zig

commit eb26aeb1e527b5f43f7f789d3a995dca8c73e2e9 (tree)
parent cd2f65ff6ace9f1e426d5e8a4721666d347b289d
Author: Andrew Kelley <superjoe30@gmail.com>
Date:   Sat, 19 Aug 2017 02:29:18 -0400

std: better int log2 implementation for number literals

Diffstat:
M
std/math/log2.zig
 | 
7
+++++--

1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/std/math/log2.zig b/std/math/log2.zig
@@ -26,8 +26,11 @@ fn log2_workaround(x: var) -> @typeOf(x) {
                 else => @compileError("log2 not implemented for " ++ @typeName(T)),
             };
         },
-        TypeId.IntLiteral => {
-            return @typeOf(1)(log2_int(u128, x))
+        TypeId.IntLiteral => comptime {
+            var result = 0;
+            var x_shifted = x;
+            while ({x_shifted >>= 1; x_shifted != 0}) : (result += 1) {}
+            return result;
         },
         TypeId.Int => {
             return log2_int(T, x);