diff --git a/src/common/bit_util.h b/src/common/bit_util.h
index ed66811e..28430063 100644
--- a/src/common/bit_util.h
+++ b/src/common/bit_util.h
@@ -72,11 +72,11 @@ inline T SignExtend(const T value) {
 }
 
 inline size_t BitCount(u32 value) {
-#ifdef _MSC_VER
-    return __popcnt(value);
-#else
-    return __builtin_popcount(value);
-#endif
+    // Portable SWAR algorithm for population count
+    value = value - ((value >> 1) & 0x55555555);                // Two-bit count
+    value = (value & 0x33333333) + ((value >> 2) & 0x33333333); // Nybble count
+    value = (value + (value >> 4)) & 0x0F0F0F0F;                // Byte count
+    return ((value * 0x01010101) >> 24) & 0xFF;                 // Summate the byte counts
 }
 
 } // namespace Common