In new code, I'm making intensive use of the functions ffs and ffsll, for
searching in a bitset. So, these functions should better be well optimized,
even for MSVC.
And while at it, also the integer_length* functions.
2020-08-03 Bruno Haible <br...@clisp.org>
integer_length_ll: Optimize for MSVC in 64-bit mode.
* lib/integer_length_l.c (MSVC_BUILTIN): Define for MSVC in 64-bit mode.
(FUNC): On MSVC, use MSVC_BUILTIN if defined.
2020-08-03 Bruno Haible <br...@clisp.org>
integer_length_ll: Optimize for MSVC in 32-bit mode.
* lib/integer_length_l.c: Include <intrin.h>.
(integer_length): Define as inline function, like in
lib/integer_length.c.
2020-08-03 Bruno Haible <br...@clisp.org>
integer_length: Optimize for MSVC.
* lib/integer_length.c: Include <intrin.h>.
(integer_length): With MSVC, use the _BitScanReverse built-in.
2020-08-03 Bruno Haible <br...@clisp.org>
ffsll: Optimize for MSVC in 64-bit mode.
* lib/ffsl.h (FUNC): On MSVC, use MSVC_BUILTIN if defined.
* lib/ffsll.c (MSVC_BUILTIN): Define for MSVC in 64-bit mode.
* lib/ffsl.c (MSVC_BUILTIN): Define for MSVC.
2020-08-03 Bruno Haible <br...@clisp.org>
ffsll: Optimize for MSVC in 32-bit mode.
* lib/ffsl.h: Include <intrin.h>.
(ffs): Define as inline function, like in lib/ffs.c.
2020-08-03 Bruno Haible <br...@clisp.org>
ffs: Optimize for MSVC.
* lib/ffs.c: Include <intrin.h>.
(ffs): With MSVC, use the _BitScanForward built-in.
>From 353cc7c6906f650fa228d295dad270637f9441c7 Mon Sep 17 00:00:00 2001
From: Bruno Haible <br...@clisp.org>
Date: Tue, 4 Aug 2020 00:05:05 +0200
Subject: [PATCH 1/6] ffs: Optimize for MSVC.
* lib/ffs.c: Include <intrin.h>.
(ffs): With MSVC, use the _BitScanForward built-in.
---
ChangeLog | 6 ++++++
lib/ffs.c | 12 ++++++++++++
2 files changed, 18 insertions(+)
diff --git a/ChangeLog b/ChangeLog
index 526747e..773a9f5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
2020-08-03 Bruno Haible <br...@clisp.org>
+ ffs: Optimize for MSVC.
+ * lib/ffs.c: Include <intrin.h>.
+ (ffs): With MSVC, use the _BitScanForward built-in.
+
+2020-08-03 Bruno Haible <br...@clisp.org>
+
sigprocmask: Try to avoid breakage for people who use an Autoconf cache.
* m4/signalblocking.m4 (gl_SIGNALBLOCKING): Change the name of the cache
variable.
diff --git a/lib/ffs.c b/lib/ffs.c
index ba4915e..d8a65ca 100644
--- a/lib/ffs.c
+++ b/lib/ffs.c
@@ -23,11 +23,23 @@
#include <limits.h>
+#if defined _MSC_VER
+# include <intrin.h>
+#endif
+
int
ffs (int i)
{
#if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4)
return __builtin_ffs (i);
+#elif defined _MSC_VER
+ /* _BitScanForward
+ <https://docs.microsoft.com/en-us/cpp/intrinsics/bitscanforward-bitscanforward64> */
+ unsigned long bit;
+ if (_BitScanForward (&bit, i))
+ return bit + 1;
+ else
+ return 0;
#else
/* <https://github.com/gibsjose/BitHacks>
gives this deBruijn constant for a branch-less computation, although
--
2.7.4
>From c728189201864850c562862fa7fc54d925c472e0 Mon Sep 17 00:00:00 2001
From: Bruno Haible <br...@clisp.org>
Date: Tue, 4 Aug 2020 00:11:02 +0200
Subject: [PATCH 2/6] ffsll: Optimize for MSVC in 32-bit mode.
* lib/ffsl.h: Include <intrin.h>.
(ffs): Define as inline function, like in lib/ffs.c.
---
ChangeLog | 6 ++++++
lib/ffsl.h | 16 ++++++++++++++++
2 files changed, 22 insertions(+)
diff --git a/ChangeLog b/ChangeLog
index 773a9f5..0a336bf 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
2020-08-03 Bruno Haible <br...@clisp.org>
+ ffsll: Optimize for MSVC in 32-bit mode.
+ * lib/ffsl.h: Include <intrin.h>.
+ (ffs): Define as inline function, like in lib/ffs.c.
+
+2020-08-03 Bruno Haible <br...@clisp.org>
+
ffs: Optimize for MSVC.
* lib/ffs.c: Include <intrin.h>.
(ffs): With MSVC, use the _BitScanForward built-in.
diff --git a/lib/ffsl.h b/lib/ffsl.h
index cea4386..d5c5a97 100644
--- a/lib/ffsl.h
+++ b/lib/ffsl.h
@@ -27,6 +27,22 @@
#include <limits.h>
#include <strings.h>
+#if defined _MSC_VER
+# include <intrin.h>
+/* Copied from ffs.c. */
+static inline int
+ffs (int i)
+{
+ /* _BitScanForward
+ <https://docs.microsoft.com/en-us/cpp/intrinsics/bitscanforward-bitscanforward64> */
+ unsigned long bit;
+ if (_BitScanForward (&bit, i))
+ return bit + 1;
+ else
+ return 0;
+}
+#endif
+
#if !defined FUNC || !defined TYPE
# error
#endif
--
2.7.4
>From 1552de7c513ffbedf675de10b77a6d5c264ee3b2 Mon Sep 17 00:00:00 2001
From: Bruno Haible <br...@clisp.org>
Date: Tue, 4 Aug 2020 00:13:46 +0200
Subject: [PATCH 3/6] ffsll: Optimize for MSVC in 64-bit mode.
* lib/ffsl.h (FUNC): On MSVC, use MSVC_BUILTIN if defined.
* lib/ffsll.c (MSVC_BUILTIN): Define for MSVC in 64-bit mode.
* lib/ffsl.c (MSVC_BUILTIN): Define for MSVC.
---
ChangeLog | 7 +++++++
lib/ffsl.c | 1 +
lib/ffsl.h | 8 ++++++++
lib/ffsll.c | 3 +++
4 files changed, 19 insertions(+)
diff --git a/ChangeLog b/ChangeLog
index 0a336bf..51b2be7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,12 @@
2020-08-03 Bruno Haible <br...@clisp.org>
+ ffsll: Optimize for MSVC in 64-bit mode.
+ * lib/ffsl.h (FUNC): On MSVC, use MSVC_BUILTIN if defined.
+ * lib/ffsll.c (MSVC_BUILTIN): Define for MSVC in 64-bit mode.
+ * lib/ffsl.c (MSVC_BUILTIN): Define for MSVC.
+
+2020-08-03 Bruno Haible <br...@clisp.org>
+
ffsll: Optimize for MSVC in 32-bit mode.
* lib/ffsl.h: Include <intrin.h>.
(ffs): Define as inline function, like in lib/ffs.c.
diff --git a/lib/ffsl.c b/lib/ffsl.c
index ee99ba7..198cacb 100644
--- a/lib/ffsl.c
+++ b/lib/ffsl.c
@@ -1,4 +1,5 @@
#define FUNC ffsl
#define TYPE long int
#define GCC_BUILTIN __builtin_ffsl
+#define MSVC_BUILTIN _BitScanForward
#include "ffsl.h"
diff --git a/lib/ffsl.h b/lib/ffsl.h
index d5c5a97..fa5c093 100644
--- a/lib/ffsl.h
+++ b/lib/ffsl.h
@@ -52,6 +52,14 @@ FUNC (TYPE i)
{
#if (__GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4)) && defined GCC_BUILTIN
return GCC_BUILTIN (i);
+#elif defined _MSC_VER && defined MSVC_BUILTIN
+ /* _BitScanForward, _BitScanForward64
+ <https://docs.microsoft.com/en-us/cpp/intrinsics/bitscanforward-bitscanforward64> */
+ unsigned long bit;
+ if (MSVC_BUILTIN (&bit, i))
+ return bit + 1;
+ else
+ return 0;
#else
unsigned TYPE j = i;
/* Split j into chunks, and look at one chunk after the other. */
diff --git a/lib/ffsll.c b/lib/ffsll.c
index f0e9425..80a273c 100644
--- a/lib/ffsll.c
+++ b/lib/ffsll.c
@@ -1,4 +1,7 @@
#define FUNC ffsll
#define TYPE long long int
#define GCC_BUILTIN __builtin_ffsll
+#ifdef _WIN64
+# define MSVC_BUILTIN _BitScanForward64
+#endif
#include "ffsl.h"
--
2.7.4
>From 8c7b90680b73580b5c257baa3c9c22239ab0c3d1 Mon Sep 17 00:00:00 2001
From: Bruno Haible <br...@clisp.org>
Date: Tue, 4 Aug 2020 00:40:24 +0200
Subject: [PATCH 4/6] integer_length: Optimize for MSVC.
* lib/integer_length.c: Include <intrin.h>.
(integer_length): With MSVC, use the _BitScanReverse built-in.
---
ChangeLog | 6 ++++++
lib/integer_length.c | 14 ++++++++++----
2 files changed, 16 insertions(+), 4 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 51b2be7..b2169e3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
2020-08-03 Bruno Haible <br...@clisp.org>
+ integer_length: Optimize for MSVC.
+ * lib/integer_length.c: Include <intrin.h>.
+ (integer_length): With MSVC, use the _BitScanReverse built-in.
+
+2020-08-03 Bruno Haible <br...@clisp.org>
+
ffsll: Optimize for MSVC in 64-bit mode.
* lib/ffsl.h (FUNC): On MSVC, use MSVC_BUILTIN if defined.
* lib/ffsll.c (MSVC_BUILTIN): Define for MSVC in 64-bit mode.
diff --git a/lib/integer_length.c b/lib/integer_length.c
index edad54b..43d8f49 100644
--- a/lib/integer_length.c
+++ b/lib/integer_length.c
@@ -25,10 +25,8 @@
#include "float+.h"
-/* MSVC with option -fp:strict refuses to compile constant initializers that
- contain floating-point operations. Pacify this compiler. */
-#ifdef _MSC_VER
-# pragma fenv_access (off)
+#if defined _MSC_VER
+# include <intrin.h>
#endif
#define NBITS (sizeof (unsigned int) * CHAR_BIT)
@@ -41,6 +39,14 @@ integer_length (unsigned int x)
return 0;
else
return NBITS - __builtin_clz (x);
+#elif defined _MSC_VER
+ /* _BitScanReverse
+ <https://docs.microsoft.com/en-us/cpp/intrinsics/bitscanreverse-bitscanreverse64> */
+ unsigned long bit;
+ if (_BitScanReverse (&bit, x))
+ return bit + 1;
+ else
+ return 0;
#else
# if defined DBL_EXPBIT0_WORD && defined DBL_EXPBIT0_BIT
if (NBITS <= DBL_MANT_BIT)
--
2.7.4
>From dc87bda7182bf9ad9034ca739f46b3dbb9dc4632 Mon Sep 17 00:00:00 2001
From: Bruno Haible <br...@clisp.org>
Date: Tue, 4 Aug 2020 01:10:23 +0200
Subject: [PATCH 5/6] integer_length_ll: Optimize for MSVC in 32-bit mode.
* lib/integer_length_l.c: Include <intrin.h>.
(integer_length): Define as inline function, like in
lib/integer_length.c.
---
ChangeLog | 7 +++++++
lib/integer_length_l.c | 16 ++++++++++++++++
2 files changed, 23 insertions(+)
diff --git a/ChangeLog b/ChangeLog
index b2169e3..bfd2ade 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,12 @@
2020-08-03 Bruno Haible <br...@clisp.org>
+ integer_length_ll: Optimize for MSVC in 32-bit mode.
+ * lib/integer_length_l.c: Include <intrin.h>.
+ (integer_length): Define as inline function, like in
+ lib/integer_length.c.
+
+2020-08-03 Bruno Haible <br...@clisp.org>
+
integer_length: Optimize for MSVC.
* lib/integer_length.c: Include <intrin.h>.
(integer_length): With MSVC, use the _BitScanReverse built-in.
diff --git a/lib/integer_length_l.c b/lib/integer_length_l.c
index 7a60357..ea52ac3 100644
--- a/lib/integer_length_l.c
+++ b/lib/integer_length_l.c
@@ -37,6 +37,22 @@
# define GCC_BUILTIN __builtin_clzl
#endif
+#if defined _MSC_VER
+# include <intrin.h>
+/* Copied from integer_length.c. */
+static inline int
+integer_length (unsigned int x)
+{
+ /* _BitScanReverse
+ <https://docs.microsoft.com/en-us/cpp/intrinsics/bitscanreverse-bitscanreverse64> */
+ unsigned long bit;
+ if (_BitScanReverse (&bit, x))
+ return bit + 1;
+ else
+ return 0;
+}
+#endif
+
#define NBITS (sizeof (TYPE) * CHAR_BIT)
/* Modify shift count to be in bounds, even in dead code, otherwise GCC
--
2.7.4
>From eb7f785f5ad4fd6a9d9e8e74e42838a27d1dff86 Mon Sep 17 00:00:00 2001
From: Bruno Haible <br...@clisp.org>
Date: Tue, 4 Aug 2020 01:17:36 +0200
Subject: [PATCH 6/6] integer_length_ll: Optimize for MSVC in 64-bit mode.
* lib/integer_length_l.c (MSVC_BUILTIN): Define for MSVC in 64-bit mode.
(FUNC): On MSVC, use MSVC_BUILTIN if defined.
---
ChangeLog | 6 ++++++
lib/integer_length_l.c | 12 ++++++++++++
2 files changed, 18 insertions(+)
diff --git a/ChangeLog b/ChangeLog
index bfd2ade..9919a40 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
2020-08-03 Bruno Haible <br...@clisp.org>
+ integer_length_ll: Optimize for MSVC in 64-bit mode.
+ * lib/integer_length_l.c (MSVC_BUILTIN): Define for MSVC in 64-bit mode.
+ (FUNC): On MSVC, use MSVC_BUILTIN if defined.
+
+2020-08-03 Bruno Haible <br...@clisp.org>
+
integer_length_ll: Optimize for MSVC in 32-bit mode.
* lib/integer_length_l.c: Include <intrin.h>.
(integer_length): Define as inline function, like in
diff --git a/lib/integer_length_l.c b/lib/integer_length_l.c
index ea52ac3..161f1af 100644
--- a/lib/integer_length_l.c
+++ b/lib/integer_length_l.c
@@ -31,10 +31,14 @@
# define FUNC integer_length_ll
# define TYPE unsigned long long
# define GCC_BUILTIN __builtin_clzll
+# ifdef _WIN64
+# define MSVC_BUILTIN _BitScanReverse64
+# endif
#else
# define FUNC integer_length_l
# define TYPE unsigned long
# define GCC_BUILTIN __builtin_clzl
+# define MSVC_BUILTIN _BitScanReverse
#endif
#if defined _MSC_VER
@@ -67,6 +71,14 @@ FUNC (TYPE x)
return 0;
else
return NBITS - GCC_BUILTIN (x);
+#elif defined _MSC_VER && defined MSVC_BUILTIN
+ /* _BitScanReverse, _BitScanReverse64
+ <https://docs.microsoft.com/en-us/cpp/intrinsics/bitscanreverse-bitscanreverse64> */
+ unsigned long bit;
+ if (MSVC_BUILTIN (&bit, x))
+ return bit + 1;
+ else
+ return 0;
#else
/* Split x into chunks, and look at one chunk after the other. */
if (sizeof (TYPE) > 2 * sizeof (unsigned int))
--
2.7.4
