[RTL ifcvt] PR 67786, 67787: Check that intermediate instructions in the basic block don't clobber a reg used in condition

        PR rtl-optimization/67786
        PR rtl-optimization/67787
        * ifcvt.c (bb_valid_for_noce_process_p): Reject basic block if
        it modifies a reg used in the condition calculation.

        * gcc.dg/pr67786.c: New test.
        * gcc.dg/pr67787.c: Likewise.

From-SVN: r228375