Arm64: Always use SIMD features

[kunalspathak]

On Arm64, we always support SIMD types but in the code base, we were sometimes relying on featureSIMD flag which can be false in case COMPlus_FeatureSIMD=0 and doesn't work on Arm64. On Arm64, we always need SIMD features to support ABI handling. Modified all the usages to instead use supportSIMDTypes().

Will fix #64972

Thanks @tannergooding for your the references:

• Assertion failed 'comp->supportSIMDTypes()' #66206
• Current state of the SIMD/HWIntrinsic configuration knobs and proposed cleanup #11701
• Decouple FEATURE_HW_INTRINSICS from FEATURE_SIMD #9473.

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Issue Details

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On Arm64, we always support SIMD types but in the code base, we were sometimes relying on featureSIMD flag which can be false in case COMPlus_FeatureSIMD=0. Modified all the usages to instead use supportSIMDTypes().

Reference: #66206, #11701 and #9473.

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

[kunalspathak]

@dotnet/jit-contrib

[kunalspathak]

The underlying problem #64972 (comment) still needs a fix, but this will unblock the outerloop.

[tannergooding]

We should also make the backing field private to enforce usage goes through the method.

Might also be good to ensure https://github.com/dotnet/runtime/blob/main/src/coreclr/jit/compiler.cpp#L2670 is either always setting the field to true on Arm64 or that the field doesn't exist on Arm64.

[kunalspathak]

We should also make the backing field private to enforce usage goes through the method.

It is already private and the usage was in Compiler methods.

Might also be good to ensure https://github.com/dotnet/runtime/blob/main/src/coreclr/jit/compiler.cpp#L2670 is either always setting the field to true on Arm64 or that the field doesn't exist on Arm64.

I can make that x64 only field.

[kunalspathak]

ping