[llvm] [AMDGPU] Move architected SGPR implementation into isel (PR #79120)

[Jay Foad via llvm-commits]

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@@ -0,0 +1,147 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=amdgcn-amd-hsa -mcpu=gfx900 -mattr=+architected-sgprs --verify-machineinstrs < %s | FileCheck -check-prefix=GFX9-SDAG %s
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jayfoad wrote:

> We have not enabled FeatureArchitectedSGPRs for GFX12 yet (I was going to do that in a later patch)

Actually I guess enabling it for GFX12 is orthogonal, so I have done that here: #79160

https://github.com/llvm/llvm-project/pull/79120