Commit 54255ee32e

Sahnvour <sahnvour@pm.me>
2019-07-16 22:32:10
autohash: force inlining of integer hashing so that the optimizer can see the fast path based on key's size which is known at comptime
otherwise it will always outline the call to hasher.update, resulting in much worse performance
master
1 parent 3faf5d3
Changed files (1)
std
hash
auto_hash.zig
std/hash/auto_hash.zig
@@ -21,7 +21,9 @@ pub fn autoHash(hasher: var, key: var) void {
         builtin.TypeId.EnumLiteral,
         => @compileError("cannot hash this type"),
 
-        builtin.TypeId.Int => hasher.update(std.mem.asBytes(&key)),
+        // Help the optimizer see that hashing an int is easy by inlining!
+        // TODO Check if the situation is better after #561 is resolved.
+        builtin.TypeId.Int => @inlineCall(hasher.update, std.mem.asBytes(&key)),
 
         builtin.TypeId.Float => |info| autoHash(hasher, @bitCast(@IntType(false, info.bits), key)),