diff --git a/polly/include/polly/Dependences.h b/polly/include/polly/Dependences.h
index d40d58f7fa0a..9a704a855492 100755
--- a/polly/include/polly/Dependences.h
+++ b/polly/include/polly/Dependences.h
@@ -91,6 +91,9 @@ public:
   ///              different kinds are 'ored' together.
   isl_union_map *getDependences(int Kinds);
 
+  /// @brief Report if valid dependences are available.
+  bool hasValidDependences();
+
   bool runOnScop(Scop &S);
   void printScop(raw_ostream &OS) const;
   virtual void releaseMemory();
diff --git a/polly/lib/Analysis/Dependences.cpp b/polly/lib/Analysis/Dependences.cpp
index 736bccaf70ea..3b0980fbc37c 100644
--- a/polly/lib/Analysis/Dependences.cpp
+++ b/polly/lib/Analysis/Dependences.cpp
@@ -317,6 +317,7 @@ void Dependences::releaseMemory() {
 }
 
 isl_union_map *Dependences::getDependences(int Kinds) {
+  assert(hasValidDependences() && "No valid dependences available");
   isl_space *Space = isl_union_map_get_space(RAW);
   isl_union_map *Deps = isl_union_map_empty(Space);
 
@@ -334,6 +335,10 @@ isl_union_map *Dependences::getDependences(int Kinds) {
   return Deps;
 }
 
+bool Dependences::hasValidDependences() {
+  return (RAW != NULL) && (WAR != NULL) && (WAW != NULL);
+}
+
 void Dependences::getAnalysisUsage(AnalysisUsage &AU) const {
   ScopPass::getAnalysisUsage(AU);
 }
diff --git a/polly/lib/DeadCodeElimination.cpp b/polly/lib/DeadCodeElimination.cpp
index 0aacd0064f49..8e6e1eacf8b7 100644
--- a/polly/lib/DeadCodeElimination.cpp
+++ b/polly/lib/DeadCodeElimination.cpp
@@ -94,9 +94,12 @@ isl_union_set *DeadCodeElim::getLastWrites(__isl_take isl_union_map *Writes,
 /// combine a certain number of precise steps with one approximating step that
 /// simplifies the life set with an affine hull.
 bool DeadCodeElim::eliminateDeadCode(Scop &S, int PreciseSteps) {
-  isl_union_set *Live = this->getLastWrites(S.getWrites(), S.getSchedule());
-
   Dependences *D = &getAnalysis<Dependences>();
+
+  if (!D->hasValidDependences())
+    return false;
+
+  isl_union_set *Live = this->getLastWrites(S.getWrites(), S.getSchedule());
   isl_union_map *Dep = D->getDependences(Dependences::TYPE_RAW);
   Dep = isl_union_map_reverse(Dep);
 
diff --git a/polly/lib/ScheduleOptimizer.cpp b/polly/lib/ScheduleOptimizer.cpp
index 9e4e4ce3c649..9d4720aa84b8 100644
--- a/polly/lib/ScheduleOptimizer.cpp
+++ b/polly/lib/ScheduleOptimizer.cpp
@@ -431,6 +431,9 @@ isl_union_map *IslScheduleOptimizer::getScheduleMap(isl_schedule *Schedule) {
 bool IslScheduleOptimizer::runOnScop(Scop &S) {
   Dependences *D = &getAnalysis<Dependences>();
 
+  if (!D->hasValidDependences())
+    return false;
+
   isl_schedule_free(LastSchedule);
   LastSchedule = NULL;
 
diff --git a/polly/test/DeadCodeElimination/computeout.ll b/polly/test/DeadCodeElimination/computeout.ll
new file mode 100644
index 000000000000..a908c4ed3142
--- /dev/null
+++ b/polly/test/DeadCodeElimination/computeout.ll
@@ -0,0 +1,64 @@
+; RUN: opt -S %loadPolly -basicaa -polly-dce -polly-ast -analyze < %s | FileCheck %s
+; RUN: opt -S %loadPolly -basicaa -polly-dce -polly-ast -analyze -polly-dependences-computeout=1 < %s | FileCheck %s -check-prefix=TIMEOUT
+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"
+target triple = "x86_64-pc-linux-gnu"
+
+;     for(i = 0; i < 100; i++ )
+; S1:   A[i] = 2;
+;
+;     for (i = 0; i < 10; i++ )
+; S2:   A[i]  = 5;
+;
+;     for (i = 0; i < 200; i++ )
+; S3:   A[i] = 5;
+
+define void @sequential_writes() {
+entry:
+  %A = alloca [200 x i32]
+  br label %S1
+
+S1:
+  %indvar.1 = phi i64 [ 0, %entry ], [ %indvar.next.1, %S1 ]
+  %arrayidx.1 = getelementptr [200 x i32]* %A, i64 0, i64 %indvar.1
+  store i32 2, i32* %arrayidx.1
+  %indvar.next.1 = add i64 %indvar.1, 1
+  %exitcond.1 = icmp ne i64 %indvar.next.1, 100
+  br i1 %exitcond.1, label %S1, label %exit.1
+
+exit.1:
+  br label %S2
+
+S2:
+  %indvar.2 = phi i64 [ 0, %exit.1 ], [ %indvar.next.2, %S2 ]
+  %arrayidx.2 = getelementptr [200 x i32]* %A, i64 0, i64 %indvar.2
+  store i32 5, i32* %arrayidx.2
+  %indvar.next.2 = add i64 %indvar.2, 1
+  %exitcond.2 = icmp ne i64 %indvar.next.2, 10
+  br i1 %exitcond.2, label %S2, label %exit.2
+
+exit.2:
+  br label %S3
+
+S3:
+  %indvar.3 = phi i64 [ 0, %exit.2 ], [ %indvar.next.3, %S3 ]
+  %arrayidx.3 = getelementptr [200 x i32]* %A, i64 0, i64 %indvar.3
+  store i32 7, i32* %arrayidx.3
+  %indvar.next.3 = add i64 %indvar.3, 1
+  %exitcond.3 = icmp ne i64 %indvar.next.3, 200
+  br i1 %exitcond.3, label %S3 , label %exit.3
+
+exit.3:
+  ret void
+}
+
+; CHECK-NOT: Stmt_S
+; CHECK: for (int c1 = 0; c1 <= 199; c1 += 1)
+; CHECK: Stmt_S3(c1);
+
+; TIMEOUT: for (int c1 = 0; c1 <= 99; c1 += 1)
+; TIMEOUT: Stmt_S1(c1);
+; TIMEOUT: for (int c1 = 0; c1 <= 9; c1 += 1)
+; TIMEOUT: Stmt_S2(c1);
+; TIMEOUT: for (int c1 = 0; c1 <= 199; c1 += 1)
+; TIMEOUT: Stmt_S3(c1);
+
diff --git a/polly/test/ScheduleOptimizer/computeout.ll b/polly/test/ScheduleOptimizer/computeout.ll
new file mode 100644
index 000000000000..578478c3a113
--- /dev/null
+++ b/polly/test/ScheduleOptimizer/computeout.ll
@@ -0,0 +1,70 @@
+; RUN: opt -S %loadPolly -basicaa -polly-opt-isl -polly-opt-fusion=max -polly-ast -analyze < %s | FileCheck %s 
+; RUN: opt -S %loadPolly -basicaa -polly-opt-isl -polly-opt-fusion=max -polly-ast -analyze -polly-dependences-computeout=1 < %s | FileCheck %s -check-prefix=TIMEOUT
+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"
+target triple = "x86_64-pc-linux-gnu"
+
+;     for(i = 0; i < 100; i++ )
+; S1:   A[i] = 2;
+;
+;     for (i = 0; i < 10; i++ )
+; S2:   A[i]  = 5;
+;
+;     for (i = 0; i < 200; i++ )
+; S3:   A[i] = 5;
+
+define void @sequential_writes() {
+entry:
+  %A = alloca [200 x i32]
+  br label %S1
+
+S1:
+  %indvar.1 = phi i64 [ 0, %entry ], [ %indvar.next.1, %S1 ]
+  %arrayidx.1 = getelementptr [200 x i32]* %A, i64 0, i64 %indvar.1
+  store i32 2, i32* %arrayidx.1
+  %indvar.next.1 = add i64 %indvar.1, 1
+  %exitcond.1 = icmp ne i64 %indvar.next.1, 100
+  br i1 %exitcond.1, label %S1, label %exit.1
+
+exit.1:
+  br label %S2
+
+S2:
+  %indvar.2 = phi i64 [ 0, %exit.1 ], [ %indvar.next.2, %S2 ]
+  %arrayidx.2 = getelementptr [200 x i32]* %A, i64 0, i64 %indvar.2
+  store i32 5, i32* %arrayidx.2
+  %indvar.next.2 = add i64 %indvar.2, 1
+  %exitcond.2 = icmp ne i64 %indvar.next.2, 10
+  br i1 %exitcond.2, label %S2, label %exit.2
+
+exit.2:
+  br label %S3
+
+S3:
+  %indvar.3 = phi i64 [ 0, %exit.2 ], [ %indvar.next.3, %S3 ]
+  %arrayidx.3 = getelementptr [200 x i32]* %A, i64 0, i64 %indvar.3
+  store i32 7, i32* %arrayidx.3
+  %indvar.next.3 = add i64 %indvar.3, 1
+  %exitcond.3 = icmp ne i64 %indvar.next.3, 200
+  br i1 %exitcond.3, label %S3 , label %exit.3
+
+exit.3:
+  ret void
+}
+
+
+; CHECK: for (int c0 = 0; c0 <= 199; c0 += 1) {
+; CHECK:   if (c0 <= 99) {
+; CHECK:     Stmt_S1(c0);
+; CHECK:     if (c0 <= 9)
+; CHECK:       Stmt_S2(c0);
+; CHECK:   }
+; CHECK:   Stmt_S3(c0);
+; CHECK: }
+
+; TIMEOUT: for (int c1 = 0; c1 <= 99; c1 += 1)
+; TIMEOUT: Stmt_S1(c1);
+; TIMEOUT: for (int c1 = 0; c1 <= 9; c1 += 1)
+; TIMEOUT: Stmt_S2(c1);
+; TIMEOUT: for (int c1 = 0; c1 <= 199; c1 += 1)
+; TIMEOUT: Stmt_S3(c1);
+