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Improve performance for Math.Abs #15823

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merged 4 commits into from Jan 11, 2018
Merged

Improve performance for Math.Abs #15823

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d510752
Improve perf for Math.Abs
benaadams Jan 11, 2018
76d996d
Inline Math.Abs
benaadams Jan 11, 2018
7b87ccc
revert inverting dec .ctor
benaadams Jan 11, 2018
7df3191
Revert Decimal change
benaadams Jan 11, 2018
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94 changes: 42 additions & 52 deletions src/mscorlib/shared/System/Math.cs
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Expand Up @@ -38,23 +38,55 @@ public static partial class Math

public static short Abs(short value)
{
return (value >= 0) ? value : AbsHelper(value);
if (value < 0)
{
value = (short)-value;
if (value < 0)
{
ThrowAbsOverflow();
}
}
return value;
}

public static int Abs(int value)
{
return (value >= 0) ? value : AbsHelper(value);
if (value < 0)
{
value = -value;
if (value < 0)
{
ThrowAbsOverflow();
}
}
return value;
}

public static long Abs(long value)
{
return (value >= 0) ? value : AbsHelper(value);
if (value < 0)
{
value = -value;
if (value < 0)
{
ThrowAbsOverflow();
}
}
return value;
}

[CLSCompliant(false)]
public static sbyte Abs(sbyte value)
{
return (value >= 0) ? value : AbsHelper(value);
if (value < 0)
{
value = (sbyte)-value;
if (value < 0)
{
ThrowAbsOverflow();
}
}
return value;
}

[MethodImpl(MethodImplOptions.AggressiveInlining)]
Expand All @@ -63,6 +95,12 @@ public static decimal Abs(decimal value)
return decimal.Abs(value);
}

[StackTraceHidden]
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What does this do, prevent inlining?

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Stops it showing up in exception stack trace #14652 so it looks like the throw was in-place rather than off a throw helper function

private static void ThrowAbsOverflow()
{
throw new OverflowException(SR.Overflow_NegateTwosCompNum);
}

public static long BigMul(int a, int b)
{
return ((long)a) * b;
Expand Down Expand Up @@ -758,54 +796,6 @@ public static unsafe double Truncate(double d)
return d;
}

private static short AbsHelper(short value)
{
Debug.Assert(value < 0, "AbsHelper should only be called for negative values! (workaround for JIT inlining)");

if (value == short.MinValue)
{
throw new OverflowException(SR.Overflow_NegateTwosCompNum);
}

return ((short)(-value));
}

private static int AbsHelper(int value)
{
Debug.Assert(value < 0, "AbsHelper should only be called for negative values! (workaround for JIT inlining)");

if (value == int.MinValue)
{
throw new OverflowException(SR.Overflow_NegateTwosCompNum);
}

return -value;
}

private static long AbsHelper(long value)
{
Debug.Assert(value < 0, "AbsHelper should only be called for negative values! (workaround for JIT inlining)");

if (value == long.MinValue)
{
throw new OverflowException(SR.Overflow_NegateTwosCompNum);
}

return -value;
}

private static sbyte AbsHelper(sbyte value)
{
Debug.Assert(value < 0, "AbsHelper should only be called for negative values! (workaround for JIT inlining)");

if (value == sbyte.MinValue)
{
throw new OverflowException(SR.Overflow_NegateTwosCompNum);
}

return ((sbyte)(-value));
}

private static unsafe double copysign(double x, double y)
{
var xbits = BitConverter.DoubleToInt64Bits(x);
Expand Down