From 81f44d352f803358e939182b19b02a2df583857f Mon Sep 17 00:00:00 2001
From: Andrew Noyes <andrew@weaselab.dev>
Date: Sat, 29 Jun 2024 15:01:18 -0700
Subject: [PATCH] SIMD scan16 for x86 + 32-bit versions

---
 ConflictSet.cpp | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/ConflictSet.cpp b/ConflictSet.cpp
index f0aa31f..3a75b45 100644
--- a/ConflictSet.cpp
+++ b/ConflictSet.cpp
@@ -1823,9 +1823,21 @@ bool scan16(const InternalVersionT *vs, const uint8_t *is, int begin, int end,
       indices, _mm_max_epu8(indices, _mm_set1_epi8(end - begin))));
 
   uint32_t compared = 0;
+#if INTERNAL_VERSION_32_BIT
+  __m128i w4[4];
+  memcpy(w4, vs, sizeof(w4));
+  uint32_t rv;
+  memcpy(&rv, &readVersion, sizeof(rv));
+  const auto rvVec = _mm_set1_epi32(rv);
+  const auto zero = _mm_setzero_si128();
+  for (int i = 0; i < 4; ++i) {
+    compared |= _mm_movemask_ps(_mm_cmpgt_epi32(_mm_sub_epi32(w4[i], rvVec), zero)) << (i * 4);
+  }
+#else
   for (int i = 0; i < 16; ++i) {
     compared |= (vs[i] > readVersion) << i;
   }
+#endif
   return !(compared & mask);
 
 #else