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Merged
merged 3 commits into from
Feb 28, 2025
Merged

Further improve ProbabilisticMap on Avx512 #107798

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b81f7b5
Further improve ProbabilisticMap on Avx512
MihaZupan Sep 13, 2024
c7e4f14
Merge branch 'main' into searchvalues-probAvx512Permute
MihaZupan Feb 7, 2025
300756a
Merge branch 'main' into searchvalues-probAvx512Permute
MihaZupan Feb 27, 2025
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56 changes: 28 additions & 28 deletions src/libraries/System.Private.CoreLib/src/System/SearchValues/ProbabilisticMap.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -110,13 +110,8 @@ private static Vector512<byte> ContainsMask64CharsAvx512(Vector512<byte> charMap
Vector512<ushort> source0 = Vector512.LoadUnsafe(ref searchSpace0);
Vector512<ushort> source1 = Vector512.LoadUnsafe(ref searchSpace1);

Vector512<byte> sourceLower = Avx512BW.PackUnsignedSaturate(
(source0 & Vector512.Create((ushort)255)).AsInt16(),
(source1 & Vector512.Create((ushort)255)).AsInt16());

Vector512<byte> sourceUpper = Avx512BW.PackUnsignedSaturate(
(source0 >>> 8).AsInt16(),
(source1 >>> 8).AsInt16());
Vector512<byte> sourceLower = Avx512Vbmi.PermuteVar64x8x2(source0.AsByte(), Vector512.CreateSequence<byte>(0, 2), source1.AsByte());
Vector512<byte> sourceUpper = Avx512Vbmi.PermuteVar64x8x2(source0.AsByte(), Vector512.CreateSequence<byte>(1, 2), source1.AsByte());

Vector512<byte> resultLower = IsCharBitNotSetAvx512(charMap, sourceLower);
Vector512<byte> resultUpper = IsCharBitNotSetAvx512(charMap, sourceUpper);
Expand All @@ -128,12 +123,17 @@ private static Vector512<byte> ContainsMask64CharsAvx512(Vector512<byte> charMap
[CompExactlyDependsOn(typeof(Avx512Vbmi))]
private static Vector512<byte> IsCharBitNotSetAvx512(Vector512<byte> charMap, Vector512<byte> values)
{
Vector512<byte> shifted = values >>> VectorizedIndexShift;
// X86 does not have an instruction for right shifting 8-bit values, so it's instead emulated
// by using a 32-bit value shift followed by an AND to mask off the bits that should be zeroed.
// We're using PermuteVar64x8, which only looks at the lower 6 bits, so we can skip the AND.
// Bits 4/5/6 will not affect the result as the bit positions vector is duplicated 8 times.
Vector512<byte> shifted = (values.AsInt32() >>> VectorizedIndexShift).AsByte();

Vector512<byte> bitPositions = Avx512BW.Shuffle(Vector512.Create(0x8040201008040201).AsByte(), shifted);
Vector512<byte> bitPositions = Avx512Vbmi.PermuteVar64x8(Vector512.Create(0x8040201008040201).AsByte(), shifted);

Vector512<byte> index = values & Vector512.Create((byte)VectorizedIndexMask);
Vector512<byte> bitMask = Avx512Vbmi.PermuteVar64x8(charMap, index);
// We want to select bytes from 'charMap' based on the low 5 bits of 'values' (values & VectorizedIndexMask).
// PermuteVar64x8 will look at the low 6 bits, but the 6th bit will not affect the result as the 'charMap' is duplicated.
Vector512<byte> bitMask = Avx512Vbmi.PermuteVar64x8(charMap, values);

return Vector512.Equals(bitMask & bitPositions, Vector512<byte>.Zero);
}
Expand All @@ -145,13 +145,8 @@ private static Vector256<byte> ContainsMask32CharsAvx512(Vector256<byte> charMap
Vector256<ushort> source0 = Vector256.LoadUnsafe(ref searchSpace0);
Vector256<ushort> source1 = Vector256.LoadUnsafe(ref searchSpace1);

Vector256<byte> sourceLower = Avx2.PackUnsignedSaturate(
(source0 & Vector256.Create((ushort)255)).AsInt16(),
(source1 & Vector256.Create((ushort)255)).AsInt16());

Vector256<byte> sourceUpper = Avx2.PackUnsignedSaturate(
(source0 >>> 8).AsInt16(),
(source1 >>> 8).AsInt16());
Vector256<byte> sourceLower = Avx512Vbmi.VL.PermuteVar32x8x2(source0.AsByte(), Vector256.CreateSequence<byte>(0, 2), source1.AsByte());
Vector256<byte> sourceUpper = Avx512Vbmi.VL.PermuteVar32x8x2(source0.AsByte(), Vector256.CreateSequence<byte>(1, 2), source1.AsByte());

Vector256<byte> resultLower = IsCharBitNotSetAvx512(charMap, sourceLower);
Vector256<byte> resultUpper = IsCharBitNotSetAvx512(charMap, sourceUpper);
Expand All @@ -163,12 +158,17 @@ private static Vector256<byte> ContainsMask32CharsAvx512(Vector256<byte> charMap
[CompExactlyDependsOn(typeof(Avx512Vbmi.VL))]
private static Vector256<byte> IsCharBitNotSetAvx512(Vector256<byte> charMap, Vector256<byte> values)
{
Vector256<byte> shifted = values >>> VectorizedIndexShift;
// X86 does not have an instruction for right shifting 8-bit values, so it's instead emulated
// by using a 32-bit value shift followed by an AND to mask off the bits that should be zeroed.
// We're using PermuteVar32x8, which only looks at the lower 5 bits, so we can skip the AND.
// Bits 4/5 will not affect the result as the bit positions vector is duplicated 4 times
Vector256<byte> shifted = (values.AsInt32() >>> VectorizedIndexShift).AsByte();

Vector256<byte> bitPositions = Avx2.Shuffle(Vector256.Create(0x8040201008040201).AsByte(), shifted);
Vector256<byte> bitPositions = Avx512Vbmi.VL.PermuteVar32x8(Vector256.Create(0x8040201008040201).AsByte(), shifted);

Vector256<byte> index = values & Vector256.Create((byte)VectorizedIndexMask);
Vector256<byte> bitMask = Avx512Vbmi.VL.PermuteVar32x8(charMap, index);
// We want to select bytes from 'charMap' based on the low 5 bits of 'values' (values & VectorizedIndexMask).
// PermuteVar32x8 already looks only at the low 5 bits, so we can skip the redundant AND.
Vector256<byte> bitMask = Avx512Vbmi.VL.PermuteVar32x8(charMap, values);

return Vector256.Equals(bitMask & bitPositions, Vector256<byte>.Zero);
}
Expand Down Expand Up @@ -436,7 +436,7 @@ private static int IndexOfAnyVectorizedAvx512<TUseFastContains>(ref char searchS

if (result != Vector512<byte>.Zero)
{
if (TryFindMatchAvx512<TUseFastContains>(ref cur, PackedSpanHelpers.FixUpPackedVector512Result(result).ExtractMostSignificantBits(), ref state, out int index))
if (TryFindMatchAvx512<TUseFastContains>(ref cur, result.ExtractMostSignificantBits(), ref state, out int index))
{
return MatchOffset(ref searchSpace, ref cur) + index;
}
Expand Down Expand Up @@ -466,7 +466,7 @@ private static int IndexOfAnyVectorizedAvx512<TUseFastContains>(ref char searchS

if (result != Vector512<byte>.Zero)
{
if (TryFindMatchOverlappedAvx512<TUseFastContains>(ref searchSpace, searchSpaceLength, PackedSpanHelpers.FixUpPackedVector512Result(result).ExtractMostSignificantBits(), ref state, out int index))
if (TryFindMatchOverlappedAvx512<TUseFastContains>(ref searchSpace, searchSpaceLength, result.ExtractMostSignificantBits(), ref state, out int index))
{
return index;
}
Expand All @@ -483,7 +483,7 @@ private static int IndexOfAnyVectorizedAvx512<TUseFastContains>(ref char searchS

if (result != Vector256<byte>.Zero)
{
if (TryFindMatchOverlappedAvx512<TUseFastContains>(ref searchSpace, searchSpaceLength, PackedSpanHelpers.FixUpPackedVector256Result(result).ExtractMostSignificantBits(), ref state, out int index))
if (TryFindMatchOverlappedAvx512<TUseFastContains>(ref searchSpace, searchSpaceLength, result.ExtractMostSignificantBits(), ref state, out int index))
{
return index;
}
Expand Down Expand Up @@ -614,7 +614,7 @@ private static int LastIndexOfAnyVectorizedAvx512<TUseFastContains>(ref char sea

if (result != Vector512<byte>.Zero)
{
if (TryFindLastMatchAvx512<TUseFastContains>(ref cur, PackedSpanHelpers.FixUpPackedVector512Result(result).ExtractMostSignificantBits(), ref state, out int index))
if (TryFindLastMatchAvx512<TUseFastContains>(ref cur, result.ExtractMostSignificantBits(), ref state, out int index))
{
return MatchOffset(ref searchSpace, ref cur) + index;
}
Expand Down Expand Up @@ -643,7 +643,7 @@ private static int LastIndexOfAnyVectorizedAvx512<TUseFastContains>(ref char sea

if (result != Vector512<byte>.Zero)
{
if (TryFindLastMatchOverlappedAvx512<TUseFastContains>(ref searchSpace, searchSpaceLength, PackedSpanHelpers.FixUpPackedVector512Result(result).ExtractMostSignificantBits(), ref state, out int index))
if (TryFindLastMatchOverlappedAvx512<TUseFastContains>(ref searchSpace, searchSpaceLength, result.ExtractMostSignificantBits(), ref state, out int index))
{
return index;
}
Expand All @@ -661,7 +661,7 @@ private static int LastIndexOfAnyVectorizedAvx512<TUseFastContains>(ref char sea

if (result != Vector256<byte>.Zero)
{
if (TryFindLastMatchOverlappedAvx512<TUseFastContains>(ref searchSpace, searchSpaceLength, PackedSpanHelpers.FixUpPackedVector256Result(result).ExtractMostSignificantBits(), ref state, out int index))
if (TryFindLastMatchOverlappedAvx512<TUseFastContains>(ref searchSpace, searchSpaceLength, result.ExtractMostSignificantBits(), ref state, out int index))
{
return index;
}
Expand Down
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