cmd/compile/internal/gc: tidy plive.go

Make boolean looking things boolean.

Change-Id: I8d1c0a32b471412b25a72908c7da6458d7bbe65b
Reviewed-on: https://go-review.googlesource.com/20723
Run-TryBot: Dave Cheney <dave@cheney.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/cmd/compile/internal/gc/bv.go

@@ -63,16 +63,16 @@ func bvandnot(dst Bvec, src1 Bvec, src2 Bvec) {
 	}
 }
 
-func bvcmp(bv1 Bvec, bv2 Bvec) int {
+func bveq(bv1 Bvec, bv2 Bvec) bool {
 	if bv1.n != bv2.n {
 		Fatalf("bvequal: lengths %d and %d are not equal", bv1.n, bv2.n)
 	}
 	for i, x := range bv1.b {
 		if x != bv2.b[i] {
-			return 1
+			return false
 		}
 	}
-	return 0
+	return true
 }
 
 func bvcopy(dst Bvec, src Bvec) {

src/cmd/compile/internal/gc/plive.go

@@ -1092,9 +1092,8 @@ func livenesssolve(lv *Liveness) {
 		bvcopy(bb.avarinitany, bb.avarinit)
 	}
 
-	change := int32(1)
-	for change != 0 {
-		change = 0
+	for change := true; change; {
+		change = false
 		for _, bb := range lv.cfg {
 			bvresetall(any)
 			bvresetall(all)
@@ -1112,13 +1111,13 @@ func livenesssolve(lv *Liveness) {
 			bvandnot(all, all, bb.varkill)
 			bvor(any, any, bb.avarinit)
 			bvor(all, all, bb.avarinit)
-			if bvcmp(any, bb.avarinitany) != 0 {
-				change = 1
+			if !bveq(any, bb.avarinitany) {
+				change = true
 				bvcopy(bb.avarinitany, any)
 			}
 
-			if bvcmp(all, bb.avarinitall) != 0 {
-				change = 1
+			if !bveq(all, bb.avarinitall) {
+				change = true
 				bvcopy(bb.avarinitall, all)
 			}
 		}
@@ -1127,10 +1126,9 @@ func livenesssolve(lv *Liveness) {
 	// Iterate through the blocks in reverse round-robin fashion. A work
 	// queue might be slightly faster. As is, the number of iterations is
 	// so low that it hardly seems to be worth the complexity.
-	change = 1
 
-	for change != 0 {
-		change = 0
+	for change := true; change; {
+		change = false
 
 		// Walk blocks in the general direction of propagation. This
 		// improves convergence.
@@ -1146,8 +1144,8 @@ func livenesssolve(lv *Liveness) {
 				bvor(newliveout, newliveout, succ.livein)
 			}
 
-			if bvcmp(bb.liveout, newliveout) != 0 {
-				change = 1
+			if !bveq(bb.liveout, newliveout) {
+				change = true
 				bvcopy(bb.liveout, newliveout)
 			}
 
@@ -1506,7 +1504,7 @@ func livenesscompact(lv *Liveness) {
 			}
 			jlocal := lv.livepointers[j]
 			jarg := lv.argslivepointers[j]
-			if bvcmp(local, jlocal) == 0 && bvcmp(arg, jarg) == 0 {
+			if bveq(local, jlocal) && bveq(arg, jarg) {
 				remap[i] = j
 				goto Next
 			}