[NFCI][SimplifyCFG] removeEmptyCleanup(): streamline PHI node updating

Author: LebedevRI

llvm/lib/Transforms/Utils/SimplifyCFG.cpp

@@ -4489,22 +4489,11 @@ static bool removeEmptyCleanup(CleanupReturnInst *RI, DomTreeUpdater *DTU) {
       // Remove the entry for the block we are deleting.
       DestPN.removeIncomingValue(Idx, false);
 
-      if (SrcPN && SrcPN->getParent() == BB) {
-        // If the incoming value was a PHI node in the cleanup pad we are
-        // removing, we need to merge that PHI node's incoming values into
-        // DestPN.
-        for (unsigned SrcIdx = 0, SrcE = SrcPN->getNumIncomingValues();
-             SrcIdx != SrcE; ++SrcIdx) {
-          DestPN.addIncoming(SrcPN->getIncomingValue(SrcIdx),
-                             SrcPN->getIncomingBlock(SrcIdx));
-        }
-      } else {
-        // Otherwise, the incoming value came from above BB and
-        // so we can just reuse it.  We must associate all of BB's
-        // predecessors with this value.
-        for (auto *pred : predecessors(BB)) {
-          DestPN.addIncoming(SrcVal, pred);
-        }
+      bool NeedPHITranslation = SrcPN && SrcPN->getParent() == BB;
+      for (auto *Pred : predecessors(BB)) {
+        Value *Incoming =
+            NeedPHITranslation ? SrcPN->getIncomingValueForBlock(Pred) : SrcVal;
+        DestPN.addIncoming(Incoming, Pred);
       }
     }