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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 00:47:55 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 00:47:55 +0000
commit26a029d407be480d791972afb5975cf62c9360a6 (patch)
treef435a8308119effd964b339f76abb83a57c29483 /mozglue/misc/SIMD.cpp
parentInitial commit. (diff)
downloadfirefox-26a029d407be480d791972afb5975cf62c9360a6.tar.xz
firefox-26a029d407be480d791972afb5975cf62c9360a6.zip
Adding upstream version 124.0.1.upstream/124.0.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'mozglue/misc/SIMD.cpp')
-rw-r--r--mozglue/misc/SIMD.cpp565
1 files changed, 565 insertions, 0 deletions
diff --git a/mozglue/misc/SIMD.cpp b/mozglue/misc/SIMD.cpp
new file mode 100644
index 0000000000..3893de57b3
--- /dev/null
+++ b/mozglue/misc/SIMD.cpp
@@ -0,0 +1,565 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/SIMD.h"
+
+#include <cstring>
+#include <stdint.h>
+#include <type_traits>
+
+#include "mozilla/EndianUtils.h"
+#include "mozilla/SSE.h"
+
+#ifdef MOZILLA_PRESUME_SSE2
+
+# include <immintrin.h>
+
+#endif
+
+namespace mozilla {
+
+template <typename TValue>
+const TValue* FindInBufferNaive(const TValue* ptr, TValue value,
+ size_t length) {
+ const TValue* end = ptr + length;
+ while (ptr < end) {
+ if (*ptr == value) {
+ return ptr;
+ }
+ ptr++;
+ }
+ return nullptr;
+}
+
+#ifdef MOZILLA_PRESUME_SSE2
+
+const __m128i* Cast128(uintptr_t ptr) {
+ return reinterpret_cast<const __m128i*>(ptr);
+}
+
+template <typename T>
+T GetAs(uintptr_t ptr) {
+ return *reinterpret_cast<const T*>(ptr);
+}
+
+// Akin to ceil/floor, AlignDown/AlignUp will return the original pointer if it
+// is already aligned.
+uintptr_t AlignDown16(uintptr_t ptr) { return ptr & ~0xf; }
+
+uintptr_t AlignUp16(uintptr_t ptr) { return AlignDown16(ptr + 0xf); }
+
+template <typename TValue>
+__m128i CmpEq128(__m128i a, __m128i b) {
+ static_assert(sizeof(TValue) == 1 || sizeof(TValue) == 2);
+ if (sizeof(TValue) == 1) {
+ return _mm_cmpeq_epi8(a, b);
+ }
+ return _mm_cmpeq_epi16(a, b);
+}
+
+# ifdef __GNUC__
+
+// Earlier versions of GCC are missing the _mm_loadu_si32 instruction. This
+// workaround from Peter Cordes (https://stackoverflow.com/a/72837992) compiles
+// down to the same instructions. We could just replace _mm_loadu_si32
+__m128i Load32BitsIntoXMM(uintptr_t ptr) {
+ int tmp;
+ memcpy(&tmp, reinterpret_cast<const void*>(ptr),
+ sizeof(tmp)); // unaligned aliasing-safe load
+ return _mm_cvtsi32_si128(tmp); // efficient on GCC/clang/MSVC
+}
+
+# else
+
+__m128i Load32BitsIntoXMM(uintptr_t ptr) {
+ return _mm_loadu_si32(Cast128(ptr));
+}
+
+# endif
+
+const char* Check4x4Chars(__m128i needle, uintptr_t a, uintptr_t b, uintptr_t c,
+ uintptr_t d) {
+ __m128i haystackA = Load32BitsIntoXMM(a);
+ __m128i cmpA = CmpEq128<char>(needle, haystackA);
+ __m128i haystackB = Load32BitsIntoXMM(b);
+ __m128i cmpB = CmpEq128<char>(needle, haystackB);
+ __m128i haystackC = Load32BitsIntoXMM(c);
+ __m128i cmpC = CmpEq128<char>(needle, haystackC);
+ __m128i haystackD = Load32BitsIntoXMM(d);
+ __m128i cmpD = CmpEq128<char>(needle, haystackD);
+ __m128i or_ab = _mm_or_si128(cmpA, cmpB);
+ __m128i or_cd = _mm_or_si128(cmpC, cmpD);
+ __m128i or_abcd = _mm_or_si128(or_ab, or_cd);
+ int orMask = _mm_movemask_epi8(or_abcd);
+ if (orMask & 0xf) {
+ int cmpMask;
+ cmpMask = _mm_movemask_epi8(cmpA);
+ if (cmpMask & 0xf) {
+ return reinterpret_cast<const char*>(a + __builtin_ctz(cmpMask));
+ }
+ cmpMask = _mm_movemask_epi8(cmpB);
+ if (cmpMask & 0xf) {
+ return reinterpret_cast<const char*>(b + __builtin_ctz(cmpMask));
+ }
+ cmpMask = _mm_movemask_epi8(cmpC);
+ if (cmpMask & 0xf) {
+ return reinterpret_cast<const char*>(c + __builtin_ctz(cmpMask));
+ }
+ cmpMask = _mm_movemask_epi8(cmpD);
+ if (cmpMask & 0xf) {
+ return reinterpret_cast<const char*>(d + __builtin_ctz(cmpMask));
+ }
+ }
+
+ return nullptr;
+}
+
+template <typename TValue>
+const TValue* Check4x16Bytes(__m128i needle, uintptr_t a, uintptr_t b,
+ uintptr_t c, uintptr_t d) {
+ __m128i haystackA = _mm_loadu_si128(Cast128(a));
+ __m128i cmpA = CmpEq128<TValue>(needle, haystackA);
+ __m128i haystackB = _mm_loadu_si128(Cast128(b));
+ __m128i cmpB = CmpEq128<TValue>(needle, haystackB);
+ __m128i haystackC = _mm_loadu_si128(Cast128(c));
+ __m128i cmpC = CmpEq128<TValue>(needle, haystackC);
+ __m128i haystackD = _mm_loadu_si128(Cast128(d));
+ __m128i cmpD = CmpEq128<TValue>(needle, haystackD);
+ __m128i or_ab = _mm_or_si128(cmpA, cmpB);
+ __m128i or_cd = _mm_or_si128(cmpC, cmpD);
+ __m128i or_abcd = _mm_or_si128(or_ab, or_cd);
+ int orMask = _mm_movemask_epi8(or_abcd);
+ if (orMask) {
+ int cmpMask;
+ cmpMask = _mm_movemask_epi8(cmpA);
+ if (cmpMask) {
+ return reinterpret_cast<const TValue*>(a + __builtin_ctz(cmpMask));
+ }
+ cmpMask = _mm_movemask_epi8(cmpB);
+ if (cmpMask) {
+ return reinterpret_cast<const TValue*>(b + __builtin_ctz(cmpMask));
+ }
+ cmpMask = _mm_movemask_epi8(cmpC);
+ if (cmpMask) {
+ return reinterpret_cast<const TValue*>(c + __builtin_ctz(cmpMask));
+ }
+ cmpMask = _mm_movemask_epi8(cmpD);
+ if (cmpMask) {
+ return reinterpret_cast<const TValue*>(d + __builtin_ctz(cmpMask));
+ }
+ }
+
+ return nullptr;
+}
+
+enum class HaystackOverlap {
+ Overlapping,
+ Sequential,
+};
+
+// Check two 16-byte chunks for the two-byte sequence loaded into needle1
+// followed by needle1. `carryOut` is an optional pointer which we will
+// populate based on whether the last character of b matches needle1. This
+// should be provided on subsequent calls via `carryIn` so we can detect cases
+// where the last byte of b's 16-byte chunk is needle1 and the first byte of
+// the next a's 16-byte chunk is needle2. `overlap` and whether
+// `carryIn`/`carryOut` are NULL should be knowable at compile time to avoid
+// branching.
+template <typename TValue>
+const TValue* Check2x2x16Bytes(__m128i needle1, __m128i needle2, uintptr_t a,
+ uintptr_t b, __m128i* carryIn, __m128i* carryOut,
+ HaystackOverlap overlap) {
+ const int shiftRightAmount = 16 - sizeof(TValue);
+ const int shiftLeftAmount = sizeof(TValue);
+ __m128i haystackA = _mm_loadu_si128(Cast128(a));
+ __m128i cmpA1 = CmpEq128<TValue>(needle1, haystackA);
+ __m128i cmpA2 = CmpEq128<TValue>(needle2, haystackA);
+ __m128i cmpA;
+ if (carryIn) {
+ cmpA = _mm_and_si128(
+ _mm_or_si128(_mm_bslli_si128(cmpA1, shiftLeftAmount), *carryIn), cmpA2);
+ } else {
+ cmpA = _mm_and_si128(_mm_bslli_si128(cmpA1, shiftLeftAmount), cmpA2);
+ }
+ __m128i haystackB = _mm_loadu_si128(Cast128(b));
+ __m128i cmpB1 = CmpEq128<TValue>(needle1, haystackB);
+ __m128i cmpB2 = CmpEq128<TValue>(needle2, haystackB);
+ __m128i cmpB;
+ if (overlap == HaystackOverlap::Overlapping) {
+ cmpB = _mm_and_si128(_mm_bslli_si128(cmpB1, shiftLeftAmount), cmpB2);
+ } else {
+ MOZ_ASSERT(overlap == HaystackOverlap::Sequential);
+ __m128i carryAB = _mm_bsrli_si128(cmpA1, shiftRightAmount);
+ cmpB = _mm_and_si128(
+ _mm_or_si128(_mm_bslli_si128(cmpB1, shiftLeftAmount), carryAB), cmpB2);
+ }
+ __m128i or_ab = _mm_or_si128(cmpA, cmpB);
+ int orMask = _mm_movemask_epi8(or_ab);
+ if (orMask) {
+ int cmpMask;
+ cmpMask = _mm_movemask_epi8(cmpA);
+ if (cmpMask) {
+ return reinterpret_cast<const TValue*>(a + __builtin_ctz(cmpMask) -
+ shiftLeftAmount);
+ }
+ cmpMask = _mm_movemask_epi8(cmpB);
+ if (cmpMask) {
+ return reinterpret_cast<const TValue*>(b + __builtin_ctz(cmpMask) -
+ shiftLeftAmount);
+ }
+ }
+
+ if (carryOut) {
+ _mm_store_si128(carryOut, _mm_bsrli_si128(cmpB1, shiftRightAmount));
+ }
+
+ return nullptr;
+}
+
+template <typename TValue>
+const TValue* FindInBuffer(const TValue* ptr, TValue value, size_t length) {
+ static_assert(sizeof(TValue) == 1 || sizeof(TValue) == 2);
+ static_assert(std::is_unsigned<TValue>::value);
+ uint64_t splat64;
+ if (sizeof(TValue) == 1) {
+ splat64 = 0x0101010101010101llu;
+ } else {
+ splat64 = 0x0001000100010001llu;
+ }
+
+ // Load our needle into a 16-byte register
+ uint64_t u64_value = static_cast<uint64_t>(value) * splat64;
+ int64_t i64_value = *reinterpret_cast<int64_t*>(&u64_value);
+ __m128i needle = _mm_set_epi64x(i64_value, i64_value);
+
+ size_t numBytes = length * sizeof(TValue);
+ uintptr_t cur = reinterpret_cast<uintptr_t>(ptr);
+ uintptr_t end = cur + numBytes;
+
+ if ((sizeof(TValue) > 1 && numBytes < 16) || numBytes < 4) {
+ while (cur < end) {
+ if (GetAs<TValue>(cur) == value) {
+ return reinterpret_cast<const TValue*>(cur);
+ }
+ cur += sizeof(TValue);
+ }
+ return nullptr;
+ }
+
+ if (numBytes < 16) {
+ // NOTE: here and below, we have some bit fiddling which could look a
+ // little weird. The important thing to note though is it's just a trick
+ // for getting the number 4 if numBytes is greater than or equal to 8,
+ // and 0 otherwise. This lets us fully cover the range without any
+ // branching for the case where numBytes is in [4,8), and [8,16). We get
+ // four ranges from this - if numbytes > 8, we get:
+ // [0,4), [4,8], [end - 8), [end - 4)
+ // and if numbytes < 8, we get
+ // [0,4), [0,4), [end - 4), [end - 4)
+ uintptr_t a = cur;
+ uintptr_t b = cur + ((numBytes & 8) >> 1);
+ uintptr_t c = end - 4 - ((numBytes & 8) >> 1);
+ uintptr_t d = end - 4;
+ const char* charResult = Check4x4Chars(needle, a, b, c, d);
+ // Note: we ensure above that sizeof(TValue) == 1 here, so this is
+ // either char to char or char to something like a uint8_t.
+ return reinterpret_cast<const TValue*>(charResult);
+ }
+
+ if (numBytes < 64) {
+ // NOTE: see the above explanation of the similar chunk of code, but in
+ // this case, replace 8 with 32 and 4 with 16.
+ uintptr_t a = cur;
+ uintptr_t b = cur + ((numBytes & 32) >> 1);
+ uintptr_t c = end - 16 - ((numBytes & 32) >> 1);
+ uintptr_t d = end - 16;
+ return Check4x16Bytes<TValue>(needle, a, b, c, d);
+ }
+
+ // Get the initial unaligned load out of the way. This will overlap with the
+ // aligned stuff below, but the overlapped part should effectively be free
+ // (relative to a mispredict from doing a byte-by-byte loop).
+ __m128i haystack = _mm_loadu_si128(Cast128(cur));
+ __m128i cmp = CmpEq128<TValue>(needle, haystack);
+ int cmpMask = _mm_movemask_epi8(cmp);
+ if (cmpMask) {
+ return reinterpret_cast<const TValue*>(cur + __builtin_ctz(cmpMask));
+ }
+
+ // Now we're working with aligned memory. Hooray! \o/
+ cur = AlignUp16(cur);
+
+ // The address of the final 48-63 bytes. We overlap this with what we check in
+ // our hot loop below to avoid branching. Again, the overlap should be
+ // negligible compared with a branch mispredict.
+ uintptr_t tailStartPtr = AlignDown16(end - 48);
+ uintptr_t tailEndPtr = end - 16;
+
+ while (cur < tailStartPtr) {
+ uintptr_t a = cur;
+ uintptr_t b = cur + 16;
+ uintptr_t c = cur + 32;
+ uintptr_t d = cur + 48;
+ const TValue* result = Check4x16Bytes<TValue>(needle, a, b, c, d);
+ if (result) {
+ return result;
+ }
+ cur += 64;
+ }
+
+ uintptr_t a = tailStartPtr;
+ uintptr_t b = tailStartPtr + 16;
+ uintptr_t c = tailStartPtr + 32;
+ uintptr_t d = tailEndPtr;
+ return Check4x16Bytes<TValue>(needle, a, b, c, d);
+}
+
+template <typename TValue>
+const TValue* TwoElementLoop(uintptr_t start, uintptr_t end, TValue v1,
+ TValue v2) {
+ static_assert(sizeof(TValue) == 1 || sizeof(TValue) == 2);
+
+ const TValue* cur = reinterpret_cast<const TValue*>(start);
+ const TValue* preEnd = reinterpret_cast<const TValue*>(end - sizeof(TValue));
+
+ uint32_t expected = static_cast<uint32_t>(v1) |
+ (static_cast<uint32_t>(v2) << (sizeof(TValue) * 8));
+ while (cur < preEnd) {
+ // NOTE: this should only ever be called on little endian architectures.
+ static_assert(MOZ_LITTLE_ENDIAN());
+ // We or cur[0] and cur[1] together explicitly and compare to expected,
+ // in order to avoid UB from just loading them as a uint16_t/uint32_t.
+ // However, it will compile down the same code after optimizations on
+ // little endian systems which support unaligned loads. Comparing them
+ // value-by-value, however, will not, and seems to perform worse in local
+ // microbenchmarking. Even after bitwise or'ing the comparison values
+ // together to avoid the short circuit, the compiler doesn't seem to get
+ // the hint and creates two branches, the first of which might be
+ // frequently mispredicted.
+ uint32_t actual = static_cast<uint32_t>(cur[0]) |
+ (static_cast<uint32_t>(cur[1]) << (sizeof(TValue) * 8));
+ if (actual == expected) {
+ return cur;
+ }
+ cur++;
+ }
+ return nullptr;
+}
+
+template <typename TValue>
+const TValue* FindTwoInBuffer(const TValue* ptr, TValue v1, TValue v2,
+ size_t length) {
+ static_assert(sizeof(TValue) == 1 || sizeof(TValue) == 2);
+ static_assert(std::is_unsigned<TValue>::value);
+ uint64_t splat64;
+ if (sizeof(TValue) == 1) {
+ splat64 = 0x0101010101010101llu;
+ } else {
+ splat64 = 0x0001000100010001llu;
+ }
+
+ // Load our needle into a 16-byte register
+ uint64_t u64_v1 = static_cast<uint64_t>(v1) * splat64;
+ int64_t i64_v1 = *reinterpret_cast<int64_t*>(&u64_v1);
+ __m128i needle1 = _mm_set_epi64x(i64_v1, i64_v1);
+ uint64_t u64_v2 = static_cast<uint64_t>(v2) * splat64;
+ int64_t i64_v2 = *reinterpret_cast<int64_t*>(&u64_v2);
+ __m128i needle2 = _mm_set_epi64x(i64_v2, i64_v2);
+
+ size_t numBytes = length * sizeof(TValue);
+ uintptr_t cur = reinterpret_cast<uintptr_t>(ptr);
+ uintptr_t end = cur + numBytes;
+
+ if (numBytes < 16) {
+ return TwoElementLoop<TValue>(cur, end, v1, v2);
+ }
+
+ if (numBytes < 32) {
+ uintptr_t a = cur;
+ uintptr_t b = end - 16;
+ return Check2x2x16Bytes<TValue>(needle1, needle2, a, b, nullptr, nullptr,
+ HaystackOverlap::Overlapping);
+ }
+
+ // Get the initial unaligned load out of the way. This will likely overlap
+ // with the aligned stuff below, but the overlapped part should effectively
+ // be free.
+ __m128i haystack = _mm_loadu_si128(Cast128(cur));
+ __m128i cmp1 = CmpEq128<TValue>(needle1, haystack);
+ __m128i cmp2 = CmpEq128<TValue>(needle2, haystack);
+ int cmpMask1 = _mm_movemask_epi8(cmp1);
+ int cmpMask2 = _mm_movemask_epi8(cmp2);
+ int cmpMask = (cmpMask1 << sizeof(TValue)) & cmpMask2;
+ if (cmpMask) {
+ return reinterpret_cast<const TValue*>(cur + __builtin_ctz(cmpMask) -
+ sizeof(TValue));
+ }
+
+ // Now we're working with aligned memory. Hooray! \o/
+ cur = AlignUp16(cur);
+
+ // The address of the final 48-63 bytes. We overlap this with what we check in
+ // our hot loop below to avoid branching. Again, the overlap should be
+ // negligible compared with a branch mispredict.
+ uintptr_t tailEndPtr = end - 16;
+ uintptr_t tailStartPtr = AlignDown16(tailEndPtr);
+
+ __m128i cmpMaskCarry = _mm_set1_epi32(0);
+ while (cur < tailStartPtr) {
+ uintptr_t a = cur;
+ uintptr_t b = cur + 16;
+ const TValue* result =
+ Check2x2x16Bytes<TValue>(needle1, needle2, a, b, &cmpMaskCarry,
+ &cmpMaskCarry, HaystackOverlap::Sequential);
+ if (result) {
+ return result;
+ }
+ cur += 32;
+ }
+
+ uint32_t carry = (cur == tailStartPtr) ? 0xffffffff : 0;
+ __m128i wideCarry = Load32BitsIntoXMM(reinterpret_cast<uintptr_t>(&carry));
+ cmpMaskCarry = _mm_and_si128(cmpMaskCarry, wideCarry);
+ uintptr_t a = tailStartPtr;
+ uintptr_t b = tailEndPtr;
+ return Check2x2x16Bytes<TValue>(needle1, needle2, a, b, &cmpMaskCarry,
+ nullptr, HaystackOverlap::Overlapping);
+}
+
+const char* SIMD::memchr8SSE2(const char* ptr, char value, size_t length) {
+ // Signed chars are just really annoying to do bit logic with. Convert to
+ // unsigned at the outermost scope so we don't have to worry about it.
+ const unsigned char* uptr = reinterpret_cast<const unsigned char*>(ptr);
+ unsigned char uvalue = static_cast<unsigned char>(value);
+ const unsigned char* uresult =
+ FindInBuffer<unsigned char>(uptr, uvalue, length);
+ return reinterpret_cast<const char*>(uresult);
+}
+
+// So, this is a bit awkward. It generally simplifies things if we can just
+// assume all the AVX2 code is 64-bit, so we have this preprocessor guard
+// in SIMD_avx2 over all of its actual code, and it also defines versions
+// of its endpoints that just assert false if the guard is not satisfied.
+// A 32 bit processor could implement the AVX2 instruction set though, which
+// would result in it passing the supports_avx2() check and landing in an
+// assertion failure. Accordingly, we just don't allow that to happen. We
+// are not particularly concerned about ensuring that newer 32 bit processors
+// get access to the AVX2 functions exposed here.
+# if defined(MOZILLA_MAY_SUPPORT_AVX2) && defined(__x86_64__)
+
+bool SupportsAVX2() { return supports_avx2(); }
+
+# else
+
+bool SupportsAVX2() { return false; }
+
+# endif
+
+const char* SIMD::memchr8(const char* ptr, char value, size_t length) {
+ if (SupportsAVX2()) {
+ return memchr8AVX2(ptr, value, length);
+ }
+ return memchr8SSE2(ptr, value, length);
+}
+
+const char16_t* SIMD::memchr16SSE2(const char16_t* ptr, char16_t value,
+ size_t length) {
+ return FindInBuffer<char16_t>(ptr, value, length);
+}
+
+const char16_t* SIMD::memchr16(const char16_t* ptr, char16_t value,
+ size_t length) {
+ if (SupportsAVX2()) {
+ return memchr16AVX2(ptr, value, length);
+ }
+ return memchr16SSE2(ptr, value, length);
+}
+
+const uint64_t* SIMD::memchr64(const uint64_t* ptr, uint64_t value,
+ size_t length) {
+ if (SupportsAVX2()) {
+ return memchr64AVX2(ptr, value, length);
+ }
+ return FindInBufferNaive<uint64_t>(ptr, value, length);
+}
+
+const char* SIMD::memchr2x8(const char* ptr, char v1, char v2, size_t length) {
+ // Signed chars are just really annoying to do bit logic with. Convert to
+ // unsigned at the outermost scope so we don't have to worry about it.
+ const unsigned char* uptr = reinterpret_cast<const unsigned char*>(ptr);
+ unsigned char uv1 = static_cast<unsigned char>(v1);
+ unsigned char uv2 = static_cast<unsigned char>(v2);
+ const unsigned char* uresult =
+ FindTwoInBuffer<unsigned char>(uptr, uv1, uv2, length);
+ return reinterpret_cast<const char*>(uresult);
+}
+
+const char16_t* SIMD::memchr2x16(const char16_t* ptr, char16_t v1, char16_t v2,
+ size_t length) {
+ return FindTwoInBuffer<char16_t>(ptr, v1, v2, length);
+}
+
+#else
+
+const char* SIMD::memchr8(const char* ptr, char value, size_t length) {
+ const void* result = ::memchr(reinterpret_cast<const void*>(ptr),
+ static_cast<int>(value), length);
+ return reinterpret_cast<const char*>(result);
+}
+
+const char* SIMD::memchr8SSE2(const char* ptr, char value, size_t length) {
+ return memchr8(ptr, value, length);
+}
+
+const char16_t* SIMD::memchr16(const char16_t* ptr, char16_t value,
+ size_t length) {
+ return FindInBufferNaive<char16_t>(ptr, value, length);
+}
+
+const char16_t* SIMD::memchr16SSE2(const char16_t* ptr, char16_t value,
+ size_t length) {
+ return memchr16(ptr, value, length);
+}
+
+const uint64_t* SIMD::memchr64(const uint64_t* ptr, uint64_t value,
+ size_t length) {
+ return FindInBufferNaive<uint64_t>(ptr, value, length);
+}
+
+const char* SIMD::memchr2x8(const char* ptr, char v1, char v2, size_t length) {
+ const char* end = ptr + length - 1;
+ while (ptr < end) {
+ ptr = memchr8(ptr, v1, end - ptr);
+ if (!ptr) {
+ return nullptr;
+ }
+ if (ptr[1] == v2) {
+ return ptr;
+ }
+ ptr++;
+ }
+ return nullptr;
+}
+
+const char16_t* SIMD::memchr2x16(const char16_t* ptr, char16_t v1, char16_t v2,
+ size_t length) {
+ const char16_t* end = ptr + length - 1;
+ while (ptr < end) {
+ ptr = memchr16(ptr, v1, end - ptr);
+ if (!ptr) {
+ return nullptr;
+ }
+ if (ptr[1] == v2) {
+ return ptr;
+ }
+ ptr++;
+ }
+ return nullptr;
+}
+
+#endif
+
+} // namespace mozilla