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[PATCH 1/3] count-one-bits: port to MSC; support types wider than 64 bit
From: |
Paul Eggert |
Subject: |
[PATCH 1/3] count-one-bits: port to MSC; support types wider than 64 bits |
Date: |
Sun, 06 Oct 2013 23:59:24 -0700 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.0 |
The ideas behind the MSC port are stolen from Emacs.
* lib/count-one-bits.c (popcount_support) [_MSC_VER]: New variable.
* lib/count-one-bits.h: Include limits.h, for CHAR_BIT.
Don't include verify.h: it's no longer needed, as types wider than
64 bits are now supported.
(COUNT_ONE_BITS_GENERIC): New macro.
(popcount_supported) [_MSC_VER]: New inline function.
(COUNT_ONE_BITS): Use it. New arg MSC_BUILTIN, for better
performance with MSC. All uses changed. Do not assume that TYPE
has at most 64 bits.
* modules/count-one-bits (Depends-on): Do not depend on 'verify'.
---
ChangeLog | 15 +++++++++
lib/count-one-bits.c | 4 +++
lib/count-one-bits.h | 83 +++++++++++++++++++++++++++++++++++++++-----------
modules/count-one-bits | 1 -
4 files changed, 85 insertions(+), 18 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 582d6e0..3d4f38d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,18 @@
+2013-10-06 Paul Eggert <address@hidden>
+
+ count-one-bits: port to MSC; support types wider than 64 bits
+ The ideas behind the MSC port are stolen from Emacs.
+ * lib/count-one-bits.c (popcount_support) [_MSC_VER]: New variable.
+ * lib/count-one-bits.h: Include limits.h, for CHAR_BIT.
+ Don't include verify.h: it's no longer needed, as types wider than
+ 64 bits are now supported.
+ (COUNT_ONE_BITS_GENERIC): New macro.
+ (popcount_supported) [_MSC_VER]: New inline function.
+ (COUNT_ONE_BITS): Use it. New arg MSC_BUILTIN, for better
+ performance with MSC. All uses changed. Do not assume that TYPE
+ has at most 64 bits.
+ * modules/count-one-bits (Depends-on): Do not depend on 'verify'.
+
2013-10-06 Andrew Borodin <address@hidden>
mountlist: fix resource leak with MOUNTED_INTERIX_STATVFS
diff --git a/lib/count-one-bits.c b/lib/count-one-bits.c
index b15aec4..66341d7 100644
--- a/lib/count-one-bits.c
+++ b/lib/count-one-bits.c
@@ -1,3 +1,7 @@
#include <config.h>
#define COUNT_ONE_BITS_INLINE _GL_EXTERN_INLINE
#include "count-one-bits.h"
+
+#if 1500 <= _MSC_VER && (defined _M_IX86 || defined _M_X64)
+int popcount_support = -1;
+#endif
diff --git a/lib/count-one-bits.h b/lib/count-one-bits.h
index ce9d67e..2a7e93c 100644
--- a/lib/count-one-bits.h
+++ b/lib/count-one-bits.h
@@ -17,10 +17,10 @@
/* Written by Ben Pfaff. */
#ifndef COUNT_ONE_BITS_H
-# define COUNT_ONE_BITS_H 1
+#define COUNT_ONE_BITS_H 1
+#include <limits.h>
#include <stdlib.h>
-#include "verify.h"
#ifndef _GL_INLINE_HEADER_BEGIN
#error "Please include config.h first."
@@ -30,21 +30,30 @@ _GL_INLINE_HEADER_BEGIN
# define COUNT_ONE_BITS_INLINE _GL_INLINE
#endif
-/* Expand the code which computes the number of 1-bits of the local
- variable 'x' of type TYPE (an unsigned integer type) and returns it
+/* Expand to code that computes the number of 1-bits of the local
+ variable 'x' of type TYPE (an unsigned integer type) and return it
+ from the current function. */
+#define COUNT_ONE_BITS_GENERIC(TYPE) \
+ do \
+ { \
+ int count = 0; \
+ int bits; \
+ for (bits = 0; bits < sizeof (TYPE) * CHAR_BIT; bits += 32) \
+ { \
+ count += count_one_bits_32 (x); \
+ x = x >> 31 >> 1; \
+ } \
+ return count; \
+ } \
+ while (0)
+
+/* Assuming the GCC builtin is BUILTIN and the MSC builtin is MSC_BUILTIN,
+ expand to code that computes the number of 1-bits of the local
+ variable 'x' of type TYPE (an unsigned integer type) and return it
from the current function. */
#if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4)
-#define COUNT_ONE_BITS(BUILTIN, TYPE) \
- return BUILTIN (x);
+# define COUNT_ONE_BITS(BUILTIN, MSC_BUILTIN, TYPE) return BUILTIN (x)
#else
-#define COUNT_ONE_BITS(BUILTIN, TYPE) \
- /* This condition is written so as to avoid shifting by more than \
- 31 bits at once, and also avoids a random HP-UX cc bug. */ \
- verify (((TYPE) -1 >> 31 >> 31 >> 2) == 0); /* TYPE has at most 64
bits */ \
- int count = count_one_bits_32 (x); \
- if (1 < (TYPE) -1 >> 31) /* TYPE has more than 32 bits? */ \
- count += count_one_bits_32 (x >> 31 >> 1); \
- return count;
/* Compute and return the number of 1-bits set in the least
significant 32 bits of X. */
@@ -57,20 +66,60 @@ count_one_bits_32 (unsigned int x)
x = ((x & 0xf0f0) >> 4) + (x & 0x0f0f);
return (x >> 8) + (x & 0x00ff);
}
+
+# if 1500 <= _MSC_VER && (defined _M_IX86 || defined _M_X64)
+
+/* While gcc falls back to its own generic code if the machine
+ on which it's running doesn't support popcount, with Microsoft's
+ compiler we need to detect and fallback ourselves. */
+# pragma intrinsic __cpuid
+# pragma intrinsic __popcnt
+# pragma intrinsic __popcnt64
+
+/* Return nonzero if popcount is supported. */
+
+/* 1 if supported, 0 if not supported, -1 if unknown. */
+extern int popcount_support;
+
+COUNT_ONE_BITS_INLINE int
+popcount_supported (void)
+{
+ if (popcount_support < 0)
+ {
+ int cpu_info[4];
+ __cpuid (cpu_info, 1);
+ popcount_support = (cpu_info[2] >> 23) & 1; /* See MSDN. */
+ }
+ return popcount_support;
+}
+
+# define COUNT_ONE_BITS(BUILTIN, MSC_BUILTIN, TYPE) \
+ do \
+ { \
+ if (popcount_supported ()) \
+ return MSC_BUILTIN (x); \
+ else \
+ COUNT_ONE_BITS_GENERIC (TYPE); \
+ } \
+ while (0)
+# else
+# define COUNT_ONE_BITS(BUILTIN, MSC_BUILTIN, TYPE) \
+ COUNT_ONE_BITS_GENERIC (TYPE)
+# endif
#endif
/* Compute and return the number of 1-bits set in X. */
COUNT_ONE_BITS_INLINE int
count_one_bits (unsigned int x)
{
- COUNT_ONE_BITS (__builtin_popcount, unsigned int);
+ COUNT_ONE_BITS (__builtin_popcount, __popcnt, unsigned int);
}
/* Compute and return the number of 1-bits set in X. */
COUNT_ONE_BITS_INLINE int
count_one_bits_l (unsigned long int x)
{
- COUNT_ONE_BITS (__builtin_popcountl, unsigned long int);
+ COUNT_ONE_BITS (__builtin_popcountl, __popcnt, unsigned long int);
}
#if HAVE_UNSIGNED_LONG_LONG_INT
@@ -78,7 +127,7 @@ count_one_bits_l (unsigned long int x)
COUNT_ONE_BITS_INLINE int
count_one_bits_ll (unsigned long long int x)
{
- COUNT_ONE_BITS (__builtin_popcountll, unsigned long long int);
+ COUNT_ONE_BITS (__builtin_popcountll, __popcnt64, unsigned long long int);
}
#endif
diff --git a/modules/count-one-bits b/modules/count-one-bits
index 3922d85..7bb18bd 100644
--- a/modules/count-one-bits
+++ b/modules/count-one-bits
@@ -8,7 +8,6 @@ m4/count-one-bits.m4
Depends-on:
extern-inline
-verify
configure.ac:
gl_COUNT_ONE_BITS
--
1.8.3.1
- [PATCH 1/3] count-one-bits: port to MSC; support types wider than 64 bits,
Paul Eggert <=