Add targets to skip running the GC passes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170836 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/Passes.cpp b/lib/CodeGen/Passes.cpp
index 96e2cf2..02ac836 100644
--- a/lib/CodeGen/Passes.cpp
+++ b/lib/CodeGen/Passes.cpp
@@ -513,9 +513,10 @@
   }
 
   // GC
-  addPass(&GCMachineCodeAnalysisID);
-  if (PrintGCInfo)
-    addPass(createGCInfoPrinter(dbgs()));
+  if (addGCPasses()) {
+    if (PrintGCInfo)
+      addPass(createGCInfoPrinter(dbgs()));
+  }
 
   // Basic block placement.
   if (getOptLevel() != CodeGenOpt::None)
@@ -732,6 +733,12 @@
     printAndVerify("After copy propagation pass");
 }
 
+/// Add standard GC passes.
+bool TargetPassConfig::addGCPasses() {
+  addPass(&GCMachineCodeAnalysisID);
+  return true;
+}
+
 /// Add standard basic block placement passes.
 void TargetPassConfig::addBlockPlacement() {
   AnalysisID PassID = 0;