15 years ago there weren't RyuJIT which replaced the JIT you learned from, MDIL (Windows 8/8.1), .NET Native (UWP), IL2CPP (Unity), and the research ones from Singularity and Midori.
In what concerns the need for it, they have been trying to make C# more relevant for the kinds of C++ workloads and getting among the first places at TechEmpower.
So .NET has been getting Modula-3 like low level handling of value types within a GC environment, RyuJIT is now tiered, supports SIMD and some automatic vectorization.
.NET Framework 4.6 got the first version of what is the .NET way of doing AppCDS.
There are a couple of blog posts regarding RyuJIT improvements with each release after its introduction.
So which of these implementations does speculation? I remember when RyuJIT came out it still wasn't speculative - has that now changed?
If you read the blog posts, they always talk about speculation being something they may try in the future. I've not seen anything where they say they went ahead and implemented it.
Seems like they started trying speculative optimizations about six months ago. Speculative optimizations are not only the foundation of Graal but also of C2, BTW.
In what concerns the need for it, they have been trying to make C# more relevant for the kinds of C++ workloads and getting among the first places at TechEmpower.
So .NET has been getting Modula-3 like low level handling of value types within a GC environment, RyuJIT is now tiered, supports SIMD and some automatic vectorization.
.NET Framework 4.6 got the first version of what is the .NET way of doing AppCDS.
There are a couple of blog posts regarding RyuJIT improvements with each release after its introduction.