Commit f67ce1e35fe3ecf19b50f64b9fe2d85747f7934d | zig

gives a 1.18x speedup on gotta-go-fast hashmap bench

2 files changed, 14 insertions(+), 9 deletions(-)

lib/std/hash/auto_hash.zig+6-6

...	...	@@ -56,9 +56,6 @@ pub fn hashPointer(hasher: anytype, key: anytype, comptime strat: HashStrategy)
56	56	pub fn hashArray(hasher: anytype, key: anytype, comptime strat: HashStrategy) void {
57	57	switch (strat) {
58	58	.Shallow => {
59		// TODO detect via a trait when Key has no padding bits to
60		// hash it as an array of bytes.
61		// Otherwise, hash every element.
62	59	for (key) \|element\| {
63	60	hash(hasher, element, .Shallow);
64	61	}
...	...	@@ -75,6 +72,12 @@ pub fn hashArray(hasher: anytype, key: anytype, comptime strat: HashStrategy) vo
75	72	/// Strategy is provided to determine if pointers should be followed or not.
76	73	pub fn hash(hasher: anytype, key: anytype, comptime strat: HashStrategy) void {
77	74	const Key = @TypeOf(key);
	75
	76	if (strat == .Shallow and comptime meta.trait.hasUniqueRepresentation(Key)) {
	77	@call(.{ .modifier = .always_inline }, hasher.update, .{mem.asBytes(&key)});
	78	return;
	79	}
	80
78	81	switch (@typeInfo(Key)) {
79	82	.NoReturn,
80	83	.Opaque,
...	...	@@ -119,9 +122,6 @@ pub fn hash(hasher: anytype, key: anytype, comptime strat: HashStrategy) void {
119	122	},
120	123
121	124	.Struct => \|info\| {
122		// TODO detect via a trait when Key has no padding bits to
123		// hash it as an array of bytes.
124		// Otherwise, hash every field.
125	125	inline for (info.fields) \|field\| {
126	126	// We reuse the hash of the previous field as the seed for the
127	127	// next one so that they're dependant.

lib/std/hash_map.zig+8-3

...	...	@@ -5,6 +5,7 @@ const testing = std.testing;
5	5	const math = std.math;
6	6	const mem = std.mem;
7	7	const meta = std.meta;
	8	const trait = meta.trait;
8	9	const autoHash = std.hash.autoHash;
9	10	const Wyhash = std.hash.Wyhash;
10	11	const Allocator = mem.Allocator;
...	...	@@ -1023,9 +1024,13 @@ pub fn getTrivialEqlFn(comptime K: type) (fn (K, K) bool) {
1023	1024	pub fn getAutoHashFn(comptime K: type) (fn (K) u32) {
1024	1025	return struct {
1025	1026	fn hash(key: K) u32 {
1026		var hasher = Wyhash.init(0);
1027		autoHash(&hasher, key);
1028		return @truncate(u32, hasher.final());
	1027	if (comptime trait.hasUniqueRepresentation(K)) {
	1028	return @truncate(u32, Wyhash.hash(0, std.mem.asBytes(&key)));
	1029	} else {
	1030	var hasher = Wyhash.init(0);
	1031	autoHash(&hasher, key);
	1032	return @truncate(u32, hasher.final());
	1033	}
1029	1034	}
1030	1035	}.hash;
1031	1036	}