diff --git a/polly/lib/CodeGen/IslAst.cpp b/polly/lib/CodeGen/IslAst.cpp
index 3d442fb21229..b5fb851c8532 100644
--- a/polly/lib/CodeGen/IslAst.cpp
+++ b/polly/lib/CodeGen/IslAst.cpp
@@ -47,6 +47,11 @@ static cl::opt<bool>
                   cl::desc("Generate thread parallel code (isl codegen only)"),
                   cl::init(false), cl::ZeroOrMore, cl::cat(PollyCategory));
 
+static cl::opt<bool> PollyParallelForce(
+    "polly-parallel-force",
+    cl::desc("Force generation of thread parallel code ignoring any cost model"),
+    cl::init(false), cl::ZeroOrMore, cl::cat(PollyCategory));
+
 static cl::opt<bool> UseContext("polly-ast-use-context",
                                 cl::desc("Use context"), cl::Hidden,
                                 cl::init(false), cl::ZeroOrMore,
@@ -454,8 +459,23 @@ bool IslAstInfo::isReductionParallel(__isl_keep isl_ast_node *Node) {
 }
 
 bool IslAstInfo::isExecutedInParallel(__isl_keep isl_ast_node *Node) {
-  return PollyParallel && isOutermostParallel(Node) &&
-         !isReductionParallel(Node);
+
+  if (!PollyParallel)
+    return false;
+
+  // Do not parallelize innermost loops.
+  //
+  // Parallelizing innermost loops is often not profitable, especially if
+  // they have a low number of iterations.
+  //
+  // TODO: Decide this based on the number of loop iterations that will be
+  //       executed. This can possibly require run-time checks, which again
+  //       raises the question of both run-time check overhead and code size
+  //       costs.
+  if (!PollyParallelForce && isInnermost(Node))
+    return false;
+
+  return isOutermostParallel(Node) && !isReductionParallel(Node);
 }
 
 isl_union_map *IslAstInfo::getSchedule(__isl_keep isl_ast_node *Node) {
diff --git a/polly/test/Isl/Ast/OpenMP/multiple_loops_outer_parallel.ll b/polly/test/Isl/Ast/OpenMP/multiple_loops_outer_parallel.ll
index bcd36bf1d311..f7cea3d9c57b 100644
--- a/polly/test/Isl/Ast/OpenMP/multiple_loops_outer_parallel.ll
+++ b/polly/test/Isl/Ast/OpenMP/multiple_loops_outer_parallel.ll
@@ -1,4 +1,4 @@
-; RUN: opt %loadPolly -polly-ast -polly-parallel -analyze < %s | FileCheck %s
+; RUN: opt %loadPolly -polly-ast -polly-parallel -polly-parallel-force -analyze < %s | FileCheck %s
 ;
 ;       void jd(int *A) {
 ; CHECK:  #pragma omp parallel for
diff --git a/polly/test/Isl/Ast/OpenMP/nested_loop_both_parallel_parametric.ll b/polly/test/Isl/Ast/OpenMP/nested_loop_both_parallel_parametric.ll
index 99e36e6261c6..de18741e7a15 100644
--- a/polly/test/Isl/Ast/OpenMP/nested_loop_both_parallel_parametric.ll
+++ b/polly/test/Isl/Ast/OpenMP/nested_loop_both_parallel_parametric.ll
@@ -1,4 +1,4 @@
-; RUN: opt %loadPolly -polly-ast -polly-parallel -analyze -polly-delinearize < %s | FileCheck %s
+; RUN: opt %loadPolly -polly-ast -polly-parallel -polly-parallel-force -analyze -polly-delinearize < %s | FileCheck %s
 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"
 ; int A[1024][1024];
diff --git a/polly/test/Isl/Ast/OpenMP/nested_loop_inner_parallel.ll b/polly/test/Isl/Ast/OpenMP/nested_loop_inner_parallel.ll
index ba798da718a4..7abd992dd439 100644
--- a/polly/test/Isl/Ast/OpenMP/nested_loop_inner_parallel.ll
+++ b/polly/test/Isl/Ast/OpenMP/nested_loop_inner_parallel.ll
@@ -1,4 +1,4 @@
-; RUN: opt %loadPolly -polly-ast -polly-parallel -analyze < %s | FileCheck %s
+; RUN: opt %loadPolly -polly-ast -polly-parallel -polly-parallel-force -analyze < %s | FileCheck %s
 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"
 
diff --git a/polly/test/Isl/Ast/OpenMP/single_loop_param_parallel.ll b/polly/test/Isl/Ast/OpenMP/single_loop_param_parallel.ll
index 35c20063d362..364a0bd77198 100644
--- a/polly/test/Isl/Ast/OpenMP/single_loop_param_parallel.ll
+++ b/polly/test/Isl/Ast/OpenMP/single_loop_param_parallel.ll
@@ -1,4 +1,4 @@
-; RUN: opt %loadPolly -polly-ast -polly-parallel -analyze < %s | FileCheck %s
+; RUN: opt %loadPolly -polly-ast -polly-parallel -polly-parallel-force -analyze < %s | FileCheck %s
 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"
 
diff --git a/polly/test/Isl/CodeGen/OpenMP/loop-body-references-outer-iv.ll b/polly/test/Isl/CodeGen/OpenMP/loop-body-references-outer-iv.ll
index 02bf3ed4a9c0..00821c181999 100644
--- a/polly/test/Isl/CodeGen/OpenMP/loop-body-references-outer-iv.ll
+++ b/polly/test/Isl/CodeGen/OpenMP/loop-body-references-outer-iv.ll
@@ -1,5 +1,5 @@
-; RUN: opt %loadPolly -polly-parallel -polly-ast -analyze < %s | FileCheck %s -check-prefix=AST
-; RUN: opt %loadPolly -polly-parallel -polly-codegen-isl -S -polly-codegen-scev -verify-dom-info < %s | FileCheck %s -check-prefix=IR
+; RUN: opt %loadPolly -polly-parallel -polly-parallel-force -polly-ast -analyze < %s | FileCheck %s -check-prefix=AST
+; RUN: opt %loadPolly -polly-parallel -polly-parallel-force -polly-codegen-isl -S -polly-codegen-scev -verify-dom-info < %s | FileCheck %s -check-prefix=IR
 
 ; This code has failed the scev based code generation as the scev in the scop
 ; contains an AddRecExpr of an outer loop. When generating code, we did not
diff --git a/polly/test/Isl/CodeGen/OpenMP/loop-body-references-outer-values-2.ll b/polly/test/Isl/CodeGen/OpenMP/loop-body-references-outer-values-2.ll
index 97f9f05581e2..2ecbaf3e4e15 100644
--- a/polly/test/Isl/CodeGen/OpenMP/loop-body-references-outer-values-2.ll
+++ b/polly/test/Isl/CodeGen/OpenMP/loop-body-references-outer-values-2.ll
@@ -1,6 +1,6 @@
-; RUN: opt %loadPolly -polly-parallel -polly-ast -analyze < %s | FileCheck %s -check-prefix=AST
-; RUN: opt %loadPolly -polly-parallel -polly-codegen-isl -S -verify-dom-info < %s | FileCheck %s -check-prefix=IR
-; RUN: opt %loadPolly -polly-parallel -polly-codegen-isl -S -polly-codegen-scev -verify-dom-info < %s | FileCheck %s -check-prefix=IR-SCEV
+; RUN: opt %loadPolly -polly-parallel -polly-parallel-force -polly-ast -analyze < %s | FileCheck %s -check-prefix=AST
+; RUN: opt %loadPolly -polly-parallel -polly-parallel-force -polly-codegen-isl -S -verify-dom-info < %s | FileCheck %s -check-prefix=IR
+; RUN: opt %loadPolly -polly-parallel -polly-parallel-force -polly-codegen-isl -S -polly-codegen-scev -verify-dom-info < %s | FileCheck %s -check-prefix=IR-SCEV
 
 ; AST: #pragma simd
 ; AST: #pragma omp parallel for
diff --git a/polly/test/Isl/CodeGen/OpenMP/loop-body-references-outer-values-3.ll b/polly/test/Isl/CodeGen/OpenMP/loop-body-references-outer-values-3.ll
index 98d39d1147ca..98072371e008 100644
--- a/polly/test/Isl/CodeGen/OpenMP/loop-body-references-outer-values-3.ll
+++ b/polly/test/Isl/CodeGen/OpenMP/loop-body-references-outer-values-3.ll
@@ -1,6 +1,6 @@
-; RUN: opt %loadPolly -basicaa -polly-parallel -polly-ast -analyze < %s | FileCheck %s -check-prefix=AST
-; RUN: opt %loadPolly -basicaa -polly-parallel -polly-codegen-isl -S -verify-dom-info < %s | FileCheck %s -check-prefix=IR
-; RUN: opt %loadPolly -basicaa -polly-parallel -polly-codegen-isl -S -polly-codegen-scev -verify-dom-info < %s | FileCheck %s -check-prefix=IR
+; RUN: opt %loadPolly -basicaa -polly-parallel -polly-parallel-force -polly-ast -analyze < %s | FileCheck %s -check-prefix=AST
+; RUN: opt %loadPolly -basicaa -polly-parallel -polly-parallel-force -polly-codegen-isl -S -verify-dom-info < %s | FileCheck %s -check-prefix=IR
+; RUN: opt %loadPolly -basicaa -polly-parallel -polly-parallel-force -polly-codegen-isl -S -polly-codegen-scev -verify-dom-info < %s | FileCheck %s -check-prefix=IR
 
 ; The interesting part of this test case is the instruction:
 ;   %tmp = bitcast i8* %call to i64**
diff --git a/polly/test/Isl/CodeGen/OpenMP/loop-body-references-outer-values.ll b/polly/test/Isl/CodeGen/OpenMP/loop-body-references-outer-values.ll
index 75b8a5f5c8dd..cbb2c7f64fe1 100644
--- a/polly/test/Isl/CodeGen/OpenMP/loop-body-references-outer-values.ll
+++ b/polly/test/Isl/CodeGen/OpenMP/loop-body-references-outer-values.ll
@@ -1,6 +1,6 @@
-; RUN: opt %loadPolly -polly-parallel -polly-ast -analyze < %s | FileCheck %s -check-prefix=AST
-; RUN: opt %loadPolly -polly-parallel -polly-codegen-isl -S < %s | FileCheck %s -check-prefix=IR
-; RUN: opt %loadPolly -polly-parallel -polly-codegen-isl -S -polly-codegen-scev < %s | FileCheck %s -check-prefix=IR
+; RUN: opt %loadPolly -polly-parallel -polly-parallel-force -polly-ast -analyze < %s | FileCheck %s -check-prefix=AST
+; RUN: opt %loadPolly -polly-parallel -polly-parallel-force -polly-codegen-isl -S < %s | FileCheck %s -check-prefix=IR
+; RUN: opt %loadPolly -polly-parallel -polly-parallel-force -polly-codegen-isl -S -polly-codegen-scev < %s | FileCheck %s -check-prefix=IR
 
 ; Make sure we correctly forward the reference to 'A' to the OpenMP subfunction.
 ;
diff --git a/polly/test/Isl/CodeGen/OpenMP/reference-other-bb.ll b/polly/test/Isl/CodeGen/OpenMP/reference-other-bb.ll
index 055f717a507d..71f183df5a79 100644
--- a/polly/test/Isl/CodeGen/OpenMP/reference-other-bb.ll
+++ b/polly/test/Isl/CodeGen/OpenMP/reference-other-bb.ll
@@ -1,4 +1,4 @@
-; RUN: opt %loadPolly -polly-parallel -polly-codegen-isl -S -polly-codegen-scev -verify-dom-info < %s | FileCheck %s -check-prefix=IR
+; RUN: opt %loadPolly -polly-parallel -polly-parallel-force -polly-codegen-isl -S -polly-codegen-scev -verify-dom-info < %s | FileCheck %s -check-prefix=IR
 
 ; IR: @foo.polly.subfn
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
diff --git a/polly/test/Isl/CodeGen/OpenMP/reference-preceeding-loop.ll b/polly/test/Isl/CodeGen/OpenMP/reference-preceeding-loop.ll
index 4d7d40027054..63fb60b4e3f4 100644
--- a/polly/test/Isl/CodeGen/OpenMP/reference-preceeding-loop.ll
+++ b/polly/test/Isl/CodeGen/OpenMP/reference-preceeding-loop.ll
@@ -1,5 +1,5 @@
-; RUN: opt %loadPolly -polly-parallel -polly-ast -analyze -polly-codegen-scev < %s | FileCheck %s -check-prefix=AST
-; RUN: opt %loadPolly -polly-parallel -polly-codegen-isl -S -polly-codegen-scev -verify-dom-info < %s | FileCheck %s -check-prefix=IR
+; RUN: opt %loadPolly -polly-parallel -polly-parallel-force -polly-ast -analyze -polly-codegen-scev < %s | FileCheck %s -check-prefix=AST
+; RUN: opt %loadPolly -polly-parallel -polly-parallel-force -polly-codegen-isl -S -polly-codegen-scev -verify-dom-info < %s | FileCheck %s -check-prefix=IR
 
 
 ; - Test the case where scalar evolution references a loop that is outside
diff --git a/polly/test/Isl/CodeGen/OpenMP/single_loop.ll b/polly/test/Isl/CodeGen/OpenMP/single_loop.ll
index 76268ab967d1..768f293cab67 100644
--- a/polly/test/Isl/CodeGen/OpenMP/single_loop.ll
+++ b/polly/test/Isl/CodeGen/OpenMP/single_loop.ll
@@ -1,10 +1,10 @@
-; RUN: opt %loadPolly -polly-parallel -polly-ast -analyze < %s | FileCheck %s -check-prefix=AST
-; RUN: opt %loadPolly -polly-parallel -polly-codegen-isl -S -verify-dom-info < %s | FileCheck %s -check-prefix=IR
-; RUN: opt %loadPolly -polly-parallel -polly-codegen-isl -S -polly-codegen-scev -verify-dom-info < %s | FileCheck %s -check-prefix=IR
+; RUN: opt %loadPolly -polly-parallel -polly-parallel-force -polly-ast -analyze < %s | FileCheck %s -check-prefix=AST
+; RUN: opt %loadPolly -polly-parallel -polly-parallel-force -polly-codegen-isl -S -verify-dom-info < %s | FileCheck %s -check-prefix=IR
+; RUN: opt %loadPolly -polly-parallel -polly-parallel-force -polly-codegen-isl -S -polly-codegen-scev -verify-dom-info < %s | FileCheck %s -check-prefix=IR
 
-; RUN: opt %loadPolly -polly-parallel -polly-import-jscop -polly-import-jscop-dir=%S -polly-ast -analyze < %s | FileCheck %s -check-prefix=AST-STRIDE4
-; RUN: opt %loadPolly -polly-parallel -polly-import-jscop -polly-import-jscop-dir=%S -polly-codegen-isl -S < %s | FileCheck %s -check-prefix=IR-STRIDE4
-; RUN: opt %loadPolly -polly-parallel -polly-import-jscop -polly-import-jscop-dir=%S -polly-codegen-isl -polly-codegen-scev -S < %s | FileCheck %s -check-prefix=IR-STRIDE4
+; RUN: opt %loadPolly -polly-parallel -polly-parallel-force -polly-import-jscop -polly-import-jscop-dir=%S -polly-ast -analyze < %s | FileCheck %s -check-prefix=AST-STRIDE4
+; RUN: opt %loadPolly -polly-parallel -polly-parallel-force -polly-import-jscop -polly-import-jscop-dir=%S -polly-codegen-isl -S < %s | FileCheck %s -check-prefix=IR-STRIDE4
+; RUN: opt %loadPolly -polly-parallel -polly-parallel-force -polly-import-jscop -polly-import-jscop-dir=%S -polly-codegen-isl -polly-codegen-scev -S < %s | FileCheck %s -check-prefix=IR-STRIDE4
 
 ; This extensive test case tests the creation of the full set of OpenMP calls
 ; as well as the subfunction creation using a trivial loop as example.
diff --git a/polly/test/Isl/CodeGen/OpenMP/single_loop_with_loop_invariant_baseptr.ll b/polly/test/Isl/CodeGen/OpenMP/single_loop_with_loop_invariant_baseptr.ll
index 570f475b5812..e35b366611b7 100644
--- a/polly/test/Isl/CodeGen/OpenMP/single_loop_with_loop_invariant_baseptr.ll
+++ b/polly/test/Isl/CodeGen/OpenMP/single_loop_with_loop_invariant_baseptr.ll
@@ -1,6 +1,6 @@
-; RUN: opt %loadPolly -tbaa -polly-parallel -polly-ast -analyze < %s | FileCheck %s -check-prefix=AST
-; RUN: opt %loadPolly -tbaa -polly-parallel -polly-codegen-isl -S -verify-dom-info < %s | FileCheck %s -check-prefix=IR
-; RUN: opt %loadPolly -tbaa -polly-parallel -polly-codegen-isl -S -polly-codegen-scev -verify-dom-info < %s | FileCheck %s -check-prefix=IR
+; RUN: opt %loadPolly -tbaa -polly-parallel -polly-parallel-force -polly-parallel-force -polly-ast -analyze < %s | FileCheck %s -check-prefix=AST
+; RUN: opt %loadPolly -tbaa -polly-parallel -polly-parallel-force -polly-parallel-force -polly-codegen-isl -S -verify-dom-info < %s | FileCheck %s -check-prefix=IR
+; RUN: opt %loadPolly -tbaa -polly-parallel -polly-parallel-force -polly-parallel-force -polly-codegen-isl -S -polly-codegen-scev -verify-dom-info < %s | FileCheck %s -check-prefix=IR
 
 ; #define N 1024
 ; float A[N];
diff --git a/polly/test/Isl/CodeGen/OpenMP/two-parallel-loops-reference-outer-indvar.ll b/polly/test/Isl/CodeGen/OpenMP/two-parallel-loops-reference-outer-indvar.ll
index 646e93d92d13..32b8b94b16ef 100644
--- a/polly/test/Isl/CodeGen/OpenMP/two-parallel-loops-reference-outer-indvar.ll
+++ b/polly/test/Isl/CodeGen/OpenMP/two-parallel-loops-reference-outer-indvar.ll
@@ -1,5 +1,5 @@
-; RUN: opt %loadPolly -polly-parallel -polly-ast -analyze -polly-codegen-scev < %s | FileCheck %s -check-prefix=AST
-; RUN: opt %loadPolly -polly-parallel -polly-codegen-isl -S -polly-codegen-scev -verify-dom-info < %s | FileCheck %s -check-prefix=IR
+; RUN: opt %loadPolly -polly-parallel -polly-parallel-force -polly-ast -analyze -polly-codegen-scev < %s | FileCheck %s -check-prefix=AST
+; RUN: opt %loadPolly -polly-parallel -polly-parallel-force -polly-codegen-isl -S -polly-codegen-scev -verify-dom-info < %s | FileCheck %s -check-prefix=IR
 
 ; This test case verifies that we create correct code even if two OpenMP loops
 ; share common outer variables.