diff --git a/llvm/include/llvm/Transforms/Scalar.h b/llvm/include/llvm/Transforms/Scalar.h
--- a/llvm/include/llvm/Transforms/Scalar.h
+++ b/llvm/include/llvm/Transforms/Scalar.h
@@ -530,6 +530,13 @@
 // transformations.
 //
 Pass *createWarnMissedTransformationsPass();
+
+//===----------------------------------------------------------------------===//
+//
+// This pass does instruction simplification on each
+// instruction in a function.
+//
+FunctionPass *createInstSimplifyLegacyPass();
 } // End llvm namespace
 
 #endif
diff --git a/llvm/include/llvm/Transforms/Scalar/InstSimplifyPass.h b/llvm/include/llvm/Transforms/Scalar/InstSimplifyPass.h
--- a/llvm/include/llvm/Transforms/Scalar/InstSimplifyPass.h
+++ b/llvm/include/llvm/Transforms/Scalar/InstSimplifyPass.h
@@ -36,10 +36,6 @@
   PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
 };
 
-/// Create a legacy pass that does instruction simplification on each
-/// instruction in a function.
-FunctionPass *createInstSimplifyLegacyPass();
-
 } // end namespace llvm
 
 #endif // LLVM_TRANSFORMS_UTILS_INSTSIMPLIFYPASS_H
diff --git a/llvm/lib/Target/Hexagon/HexagonTargetMachine.cpp b/llvm/lib/Target/Hexagon/HexagonTargetMachine.cpp
--- a/llvm/lib/Target/Hexagon/HexagonTargetMachine.cpp
+++ b/llvm/lib/Target/Hexagon/HexagonTargetMachine.cpp
@@ -101,6 +101,10 @@
   cl::Hidden, cl::ZeroOrMore, cl::init(true),
   cl::desc("Simplify the CFG after atomic expansion pass"));
 
+static cl::opt<bool> EnableInstSimplify("hexagon-instsimplify", cl::Hidden,
+                                        cl::ZeroOrMore, cl::init(true),
+                                        cl::desc("Enable instsimplify"));
+
 /// HexagonTargetMachineModule - Note that this is used on hosts that
 /// cannot link in a library unless there are references into the
 /// library.  In particular, it seems that it is not possible to get
@@ -312,7 +316,8 @@
   bool NoOpt = (getOptLevel() == CodeGenOpt::None);
 
   if (!NoOpt) {
-    addPass(createConstantPropagationPass());
+    if (EnableInstSimplify)
+      addPass(createInstSimplifyLegacyPass());
     addPass(createDeadCodeEliminationPass());
   }
 
diff --git a/llvm/lib/Transforms/Scalar/InstSimplifyPass.cpp b/llvm/lib/Transforms/Scalar/InstSimplifyPass.cpp
--- a/llvm/lib/Transforms/Scalar/InstSimplifyPass.cpp
+++ b/llvm/lib/Transforms/Scalar/InstSimplifyPass.cpp
@@ -20,6 +20,7 @@
 #include "llvm/IR/Type.h"
 #include "llvm/InitializePasses.h"
 #include "llvm/Pass.h"
+#include "llvm/Transforms/Scalar.h"
 #include "llvm/Transforms/Utils.h"
 #include "llvm/Transforms/Utils/Local.h"
 using namespace llvm;
diff --git a/llvm/test/CodeGen/Hexagon/autohvx/isel-qfalse.ll b/llvm/test/CodeGen/Hexagon/autohvx/isel-qfalse.ll
--- a/llvm/test/CodeGen/Hexagon/autohvx/isel-qfalse.ll
+++ b/llvm/test/CodeGen/Hexagon/autohvx/isel-qfalse.ll
@@ -1,4 +1,4 @@
-; RUN: llc -march=hexagon -hexagon-initial-cfg-cleanup=0 < %s | FileCheck %s
+; RUN: llc -march=hexagon -hexagon-initial-cfg-cleanup=0 -hexagon-instsimplify=0 < %s | FileCheck %s
   
 ; Make sure we can select QFALSE.
 ; CHECK: vcmp.gt(v0.w,v0.w)
diff --git a/llvm/test/CodeGen/Hexagon/autohvx/isel-setcc-pair.ll b/llvm/test/CodeGen/Hexagon/autohvx/isel-setcc-pair.ll
--- a/llvm/test/CodeGen/Hexagon/autohvx/isel-setcc-pair.ll
+++ b/llvm/test/CodeGen/Hexagon/autohvx/isel-setcc-pair.ll
@@ -1,4 +1,4 @@
-; RUN: llc -march=hexagon -hexagon-initial-cfg-cleanup=0 < %s | FileCheck %s
+; RUN: llc -march=hexagon -hexagon-initial-cfg-cleanup=0 -hexagon-instsimplify=0 < %s | FileCheck %s
 
 ; Check that a setcc of a vector pair is handled (without crashing).
 ; CHECK: vcmp
diff --git a/llvm/test/CodeGen/Hexagon/bit-bitsplit-regclass.ll b/llvm/test/CodeGen/Hexagon/bit-bitsplit-regclass.ll
--- a/llvm/test/CodeGen/Hexagon/bit-bitsplit-regclass.ll
+++ b/llvm/test/CodeGen/Hexagon/bit-bitsplit-regclass.ll
@@ -1,4 +1,4 @@
-; RUN: llc -march=hexagon -hexagon-initial-cfg-cleanup=0 < %s | FileCheck %s
+; RUN: llc -march=hexagon -hexagon-initial-cfg-cleanup=0 -hexagon-instsimplify=0 < %s | FileCheck %s
 
 ; Check for successful compilation.
 ; CHECK: r{{[0-9]+}} = insert(r{{[0-9]+}},#1,#31)
diff --git a/llvm/test/CodeGen/Hexagon/hvx-bitcast-v64i1.ll b/llvm/test/CodeGen/Hexagon/hvx-bitcast-v64i1.ll
--- a/llvm/test/CodeGen/Hexagon/hvx-bitcast-v64i1.ll
+++ b/llvm/test/CodeGen/Hexagon/hvx-bitcast-v64i1.ll
@@ -1,4 +1,4 @@
-; RUN: llc -march=hexagon  < %s | FileCheck %s
+; RUN: llc -march=hexagon -hexagon-instsimplify=0  < %s | FileCheck %s
 
 ; Test that LLVM does not assert and bitcast v64i1 to i64 is lowered
 ; without crashing.
diff --git a/llvm/test/CodeGen/Hexagon/isel-simplify-crash.ll b/llvm/test/CodeGen/Hexagon/isel-simplify-crash.ll
--- a/llvm/test/CodeGen/Hexagon/isel-simplify-crash.ll
+++ b/llvm/test/CodeGen/Hexagon/isel-simplify-crash.ll
@@ -1,4 +1,4 @@
-; RUN: llc -march=hexagon < %s | FileCheck %s
+; RUN: llc -march=hexagon -hexagon-instsimplify=0 < %s | FileCheck %s
 
 ; This used to crash in SimplifyDemandedBits due to a type mismatch
 ; caused by a missing bitcast in vectorizing mul.
diff --git a/llvm/test/CodeGen/Hexagon/loop_correctness.ll b/llvm/test/CodeGen/Hexagon/loop_correctness.ll
--- a/llvm/test/CodeGen/Hexagon/loop_correctness.ll
+++ b/llvm/test/CodeGen/Hexagon/loop_correctness.ll
@@ -1,4 +1,4 @@
-; RUN: llc -march=hexagon -O3 < %s | FileCheck %s
+; RUN: llc -march=hexagon -O3 -hexagon-instsimplify=0 < %s | FileCheck %s
 
 ; CHECK-LABEL: f0:
 ; CHECK: loop0(.LBB{{[0-9]+}}_{{[0-9]+}},#3)
diff --git a/llvm/test/CodeGen/Hexagon/newvaluejump-kill.ll b/llvm/test/CodeGen/Hexagon/newvaluejump-kill.ll
--- a/llvm/test/CodeGen/Hexagon/newvaluejump-kill.ll
+++ b/llvm/test/CodeGen/Hexagon/newvaluejump-kill.ll
@@ -1,4 +1,4 @@
-; RUN: llc -march=hexagon -O3 -verify-machineinstrs -hexagon-initial-cfg-cleanup=0 < %s | FileCheck %s
+; RUN: llc -march=hexagon -O3 -verify-machineinstrs -hexagon-initial-cfg-cleanup=0 -hexagon-instsimplify=0 < %s | FileCheck %s
 ;
 ; Check that this testcase compiles successfully and that a new-value jump
 ; has been created.
diff --git a/llvm/test/CodeGen/Hexagon/packetize-impdef-1.ll b/llvm/test/CodeGen/Hexagon/packetize-impdef-1.ll
--- a/llvm/test/CodeGen/Hexagon/packetize-impdef-1.ll
+++ b/llvm/test/CodeGen/Hexagon/packetize-impdef-1.ll
@@ -1,4 +1,4 @@
-; RUN: llc -march=hexagon -hexagon-initial-cfg-cleanup=0 < %s | FileCheck %s
+; RUN: llc -march=hexagon -hexagon-initial-cfg-cleanup=0 -hexagon-instsimplify=0 < %s | FileCheck %s
 ; REQUIRES: asserts
 
 ; Test that the compiler doesn't assert because IMPLICIT_DEF instructions are
diff --git a/llvm/test/CodeGen/Hexagon/store-vector-pred.ll b/llvm/test/CodeGen/Hexagon/store-vector-pred.ll
--- a/llvm/test/CodeGen/Hexagon/store-vector-pred.ll
+++ b/llvm/test/CodeGen/Hexagon/store-vector-pred.ll
@@ -1,4 +1,4 @@
-; RUN: llc -march=hexagon < %s | FileCheck %s
+; RUN: llc -march=hexagon -hexagon-instsimplify=0 < %s | FileCheck %s
 
 ; This test checks that store a vector predicate of type v128i1 is lowered
 ; without crashing.
diff --git a/llvm/test/CodeGen/Hexagon/vect/zext-v4i1.ll b/llvm/test/CodeGen/Hexagon/vect/zext-v4i1.ll
--- a/llvm/test/CodeGen/Hexagon/vect/zext-v4i1.ll
+++ b/llvm/test/CodeGen/Hexagon/vect/zext-v4i1.ll
@@ -1,4 +1,4 @@
-; RUN: llc -march=hexagon < %s | FileCheck %s
+; RUN: llc -march=hexagon -hexagon-instsimplify=0 < %s | FileCheck %s
 
 ; Check that this compiles successfully.
 ; CHECK: vcmph.eq