combine.c (simplify_comparison, [...]): Do not drop the extend if we'd have to add a paradoxical subreg later.

gcc/ChangeLog:
* combine.c (simplify_comparison, case SIGN_EXTEND, ZERO_EXTEND):
Do not drop the extend if we'd have to add a paradoxical subreg
later.  Include optabs.h and insn-codes.h.
* Makefile.in (combine.o): Depend on $(OPTABS_H).
gcc/testsuite/ChangeLog:
* gcc.c-torture/execute/20050203-1.c: New.

From-SVN: r94655