[llvm] [X86]Remove X86-specific dead code in ScheduleDAGRRList.cpp (PR #67629)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-selectiondag

<details>
<summary>Changes</summary>

After patch https://github.com/llvm/llvm-project/pull/67288 landed, unfoldMemoryOperand would not return NewMIs whose size ==3. So the removed line is useless.

---
Full diff: https://github.com/llvm/llvm-project/pull/67629.diff


1 Files Affected:

- (modified) llvm/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp (-5) 


``````````diff
diff --git a/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp b/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp
index 36f68e9363ebd55..47c137d2bcad733 100644
--- a/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp
@@ -986,11 +986,6 @@ SUnit *ScheduleDAGRRList::TryUnfoldSU(SUnit *SU) {
   if (!TII->unfoldMemoryOperand(*DAG, N, NewNodes))
     return nullptr;
 
-  // unfolding an x86 DEC64m operation results in store, dec, load which
-  // can't be handled here so quit
-  if (NewNodes.size() == 3)
-    return nullptr;
-
   assert(NewNodes.size() == 2 && "Expected a load folding node!");
 
   N = NewNodes[1];

``````````

</details>


https://github.com/llvm/llvm-project/pull/67629