[X86] Add option for enabling LEA optimization pass, by Andrey Turetsky

Add option to enable/disable LEA optimization pass. By default the pass is disabled.
Differential Revision: http://reviews.llvm.org/D15573

llvm-svn: 255881

1 files changed, 5 insertions, 1 deletions

diff --git a/llvm/lib/Target/X86/X86OptimizeLEAs.cpp b/llvm/lib/Target/X86/X86OptimizeLEAs.cpp
index da83c8ad824..58020d909a4 100644
--- a/llvm/lib/Target/X86/X86OptimizeLEAs.cpp
+++ b/llvm/lib/Target/X86/X86OptimizeLEAs.cpp
@@ -33,6 +33,10 @@ using namespace llvm;
 
 #define DEBUG_TYPE "x86-optimize-LEAs"
 
+static cl::opt<bool> EnableX86LEAOpt("enable-x86-lea-opt", cl::Hidden,
+                                     cl::desc("X86: Enable LEA optimizations."),
+                                     cl::init(false));
+
 STATISTIC(NumSubstLEAs, "Number of LEA instruction substitutions");
 
 namespace {
@@ -296,7 +300,7 @@ bool OptimizeLEAPass::runOnMachineFunction(MachineFunction &MF) {
   bool Changed = false;
 
   // Perform this optimization only if we care about code size.
-  if (!MF.getFunction()->optForSize())
+  if (!EnableX86LEAOpt || !MF.getFunction()->optForSize())
     return false;
 
   MRI = &MF.getRegInfo();