diff --git a/llvm/include/llvm/Transforms/Utils/SSAUpdaterImpl.h b/llvm/include/llvm/Transforms/Utils/SSAUpdaterImpl.h
index 15d65bcf8c6d7299e0e07b3ed95cd7686a37bbf1..a9adbd73c152e590894bb730533575864ddee28a 100644
--- a/llvm/include/llvm/Transforms/Utils/SSAUpdaterImpl.h
+++ b/llvm/include/llvm/Transforms/Utils/SSAUpdaterImpl.h
@@ -380,7 +380,7 @@ public:
       if (!SomePHI)
         break;
       if (CheckIfPHIMatches(SomePHI)) {
-        RecordMatchingPHI(SomePHI);
+        RecordMatchingPHIs(BlockList);
         break;
       }
       // Match failed: clear all the PHITag values.
@@ -437,38 +437,17 @@ public:
     return true;
   }
 
-  /// RecordMatchingPHI - For a PHI node that matches, record it and its input
-  /// PHIs in both the BBMap and the AvailableVals mapping.
-  void RecordMatchingPHI(PhiT *PHI) {
-    SmallVector<PhiT*, 20> WorkList;
-    WorkList.push_back(PHI);
-
-    // Record this PHI.
-    BlkT *BB = PHI->getParent();
-    ValT PHIVal = Traits::GetPHIValue(PHI);
-    (*AvailableVals)[BB] = PHIVal;
-    BBMap[BB]->AvailableVal = PHIVal;
-
-    while (!WorkList.empty()) {
-      PHI = WorkList.pop_back_val();
-
-      // Iterate through the PHI's incoming values.
-      for (typename Traits::PHI_iterator I = Traits::PHI_begin(PHI),
-             E = Traits::PHI_end(PHI); I != E; ++I) {
-        ValT IncomingVal = I.getIncomingValue();
-        PhiT *IncomingPHI = Traits::ValueIsPHI(IncomingVal, Updater);
-        if (!IncomingPHI) continue;
-        BB = IncomingPHI->getParent();
-        BBInfo *Info = BBMap[BB];
-        if (!Info || Info->AvailableVal)
-          continue;
-
-        // Record the PHI and add it to the worklist.
-        (*AvailableVals)[BB] = IncomingVal;
-        Info->AvailableVal = IncomingVal;
-        WorkList.push_back(IncomingPHI);
+  /// RecordMatchingPHIs - For each PHI node that matches, record it in both
+  /// the BBMap and the AvailableVals mapping.
+  void RecordMatchingPHIs(BlockListTy *BlockList) {
+    for (typename BlockListTy::iterator I = BlockList->begin(),
+           E = BlockList->end(); I != E; ++I)
+      if (PhiT *PHI = (*I)->PHITag) {
+        BlkT *BB = PHI->getParent();
+        ValT PHIVal = Traits::GetPHIValue(PHI);
+        (*AvailableVals)[BB] = PHIVal;
+        BBMap[BB]->AvailableVal = PHIVal;
       }
-    }
   }
 };
 
diff --git a/llvm/test/Transforms/ScalarRepl/phi-cycle.ll b/llvm/test/Transforms/ScalarRepl/phi-cycle.ll
new file mode 100644
index 0000000000000000000000000000000000000000..cb5101c2dd8eb7827038eb6b2751ff660816f234
--- /dev/null
+++ b/llvm/test/Transforms/ScalarRepl/phi-cycle.ll
@@ -0,0 +1,77 @@
+; RUN: opt -S -scalarrepl-ssa < %s | FileCheck %s
+; rdar://10589171
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+%struct.foo = type { i32, i32 }
+
+@.str = private unnamed_addr constant [6 x i8] c"x=%d\0A\00", align 1
+
+define i32 @main(i32 %argc, i8** nocapture %argv) nounwind uwtable {
+entry:
+  %f = alloca %struct.foo, align 4
+  %x.i = getelementptr inbounds %struct.foo* %f, i64 0, i32 0
+  store i32 1, i32* %x.i, align 4
+  %y.i = getelementptr inbounds %struct.foo* %f, i64 0, i32 1
+  br label %while.cond.i
+
+; CHECK: while.cond.i:
+; CHECK-NEXT: %tmp = phi i32 [ 1, %entry ], [ %tmp2, %while.cond.backedge.i ]
+; CHECK-NEXT: %pos.0.i = phi i32 [ 1, %entry ], [ %xtmp.i, %while.cond.backedge.i ]
+; CHECK-NEXT: %left.0.i = phi i32 [ 1, %entry ], [ %dec.i, %while.cond.backedge.i ]
+; CHECK-NOT: phi
+while.cond.i:                                     ; preds = %while.cond.backedge.i, %entry
+  %tmp = phi i32 [ 1, %entry ], [ %tmp2, %while.cond.backedge.i ]
+  %pos.0.i = phi i32 [ 1, %entry ], [ %xtmp.i, %while.cond.backedge.i ]
+  %left.0.i = phi i32 [ 1, %entry ], [ %dec.i, %while.cond.backedge.i ]
+  %cmp.i = icmp sgt i32 %left.0.i, 0
+  br i1 %cmp.i, label %while.body.i, label %while.cond.i.func.exit_crit_edge
+
+while.cond.i.func.exit_crit_edge:                 ; preds = %while.cond.i
+  br label %func.exit
+
+while.body.i:                                     ; preds = %while.cond.i
+  %dec.i = add nsw i32 %left.0.i, -1
+  switch i32 1, label %while.body.i.func.exit_crit_edge [
+    i32 0, label %while.cond.backedge.i
+    i32 1, label %sw.bb.i
+  ]
+
+while.body.i.func.exit_crit_edge:                 ; preds = %while.body.i
+  br label %func.exit
+
+sw.bb.i:                                          ; preds = %while.body.i
+  %cmp2.i = icmp eq i32 %tmp, 1
+  br i1 %cmp2.i, label %if.then.i, label %if.end.i
+
+if.then.i:                                        ; preds = %sw.bb.i
+  store i32 %pos.0.i, i32* %x.i, align 4
+  br label %if.end.i
+
+; CHECK: if.end.i:
+; CHECK-NEXT: %tmp1 = phi i32 [ %pos.0.i, %if.then.i ], [ %tmp, %sw.bb.i ]
+; CHECK-NOT: phi
+if.end.i:                                         ; preds = %if.then.i, %sw.bb.i
+  %tmp1 = phi i32 [ %pos.0.i, %if.then.i ], [ %tmp, %sw.bb.i ]
+  store i32 %tmp1, i32* %y.i, align 4
+  br label %while.cond.backedge.i
+
+; CHECK: while.cond.backedge.i:
+; CHECK-NEXT: %tmp2 = phi i32 [ %tmp1, %if.end.i ], [ %tmp, %while.body.i ]
+; CHECK-NOT: phi
+while.cond.backedge.i:                            ; preds = %if.end.i, %while.body.i
+  %tmp2 = phi i32 [ %tmp1, %if.end.i ], [ %tmp, %while.body.i ]
+  %xtmp.i = add i32 %pos.0.i, 1
+  br label %while.cond.i
+
+; CHECK: func.exit:
+; CHECK-NOT: load
+; CHECK: %call = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([6 x i8]* @.str, i64 0, i64 0), i32 %tmp) nounwind
+func.exit:                                        ; preds = %while.body.i.func.exit_crit_edge, %while.cond.i.func.exit_crit_edge
+  %tmp3 = load i32* %x.i, align 4
+  %call = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([6 x i8]* @.str, i64 0, i64 0), i32 %tmp3) nounwind
+  ret i32 0
+}
+
+declare i32 @printf(i8* nocapture, ...) nounwind