Add switch instruction to Subzero bitcode reader.

BUG= https://code.google.com/p/nativeclient/issues/detail?id=3892
R=stichnot@chromium.org

Review URL: https://codereview.chromium.org/576243002
diff --git a/src/IceTypes.cpp b/src/IceTypes.cpp
index a3e19ae..29ff4de 100644
--- a/src/IceTypes.cpp
+++ b/src/IceTypes.cpp
@@ -228,6 +228,13 @@
   return IceType_void;
 }
 
+SizeT getScalarIntBitWidth(Type Ty) {
+  assert(isScalarIntegerType(Ty));
+  if (Ty == Ice::IceType_i1)
+    return 1;
+  return typeWidthInBytes(Ty) * CHAR_BIT;
+}
+
 // ======================== Dump routines ======================== //
 
 const char *typeString(Type Ty) {