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gen, bitset: use clz() to simplify

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Fixes #448.

* spot/gen/automata.cc (ulog2): Here.
* spot/misc/bitset.hh: And there.
This commit is contained in:
Alexandre Duret-Lutz 2021-01-17 16:09:14 +01:00
parent d1cc45f223
commit 8e8f77756d
2 changed files with 7 additions and 25 deletions
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17
spot/gen/automata.cc
View file

@ -1,6 +1,6 @@
// -*- coding: utf-8 -*-
// Copyright (C) 2017-2019 Laboratoire de Recherche et Developpement
// de l'EPITA (LRDE).
// Copyright (C) 2017-2019, 2021 Laboratoire de Recherche et
// Developpement de l'EPITA (LRDE).
//
// This file is part of Spot, a model checking library.
//
@ -21,6 +21,7 @@
#include <spot/twa/twagraph.hh>
#include <spot/gen/automata.hh>
#include <spot/tl/parse.hh>
#include <spot/misc/clz.hh>
namespace spot
{
@ -177,17 +178,7 @@ namespace spot
{
assert(n>0);
--n;
#ifdef __GNUC__
return 8*sizeof(unsigned) - __builtin_clz(n);
#else
unsigned res = 0;
while (n)
{
++res;
n >>= 1;
}
return res;
#endif
return CHAR_BIT*sizeof(unsigned) - clz(n);
}
static twa_graph_ptr

15
spot/misc/bitset.hh
View file

@ -1,5 +1,5 @@
// -*- coding: utf-8 -*-
// Copyright (C) 2018 Laboratoire de Recherche et Développement
// Copyright (C) 2018, 2021 Laboratoire de Recherche et Développement
// de l'Epita (LRDE).
//
// This file is part of Spot, a model checking library.
@ -359,19 +359,10 @@ namespace spot
auto v = data[i];
if (v == 0)
{
res -= 8*sizeof(word_t);
res -= CHAR_BIT*sizeof(word_t);
continue;
}
#ifdef __GNUC__
res += 8*sizeof(word_t) - clz(v);
#else
while (v)
{
++res;
v >>= 1;
}
#endif
return res-1;
return res + CHAR_BIT*sizeof(word_t) - clz(v) - 1;
}
return 0;
}