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

["H.J. Lu" <hjl.tools@gmail.com>]

On Wed, Sep 11, 2019 at 12:14 PM Richard Sandiford
<richard.sandiford@arm.com> 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.

This caused:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91994

-- 
H.J.