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Use .tail prefix to optimize JIT-generated code #13

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Merged
merged 2 commits into from
Nov 7, 2023
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Use .tail prefix to optimize JIT-generated code #13

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224f2fb
Use .tail to optimize JIT-generated code
SergeiPavlov Nov 4, 2023
c710a14
Fix .Tail -> Tailcall
SergeiPavlov Nov 6, 2023
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1 change: 1 addition & 0 deletions LazyProxy/LazyProxyBuilder.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -235,6 +235,7 @@ private static TypeBuilder AddMethods(this TypeBuilder typeBuilder, Type type, F
generator.Emit(OpCodes.Ldarg, i);
}

generator.Emit(OpCodes.Tail);
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@hypercodeplace hypercodeplace Nov 6, 2023 •
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Just wondering, why is the difference with OpCodes.Tailcall? (I could't find any info about OpCodes.Tail in the docs).
And also, does this optimization work for all calls or for the recursion calls only?

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@SergeiPavlov SergeiPavlov Nov 6, 2023 •
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Ah, OpCodes.Tailcall is correct vor .NET (fixed the code)
And .Tail is for Cecil library used in DO

It works only before sequence call, ret
And this is not always recursive

I have already applied such change before and then reverted it c67bd84

My new understanding based on Debugger & StackTraces from dumps is:
Without .tail prefix the JIT optimizer SOMETIME can guess to do it, but not in 100% cases.
tail. prefix guarantees this kind of optimization

generator.Emit(OpCodes.Callvirt, method);
generator.Emit(OpCodes.Ret);

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