The early if conversion pass is ready to be used as an opt-in.

Enable the pass by default for targets that request it, and change the
-enable-early-ifcvt to the opposite -disable-early-ifcvt.

There are still some x86 regressions when enabling early if-conversion
because of the missing machine models. Disable the pass for x86 until
machine models are added.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165075 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/Passes.cpp b/lib/CodeGen/Passes.cpp
index a6dd5de..4ea21d4 100644
--- a/lib/CodeGen/Passes.cpp
+++ b/lib/CodeGen/Passes.cpp
@@ -49,8 +49,8 @@
     cl::desc("Disable Stack Slot Coloring"));
 static cl::opt<bool> DisableMachineDCE("disable-machine-dce", cl::Hidden,
     cl::desc("Disable Machine Dead Code Elimination"));
-static cl::opt<bool> EnableEarlyIfConversion("enable-early-ifcvt", cl::Hidden,
-    cl::desc("Enable Early If-conversion"));
+static cl::opt<bool> DisableEarlyIfConversion("disable-early-ifcvt", cl::Hidden,
+    cl::desc("Disable Early If-conversion"));
 static cl::opt<bool> DisableMachineLICM("disable-machine-licm", cl::Hidden,
     cl::desc("Disable Machine LICM"));
 static cl::opt<bool> DisableMachineCSE("disable-machine-cse", cl::Hidden,
@@ -161,7 +161,7 @@
     return applyDisable(TargetID, DisableMachineDCE);
 
   if (StandardID == &EarlyIfConverterID)
-    return applyDisable(TargetID, !EnableEarlyIfConversion);
+    return applyDisable(TargetID, DisableEarlyIfConversion);
 
   if (StandardID == &MachineLICMID)
     return applyDisable(TargetID, DisableMachineLICM);