Merge branch 'master' of https://github.com/p32929/go_easy

Author: Fayaz

src/internal/runtime/maps/map.go

@@ -439,15 +439,10 @@ func (m *Map) getWithKeySmall(typ *abi.SwissMapType, hash uintptr, key unsafe.Po
 		data: m.dirPtr,
 	}
 
-	h2 := uint8(h2(hash))
-	ctrls := *g.ctrls()
+	match := g.ctrls().matchH2(h2(hash))
 
-	for i := uintptr(0); i < abi.SwissMapGroupSlots; i++ {
-		c := uint8(ctrls)
-		ctrls >>= 8
-		if c != h2 {
-			continue
-		}
+	for match != 0 {
+		i := match.first()
 
 		slotKey := g.key(typ, i)
 		if typ.IndirectKey() {
@@ -461,8 +456,12 @@ func (m *Map) getWithKeySmall(typ *abi.SwissMapType, hash uintptr, key unsafe.Po
 			}
 			return slotKey, slotElem, true
 		}
+
+		match = match.removeFirst()
 	}
 
+	// No match here means key is not in the map.
+	// (A single group means no need to probe or check for empty).
 	return nil, nil, false
 }
 

src/runtime/map_benchmark_test.go

@@ -1182,9 +1182,12 @@ func BenchmarkMapSmallAccessHit(b *testing.B) {
 	b.Run("Key=int32/Elem=int32", smallBenchSizes(benchmarkMapAccessHit[int32, int32]))
 	b.Run("Key=int64/Elem=int64", smallBenchSizes(benchmarkMapAccessHit[int64, int64]))
 	b.Run("Key=string/Elem=string", smallBenchSizes(benchmarkMapAccessHit[string, string]))
+	b.Run("Key=smallType/Elem=int32", smallBenchSizes(benchmarkMapAccessHit[smallType, int32]))
 }
+
 func BenchmarkMapSmallAccessMiss(b *testing.B) {
 	b.Run("Key=int32/Elem=int32", smallBenchSizes(benchmarkMapAccessMiss[int32, int32]))
 	b.Run("Key=int64/Elem=int64", smallBenchSizes(benchmarkMapAccessMiss[int64, int64]))
 	b.Run("Key=string/Elem=string", smallBenchSizes(benchmarkMapAccessMiss[string, string]))
+	b.Run("Key=smallType/Elem=int32", smallBenchSizes(benchmarkMapAccessMiss[smallType, int32]))
 }