Most significant bit and bool-to-int conversions.

[redknightlois]

It appears that the JIT is quite bad at optimizing Convert.Int32(bool)

// BenchmarkDotNet=v0.7.6.0
// OS=Microsoft Windows NT 6.2.9200.0
// Processor=Intel(R) Core(TM) i5-2500K CPU @ 3.30GHz, ProcessorCount=4
// CLR=MS.NET 4.0.30319.42000, Arch=64-bit [RyuJIT]
Common: Type=Jit_BoolToInt Mode=Throughput Platform=X64 .NET=Current

Method	Jit	AvrTime	StdDev	op/s
Framework	LegacyJit	1.16 us	28.20 ns	858517.79
IfThenElse	LegacyJit	1.08 us	44.58 ns	929458.93
UnsafeConvert	LegacyJit	595.83 ns	5.79 ns	1678333.61
Framework	RyuJit	1.31 us	18.64 ns	765539.56
IfThenElse	RyuJit	1.31 us	16.05 ns	761023.73
UnsafeConvert	RyuJit	896.80 ns	6.27 ns	1115078.04

[redknightlois]

Updated the bool-to-int to avoid the use of arrays.

Results are even worse for RyuJIT

// BenchmarkDotNet=v0.7.6.0
// OS=Microsoft Windows NT 6.2.9200.0
// Processor=Intel(R) Core(TM) i5-3470 CPU @ 3.20GHz, ProcessorCount=4
// CLR=MS.NET 4.0.30319.42000, Arch=64-bit [RyuJIT]
Common: Type=Jit_BoolToInt Mode=Throughput Platform=X64 .NET=Current

Method	Jit	AvrTime	StdDev	op/s
Framework	LegacyJit	1.47 ns	0.0191 ns	678168087.72
IfThenElse	LegacyJit	1.48 ns	0.0249 ns	676316149.82
UnsafeConvert	LegacyJit	0.299 ns	0.00806 ns	3340169067.7
Framework	RyuJit	2.97 ns	0.0216 ns	336993897.01
IfThenElse	RyuJit	2.96 ns	0.0141 ns	338053580.07
UnsafeConvert	RyuJit	8.59 ns	0.0329 ns	116442151.41