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Intrinsicify SpanHelpers.IndexOfAny(char,char,char,char,char)
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@benaadams
benaadams committed Feb 7, 2019
1 parent 733a137 commit 991ced6
Showing 1 changed file with 123 additions and 3 deletions.
126 changes: 123 additions & 3 deletions src/System.Private.CoreLib/shared/System/SpanHelpers.Char.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -1120,7 +1120,15 @@ public static int IndexOfAny(ref char searchSpace, char value0, char value1, cha
int offset = 0; // Use nint for arithmetic to avoid unnecessary 64->32->64 truncations
int lengthToExamine = length;

if (Vector.IsHardwareAccelerated)
if (Avx2.IsSupported || Sse2.IsSupported)
{
// Avx2 branch also operates on Sse2 sizes, so check is combined.
if (length >= Vector128<byte>.Count * 2)
{
lengthToExamine = UnalignedCountVector128(ref searchSpace);
}
}
else if (Vector.IsHardwareAccelerated)
{
if (length >= Vector<ushort>.Count * 2)
{
Expand Down Expand Up @@ -1161,9 +1169,121 @@ public static int IndexOfAny(ref char searchSpace, char value0, char value1, cha
offset += 1;
}

// We get past SequentialScan only if IsHardwareAccelerated is true. However, we still have the redundant check to allow
// We get past SequentialScan only if IsHardwareAccelerated or intrinsic .IsSupported is true. However, we still have the redundant check to allow
// the JIT to see that the code is unreachable and eliminate it when the platform does not have hardware accelerated.
if (Vector.IsHardwareAccelerated)
if (Avx2.IsSupported)
{
if (offset < length)
{
lengthToExamine = GetCharVector256SpanLength(offset, length);
if (lengthToExamine > offset)
{
Vector256<ushort> values0 = Vector256.Create(value0);
Vector256<ushort> values1 = Vector256.Create(value1);
Vector256<ushort> values2 = Vector256.Create(value2);
Vector256<ushort> values3 = Vector256.Create(value3);
Vector256<ushort> values4 = Vector256.Create(value4);
do
{
Vector256<ushort> search = LoadVector256(ref searchSpace, offset);
// Note that MoveMask has converted the equal vector elements into a set of bit flags,
// So the bit position in 'matches' corresponds to the element offset.
int matches = Avx2.MoveMask(Avx2.CompareEqual(values0, search).AsByte());
// Bitwise Or to combine the flagged matches for the second, third, fourth and fifth values to our match flags
matches |= Avx2.MoveMask(Avx2.CompareEqual(values1, search).AsByte());
matches |= Avx2.MoveMask(Avx2.CompareEqual(values2, search).AsByte());
matches |= Avx2.MoveMask(Avx2.CompareEqual(values3, search).AsByte());
matches |= Avx2.MoveMask(Avx2.CompareEqual(values4, search).AsByte());
if (matches == 0)
{
// Zero flags set so no matches
offset += Vector256<ushort>.Count;
continue;
}

// Find bitflag offset of first match and add to current offset,
// flags are in bytes so divide for chars
return offset + (BitOps.TrailingZeroCount(matches) / sizeof(char));
} while (lengthToExamine > offset);
}

lengthToExamine = GetCharVector128SpanLength(offset, length);
if (lengthToExamine > offset)
{
Vector128<ushort> values0 = Vector128.Create(value0);
Vector128<ushort> values1 = Vector128.Create(value1);
Vector128<ushort> values2 = Vector128.Create(value2);
Vector128<ushort> values3 = Vector128.Create(value3);
Vector128<ushort> values4 = Vector128.Create(value4);
Vector128<ushort> search = LoadVector128(ref searchSpace, offset);

// Same method as above
int matches = Sse2.MoveMask(Sse2.CompareEqual(values0, search).AsByte());
matches |= Sse2.MoveMask(Sse2.CompareEqual(values1, search).AsByte());
matches |= Sse2.MoveMask(Sse2.CompareEqual(values2, search).AsByte());
matches |= Sse2.MoveMask(Sse2.CompareEqual(values3, search).AsByte());
matches |= Sse2.MoveMask(Sse2.CompareEqual(values4, search).AsByte());
if (matches == 0)
{
// Zero flags set so no matches
offset += Vector128<ushort>.Count;
}
else
{
// Find bitflag offset of first match and add to current offset,
// flags are in bytes so divide for chars
return offset + (BitOps.TrailingZeroCount(matches) / sizeof(char));
}
}

if (offset < length)
{
lengthToExamine = length - offset;
goto SequentialScan;
}
}
}
else if (Sse2.IsSupported)
{
if (offset < length)
{
lengthToExamine = GetCharVector128SpanLength(offset, length);

Vector128<ushort> values0 = Vector128.Create(value0);
Vector128<ushort> values1 = Vector128.Create(value1);
Vector128<ushort> values2 = Vector128.Create(value2);
Vector128<ushort> values3 = Vector128.Create(value3);
Vector128<ushort> values4 = Vector128.Create(value4);
while (lengthToExamine > offset)
{
Vector128<ushort> search = LoadVector128(ref searchSpace, offset);

// Same method as above
int matches = Sse2.MoveMask(Sse2.CompareEqual(values0, search).AsByte());
matches |= Sse2.MoveMask(Sse2.CompareEqual(values1, search).AsByte());
matches |= Sse2.MoveMask(Sse2.CompareEqual(values2, search).AsByte());
matches |= Sse2.MoveMask(Sse2.CompareEqual(values3, search).AsByte());
matches |= Sse2.MoveMask(Sse2.CompareEqual(values4, search).AsByte());
if (matches == 0)
{
// Zero flags set so no matches
offset += Vector128<ushort>.Count;
continue;
}

// Find bitflag offset of first match and add to current offset,
// flags are in bytes so divide for chars
return offset + (BitOps.TrailingZeroCount(matches) / sizeof(char));
}

if (offset < length)
{
lengthToExamine = length - offset;
goto SequentialScan;
}
}
}
else if (Vector.IsHardwareAccelerated)
{
if (offset < length)
{
Expand Down

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