[llvm] [AMDGPU] Add new GFX12 image atomic float instructions (PR #76946)

[Matt Arsenault via llvm-commits]

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@@ -0,0 +1,40 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -march=amdgcn -mcpu=gfx1200 -verify-machineinstrs < %s | FileCheck -check-prefix=GFX12 %s
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arsenm wrote:

Should use an explicit -global-isel=0 for the DAG test; also don't really need -verify-machineinstrs 

https://github.com/llvm/llvm-project/pull/76946