Remove global call sets: rtlanal.c

Remove global call sets: rtlanal.c

The reg_set_p part is simple, since the caller is asking about
a specific REG rtx, with a known register number and mode.

The find_all_hard_reg_sets part emphasises that the "implicit"
behaviour was always a bit suspect, since it includes fully-clobbered
registers but not partially-clobbered registers.  The only current
user of this path is the c6x-specific scheduler predication code,
and c6x doesn't have partly call-clobbered registers, so in practice
it's fine.  I've added a comment to try to disuade future users.
(The !implicit path is OK and useful though.)

2019-09-30  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* rtlanal.c: Include function-abi.h.
	(reg_set_p): Use insn_callee_abi to get the ABI of the called
	function and clobbers_reg_p to test whether the register
	is call-clobbered.
	(find_all_hard_reg_sets): When implicit is true, use insn_callee_abi
	to get the ABI of the called function and full_reg_clobbers to
	get the set of fully call-clobbered registers.  Warn about the
	pitfalls of using this mode.

From-SVN: r276334