Removed an assert which was causing significant slowdowns in debug builds.

This assert was very conservative to begin with (the error condition is well
covered by tests elsewhere in the code) so we won't miss much by removing it.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86088 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/SlotIndexes.h

@@ -131,7 +131,6 @@ namespace llvm {
     }
 
     IndexListEntry& entry() const {
-      assert(lie.getPointer() != 0 && "Use of invalid index.");
       return *lie.getPointer();
     }