	if(lastr != R) {
+		lastr->link = freer;
 		freer = firstr;
 	}
 

src/cmd/6g/reg.c

@@ -780,8 +780,8 @@ brk:
 				p->to.branch = p->to.branch->link;
 	}
 
-	if(r1 != R) {
-		r1->link = freer;
+	if(lastr != R) {
+		lastr->link = freer;
 		freer = firstr;
 	}
 

src/cmd/8g/reg.c

@@ -677,8 +677,8 @@ brk:
 				p->to.branch = p->to.branch->link;
 	}
 
-	if(r1 != R) {
-		r1->link = freer;
+	if(lastr != R) {
+		lastr->link = freer;
 		freer = firstr;
 	}