Fix bitarray unittest on Win32

Author: MoonlightSentinel

src/dmd/root/bitarray.d

@@ -50,7 +50,7 @@ nothrow:
         if (!len)
             length(b.len);
         assert(len == b.len);
-        memcpy(ptr, b.ptr, (len + BitsPerChunk - 1) / 8);
+        memcpy(ptr, b.ptr, bytes(len));
     }
 
     bool opIndex(size_t idx) const pure nothrow @nogc
@@ -74,12 +74,12 @@ nothrow:
 
     bool opEquals(const ref BitArray b) const
     {
-        return len == b.len && memcmp(ptr, b.ptr, (len + BitsPerChunk - 1) / 8) == 0;
+        return len == b.len && memcmp(ptr, b.ptr, bytes(len)) == 0;
     }
 
     void zero()
     {
-        memset(ptr, 0, (len + BitsPerChunk - 1) / 8);
+        memset(ptr, 0, bytes(len));
     }
 
     /******
@@ -142,6 +142,16 @@ nothrow:
 private:
     size_t len;         // length in bits
     size_t *ptr;
+
+    static size_t chunks(const size_t len) @nogc nothrow pure @safe
+    {
+        return (len + BitsPerChunk - 1) / BitsPerChunk;
+    }
+
+    static size_t bytes(const size_t len) @nogc nothrow pure @safe
+    {
+        return chunks(len) * ChunkSize;
+    }
 }
 
 unittest