diff --git a/include/simdjson/stage1_find_marks_flatten_haswell.h b/include/simdjson/stage1_find_marks_flatten_haswell.h
index 4d1a9c36e..a54eb712a 100644
--- a/include/simdjson/stage1_find_marks_flatten_haswell.h
+++ b/include/simdjson/stage1_find_marks_flatten_haswell.h
@@ -24,46 +24,46 @@ really_inline void flatten_bits(uint32_t *base_ptr, uint32_t &base,
   // Unfortunately, in other cases,
   // it helps tremendously.
   if(bits == 0) return; 
-  uint32_t cnt = _popcnt64(bits);
+  uint32_t cnt = _mm_popcnt_u64(bits);
   uint32_t next_base = base + cnt;
   idx -= 64;
   base_ptr += base;
   { 
-    base_ptr[0] = idx + __tzcnt_u64(bits);
+    base_ptr[0] = idx + _tzcnt_u64(bits);
     bits = _blsr_u64(bits);
-    base_ptr[1] = idx + __tzcnt_u64(bits);
+    base_ptr[1] = idx + _tzcnt_u64(bits);
     bits = _blsr_u64(bits);
-    base_ptr[2] = idx + __tzcnt_u64(bits);
+    base_ptr[2] = idx + _tzcnt_u64(bits);
     bits = _blsr_u64(bits);
-    base_ptr[3] = idx + __tzcnt_u64(bits);
+    base_ptr[3] = idx + _tzcnt_u64(bits);
     bits = _blsr_u64(bits);
-    base_ptr[4] = idx + __tzcnt_u64(bits);
+    base_ptr[4] = idx + _tzcnt_u64(bits);
     bits = _blsr_u64(bits);
-    base_ptr[5] = idx + __tzcnt_u64(bits);
+    base_ptr[5] = idx + _tzcnt_u64(bits);
     bits = _blsr_u64(bits);
-    base_ptr[6] = idx + __tzcnt_u64(bits);
+    base_ptr[6] = idx + _tzcnt_u64(bits);
     bits = _blsr_u64(bits);
-    base_ptr[7] = idx + __tzcnt_u64(bits);
+    base_ptr[7] = idx + _tzcnt_u64(bits);
     bits = _blsr_u64(bits);
     base_ptr += 8;
   }
   // We hope that the next branch is easily predicted.
   if (cnt > 8) {
-    base_ptr[0] = idx + __tzcnt_u64(bits);
+    base_ptr[0] = idx + _tzcnt_u64(bits);
     bits = _blsr_u64(bits);
-    base_ptr[1] = idx + __tzcnt_u64(bits);
+    base_ptr[1] = idx + _tzcnt_u64(bits);
     bits = _blsr_u64(bits);
-    base_ptr[2] = idx + __tzcnt_u64(bits);
+    base_ptr[2] = idx + _tzcnt_u64(bits);
     bits = _blsr_u64(bits);
-    base_ptr[3] = idx + __tzcnt_u64(bits);
+    base_ptr[3] = idx + _tzcnt_u64(bits);
     bits = _blsr_u64(bits);
-    base_ptr[4] = idx + __tzcnt_u64(bits);
+    base_ptr[4] = idx + _tzcnt_u64(bits);
     bits = _blsr_u64(bits);
-    base_ptr[5] = idx + __tzcnt_u64(bits);
+    base_ptr[5] = idx + _tzcnt_u64(bits);
     bits = _blsr_u64(bits);
-    base_ptr[6] = idx + __tzcnt_u64(bits);
+    base_ptr[6] = idx + _tzcnt_u64(bits);
     bits = _blsr_u64(bits);
-    base_ptr[7] = idx + __tzcnt_u64(bits);
+    base_ptr[7] = idx + _tzcnt_u64(bits);
     bits = _blsr_u64(bits);
     base_ptr += 8;
   }
@@ -71,7 +71,7 @@ really_inline void flatten_bits(uint32_t *base_ptr, uint32_t &base,
     // since it means having one structural or pseudo-structral element 
     // every 4 characters (possible with inputs like "","","",...).
     do {
-      base_ptr[0] = idx + __tzcnt_u64(bits);
+      base_ptr[0] = idx + _tzcnt_u64(bits);
       bits = _blsr_u64(bits);
       base_ptr++;
     } while(bits != 0);
diff --git a/include/simdjson/stage1_find_marks_haswell.h b/include/simdjson/stage1_find_marks_haswell.h
index a2e707614..6cb979160 100644
--- a/include/simdjson/stage1_find_marks_haswell.h
+++ b/include/simdjson/stage1_find_marks_haswell.h
@@ -3,7 +3,7 @@
 
 #include "simdjson/stage1_find_marks.h"
 #include "simdjson/stage1_find_marks_macros.h"
-#include "simdjson/stage1_find_marks_flatten.h"
+#include "simdjson/stage1_find_marks_flatten_haswell.h"
 #include "simdjson/simdutf8check_haswell.h"
 
 #ifdef IS_X86_64
diff --git a/src/stage1_find_marks.cpp b/src/stage1_find_marks.cpp
index 38a500063..605dbc976 100644
--- a/src/stage1_find_marks.cpp
+++ b/src/stage1_find_marks.cpp
@@ -9,7 +9,7 @@ TARGET_HASWELL
 namespace simdjson {
 template<>
 int find_structural_bits<architecture::haswell>(const uint8_t *buf, size_t len, ParsedJson &pj) {
-  FIND_STRUCTURAL_BITS(architecture::haswell, buf, len, pj, simdjson::flatten_bits);
+  FIND_STRUCTURAL_BITS(architecture::haswell, buf, len, pj, simdjson::haswell::flatten_bits);
 }
 } // simdjson
 UNTARGET_REGION