Introduction of improved switch lowering.

src/IceClFlags.h

Index: src/IceClFlags.h
diff --git a/src/IceClFlags.h b/src/IceClFlags.h
index 549bf1693811a54044dbee7c80ccc6f7cfae9d19..97420eaa4c7ce870ef86eabde0a7d3215c13287a 100644
--- a/src/IceClFlags.h
+++ b/src/IceClFlags.h
@@ -103,6 +103,13 @@ public:
   }
   void setTimeEachFunction(bool NewValue) { TimeEachFunction = NewValue; }
 
+  bool getUseAdvancedSwitchLowering() const {
+    return UseAdvancedSwitchLowering;
+  }
+  void setUseAdvancedSwitchLowering(bool NewValue) {
+    UseAdvancedSwitchLowering = NewValue;
+  }
+
   bool getUseSandboxing() const { return UseSandboxing; }
   void setUseSandboxing(bool NewValue) { UseSandboxing = NewValue; }
 
@@ -235,6 +242,7 @@ private:
   bool SkipUnimplemented;
   bool SubzeroTimingEnabled;
   bool TimeEachFunction;
+  bool UseAdvancedSwitchLowering;
   bool UseSandboxing;
 
   OptLevel Opt;