Index: lib/Transforms/IPO/PartialInlining.cpp
===================================================================
--- lib/Transforms/IPO/PartialInlining.cpp
+++ lib/Transforms/IPO/PartialInlining.cpp
@@ -834,42 +834,41 @@
 int PartialInlinerImpl::computeBBInlineCost(BasicBlock *BB) {
   int InlineCost = 0;
   const DataLayout &DL = BB->getParent()->getParent()->getDataLayout();
-  for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
-    if (isa<DbgInfoIntrinsic>(I))
-      continue;
-
-    switch (I->getOpcode()) {
+  for (Instruction &I : BB->instructionsWithoutDebug()) {
+    // Skip free instructions.
+    switch (I.getOpcode()) {
     case Instruction::BitCast:
     case Instruction::PtrToInt:
     case Instruction::IntToPtr:
     case Instruction::Alloca:
+    case Instruction::PHI:
       continue;
     case Instruction::GetElementPtr:
-      if (cast<GetElementPtrInst>(I)->hasAllZeroIndices())
+      if (cast<GetElementPtrInst>(&I)->hasAllZeroIndices())
         continue;
       break;
     default:
       break;
     }
 
-    IntrinsicInst *IntrInst = dyn_cast<IntrinsicInst>(I);
+    IntrinsicInst *IntrInst = dyn_cast<IntrinsicInst>(&I);
     if (IntrInst) {
       if (IntrInst->getIntrinsicID() == Intrinsic::lifetime_start ||
           IntrInst->getIntrinsicID() == Intrinsic::lifetime_end)
         continue;
     }
 
-    if (CallInst *CI = dyn_cast<CallInst>(I)) {
+    if (CallInst *CI = dyn_cast<CallInst>(&I)) {
       InlineCost += getCallsiteCost(CallSite(CI), DL);
       continue;
     }
 
-    if (InvokeInst *II = dyn_cast<InvokeInst>(I)) {
+    if (InvokeInst *II = dyn_cast<InvokeInst>(&I)) {
       InlineCost += getCallsiteCost(CallSite(II), DL);
       continue;
     }
 
-    if (SwitchInst *SI = dyn_cast<SwitchInst>(I)) {
+    if (SwitchInst *SI = dyn_cast<SwitchInst>(&I)) {
       InlineCost += (SI->getNumCases() + 1) * InlineConstants::InstrCost;
       continue;
     }
Index: test/Transforms/CodeExtractor/PartialInlineEntryPHICost.ll
===================================================================
--- /dev/null
+++ test/Transforms/CodeExtractor/PartialInlineEntryPHICost.ll
@@ -0,0 +1,40 @@
+; RUN: opt < %s -partial-inliner -S | FileCheck %s
+; RUN: opt < %s -passes=partial-inliner -S | FileCheck %s
+
+; Check that we do not overcompute the outlined region cost, where the PHIs in
+; the outlined region entry (BB4) are moved outside the region by CodeExtractor.
+
+define i32 @bar(i32 %arg) {
+bb:
+  %tmp = icmp slt i32 %arg, 0
+  br i1 %tmp, label %bb1, label %bb2
+
+bb1:
+  br i1 undef, label %bb4, label %bb2
+
+bb2:                                              ; preds = %bb, %bb1
+  br i1 undef, label %bb4, label %bb5
+
+bb4:                                              ; preds = %bb1, %bb2
+  %xx1 = phi i32 [ 1, %bb1 ], [ 9, %bb2 ]
+  %xx2 = phi i32 [ 1, %bb1 ], [ 9, %bb2 ]
+  %xx3 = phi i32 [ 1, %bb1 ], [ 9, %bb2 ]
+  tail call void (...) @foo() #2
+  br label %bb5
+
+bb5:                                              ; preds = %bb4, %bb2
+  %tmp6 = phi i32 [ 1, %bb2 ], [ 9, %bb4 ]
+  ret i32 %tmp6
+}
+
+declare void @foo(...)
+
+define i32 @dummy_caller(i32 %arg) {
+bb:
+; CHECK-LABEL: @dummy_caller
+; CHECK: br i1
+; CHECK: br i1
+; CHECK: call void @bar.1.
+  %tmp = tail call i32 @bar(i32 %arg)
+  ret i32 %tmp
+}