From 1059f2a237ba8f587bb0745f3fdbe24179f0f862 Mon Sep 17 00:00:00 2001
From: Andrew Noyes <andrew@weaselab.dev>
Date: Mon, 12 Feb 2024 17:32:05 -0800
Subject: [PATCH] Use std::countr_zero

---
 ConflictSet.cpp | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/ConflictSet.cpp b/ConflictSet.cpp
index c0707b9..51b24a1 100644
--- a/ConflictSet.cpp
+++ b/ConflictSet.cpp
@@ -791,7 +791,7 @@ int firstNeqStride(const uint8_t *ap, const uint8_t *bp) {
     const auto compared = _mm_cmpeq_epi8(a, b);
     c[i / 16] = _mm_movemask_epi8(compared) & 0xffff;
   }
-  return __builtin_ctzll(~(c[0] | c[1] << 16 | c[2] << 32 | c[3] << 48));
+  return std::countr_zero(~(c[0] | c[1] << 16 | c[2] << 32 | c[3] << 48));
 #elif defined(HAS_ARM_NEON)
   static_assert(kStride == 64);
   for (int i = 0; i < kStride; i += 16) {
@@ -802,7 +802,7 @@ int firstNeqStride(const uint8_t *ap, const uint8_t *bp) {
     uint64_t bitfield =
         ~vget_lane_u64(vreinterpret_u64_u8(vshrn_n_u16(results, 4)), 0);
     if (bitfield) {
-      return i + (__builtin_ctzll(bitfield) >> 2);
+      return i + (std::countr_zero(bitfield) >> 2);
     }
   }
   __builtin_unreachable();
@@ -833,7 +833,7 @@ int longestCommonPrefix(const uint8_t *ap, const uint8_t *bp, int cl) {
     memcpy(&b, bp, 8);
     const auto mismatched = a ^ b;
     if (mismatched) {
-      return __builtin_ctzll(mismatched) / 8;
+      return std::countr_zero(mismatched) / 8;
     }
   }
 
@@ -870,7 +870,7 @@ int longestCommonPrefix(const uint8_t *ap, const uint8_t *bp, int cl) {
     memcpy(&b, bp, 8);
     const auto mismatched = a ^ b;
     if (mismatched) {
-      return i + __builtin_ctzll(mismatched) / 8;
+      return i + std::countr_zero(mismatched) / 8;
     }
     i += 8;
     ap += 8;