* ifcvt.c: Include except.h.
        (block_has_only_trap): Break out from find_cond_trap.
        (find_cond_trap): Use it.  Always delete the trap block.
        (merge_if_block): Allow then block null.  Be less simplistic about
        what insns can end a block.
        * Makefile.in (ifcvt.o): Depend on except.h.

        * gcc.c-torture/compile/iftrap-1.c: New.
        * gcc.dg/iftrap-1.c: Adjust for ia64.
        * gcc.dg/iftrap-2.c: New.

From-SVN: r52489