Casting via generic math doesn't always inline in R2R

[xtqqczze]

Related: #78648.

uint M0() => uint.CreateTruncating(42u);
uint M1() => uint.CreateTruncating((byte)42);
uint M2() => uint.CreateTruncating(42UL);
uint M3() => uint.CreateTruncating(42);
uint M4() => uint.CreateTruncating((sbyte)42);
int M5() => int.CreateTruncating(42);
int M6() => int.CreateTruncating((sbyte)42);
int M7() => int.CreateTruncating(42L);
int M8() => int.CreateTruncating(42u);
int M9() => int.CreateTruncating((byte)42);

// crossgen2 8.0.0-preview.4.23206.99+18e2c5fd9e2239a8b06fe49dbb6492d40f5e5e19

C:M0():uint:this:
; Emitting BLENDED_CODE for X64 CPU with SSE2 - Unix
						;; size=0 bbWeight=1 PerfScore 0.00
       mov      eax, 42
						;; size=5 bbWeight=1 PerfScore 0.25
       ret      
						;; size=1 bbWeight=1 PerfScore 1.00

C:M1():uint:this:
; Emitting BLENDED_CODE for X64 CPU with SSE2 - Unix
						;; size=0 bbWeight=1 PerfScore 0.00
       lea      rax, [(reloc)]
       mov      edi, 42
						;; size=12 bbWeight=1 PerfScore 0.75
       tail.jmp [rax]System.UInt32:CreateTruncating[ubyte](ubyte):uint
						;; size=3 bbWeight=1 PerfScore 2.00

C:M2():uint:this:
; Emitting BLENDED_CODE for X64 CPU with SSE2 - Unix
						;; size=0 bbWeight=1 PerfScore 0.00
       lea      rax, [(reloc)]
       mov      edi, 42
						;; size=12 bbWeight=1 PerfScore 0.75
       tail.jmp [rax]System.UInt32:CreateTruncating[ulong](ulong):uint
						;; size=3 bbWeight=1 PerfScore 2.00

C:M3():uint:this:
; Emitting BLENDED_CODE for X64 CPU with SSE2 - Unix
						;; size=0 bbWeight=1 PerfScore 0.00
       lea      rax, [(reloc)]
       mov      edi, 42
						;; size=12 bbWeight=1 PerfScore 0.75
       tail.jmp [rax]System.UInt32:CreateTruncating[int](int):uint
						;; size=3 bbWeight=1 PerfScore 2.00

C:M4():uint:this:
; Emitting BLENDED_CODE for X64 CPU with SSE2 - Unix
						;; size=0 bbWeight=1 PerfScore 0.00
       lea      rax, [(reloc)]
       mov      edi, 42
						;; size=12 bbWeight=1 PerfScore 0.75
       tail.jmp [rax]System.UInt32:CreateTruncating[byte](byte):uint
						;; size=3 bbWeight=1 PerfScore 2.00

C:M5():int:this:
; Emitting BLENDED_CODE for X64 CPU with SSE2 - Unix
						;; size=0 bbWeight=1 PerfScore 0.00
       mov      eax, 42
						;; size=5 bbWeight=1 PerfScore 0.25
       ret      
						;; size=1 bbWeight=1 PerfScore 1.00

C:M6():int:this:
; Emitting BLENDED_CODE for X64 CPU with SSE2 - Unix
						;; size=0 bbWeight=1 PerfScore 0.00
       lea      rax, [(reloc)]
       mov      edi, 42
						;; size=12 bbWeight=1 PerfScore 0.75
       tail.jmp [rax]System.Int32:CreateTruncating[byte](byte):int
						;; size=3 bbWeight=1 PerfScore 2.00

C:M7():int:this:
; Emitting BLENDED_CODE for X64 CPU with SSE2 - Unix
						;; size=0 bbWeight=1 PerfScore 0.00
       lea      rax, [(reloc)]
       mov      edi, 42
						;; size=12 bbWeight=1 PerfScore 0.75
       tail.jmp [rax]System.Int32:CreateTruncating[long](long):int
						;; size=3 bbWeight=1 PerfScore 2.00

C:M8():int:this:
; Emitting BLENDED_CODE for X64 CPU with SSE2 - Unix
						;; size=0 bbWeight=1 PerfScore 0.00
       lea      rax, [(reloc)]
       mov      edi, 42
						;; size=12 bbWeight=1 PerfScore 0.75
       tail.jmp [rax]System.Int32:CreateTruncating[uint](uint):int
						;; size=3 bbWeight=1 PerfScore 2.00

C:M9():int:this:
; Emitting BLENDED_CODE for X64 CPU with SSE2 - Unix
						;; size=0 bbWeight=1 PerfScore 0.00
       lea      rax, [(reloc)]
       mov      edi, 42
						;; size=12 bbWeight=1 PerfScore 0.75
       tail.jmp [rax]System.Int32:CreateTruncating[ubyte](ubyte):int
						;; size=3 bbWeight=1 PerfScore 2.00

https://csharp.godbolt.org/z/K6xM8hP6P

Tagging subscribers to this area: @JulieLeeMSFT, @jakobbotsch, @kunalspathak
See info in area-owners.md if you want to be subscribed.

Issue Details

---

See #78648.

cc: @EgorBo

https://csharp.godbolt.org/z/K6xM8hP6P

// crossgen2 8.0.0-preview.4.23206.99+18e2c5fd9e2239a8b06fe49dbb6492d40f5e5e19

C:M0():uint:this:
; Emitting BLENDED_CODE for X64 CPU with SSE2 - Unix
						;; size=0 bbWeight=1 PerfScore 0.00
       mov      eax, 42
						;; size=5 bbWeight=1 PerfScore 0.25
       ret      
						;; size=1 bbWeight=1 PerfScore 1.00

C:M1():uint:this:
; Emitting BLENDED_CODE for X64 CPU with SSE2 - Unix
						;; size=0 bbWeight=1 PerfScore 0.00
       lea      rax, [(reloc)]
       mov      edi, 42
						;; size=12 bbWeight=1 PerfScore 0.75
       tail.jmp [rax]System.UInt32:CreateTruncating[ubyte](ubyte):uint
						;; size=3 bbWeight=1 PerfScore 2.00

C:M2():uint:this:
; Emitting BLENDED_CODE for X64 CPU with SSE2 - Unix
						;; size=0 bbWeight=1 PerfScore 0.00
       lea      rax, [(reloc)]
       mov      edi, 42
						;; size=12 bbWeight=1 PerfScore 0.75
       tail.jmp [rax]System.UInt32:CreateTruncating[ulong](ulong):uint
						;; size=3 bbWeight=1 PerfScore 2.00

C:M3():uint:this:
; Emitting BLENDED_CODE for X64 CPU with SSE2 - Unix
						;; size=0 bbWeight=1 PerfScore 0.00
       lea      rax, [(reloc)]
       mov      edi, 42
						;; size=12 bbWeight=1 PerfScore 0.75
       tail.jmp [rax]System.UInt32:CreateTruncating[int](int):uint
						;; size=3 bbWeight=1 PerfScore 2.00

C:M4():uint:this:
; Emitting BLENDED_CODE for X64 CPU with SSE2 - Unix
						;; size=0 bbWeight=1 PerfScore 0.00
       lea      rax, [(reloc)]
       mov      edi, 42
						;; size=12 bbWeight=1 PerfScore 0.75
       tail.jmp [rax]System.UInt32:CreateTruncating[byte](byte):uint
						;; size=3 bbWeight=1 PerfScore 2.00

C:M5():int:this:
; Emitting BLENDED_CODE for X64 CPU with SSE2 - Unix
						;; size=0 bbWeight=1 PerfScore 0.00
       mov      eax, 42
						;; size=5 bbWeight=1 PerfScore 0.25
       ret      
						;; size=1 bbWeight=1 PerfScore 1.00

C:M6():int:this:
; Emitting BLENDED_CODE for X64 CPU with SSE2 - Unix
						;; size=0 bbWeight=1 PerfScore 0.00
       lea      rax, [(reloc)]
       mov      edi, 42
						;; size=12 bbWeight=1 PerfScore 0.75
       tail.jmp [rax]System.Int32:CreateTruncating[byte](byte):int
						;; size=3 bbWeight=1 PerfScore 2.00

C:M7():int:this:
; Emitting BLENDED_CODE for X64 CPU with SSE2 - Unix
						;; size=0 bbWeight=1 PerfScore 0.00
       lea      rax, [(reloc)]
       mov      edi, 42
						;; size=12 bbWeight=1 PerfScore 0.75
       tail.jmp [rax]System.Int32:CreateTruncating[long](long):int
						;; size=3 bbWeight=1 PerfScore 2.00

C:M8():int:this:
; Emitting BLENDED_CODE for X64 CPU with SSE2 - Unix
						;; size=0 bbWeight=1 PerfScore 0.00
       lea      rax, [(reloc)]
       mov      edi, 42
						;; size=12 bbWeight=1 PerfScore 0.75
       tail.jmp [rax]System.Int32:CreateTruncating[uint](uint):int
						;; size=3 bbWeight=1 PerfScore 2.00

C:M9():int:this:
; Emitting BLENDED_CODE for X64 CPU with SSE2 - Unix
						;; size=0 bbWeight=1 PerfScore 0.00
       lea      rax, [(reloc)]
       mov      edi, 42
						;; size=12 bbWeight=1 PerfScore 0.75
       tail.jmp [rax]System.Int32:CreateTruncating[ubyte](ubyte):int
						;; size=3 bbWeight=1 PerfScore 2.00

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

[JulieLeeMSFT]

We will push this to Future becuase we will not have time to work on this in .NET 8.

[EgorBo]

@xtqqczze it emits expected codegen for JIT and NativeAOT, seems to be R2R specific, from what I see R2R runtime throws

Internal.JitInterface.RequiresRuntimeJitException: SVM
   at Internal.JitInterface.CorInfoImpl.getCallInfo(CORINFO_RESOLVED_TOKEN& pResolvedToken, CORINFO_RESOLVED_TOKEN* pConstrainedResolvedToken, CORINFO_METHOD_STRUCT_* callerHandle, CORINFO_CALLINFO_FLAGS flags, CORINFO_CALL_INFO* pResult) in C:\prj\runtime\src\coreclr\tools\aot\ILCompiler.ReadyToRun\JitInterface\CorInfoImpl.ReadyToRun.cs:line 2109
   at Internal.JitInterface.CorInfoImpl._getCallInfo(IntPtr thisHandle, IntPtr* ppException, CORINFO_RESOLVED_TOKEN* pResolvedToken, CORINFO_RESOLVED_TOKEN* pConstrainedResolvedToken, CORINFO_METHOD_STRUCT_* callerHandle, CORINFO_CALLINFO_FLAGS flags, CORINFO_CALL_INFO* pResult) in C:\prj\runtime\src\coreclr\tools\Common\JitInterface\CorInfoImpl_generated.cs:line 2178

for getCallInfo during inlining so JIT gives up on inlining due to error

[stephentoub]

We will push this to Future becuase we will not have time to work on this in .NET 8.

seems to be R2R specific

In case it impacts prioritization, we're on a path to make fairly heavy use of this throughout core formatting/parsing logic, as in #84469.

[EgorBo]

@dotnet/crossgen-contrib any idea what we can do here for crossgen, is it simply not supported?

uint M1() => uint.CreateTruncating((byte)42);

This exception leads to this codegen for R2R:

C:M1():uint:this:
; Emitting BLENDED_CODE for X64 CPU with SSE2 - Unix
       lea      rax, [(reloc)]
       mov      edi, 42
       tail.jmp [rax]System.UInt32:CreateTruncating[ubyte](ubyte):uint

because JIT caught the exception and decided that it can't inline it

[trylek]

Well, Crossgen2 doesn't yet support static virtual method resolution, that was planned for .NET 7 but it got cut as it turned out to be quite challenging and we didn't get to it early enough in the release cycle. If it becomes more of a perf problem now we can discuss its prioritization among .NET 8 Crossgen2 work. If the method is not a static virtual then that's just a bug in the check that should be easy to fix.

[EgorBo]

Yes it's static virtual TSelf CreateTruncating.

If it becomes more of a perf problem

I assume it could be e.g. for customers who disable tiering since we now use more and more of these

[trylek]

OK, thanks for pointing it out, I'll discuss it at today Crossgen2 weekly sync. Maybe we could start supporting at least some cases, IIRC the main problem is precompilation of canonical methods where the resolution depends on the actual type passed at runtime i.o.w. there's no way to resolve the call at compile time.