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Commit2e28124

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Add POPCNT support for MSVC x86_64 builds
02a6a54 added code to make use of the POPCNT instruction when availablefor many of our common platforms. Here we do the same for MSVC for x86_64machines.MSVC's intrinsic functions for popcnt seem to differ from GCCs in thatthey always appear to emit the popcnt instructions. In GCC the behaviorwill depend on if the source file was compiled with -mpopcnt or not. Forthis reason, the MSVC intrinsic function has been lumped into thepg_popcount*_asm function, however doing that sort of invalidates the nameof that function, so let's rename it to pg_popcount*_fast().Author: David RowleyReviewed-by: John NaylorDiscussion:https://postgr.es/m/CAApHDvqL3cbbK%3DGzNcwzsNR9Gi%2BaUvTudKkC4XgnQfXirJ_oRQ%40mail.gmail.com
1 parentd8a75b1 commit2e28124

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+33
-15
lines changed

1 file changed

+33
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‎src/port/pg_bitutils.c

Lines changed: 33 additions & 15 deletions
Original file line numberDiff line numberDiff line change
@@ -103,6 +103,16 @@ const uint8 pg_number_of_ones[256] = {
103103
4,5,5,6,5,6,6,7,5,6,6,7,6,7,7,8
104104
};
105105

106+
/*
107+
* With MSVC on x86_64 builds, try using native popcnt instructions via the
108+
* __popcnt and __popcnt64 intrinsics. These don't work the same as GCC's
109+
* __builtin_popcount* intrinsic functions as they always emit popcnt
110+
* instructions.
111+
*/
112+
#if defined(_MSC_VER)&& defined(_M_AMD64)
113+
#defineHAVE_X86_64_POPCNTQ
114+
#endif
115+
106116
/*
107117
* On x86_64, we can use the hardware popcount instruction, but only if
108118
* we can verify that the CPU supports it via the cpuid instruction.
@@ -112,28 +122,28 @@ const uint8 pg_number_of_ones[256] = {
112122
*/
113123
#ifdefHAVE_X86_64_POPCNTQ
114124
#if defined(HAVE__GET_CPUID)|| defined(HAVE__CPUID)
115-
#defineUSE_POPCNT_ASM 1
125+
#defineTRY_POPCNT_FAST 1
116126
#endif
117127
#endif
118128

119129
staticintpg_popcount32_slow(uint32word);
120130
staticintpg_popcount64_slow(uint64word);
121131

122-
#ifdefUSE_POPCNT_ASM
132+
#ifdefTRY_POPCNT_FAST
123133
staticboolpg_popcount_available(void);
124134
staticintpg_popcount32_choose(uint32word);
125135
staticintpg_popcount64_choose(uint64word);
126-
staticintpg_popcount32_asm(uint32word);
127-
staticintpg_popcount64_asm(uint64word);
136+
staticintpg_popcount32_fast(uint32word);
137+
staticintpg_popcount64_fast(uint64word);
128138

129139
int(*pg_popcount32) (uint32word)=pg_popcount32_choose;
130140
int(*pg_popcount64) (uint64word)=pg_popcount64_choose;
131141
#else
132142
int(*pg_popcount32) (uint32word)=pg_popcount32_slow;
133143
int(*pg_popcount64) (uint64word)=pg_popcount64_slow;
134-
#endif/*USE_POPCNT_ASM */
144+
#endif/*TRY_POPCNT_FAST */
135145

136-
#ifdefUSE_POPCNT_ASM
146+
#ifdefTRY_POPCNT_FAST
137147

138148
/*
139149
* Return true if CPUID indicates that the POPCNT instruction is available.
@@ -165,8 +175,8 @@ pg_popcount32_choose(uint32 word)
165175
{
166176
if (pg_popcount_available())
167177
{
168-
pg_popcount32=pg_popcount32_asm;
169-
pg_popcount64=pg_popcount64_asm;
178+
pg_popcount32=pg_popcount32_fast;
179+
pg_popcount64=pg_popcount64_fast;
170180
}
171181
else
172182
{
@@ -182,8 +192,8 @@ pg_popcount64_choose(uint64 word)
182192
{
183193
if (pg_popcount_available())
184194
{
185-
pg_popcount32=pg_popcount32_asm;
186-
pg_popcount64=pg_popcount64_asm;
195+
pg_popcount32=pg_popcount32_fast;
196+
pg_popcount64=pg_popcount64_fast;
187197
}
188198
else
189199
{
@@ -195,32 +205,40 @@ pg_popcount64_choose(uint64 word)
195205
}
196206

197207
/*
198-
*pg_popcount32_asm
208+
*pg_popcount32_fast
199209
*Return the number of 1 bits set in word
200210
*/
201211
staticint
202-
pg_popcount32_asm(uint32word)
212+
pg_popcount32_fast(uint32word)
203213
{
214+
#ifdef_MSC_VER
215+
return__popcnt(word);
216+
#else
204217
uint32res;
205218

206219
__asm__ __volatile__(" popcntl %1,%0\n":"=q"(res):"rm"(word):"cc");
207220
return (int)res;
221+
#endif
208222
}
209223

210224
/*
211-
*pg_popcount64_asm
225+
*pg_popcount64_fast
212226
*Return the number of 1 bits set in word
213227
*/
214228
staticint
215-
pg_popcount64_asm(uint64word)
229+
pg_popcount64_fast(uint64word)
216230
{
231+
#ifdef_MSC_VER
232+
return__popcnt64(word);
233+
#else
217234
uint64res;
218235

219236
__asm__ __volatile__(" popcntq %1,%0\n":"=q"(res):"rm"(word):"cc");
220237
return (int)res;
238+
#endif
221239
}
222240

223-
#endif/*USE_POPCNT_ASM */
241+
#endif/*TRY_POPCNT_FAST */
224242

225243

226244
/*

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