Subzero: Minor refactoring/additions in preparation for phi edge splitting.

src/IceInstX8632.h

Index: src/IceInstX8632.h
diff --git a/src/IceInstX8632.h b/src/IceInstX8632.h
index 8235d1fe264e284f355e8adbb6d1bc19d1ec573c..5eeef06f70409fb38c0d4c6a6fde4d072de9a1b3 100644
--- a/src/IceInstX8632.h
+++ b/src/IceInstX8632.h
@@ -341,6 +341,7 @@ public:
   // Create a conditional branch to a node.
   static InstX8632Br *create(Cfg *Func, CfgNode *TargetTrue,
                              CfgNode *TargetFalse, CondX86::BrCond Condition) {
+    assert(Condition != CondX86::Br_None);
     const InstX8632Label *NoLabel = NULL;
     return new (Func->allocate<InstX8632Br>())
         InstX8632Br(Func, TargetTrue, TargetFalse, NoLabel, Condition);
@@ -357,6 +358,7 @@ public:
   // used for switch lowering.
   static InstX8632Br *create(Cfg *Func, CfgNode *Target,
                              CondX86::BrCond Condition) {
+    assert(Condition != CondX86::Br_None);
     const CfgNode *NoUncondTarget = NULL;
     const InstX8632Label *NoLabel = NULL;
     return new (Func->allocate<InstX8632Br>())