Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

[release/7.0] Ensure that the result for PowMod is fully initialized #74672

Merged
merged 2 commits into from
Aug 28, 2022
Merged

[release/7.0] Ensure that the result for PowMod is fully initialized #74672

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
4b39bb4
Adding a regression test for dotnet/performance#2575
tannergooding Aug 25, 2022
e565249
Ensure that the result span is fully initialized.
tannergooding Aug 25, 2022
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
30 changes: 20 additions & 10 deletions src/libraries/System.Runtime.Numerics/src/System/Numerics/BigIntegerCalculator.PowMod.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -35,7 +35,9 @@ stackalloc uint[StackAllocThreshold]
value.CopyTo(valueCopy);
valueCopy.Slice(value.Length).Clear();

PowCore(valueCopy, value.Length, temp, power, bits).CopyTo(bits);
Span<uint> result = PowCore(valueCopy, value.Length, temp, power, bits);
result.CopyTo(bits);
bits.Slice(result.Length).Clear();

if (tempFromPool != null)
ArrayPool<uint>.Shared.Return(tempFromPool);
Expand All @@ -50,19 +52,19 @@ private static Span<uint> PowCore(Span<uint> value, int valueLength, Span<uint>
Debug.Assert(value.Length == temp.Length);

result[0] = 1;
int bitsLength = 1;
int resultLength = 1;

// The basic pow algorithm using square-and-multiply.
while (power != 0)
{
if ((power & 1) == 1)
bitsLength = MultiplySelf(ref result, bitsLength, value.Slice(0, valueLength), ref temp);
resultLength = MultiplySelf(ref result, resultLength, value.Slice(0, valueLength), ref temp);
if (power != 1)
valueLength = SquareSelf(ref value, valueLength, ref temp);
power >>= 1;
}

return result;
return result.Slice(0, resultLength);
}

private static int MultiplySelf(ref Span<uint> left, int leftLength, ReadOnlySpan<uint> right, ref Span<uint> temp)
Expand Down Expand Up @@ -313,7 +315,9 @@ private static void PowCore(Span<uint> value, int valueLength,

if (modulus.Length < ReducerThreshold)
{
PowCore(value, valueLength, power, modulus, bits, 1, temp).CopyTo(bits);
Span<uint> result = PowCore(value, valueLength, power, modulus, bits, 1, temp);
result.CopyTo(bits);
bits.Slice(result.Length).Clear();
}
else
{
Expand Down Expand Up @@ -349,7 +353,9 @@ stackalloc uint[StackAllocThreshold]
if (rFromPool != null)
ArrayPool<uint>.Shared.Return(rFromPool);

PowCore(value, valueLength, power, reducer, bits, 1, temp).CopyTo(bits);
Span<uint> result = PowCore(value, valueLength, power, reducer, bits, 1, temp);
result.CopyTo(bits);
bits.Slice(result.Length).Clear();

if (muFromPool != null)
ArrayPool<uint>.Shared.Return(muFromPool);
Expand All @@ -369,7 +375,9 @@ private static void PowCore(Span<uint> value, int valueLength,

if (modulus.Length < ReducerThreshold)
{
PowCore(value, valueLength, power, modulus, bits, 1, temp).CopyTo(bits);
Span<uint> result = PowCore(value, valueLength, power, modulus, bits, 1, temp);
result.CopyTo(bits);
bits.Slice(result.Length).Clear();
}
else
{
Expand Down Expand Up @@ -405,7 +413,9 @@ stackalloc uint[StackAllocThreshold]
if (rFromPool != null)
ArrayPool<uint>.Shared.Return(rFromPool);

PowCore(value, valueLength, power, reducer, bits, 1, temp).CopyTo(bits);
Span<uint> result = PowCore(value, valueLength, power, reducer, bits, 1, temp);
result.CopyTo(bits);
bits.Slice(result.Length).Clear();

if (muFromPool != null)
ArrayPool<uint>.Shared.Return(muFromPool);
Expand Down Expand Up @@ -472,7 +482,7 @@ private static Span<uint> PowCore(Span<uint> value, int valueLength,
power >>= 1;
}

return result;
return result.Slice(0, resultLength);
}

private static Span<uint> PowCore(Span<uint> value, int valueLength,
Expand Down Expand Up @@ -531,7 +541,7 @@ private static Span<uint> PowCore(Span<uint> value, int valueLength,
power >>= 1;
}

return result;
return result.Slice(0, resultLength);
}
}
}
15 changes: 14 additions & 1 deletion src/libraries/System.Runtime.Numerics/tests/BigInteger/modpow.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -275,7 +275,7 @@ public static void ModPowAxiom()
}

[Fact]
public static void RegressionIssue70330()
public static void RegressionIssueRuntime70330()
{
byte[] tempByteArray1 = { 226, 32 };
byte[] tempByteArray2 = { 113 };
Expand All @@ -286,6 +286,19 @@ public static void RegressionIssue70330()
);
}

[Fact]
public static void RegressionIssuePerformance2575()
{
byte[] tempByteArray1 = { 0x93, 0x30, 0x70, 0xD8, 0x74, 0x0A, 0x70, 0x79, 0x18, 0x5A, 0xCD, 0x2D, 0x39, 0xBF, 0x36, 0xC6, 0x24, 0xDE, 0x4B, 0xD5, 0xC7, 0xB4, 0x56, 0x23, 0xB2, 0xB4, 0xB7, 0x43, 0xE5, 0x05, 0xDD, 0xAF, 0x97, 0x81, 0x67, 0xCB, 0x67, 0xE9, 0x53, 0x5A, 0x00, 0x42, 0x9B, 0x20, 0x56, 0xFA, 0xBE, 0x27, 0x6A, 0x14, 0x36, 0x17, 0x49, 0xC5, 0xAC, 0xDF, 0xDA, 0x4C, 0x26, 0xC0, 0x52, 0x2C, 0x93, 0x13, 0x7D, 0x1E, 0x96, 0xB8, 0x58, 0x6B, 0x5F, 0x3A, 0x8B, 0xF1, 0xD5, 0x84, 0x18, 0x36, 0xCC, 0xB7, 0xF5, 0x90, 0xD9, 0xD1, 0xCE, 0xC5, 0x65, 0xD2, 0xD5, 0x87, 0xF0, 0x1B, 0xC3, 0x92, 0x07, 0xD3, 0xAF, 0x88, 0xA2, 0x38, 0x64, 0x06, 0xCE, 0xFE, 0xB5, 0xFC, 0x8C, 0x58, 0xEF, 0x27, 0xC6, 0xA4, 0x7F, 0x6E, 0xCA, 0xC2, 0x53, 0xC2, 0x44, 0xB7, 0xB8, 0xC3, 0xE2, 0xD0, 0x7A, 0x43, 0x76, 0xF8, 0x00 };
byte[] tempByteArray2 = { 0x02, 0xD4, 0x90, 0x93, 0x94, 0x52, 0xEF, 0xC1, 0xDA, 0x1B, 0xD2, 0x39, 0x0D, 0xE3, 0xAD, 0xC1, 0x4C, 0x9B, 0x54, 0xC8, 0x44, 0x7F, 0xED, 0x43, 0xEA, 0x7F, 0xA1, 0x23, 0xFE, 0x84, 0x71, 0x85, 0x93, 0x6E, 0xEC, 0x53, 0x35, 0x10, 0xEB, 0x1C, 0xDA, 0x01, 0x78, 0xA6, 0x71, 0x7E, 0xAB, 0xE0, 0x35, 0x0F, 0x2E, 0xA8, 0x21, 0x30, 0xA5, 0x83, 0xE7, 0x4C, 0xA9, 0x14, 0xB0, 0xCC, 0xC3, 0x56, 0xAA, 0x4C, 0xA5, 0x9E, 0xF6, 0x5A, 0x8B, 0x3C, 0xAF, 0x38, 0xED, 0x43, 0x06, 0x46, 0xD2, 0x6C, 0xD3, 0xC1, 0xED, 0xEE, 0x55, 0xC8, 0x63, 0x63, 0xC9, 0x69, 0x6B, 0xE8, 0x67, 0xD6, 0x6B, 0x0D, 0x3E, 0x22, 0xFC, 0x24, 0xD8, 0x0C, 0xEA, 0xDB, 0x83, 0xF2, 0xF9, 0xE9, 0x43, 0x61, 0x7C, 0xA0, 0x7A, 0x3D, 0x41, 0xEF, 0xDF, 0xD4, 0x00, 0xE1, 0xE9, 0x42, 0xD5, 0x8C, 0xEE, 0xA3, 0xD5, 0xD8, 0x00 };
byte[] tempByteArray3 = { 0xDF, 0x05, 0xE4, 0x4A, 0xAD, 0x93, 0xC6, 0xD7, 0x00 };
byte[] tempByteArray4 = { 0xC6, 0x57, 0x30, 0x3F, 0xCE, 0x21, 0xA0, 0x3D };
VerifyIdentityString(
Print(tempByteArray3) + Print(tempByteArray2) + Print(tempByteArray1) + "tModPow",
Print(tempByteArray4)
);
}

[Fact]
public static void ModPowBoundary()
{
Expand Down