Enable Dynamic PGO for IsIntanceOfAny and ChkCastAny

[EgorBo]

public class Class1 {}
public class Class2 : Class1 {}

[Benchmark]
public bool Test() => GenericCast<Class1>(new Class2());

[MethodImpl(MethodImplOptions.NoInlining)]
public bool GenericCast<T>(object o) => o is T;

Method	Toolchain	Mean	Ratio	Code Size
Test	\Core_Root_PR\corerun.exe	2.292 ns	1.00	112 B
Test	\Core_Root_base\corerun.exe	3.489 ns	1.54	89 B

; Assembly listing for method Program:GenericCast[System.__Canon](System.Object):bool:this
       sub      rsp, 40
       mov      qword ptr [rsp+20H], rdx
+      mov      rax, r8
+      test     rax, rax
+      je       SHORT G_M24407_IG05
+      mov      rcx, 0x7FFBE47CAF78  ;; Class2
+      cmp      qword ptr [rax], rcx
+      je       SHORT G_M24407_IG05
       mov      rcx, qword ptr [rdx+38H]
       mov      rcx, qword ptr [rcx]
       mov      rdx, r8
       call     [CORINFO_HELP_ISINSTANCEOFANY]
+G_M24407_IG05:  
       test     rax, rax
       setne    al
       movzx    rax, al
       add      rsp, 40
       ret      
-; Total bytes of code 39
+; Total bytes of code 62

(T)o is also improved because in #86728 we made it to use T as a fast path which won't help here (T is Class1 while the actual object is Class2).

[ghost]

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Issue Details

---

public class Class1 {}
public class Class2 : Class1 {}

[Benchmark]
public bool Test() => GenericCast<Class1>(new Class2());

[MethodImpl(MethodImplOptions.NoInlining)]
public bool GenericCast<T>(object o) => o is T;

Method	Toolchain	Mean	Ratio	Code Size
Test	\Core_Root_PR\corerun.exe	2.292 ns	1.00	112 B
Test	\Core_Root_base\corerun.exe	3.489 ns	1.54	89 B

; Assembly listing for method Program:GenericCast[System.__Canon](System.Object):bool:this
       sub      rsp, 40
       mov      qword ptr [rsp+20H], rdx
+      mov      rax, r8
+      test     rax, rax
+      je       SHORT G_M24407_IG05
+      mov      rcx, 0x7FFBE47CAF78  ;; Class2
+      cmp      qword ptr [rax], rcx
+      je       SHORT G_M24407_IG05
       mov      rcx, qword ptr [rdx+38H]
       mov      rcx, qword ptr [rcx]
       mov      rdx, r8
       call     [CORINFO_HELP_ISINSTANCEOFANY]
+G_M24407_IG05:  
       test     rax, rax
       setne    al
       movzx    rax, al
       add      rsp, 40
       ret      
-; Total bytes of code 39
+; Total bytes of code 62

(T)o is also improved because in #86728 we made it to use T as a fast path which won't help here (T is Class1 while the actual object is Class2).

Author:	EgorBo
Assignees:	-
Labels:	area-CodeGen-coreclr
Milestone:	-

[EgorBo]

I seem to see stable improvements in TechEmpower with DOTNET_JitProfileCasts=1 🤔, e.g. +2-3% in Plaintext-MVC (default vs this PR + DOTNET_JitProfileCasts=1)

(12 runs in total)

[EgorBo]

/azp run runtime-coreclr pgostress

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[EgorBo]

Actually, it's not legal in the current shape I guess.

 bool GenericCast<T>(object o) => o is T;

if we bake o is Class2 here and then use this shared method for completely differen type we might get a false-positive case.