runtime: remove indentation in evacuate

Combine conditions into a single if statement.
This is more readable.

It should generate identical machine code, but it doesn't.
The new code is shorter.

Change-Id: I9bf52f8f288b0df97a2b9b4e4183f6ca74175e8a
Reviewed-on: https://go-review.googlesource.com/54651
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Martin Möhrmann <moehrmann@google.com>

src/runtime/hashmap.go

@@ -1088,28 +1088,26 @@ func evacuate(t *maptype, h *hmap, oldbucket uintptr) {
 					// Compute hash to make our evacuation decision (whether we need
 					// to send this key/value to bucket x or bucket y).
 					hash := alg.hash(k2, uintptr(h.hash0))
-					if h.flags&iterator != 0 {
-						if !t.reflexivekey && !alg.equal(k2, k2) {
-							// If key != key (NaNs), then the hash could be (and probably
-							// will be) entirely different from the old hash. Moreover,
-							// it isn't reproducible. Reproducibility is required in the
-							// presence of iterators, as our evacuation decision must
-							// match whatever decision the iterator made.
-							// Fortunately, we have the freedom to send these keys either
-							// way. Also, tophash is meaningless for these kinds of keys.
-							// We let the low bit of tophash drive the evacuation decision.
-							// We recompute a new random tophash for the next level so
-							// these keys will get evenly distributed across all buckets
-							// after multiple grows.
-							if top&1 != 0 {
-								hash |= newbit
-							} else {
-								hash &^= newbit
-							}
-							top = uint8(hash >> (sys.PtrSize*8 - 8))
-							if top < minTopHash {
-								top += minTopHash
-							}
+					if h.flags&iterator != 0 && !t.reflexivekey && !alg.equal(k2, k2) {
+						// If key != key (NaNs), then the hash could be (and probably
+						// will be) entirely different from the old hash. Moreover,
+						// it isn't reproducible. Reproducibility is required in the
+						// presence of iterators, as our evacuation decision must
+						// match whatever decision the iterator made.
+						// Fortunately, we have the freedom to send these keys either
+						// way. Also, tophash is meaningless for these kinds of keys.
+						// We let the low bit of tophash drive the evacuation decision.
+						// We recompute a new random tophash for the next level so
+						// these keys will get evenly distributed across all buckets
+						// after multiple grows.
+						if top&1 != 0 {
+							hash |= newbit
+						} else {
+							hash &^= newbit
+						}
+						top = uint8(hash >> (sys.PtrSize*8 - 8))
+						if top < minTopHash {
+							top += minTopHash
 						}
 					}
 					useX = hash&newbit == 0