diff --git a/lib/Target/X86/X86TargetMachine.cpp b/lib/Target/X86/X86TargetMachine.cpp
index 8adce3115de..de7004d97a0 100644
--- a/lib/Target/X86/X86TargetMachine.cpp
+++ b/lib/Target/X86/X86TargetMachine.cpp
@@ -37,6 +37,10 @@ namespace {
   cl::opt<bool> DisableOutput("disable-x86-llc-output", cl::Hidden,
                               cl::desc("Disable the X86 asm printer, for use "
                                        "when profiling the code generator."));
+
+  cl::opt<bool> EnableX86LSR("enable-x86-lsr", cl::Hidden,
+                              cl::desc("Enable the X86 loop strength reduction "
+                                       "pass."));
   // Register the target.
   RegisterTarget<X86TargetMachine> X("x86", "  IA-32 (Pentium and above)");
 }
@@ -92,6 +96,9 @@ bool X86TargetMachine::addPassesToEmitFile(PassManager &PM, std::ostream &Out,
   if (FileType != TargetMachine::AssemblyFile &&
       FileType != TargetMachine::ObjectFile) return true;
 
+  // Run loop strength reduction before anything else.
+  if (EnableX86LSR) PM.add(createLoopStrengthReducePass());
+
   // FIXME: Implement efficient support for garbage collection intrinsics.
   PM.add(createLowerGCPass());