Index: llvm/lib/Transforms/IPO/IROutliner.cpp
===================================================================
--- llvm/lib/Transforms/IPO/IROutliner.cpp
+++ llvm/lib/Transforms/IPO/IROutliner.cpp
@@ -264,13 +264,29 @@
   // We iterate over the instructions in the region, if we find a PHINode, we
   // check if there are predecessors outside of the region, if there are,
   // we ignore this region since we are unable to handle the severing of the
-  // phi node right now. 
+  // phi node right now.
+
+  // TODO: Handle extraneous inputs for PHINodes through variable number of
+  // inputs, similar to how outputs are handled.
   BasicBlock::iterator It = StartInst->getIterator();
+  EndBB = BackInst->getParent();
+  BasicBlock *IBlock;
+  bool EndBBTermAndBackInstDifferent = EndBB->getTerminator() != BackInst;
   while (PHINode *PN = dyn_cast<PHINode>(&*It)) {
     unsigned NumPredsOutsideRegion = 0;
-    for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
-      if (!BBSet.contains(PN->getIncomingBlock(i)))
+    for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
+      if (!BBSet.contains(PN->getIncomingBlock(i))) {
+        ++NumPredsOutsideRegion;
+        continue;
+      }
+
+      // We must consider the case there the incoming block to the PHINode is
+      // the same as the final block of the OutlinableRegion.  If this is the
+      // case, the branch from this block must also be outlined to be valid.
+      IBlock = PN->getIncomingBlock(i);
+      if (IBlock == EndBB && EndBBTermAndBackInstDifferent)
         ++NumPredsOutsideRegion;
+    }
 
     if (NumPredsOutsideRegion > 1)
       return;
@@ -285,11 +301,9 @@
   
   // If the region ends with a PHINode, but does not contain all of the phi node
   // instructions of the region, we ignore it for now.
-  if (isa<PHINode>(BackInst)) {
-    EndBB = BackInst->getParent();
-    if (BackInst != &*std::prev(EndBB->getFirstInsertionPt()))
-      return;
-  }
+  if (isa<PHINode>(BackInst) &&
+      BackInst != &*std::prev(EndBB->getFirstInsertionPt()))
+    return;
 
   // The basic block gets split like so:
   // block:                 block:
Index: llvm/test/Transforms/IROutliner/phi-nodes-parent-block-referential.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/IROutliner/phi-nodes-parent-block-referential.ll
@@ -0,0 +1,100 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --include-generated-funcs
+; RUN: opt -S -verify -iroutliner -ir-outlining-no-cost < %s | FileCheck %s
+
+; Show that we do not outline when all of the phi nodes in the beginning
+; block are included not in the region.
+
+define void @function1(i32* %a, i32* %b) {
+entry:
+  %0 = alloca i32, align 4
+  %c = load i32, i32* %0, align 4
+  %y = add i32 %c, %c
+  br label %test1
+dummy:
+  ret void
+test1:
+  %1 = phi i32 [ %e, %test1 ], [ %y, %entry ]
+  %2 = phi i32 [ %e, %test1 ], [ %y, %entry  ]
+  %e = load i32, i32* %0, align 4
+  %3 = add i32 %c, %c
+  %4 = sub i32 %c, %c
+  br i1 true, label %first, label %test1
+first:
+  ret void
+}
+
+define void @function2(i32* %a, i32* %b) {
+entry:
+  %0 = alloca i32, align 4
+  %c = load i32, i32* %0, align 4
+  %y = mul i32 %c, %c
+  br label %test1
+dummy:
+  ret void
+test1:
+  %1 = phi i32 [ %e, %test1 ], [ %y, %entry ]
+  %2 = phi i32 [ %y, %entry ], [ %e, %test1 ]
+  %e = load i32, i32* %0, align 4
+  %3 = add i32 %c, %c
+  %4 = mul i32 %c, %c
+  br i1 true, label %first, label %test1
+first:
+  ret void
+}
+; CHECK-LABEL: @function1(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[E_LOC:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[TMP0:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[C:%.*]] = load i32, i32* [[TMP0]], align 4
+; CHECK-NEXT:    [[Y:%.*]] = add i32 [[C]], [[C]]
+; CHECK-NEXT:    br label [[TEST1:%.*]]
+; CHECK:       dummy:
+; CHECK-NEXT:    ret void
+; CHECK:       test1:
+; CHECK-NEXT:    [[TMP1:%.*]] = phi i32 [ [[E_RELOAD:%.*]], [[TEST1]] ], [ [[Y]], [[ENTRY:%.*]] ]
+; CHECK-NEXT:    [[TMP2:%.*]] = phi i32 [ [[E_RELOAD]], [[TEST1]] ], [ [[Y]], [[ENTRY]] ]
+; CHECK-NEXT:    [[LT_CAST:%.*]] = bitcast i32* [[E_LOC]] to i8*
+; CHECK-NEXT:    call void @llvm.lifetime.start.p0i8(i64 -1, i8* [[LT_CAST]])
+; CHECK-NEXT:    call void @outlined_ir_func_0(i32* [[TMP0]], i32 [[C]], i32* [[E_LOC]])
+; CHECK-NEXT:    [[E_RELOAD]] = load i32, i32* [[E_LOC]], align 4
+; CHECK-NEXT:    call void @llvm.lifetime.end.p0i8(i64 -1, i8* [[LT_CAST]])
+; CHECK-NEXT:    [[TMP3:%.*]] = sub i32 [[C]], [[C]]
+; CHECK-NEXT:    br i1 true, label [[FIRST:%.*]], label [[TEST1]]
+; CHECK:       first:
+; CHECK-NEXT:    ret void
+;
+;
+; CHECK-LABEL: @function2(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[E_LOC:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[TMP0:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[C:%.*]] = load i32, i32* [[TMP0]], align 4
+; CHECK-NEXT:    [[Y:%.*]] = mul i32 [[C]], [[C]]
+; CHECK-NEXT:    br label [[TEST1:%.*]]
+; CHECK:       dummy:
+; CHECK-NEXT:    ret void
+; CHECK:       test1:
+; CHECK-NEXT:    [[TMP1:%.*]] = phi i32 [ [[E_RELOAD:%.*]], [[TEST1]] ], [ [[Y]], [[ENTRY:%.*]] ]
+; CHECK-NEXT:    [[TMP2:%.*]] = phi i32 [ [[Y]], [[ENTRY]] ], [ [[E_RELOAD]], [[TEST1]] ]
+; CHECK-NEXT:    [[LT_CAST:%.*]] = bitcast i32* [[E_LOC]] to i8*
+; CHECK-NEXT:    call void @llvm.lifetime.start.p0i8(i64 -1, i8* [[LT_CAST]])
+; CHECK-NEXT:    call void @outlined_ir_func_0(i32* [[TMP0]], i32 [[C]], i32* [[E_LOC]])
+; CHECK-NEXT:    [[E_RELOAD]] = load i32, i32* [[E_LOC]], align 4
+; CHECK-NEXT:    call void @llvm.lifetime.end.p0i8(i64 -1, i8* [[LT_CAST]])
+; CHECK-NEXT:    [[TMP3:%.*]] = mul i32 [[C]], [[C]]
+; CHECK-NEXT:    br i1 true, label [[FIRST:%.*]], label [[TEST1]]
+; CHECK:       first:
+; CHECK-NEXT:    ret void
+;
+;
+; CHECK-LABEL: define internal void @outlined_ir_func_0(
+; CHECK-NEXT:  newFuncRoot:
+; CHECK-NEXT:    br label [[TEST1_TO_OUTLINE:%.*]]
+; CHECK:       test1_to_outline:
+; CHECK-NEXT:    [[E:%.*]] = load i32, i32* [[TMP0:%.*]], align 4
+; CHECK-NEXT:    [[TMP3:%.*]] = add i32 [[TMP1:%.*]], [[TMP1]]
+; CHECK-NEXT:    br label [[TEST1_AFTER_OUTLINE_EXITSTUB:%.*]]
+; CHECK:       test1_after_outline.exitStub:
+; CHECK-NEXT:    store i32 [[E]], i32* [[TMP2:%.*]], align 4
+; CHECK-NEXT:    ret void
+;