diff --git a/llvm/include/llvm/Transforms/IPO/IROutliner.h b/llvm/include/llvm/Transforms/IPO/IROutliner.h
--- a/llvm/include/llvm/Transforms/IPO/IROutliner.h
+++ b/llvm/include/llvm/Transforms/IPO/IROutliner.h
@@ -85,6 +85,13 @@
   DenseMap<unsigned, unsigned> ExtractedArgToAgg;
   DenseMap<unsigned, unsigned> AggArgToExtracted;
 
+  /// Values in the outlined functions will often be replaced by arguments. When
+  /// finding corresponding values from one region to another, the found value
+  /// will be the value the argument previously replaced.  This structure maps
+  /// any replaced values for the region to the aggregate aggregate argument
+  /// in the overall function.
+  DenseMap<Value *, Value *> RemappedArguments;
+
   /// Marks whether we need to change the order of the arguments when mapping
   /// the old extracted function call to the new aggregate outlined function
   /// call.
diff --git a/llvm/lib/Transforms/IPO/IROutliner.cpp b/llvm/lib/Transforms/IPO/IROutliner.cpp
--- a/llvm/lib/Transforms/IPO/IROutliner.cpp
+++ b/llvm/lib/Transforms/IPO/IROutliner.cpp
@@ -1737,6 +1737,10 @@
     IncomingVal = findOutputMapping(OutputMappings, IncomingVal);
     Value *Val = Region.findCorrespondingValueIn(*FirstRegion, IncomingVal);
     assert(Val && "Value is nullptr?");
+    DenseMap<Value *, Value *>::iterator RemappedIt =
+        FirstRegion->RemappedArguments.find(Val);
+    if (RemappedIt != FirstRegion->RemappedArguments.end())
+      Val = RemappedIt->second;
     NewPN->setIncomingValue(Idx, Val);
   }
   return NewPN;
@@ -1780,6 +1784,8 @@
                         << *Region.ExtractedFunction << " with " << *AggArg
                         << " in function " << *Group.OutlinedFunction << "\n");
       Arg->replaceAllUsesWith(AggArg);
+      Value *V = Region.Call->getArgOperand(ArgIdx);
+      Region.RemappedArguments.insert(std::make_pair(V, AggArg));
       continue;
     }
 
diff --git a/llvm/test/Transforms/IROutliner/exit-phi-nodes-incoming-value-constant-argument.ll b/llvm/test/Transforms/IROutliner/exit-phi-nodes-incoming-value-constant-argument.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/Transforms/IROutliner/exit-phi-nodes-incoming-value-constant-argument.ll
@@ -0,0 +1,111 @@
+; 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
+
+; When consolidating PHINodes, the outliner replaces the incoming value with
+; a corresponding value from the first outlined section.  When this replaced
+; value is passed in as an argument, the corresponding value is found outside
+; of the outlined region, and must be replaced with an argument to avoid
+; dominating value errors. This checks that we use the argument to replace
+; the incoming value.
+
+define void @func1(i32 %0, i32 %1) local_unnamed_addr #0 {
+bb1:
+  br label %bb5s
+
+bb2:
+  %a = add i32 %0, %1
+  %b = add i32 %0, %1
+  %c = icmp eq i32 %b, %a
+  br i1 %c, label %bb5, label %bb3
+
+bb3:
+  %d = add i32 %0, %1
+  br label %bb5
+
+bb4:
+  %e = sub i32 %0, %1
+  br label %bb2
+
+bb5:
+  ret void
+}
+
+define void @func2(i32 %0, i32 %1) local_unnamed_addr #0 {
+bb1:
+  br label %bb5
+
+bb2:
+  %a = sub i32 %0, %1
+  %b = add i32 %0, %1
+  %c = icmp eq i32 %b, 1
+  br i1 %c, label %bb5, label %bb3
+
+bb3:
+  %d = add i32 %0, %1
+  br label %bb5
+
+bb4:
+  %e = add i32 %0, %1
+  br label %bb2
+
+bb5:
+  %f = phi i32 [ 0, %bb1 ], [ 1, %bb2 ], [ 1, %bb3 ]
+  ret void
+}
+; CHECK-LABEL: @func1(
+; CHECK-NEXT:  bb1:
+; CHECK-NEXT:    br label [[BB5:%.*]]
+; CHECK:       bb2:
+; CHECK-NEXT:    [[A:%.*]] = add i32 [[TMP0:%.*]], [[TMP1:%.*]]
+; CHECK-NEXT:    call void @outlined_ir_func_0(i32 [[TMP0]], i32 [[TMP1]], i32 [[A]], i32* null, i32 -1)
+; CHECK-NEXT:    br label [[BB5]]
+; CHECK:       bb4:
+; CHECK-NEXT:    [[E:%.*]] = sub i32 [[TMP0]], [[TMP1]]
+; CHECK-NEXT:    br label [[BB2:%.*]]
+; CHECK:       bb5:
+; CHECK-NEXT:    ret void
+;
+;
+; CHECK-LABEL: @func2(
+; CHECK-NEXT:  bb1:
+; CHECK-NEXT:    [[F_CE_LOC:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    br label [[BB5:%.*]]
+; CHECK:       bb2:
+; CHECK-NEXT:    [[A:%.*]] = sub i32 [[TMP0:%.*]], [[TMP1:%.*]]
+; CHECK-NEXT:    [[LT_CAST:%.*]] = bitcast i32* [[F_CE_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 [[TMP1]], i32 1, i32* [[F_CE_LOC]], i32 0)
+; CHECK-NEXT:    [[F_CE_RELOAD:%.*]] = load i32, i32* [[F_CE_LOC]], align 4
+; CHECK-NEXT:    call void @llvm.lifetime.end.p0i8(i64 -1, i8* [[LT_CAST]])
+; CHECK-NEXT:    br label [[BB5]]
+; CHECK:       bb4:
+; CHECK-NEXT:    [[E:%.*]] = add i32 [[TMP0]], [[TMP1]]
+; CHECK-NEXT:    br label [[BB2:%.*]]
+; CHECK:       bb5:
+; CHECK-NEXT:    [[F:%.*]] = phi i32 [ 0, [[BB1:%.*]] ], [ [[F_CE_RELOAD]], [[BB2]] ]
+; CHECK-NEXT:    ret void
+;
+;
+; CHECK-LABEL: define internal void @outlined_ir_func_0(
+; CHECK-NEXT:  newFuncRoot:
+; CHECK-NEXT:    br label [[BB2_TO_OUTLINE:%.*]]
+; CHECK:       bb2_to_outline:
+; CHECK-NEXT:    [[B:%.*]] = add i32 [[TMP0:%.*]], [[TMP1:%.*]]
+; CHECK-NEXT:    [[C:%.*]] = icmp eq i32 [[B]], [[TMP2:%.*]]
+; CHECK-NEXT:    br i1 [[C]], label [[PHI_BLOCK:%.*]], label [[BB3:%.*]]
+; CHECK:       bb3:
+; CHECK-NEXT:    [[D:%.*]] = add i32 [[TMP0]], [[TMP1]]
+; CHECK-NEXT:    br label [[PHI_BLOCK]]
+; CHECK:       bb5.exitStub:
+; CHECK-NEXT:    switch i32 [[TMP4:%.*]], label [[FINAL_BLOCK_0:%.*]] [
+; CHECK-NEXT:    i32 0, label [[OUTPUT_BLOCK_1_0:%.*]]
+; CHECK-NEXT:    ]
+; CHECK:       output_block_1_0:
+; CHECK-NEXT:    store i32 [[TMP5:%.*]], i32* [[TMP3:%.*]], align 4
+; CHECK-NEXT:    br label [[FINAL_BLOCK_0]]
+; CHECK:       phi_block:
+; CHECK-NEXT:    [[TMP5]] = phi i32 [ [[TMP2]], [[BB2_TO_OUTLINE]] ], [ [[TMP2]], [[BB3]] ]
+; CHECK-NEXT:    br label [[BB5_EXITSTUB:%.*]]
+; CHECK:       final_block_0:
+; CHECK-NEXT:    ret void
+;