Make sure constant expression instructions are always destroyed.
Make sure constant expression instructions are always destroyed.

mpflanzer/Oclgrind,bitfusionio/Oclgrind,bitfusionio/Oclgrind,bitfusionio/Oclgrind,mpflanzer/Oclgrind,mpflanzer/Oclgrind,mpflanzer/Oclgrind,surround-io/oclgrind,bitfusionio/Oclgrind,surround-io/oclgrind,surround-io/oclgrind,surround-io/oclgrind