diff --git a/polly/lib/CodeGen/BlockGenerators.cpp b/polly/lib/CodeGen/BlockGenerators.cpp
index 91be1aa3b056..5dd227990c73 100644
--- a/polly/lib/CodeGen/BlockGenerators.cpp
+++ b/polly/lib/CodeGen/BlockGenerators.cpp
@@ -1012,6 +1012,8 @@ void RegionGenerator::copyStmt(ScopStmt &Stmt, LoopToScevMapT &LTS,
   assert(Stmt.isRegionStmt() &&
          "Only region statements can be copied by the region generator");
 
+  Scop *S = Stmt.getParent();
+
   // Forget all old mappings.
   BlockMap.clear();
   RegionMaps.clear();
@@ -1037,6 +1039,17 @@ void RegionGenerator::copyStmt(ScopStmt &Stmt, LoopToScevMapT &LTS,
     if (!R->contains(*PI))
       BlockMap[*PI] = EntryBBCopy;
 
+  // Determine the original exit block of this subregion. If it the exit block
+  // is also the scop's exit, it it has been changed to polly.merge_new_and_old.
+  // We move one block back to find the original block. This only happens if the
+  // scop required simplification.
+  // If the whole scop consists of only this non-affine region, then they share
+  // the same Region object, such that we cannot change the exit of one and not
+  // the other.
+  BasicBlock *ExitBB = R->getExit();
+  if (!S->hasSingleExitEdge() && ExitBB == S->getRegion().getExit())
+    ExitBB = *(++pred_begin(ExitBB));
+
   // Iterate over all blocks in the region in a breadth-first search.
   std::deque<BasicBlock *> Blocks;
   SmallPtrSet<BasicBlock *, 8> SeenBlocks;
@@ -1078,7 +1091,7 @@ void RegionGenerator::copyStmt(ScopStmt &Stmt, LoopToScevMapT &LTS,
         Blocks.push_back(*SI);
 
     // Remember value in case it is visible after this subregion.
-    if (DT.dominates(BB, R->getExit()))
+    if (DT.dominates(BB, ExitBB))
       ValueMap.insert(RegionMap.begin(), RegionMap.end());
   }
 
@@ -1088,7 +1101,10 @@ void RegionGenerator::copyStmt(ScopStmt &Stmt, LoopToScevMapT &LTS,
   ExitBBCopy->setName("polly.stmt." + R->getExit()->getName() + ".exit");
   BlockMap[R->getExit()] = ExitBBCopy;
 
-  repairDominance(R->getExit(), ExitBBCopy);
+  if (ExitBB == R->getExit())
+    repairDominance(ExitBB, ExitBBCopy);
+  else
+    DT.changeImmediateDominator(ExitBBCopy, BlockMap.lookup(ExitBB));
 
   // As the block generator doesn't handle control flow we need to add the
   // region control flow by hand after all blocks have been copied.
diff --git a/polly/test/Isl/CodeGen/non-affine-exit-node-dominance.ll b/polly/test/Isl/CodeGen/non-affine-exit-node-dominance.ll
new file mode 100644
index 000000000000..077dd2de5007
--- /dev/null
+++ b/polly/test/Isl/CodeGen/non-affine-exit-node-dominance.ll
@@ -0,0 +1,30 @@
+; RUN: opt %loadPolly -polly-codegen -S < %s | FileCheck %s
+;
+; llvm.org/PR25439
+; The dominance of the generated non-affine subregion block was based on the
+; scop's merge block, therefore resulted in an invalid DominanceTree.
+; It resulted in some values as assumed to be unusable in the actual generated
+; exit block. Here we check whether the value %escaping is taken from the
+; generated block.
+;
+; CHECK-LABEL: polly.stmt.subregion_entry:
+; CHECK:         %p_escaping = select i1 undef, i32 undef, i32 undef
+;
+; CHECK-LABEL: polly.stmt.polly.merge_new_and_old.exit:
+; CHECK:         store i32 %p_escaping, i32* %escaping.s2a
+
+define i32 @func() {
+entry:
+  br label %subregion_entry
+
+subregion_entry:
+  %escaping = select i1 undef, i32 undef, i32 undef
+  %cond = or i1 undef, undef
+  br i1 %cond, label %subregion_exit, label %subregion_if
+
+subregion_if:
+  br label %subregion_exit
+
+subregion_exit:
+  ret i32 %escaping
+}
diff --git a/polly/test/Isl/CodeGen/non-affine-region-implicit-store.ll b/polly/test/Isl/CodeGen/non-affine-region-implicit-store.ll
index a0c0ba4becd4..e31b872a7b81 100644
--- a/polly/test/Isl/CodeGen/non-affine-region-implicit-store.ll
+++ b/polly/test/Isl/CodeGen/non-affine-region-implicit-store.ll
@@ -1,5 +1,5 @@
 ; RUN: opt %loadPolly -polly-codegen -S < %s | FileCheck %s
-; XFAIL: *
+;
 ; llvm.org/PR25438
 ; After loop versioning, a dominance check of a non-affine subregion's exit node
 ; causes the dominance check to always fail any block in the scop. The
@@ -13,7 +13,7 @@
 ; CHECK:        a.phiops.reload = load i32, i32* %a.phiops
 ;
 ; CHECK-LABEL: polly.stmt.polly.merge_new_and_old.exit:
-; CHECK:         store i32 %a.phiops.reload, i32* %a.s2a
+; CHECK:         store i32 %polly.a, i32* %a.s2a
 
 define void @func() {
 entry:
diff --git a/polly/test/Isl/CodeGen/pr25241.ll b/polly/test/Isl/CodeGen/pr25241.ll
index e3cf817d25cb..c8f9c59ade8c 100644
--- a/polly/test/Isl/CodeGen/pr25241.ll
+++ b/polly/test/Isl/CodeGen/pr25241.ll
@@ -6,10 +6,11 @@
 
 ; CHECK-LABEL: polly.stmt.if.then.862:
 ; CHECK:         %[[R1:[0-9]+]] = add i32 %tmp, 1
+; CHECK:         store i32 %0, i32* %curr.3.s2a
 ; CHECK:         br label
 
-; CHECK-LABEL: polly.stmt.while.body.740.region_exiting:
-; CHECK:         %polly.curr.3.ph = phi i32 [ undef, %polly.stmt.if.else.864 ], [ %[[R1]], %polly.stmt.if.then.862 ]
+; CHECK-LABEL: polly.stmt.polly.merge_new_and_old.exit:
+; CHECK:         %curr.3.ph.final_reload = load i32, i32* %curr.3.s2a
 ; CHECK:         br label