re PR rtl-optimization/21803 ([ia64] gcc produces really odd predicated code)

re PR rtl-optimization/21803 ([ia64] gcc produces really odd predicated code)

gcc/
	PR target/21803
	* ifcvt.c (cond_exec_process_if_block): Look for identical sequences
	at the start and end of the then/else blocks, and omit them from the
	conversion.
	* cfgcleanup.c (flow_find_cross_jump): No longer static.  Remove MODE
	argument; all callers changed.  Pass zero to old_insns_match_p instead.
	(flow_find_head_matching_sequence): New function.
	(old_insns_match_p): Check REG_EH_REGION notes for calls.
	* basic-block.h (flow_find_cross_jump,
	flow_find_head_matching_sequence): Declare functions.

gcc/testsuite/
	PR target/21803
	* gcc.target/arm/pr42496.c: New test.

From-SVN: r158357