From 8a9d4184e6e175194e262bde5fe321838b5d40c4 Mon Sep 17 00:00:00 2001 From: Josh Bleecher Snyder Date: Thu, 17 Aug 2017 17:41:44 -0700 Subject: [PATCH] runtime: simplify evacuate's handling of NaNs The new code is not quite equivalent to the old, in that if newbit was very large it might have altered the new tophash. The old behavior is unnecessary and probably undesirable. Change-Id: I7fb3222520cb61081a857adcddfbb9078ead7122 Reviewed-on: https://go-review.googlesource.com/56930 Run-TryBot: Josh Bleecher Snyder TryBot-Result: Gobot Gobot Reviewed-by: Keith Randall --- src/runtime/hashmap.go | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-) diff --git a/src/runtime/hashmap.go b/src/runtime/hashmap.go index f39fb7d3bf..cef41be484 100644 --- a/src/runtime/hashmap.go +++ b/src/runtime/hashmap.go @@ -1086,15 +1086,12 @@ func evacuate(t *maptype, h *hmap, oldbucket uintptr) { // 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 - } + useY = top & 1 top = tophash(hash) - } - if hash&newbit != 0 { - useY = 1 + } else { + if hash&newbit != 0 { + useY = 1 + } } }