diff --git a/ConflictSet.cpp b/ConflictSet.cpp
index 3997c61..f0e4ccf 100644
--- a/ConflictSet.cpp
+++ b/ConflictSet.cpp
@@ -2925,11 +2925,18 @@ horizontalMaxUpTo16(InternalVersionT *vs, InternalVersionT z, int len) {
   uint32_t zero;
   memcpy(&zero, &z, sizeof(zero));
   auto zeroVec = _mm512_set1_epi32(zero);
-  return InternalVersionT(
+  auto actual = InternalVersionT(
       zero +
-      _mm512_reduce_max_epu32(_mm512_sub_epi32(
+      _mm512_reduce_max_epi32(_mm512_sub_epi32(
           _mm512_mask_loadu_epi32(zeroVec, _mm512_int2mask((1 << len) - 1), vs),
           zeroVec)));
+  // Hope it gets vectorized
+  InternalVersionT max = vs[0];
+  for (int i = 1; i < len; ++i) {
+    max = std::max(vs[i], max);
+  }
+  assert(actual == max);
+  return max;
 #endif
 }
 __attribute__((target("default")))
@@ -2959,7 +2966,7 @@ horizontalMax16(InternalVersionT *vs, InternalVersionT z) {
   uint32_t zero;
   memcpy(&zero, &z, sizeof(zero));
   auto zeroVec = _mm512_set1_epi32(zero);
-  return InternalVersionT(zero + _mm512_reduce_max_epu32(_mm512_sub_epi32(
+  return InternalVersionT(zero + _mm512_reduce_max_epi32(_mm512_sub_epi32(
                                      _mm512_loadu_epi32(vs), zeroVec)));
 #endif
 }