[llvm] [mlir] Add usub_cond and usub_sat operations to atomicrmw (PR #105568)

[via llvm-commits]

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@@ -1562,6 +1564,8 @@ bool AtomicExpandImpl::isIdempotentRMW(AtomicRMWInst *RMWI) {
   case AtomicRMWInst::Sub:
   case AtomicRMWInst::Or:
   case AtomicRMWInst::Xor:
+  case AtomicRMWInst::USubCond:
+  case AtomicRMWInst::USubSat:
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anjenner wrote:

If the optimization is likely to be deleted soon, then removing this part of the change seems like a better idea than adding new tests for it, so I have done that.

https://github.com/llvm/llvm-project/pull/105568