This is an alternative way of D139627 suggested by Craig. I'm not sure if there are other targets care about this attribute. Let's just start from AMDGPU.

This is an alternative way of D139627 suggested by Craig. Creently only X86 backend uses this attribute. Let's just emit for X86 only.

This is an alternative way of D139627 suggested by Craig. I'm not sure if there are other targets care aboutCreently only X86 backend uses this attribute. Let's just start from AMDGPUemit for X86 only.