Add an option to enable StrongPHIElimination, for ease of testing.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57259 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/TwoAddressInstructionPass.cpp b/lib/CodeGen/TwoAddressInstructionPass.cpp
index dbfd770..7d9e44a 100644
--- a/lib/CodeGen/TwoAddressInstructionPass.cpp
+++ b/lib/CodeGen/TwoAddressInstructionPass.cpp
@@ -37,6 +37,7 @@
 #include "llvm/Target/TargetRegisterInfo.h"
 #include "llvm/Target/TargetInstrInfo.h"
 #include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetOptions.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/ADT/BitVector.h"
@@ -76,7 +77,10 @@
       AU.addPreserved<LiveVariables>();
       AU.addPreservedID(MachineLoopInfoID);
       AU.addPreservedID(MachineDominatorsID);
-      AU.addPreservedID(PHIEliminationID);
+      if (StrongPHIElim)
+        AU.addPreservedID(StrongPHIEliminationID);
+      else
+        AU.addPreservedID(PHIEliminationID);
       MachineFunctionPass::getAnalysisUsage(AU);
     }