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altivec version of find_next_json_quotable_character (#2622)

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* altivec version of find_next_json_quotable_character

* simplify

* saving.
This commit is contained in:
Daniel Lemire
2026-03-08 14:06:01 -04:00
committed by GitHub
parent 262ddad037
commit 2922822622
2 changed files with 109 additions and 9 deletions
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include/simdjson/fallback/bitmanipulation.h
+13
View File
@@ -41,6 +41,19 @@ simdjson_inline int leading_zeroes(uint64_t input_num) {
#endif// _MSC_VER
}
simdjson_inline int trailing_zeroes(uint64_t input_num) {
#ifdef _MSC_VER
unsigned long trailing_zero = 0;
// Search the mask data from least significant bit (LSB)
// to most significant bit (MSB) for a set bit (1).
if (_BitScanForward64(&trailing_zero, input_num))
return (int)trailing_zero;
else return 64;
#else
return __builtin_ctzll(input_num);
#endif// _MSC_VER
}
} // unnamed namespace
} // namespace fallback
} // namespace simdjson
include/simdjson/generic/builder/json_string_builder-inl.h
+96 -9
View File
@@ -37,6 +37,11 @@
#define SIMDJSON_EXPERIMENTAL_HAS_RVV 1
#endif
#endif
#if defined(__PPC64__) || defined(_M_PPC64)
#ifndef SIMDJSON_EXPERIMENTAL_HAS_PPC64
#define SIMDJSON_EXPERIMENTAL_HAS_PPC64 1
#endif
#endif
#if SIMDJSON_EXPERIMENTAL_HAS_NEON
#include <arm_neon.h>
#ifdef _MSC_VER
@@ -55,6 +60,15 @@
#if SIMDJSON_EXPERIMENTAL_HAS_RVV
#include <riscv_vector.h>
#endif
#if SIMDJSON_EXPERIMENTAL_HAS_PPC64
#include <altivec.h>
#ifdef bool
#undef bool
#endif
#ifdef vector
#undef vector
#endif
#endif
namespace simdjson {
@@ -156,6 +170,35 @@ simdjson_inline bool fast_needs_escaping(std::string_view view) {
}
return _mm_movemask_epi8(running) != 0;
}
#elif SIMDJSON_EXPERIMENTAL_HAS_PPC64
simdjson_inline bool fast_needs_escaping(std::string_view view) {
if (view.size() < 16) {
return simple_needs_escaping(view);
}
size_t i = 0;
__vector unsigned char running = vec_splats((unsigned char)0);
__vector unsigned char v34 = vec_splats((unsigned char)34);
__vector unsigned char v92 = vec_splats((unsigned char)92);
__vector unsigned char v32 = vec_splats((unsigned char)32);
for (; i + 15 < view.size(); i += 16) {
__vector unsigned char word =
vec_vsx_ld(0, reinterpret_cast<const unsigned char *>(view.data() + i));
running = vec_or(running, (__vector unsigned char)vec_cmpeq(word, v34));
running = vec_or(running, (__vector unsigned char)vec_cmpeq(word, v92));
running = vec_or(running,
(__vector unsigned char)vec_cmplt(word, v32));
}
if (i < view.size()) {
__vector unsigned char word = vec_vsx_ld(
0, reinterpret_cast<const unsigned char *>(view.data() + view.length() - 16));
running = vec_or(running, (__vector unsigned char)vec_cmpeq(word, v34));
running = vec_or(running, (__vector unsigned char)vec_cmpeq(word, v92));
running = vec_or(running,
(__vector unsigned char)vec_cmplt(word, v32));
}
return !vec_all_eq(running, vec_splats((unsigned char)0));
}
#else
simdjson_inline bool fast_needs_escaping(std::string_view view) {
return simple_needs_escaping(view);
@@ -242,13 +285,7 @@ find_next_json_quotable_character(const std::string_view view,
if (mask != 0) {
// Found quotable character - use trailing zero count to find position
size_t offset = ptr - reinterpret_cast<const uint8_t *>(view.data());
#ifdef _MSC_VER
unsigned long trailing_zero = 0;
_BitScanForward(&trailing_zero, mask);
return offset + trailing_zero;
#else
return offset + __builtin_ctz(mask);
#endif
return offset + trailing_zeroes(mask);
}
ptr += 16;
remaining -= 16;
@@ -287,9 +324,9 @@ find_next_json_quotable_character(const std::string_view view,
uint64_t hi = __lsx_vpickve2gr_du(needs_escape,1);
size_t offset = ptr - reinterpret_cast<const uint8_t *>(view.data());
if ( lo != 0) {
return offset + __builtin_ctzll(lo) / 8;
return offset + trailing_zeroes(lo) / 8;
} else {
return offset + 8 + __builtin_ctzll(hi) / 8;
return offset + 8 + trailing_zeroes(hi) / 8;
}
}
ptr += 16;
@@ -329,6 +366,56 @@ find_next_json_quotable_character(const std::string_view view,
return len;
}
#elif SIMDJSON_EXPERIMENTAL_HAS_PPC64
simdjson_inline size_t
find_next_json_quotable_character(const std::string_view view,
size_t location) noexcept {
const size_t len = view.size();
const uint8_t *ptr =
reinterpret_cast<const uint8_t *>(view.data()) + location;
size_t remaining = len - location;
// SIMD constants for characters requiring escape
__vector unsigned char v34 = vec_splats((unsigned char)34); // '"'
__vector unsigned char v92 = vec_splats((unsigned char)92); // '\\'
__vector unsigned char v32 = vec_splats((unsigned char)32); // control char threshold
// Bitmask for vec_vbpermq to extract one bit per byte
const __vector unsigned char perm_mask = {0x78, 0x70, 0x68, 0x60, 0x58, 0x50,
0x48, 0x40, 0x38, 0x30, 0x28, 0x20,
0x18, 0x10, 0x08, 0x00};
while (remaining >= 16) {
__vector unsigned char word =
vec_vsx_ld(0, reinterpret_cast<const unsigned char *>(ptr));
// Check for quotable characters: '"', '\\', or control chars (< 32)
__vector unsigned char needs_escape =
(__vector unsigned char)vec_cmpeq(word, v34);
needs_escape = vec_or(needs_escape,
(__vector unsigned char)vec_cmpeq(word, v92));
needs_escape = vec_or(needs_escape,
(__vector unsigned char)vec_cmplt(word, v32));
__vector unsigned long long result =
(__vector unsigned long long)vec_vbpermq(needs_escape, perm_mask);
#ifdef __LITTLE_ENDIAN__
unsigned int mask = static_cast<unsigned int>(result[1]);
#else
unsigned int mask = static_cast<unsigned int>(result[0]);
#endif
if (mask != 0) {
size_t offset = ptr - reinterpret_cast<const uint8_t *>(view.data());
return offset + __builtin_ctz(mask);
}
ptr += 16;
remaining -= 16;
}
// Scalar fallback for remaining bytes
size_t current = len - remaining;
return find_next_json_quotable_character_scalar(view, current);
}
#else
SIMDJSON_CONSTEXPR_LAMBDA simdjson_inline size_t
find_next_json_quotable_character(const std::string_view view,