Re: [21/32] Remove global call sets: LRA

[Jeff Law <law@redhat.com>]

On 9/11/19 1:14 PM, Richard Sandiford wrote:
> lra_reg has an actual_call_used_reg_set field that is only used during
> inheritance.  This in turn required a special lra_create_live_ranges
> pass for flag_ipa_ra to set up this field.  This patch instead makes
> the inheritance code do its own live register tracking, using the
> same ABI-mask-and-clobber-set pair as for IRA.
> 
> Tracking ABIs simplifies (and cheapens) the logic in lra-lives.c and
> means we no longer need a separate path for -fipa-ra.  It also means
> we can remove TARGET_RETURN_CALL_WITH_MAX_CLOBBERS.
> 
> The patch also strengthens the sanity check in lra_assigns so that
> we check that reg_renumber is consistent with the whole conflict set,
> not just the call-clobbered registers.
> 
> 
> 2019-09-11  Richard Sandiford  <richard.sandiford@arm.com>
> 
> gcc/
> 	* target.def (return_call_with_max_clobbers): Delete.
> 	* doc/tm.texi.in (TARGET_RETURN_CALL_WITH_MAX_CLOBBERS): Delete.
> 	* doc/tm.texi: Regenerate.
> 	* config/aarch64/aarch64.c (aarch64_return_call_with_max_clobbers)
> 	(TARGET_RETURN_CALL_WITH_MAX_CLOBBERS): Delete.
> 	* lra-int.h (lra_reg::actual_call_used_reg_set): Delete.
> 	(lra_reg::call_insn): Delete.
> 	* lra.c: Include function-abi.h.
> 	(initialize_lra_reg_info_element): Don't initialize the fields above.
> 	(lra): Use crtl->abi to test whether the current function needs to
> 	save a register in the prologue.  Remove special pre-inheritance
> 	lra_create_live_ranges pass for flag_ipa_ra.
> 	* lra-assigns.c: Include function-abi.h
> 	(find_hard_regno_for_1): Use crtl->abi to test whether the current
> 	function needs to save a register in the prologue.
> 	(lra_assign): Assert that registers aren't allocated to a
> 	conflicting register, rather than checking only for overlaps
> 	with call_used_or_fixed_regs.  Do this even for flag_ipa_ra,
> 	and for registers that are not live across a call.
> 	* lra-constraints.c (last_call_for_abi): New variable.
> 	(full_and_partial_call_clobbers): Likewise.
> 	(setup_next_usage_insn): Remove the register from
> 	full_and_partial_call_clobbers.
> 	(need_for_call_save_p): Use call_clobbered_in_region_p to test
> 	whether the register needs a caller save.
> 	(need_for_split_p): Use full_and_partial_reg_clobbers instead
> 	of call_used_or_fixed_regs.
> 	(inherit_in_ebb): Initialize and maintain last_call_for_abi and
> 	full_and_partial_call_clobbers.
> 	* lra-lives.c (check_pseudos_live_through_calls): Replace
> 	last_call_used_reg_set and call_insn arguments with an abi argument.
> 	Remove handling of lra_reg::call_insn.  Use function_abi::mode_clobbers
> 	as the set of conflicting registers.
> 	(calls_have_same_clobbers_p): Delete.
> 	(process_bb_lives): Track the ABI of the last call instead of an
> 	insn/HARD_REG_SET pair.  Update calls to
> 	check_pseudos_live_through_calls.  Use eh_edge_abi to calculate
> 	the set of registers that could be clobbered by an EH edge.
> 	Include partially-clobbered as well as fully-clobbered registers.
> 	(lra_create_live_ranges_1): Don't initialize lra_reg::call_insn.
> 	* lra-remat.c: Include function-abi.h.
> 	(call_used_regs_arr_len, call_used_regs_arr): Delete.
> 	(set_bb_regs): Use call_insn_abi to get the set of call-clobbered
> 	registers and bitmap_view to combine them into dead_regs.
> 	(call_used_input_regno_present_p): Take a function_abi argument
> 	and use it to test whether a register is call-clobbered.
> 	(calculate_gen_cands): Use call_insn_abi to get the ABI of the
> 	call insn target.  Update tje call to call_used_input_regno_present_p.
> 	(do_remat): Likewise.
> 	(lra_remat): Remove the initialization of call_used_regs_arr_len
> 	and call_used_regs_arr.
OK
jeff