From c6c085ab2264e99ea0f6ff93669223e21b7033cc Mon Sep 17 00:00:00 2001
From: Maximilien Colange <colange@lrde.epita.fr>
Date: Tue, 22 May 2018 16:07:30 +0200
Subject: [PATCH] various fixes to bitset

* spot/misc/bitset.hh: here
* tests/core/acc.cc: test it
---
 spot/misc/bitset.hh | 20 +++++++++++++++-----
 tests/core/acc.cc   |  3 +++
 2 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/spot/misc/bitset.hh b/spot/misc/bitset.hh
index 320e2d067..d824e00d3 100644
--- a/spot/misc/bitset.hh
+++ b/spot/misc/bitset.hh
@@ -115,7 +115,7 @@ namespace spot
 
     bool operator>=(const bitset& other) const
     {
-      return other.operator>(*this);
+      return other.operator<=(*this);
     }
 
     bitset operator<<(unsigned s) const
@@ -295,19 +295,25 @@ namespace spot
 
     unsigned highest() const
     {
-      unsigned res = 0;
-      for (auto v: data)
+      unsigned res = (N-1)*8*sizeof(word_t);
+      unsigned i = N;
+      while (i--)
         {
+          auto v = data[i];
           if (v == 0)
             {
-              res += 8*sizeof(v);
+              res -= 8*sizeof(word_t);
               continue;
             }
+#ifdef __GNUC__
+          res += 8*sizeof(word_t) - __builtin_clz(v);
+#else
           while (v)
             {
               ++res;
               v >>= 1;
             }
+#endif
           return res-1;
         }
       return 0;
@@ -315,7 +321,7 @@ namespace spot
 
     unsigned lowest() const
     {
-      unsigned res = 0;
+      unsigned res = 0U;
       for (auto v: data)
         {
           if (v == 0)
@@ -323,11 +329,15 @@ namespace spot
               res += 8*sizeof(v);
               continue;
             }
+#ifdef __GNUC__
+          res += __builtin_ctz(v);
+#else
           while ((v & 1) == 0)
             {
               ++res;
               v >>= 1;
             }
+#endif
           return res;
         }
       return 0;
diff --git a/tests/core/acc.cc b/tests/core/acc.cc
index 069e0745b..7ac6e5aeb 100644
--- a/tests/core/acc.cc
+++ b/tests/core/acc.cc
@@ -64,6 +64,9 @@ int main()
   auto m1 = spot::acc_cond::mark_t({0, 2});
   auto m2 = spot::acc_cond::mark_t({0, 3});
   auto m3 = spot::acc_cond::mark_t({2, 1});
+  auto m4 = spot::acc_cond::mark_t({0, SPOT_NB_ACC-2});
+  if (!(m4.min_set() == 1 && m4.max_set() == SPOT_NB_ACC-1))
+    return 1;
 
   spot::acc_cond::mark_t m0 = {};
   std::cout << m0.max_set() << ' ' << m0.min_set() << '\n';