The inheritance code in find_equiv_reg can use clobbers_reg_p
to test whether a call clobbers either of the equivalent registers.

reload and find_reg use crtl->abi to test whether a register needs
to be saved in the prologue before use.

reload_as_needed can use full_and_partial_reg_clobbers and thus
avoid needing to keep its own record of which registers are part
call-clobbered.

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

gcc/
	* reload.c: Include function-abi.h.
	(find_equiv_reg): Use clobbers_reg_p to test whether either
	of the equivalent registers is clobbered by a call.
	* reload1.c: Include function-abi.h.
	(reg_reloaded_call_part_clobbered): Delete.
	(reload): Use crtl->abi to test which registers would need
	saving in the prologue before use.
	(find_reg): Likewise.
	(emit_reload_insns): Remove code for reg_reloaded_call_part_clobbered.
	(reload_as_needed): Likewise.  Use full_and_partial_reg_clobbers
	instead of call_used_or_fixed_regs | reg_reloaded_call_part_clobbered.

From-SVN: r276333