[llvm] AMDGPU: Drop and upgrade llvm.amdgcn.atomic.csub/cond.sub to atomicrmw (PR #105553)

[Matt Arsenault via llvm-commits]

================
@@ -0,0 +1,197 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -global-isel -mtriple=amdgcn-amd-amdhsa -mcpu=gfx1200 < %s | FileCheck %s -check-prefix=GFX12-GISEL
+; RUN: llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx1200 < %s | FileCheck %s -check-prefix=GFX12-SDAG
+
----------------
arsenm wrote:

Filename should be renamed to match usub_cond 

https://github.com/llvm/llvm-project/pull/105553