Replaced tabs with four spaces.
Made the test-cases work, added a cast to the actual test data type to forbid widening of the result type (e.g. from signed short to signed int, rendering the potential correct result larger or smaller than the range of a signed short can be).
For failed tests, .ll files will now be placed in the tests directory. These can be used to track down the reason for the test failure.
Updated llvm and clang to the latest HEAD (now already more than a week old, though), had to ignore more warnings because of warnings in llvm/clang code.