Add an option to disable buggy copy propagation pass


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148662 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LLVMTargetMachine.cpp b/lib/CodeGen/LLVMTargetMachine.cpp
index a04f3ed..3a9f0f0 100644
--- a/lib/CodeGen/LLVMTargetMachine.cpp
+++ b/lib/CodeGen/LLVMTargetMachine.cpp
@@ -72,6 +72,8 @@
     cl::desc("Disable Loop Strength Reduction Pass"));
 static cl::opt<bool> DisableCGP("disable-cgp", cl::Hidden,
     cl::desc("Disable Codegen Prepare"));
+static cl::opt<bool> DisableCopyProp("disable-copyprop", cl::Hidden,
+    cl::desc("Disable Copy Propagation pass"));
 static cl::opt<bool> PrintLSR("print-lsr-output", cl::Hidden,
     cl::desc("Print LLVM IR produced by the loop-reduce pass"));
 static cl::opt<bool> PrintISelInput("print-isel-input", cl::Hidden,
@@ -463,7 +465,7 @@
   }
 
   // Copy propagation.
-  if (getOptLevel() != CodeGenOpt::None) {
+  if (getOptLevel() != CodeGenOpt::None && !DisableCopyProp) {
     PM.add(createMachineCopyPropagationPass());
     printNoVerify(PM, "After copy propagation pass");
   }