Re: RFA: always supply a mode to plus_constant

[Richard Earnshaw <rearnsha at arm dot com>]

On 15/04/12 10:29, Richard Sandiford wrote:
> As mentioned in the discussion of Mike's >2HWI patch, plus_constant is
> AFAIK the only rtl routine that handles arithmetic on CONST_INT without
> specifying the mode of the CONST_INT.  That means it isn't always able
> to generate the right result.  E.g. it returns 0x80 for a QImode add of
> 0x7f and 0x1, whereas the correct result is 0xff....ff80.
> 
> Mike's patch therefore introduced plus_constant_mode.  This allowed
> the routine to call itself recursively for CONST_INTs embedded in PLUSes,
> rather than having to treat them as a special case.
> 
> This patch fixes the FIXME introduced in that patch: that all callers
> really ought to specify the mode.  It's true that many callers are known
> to pass a register, but rather than try to justify on a case-by-case
> basis why a mode doesn't need to be passed, it seems better to always
> pass one.  Most other rtl routines (e.g. the simplify_* ones) work in
> just the same way.
> 
> One way of doing this would have been to semd patches that make
> individual files use plus_constant_mode.  Then, once all the calls had
> been converted, and nothing called plus_constant, we could mechanically
> rename plus_constant_mode to plus_constant (because the _mode would be
> redundant, and inconsistent with things like the simplify routines).
> But that would mean a lot of SVN churn.  Many calls to plus_constant are
> pressed up against the right side of the screen, and would need to be
> reformatted for the longer name.  Then the mechanical rename would have
> to reformat them again, in many cases going back to the original.
> 
> So I think the best way is simply to do the whole thing as one patch.
> Which means it needs a GWP...
> 
> I did actually develop the patch by renaming the function (so that grep
> would tell me if I'd caught all calls) then renaming it back.  If there
> are strong objections to doing it in one step, I can go back to that.
> 
> Bootstrapped & regression-tested on x86_64-linux-gnu.  Also tested by
> compiling gcc for the following targets and making sure that the output
> of the gcc.c-torture and gcc.dg testsuites were the same at -O3 -g:
> 
>         alpha-linux-gnu arm-linux-gnueabi avr-rtems bfin-elf c6x-elf
>         cr16-elf cris-elf epiphany-elf fr30-elf frv-linux-gnu h8300-elf
>         ia64-linux-gnu iq2000-elf lm32-elf m32c-elf m32r-elf
>         m68k-linux-gnu mcore-elf mep-elf microblaze-elf mips-linux-gnu
>         mmix mn10300-elf moxie-elf hppa64-hp-hpux11.23 pdp11
>         picochip-elf powerpc-linux-gnu powerpc-eabispe rl78-elf rx-elf
>         s390-linux-gnu score-elf sh-linux-gnu sparc-linux-gnu spu-elf
>         tilegx-elf tilepro-elf xstormy16-elf v850-elf vax-netbsdelf
>         xtensa-elf
> 
> OK to install?
> 
> Richard
> 

The ARM bits are OK.

R.

> 
> gcc/
>         * rtl.h (plus_constant, plus_constant_mode): Merge into a single
>         plus_constant function.
>         * explow.c (plus_constant, plus_constant_mode): Likewise.  Assert
>         that the mode is sensible.
>         (use_anchored_address, round_push, allocate_dynamic_stack_space)
>         (probe_stack_range, anti_adjust_stack_and_probe): Update calls to
>         plus_constant.
> 
>         * alias.c (canon_rtx): Likewise.
>         (init_alias_analysis): Likewise.
>         * builtins.c (expand_builtin_return_addr)
>         (expand_builtin_setjmp_setup, expand_builtin_longjmp)
>         (expand_builtin_nonlocal_goto, expand_builtin_update_setjmp_buf)
>         (expand_builtin_apply_args_1, expand_builtin_apply, expand_movstr)
>         (expand_builtin_stpcpy): Likewise.
>         * calls.c (save_fixed_argument_area, restore_fixed_argument_area)
>         (compute_argument_addresses, internal_arg_pointer_based_exp)
>         (expand_call, emit_library_call_value_1): Likewise.
>         * cfgexpand.c (expand_one_stack_var_at, expand_debug_expr): Likewise.
>         * combine-stack-adj.c (try_apply_stack_adjustment): Likewise.
>         * combine.c (combine_simplify_rtx, force_to_mode): Likewise.
>         * cse.c (insert_const_anchor, find_reg_offset_for_const)
>         (use_related_value, fold_rtx): Likewise.
>         * cselib.c (cselib_subst_to_values): Likewise.
>         * dse.c (record_store, check_mem_read_rtx): Likewise.
>         * dwarf2out.c (rtl_for_decl_location, gen_variable_die): Likewise.
>         * emit-rtl.c (adjust_address_1): Likewise.
>         * except.c (sjlj_emit_function_enter)
>         (expand_builtin_extract_return_addr)
>         (expand_builtin_frob_return_addr): Likewise.
>         * expmed.c (expand_divmod): Likewise.
>         * expr.c (move_by_pieces, store_by_pieces, store_by_pieces_1)
>         (emit_move_resolve_push, push_block, emit_push_insn, store_expr)
>         (expand_expr_addr_expr_1, expand_expr_real_1): Likewise.
>         * function.c (assign_stack_local_1)
>         (instantiate_virtual_regs_in_rtx): Likewise.
>         * optabs.c (prepare_cmp_insn): Likewise.
>         * recog.c (offsettable_address_addr_space_p): Likewise.
>         * reload.c (find_reloads_address, form_sum)
>         (find_reloads_subreg_address): Likewise.
>         * reload1.c (init_reload, eliminate_regs_1)
>         (eliminate_regs_in_insn): Likewise.
>         * simplify-rtx.c (simplify_unary_operation_1)
>         (simplify_binary_operation_1, simplify_plus_minus): Likewise.
>         * var-tracking.c (compute_cfa_pointer, prepare_call_arguments)
>         (vt_add_function_parameter): Likewise.
> 
>         * config/alpha/alpha.h (EH_RETURN_HANDLER_RTX): Likewise.
>         * config/alpha/vms.h (EH_RETURN_HANDLER_RTX): Likewise.
>         * config/alpha/alpha.c (alpha_legitimize_address_1)
>         (get_unaligned_address, alpha_expand_unaligned_load)
>         (alpha_expand_unaligned_store, alpha_expand_unaligned_load_words)
>         (alpha_expand_unaligned_store_words, alpha_expand_block_clear)
>         (alpha_expand_builtin_establish_vms_condition_handler)
>         (alpha_setup_incoming_varargs, emit_frame_store_1)
>         (alpha_expand_prologue, alpha_expand_epilogue)
>         (alpha_use_linkage): Likewise.
>         * config/alpha/alpha.md: Likewise.
> 
>         * config/arm/arm.c (arm_trampoline_init, legitimize_pic_address)
>         (arm_load_pic_register, arm_pic_static_addr, arm_legitimize_address)
>         (thumb_legitimize_address, arm_gen_load_multiple_1)
>         (arm_gen_store_multiple_1, arm_gen_multiple_op, gen_ldm_seq)
>         (gen_stm_seq, gen_const_stm_seq, arm_block_move_unaligned_straight)
>         (arm_block_move_unaligned_loop, arm_gen_movmemqi, arm_reload_in_hi)
>         (arm_reload_out_hi, arm_reorg, vfp_emit_fstmd, emit_multi_reg_push)
>         (emit_sfm, thumb_set_frame_pointer, arm_expand_prologue)
>         (thumb1_emit_multi_reg_push, thumb1_expand_prologue)
>         (thumb_expand_movmemqi, arm_set_return_address)
>         (thumb_set_return_address): Likewise.
>         * config/arm/arm.md: Likewise.
> 
>         * config/avr/avr.c (avr_incoming_return_addr_rtx)
>         (avr_prologue_setup_frame, expand_epilogue)
>         (avr_const_address_lo16): Likewise.
> 
>         * config/bfin/bfin.h (EH_RETURN_HANDLER_RTX): Likewise.
>         * config/bfin/bfin.c (setup_incoming_varargs, bfin_load_pic_reg)
>         (bfin_expand_prologue, bfin_trampoline_init, bfin_expand_call)
>         (bfin_output_mi_thunk): Likewise.
> 
>         * config/c6x/c6x.c (c6x_initialize_trampoline)
>         (c6x_output_mi_thunk): Likewise.
> 
>         * config/cr16/cr16.h (EH_RETURN_HANDLER_RTX): Likewise.
>         * config/cr16/cr16.c (cr16_create_dwarf_for_multi_push): Likewise.
> 
>         * config/cris/cris.c (cris_return_addr_rtx, cris_split_movdx)
>         (cris_expand_prologue, cris_expand_epilogue, cris_gen_movem_load)
>         (cris_emit_movem_store, cris_trampoline_init): Likewise.
>         * config/cris/cris.md: Likewise.
> 
>         * config/darwin.c (machopic_indirect_data_reference)
>         (machopic_legitimize_pic_address): Likewise.
> 
>         * config/epiphany/epiphany.c (epiphany_emit_save_restore)
>         (epiphany_expand_prologue, epiphany_expand_epilogue)
>         (epiphany_trampoline_init): Likewise.
>         * config/epiphany/epiphany.md: Likewise.
> 
>         * config/fr30/fr30.c (fr30_move_double): Likewise.
> 
>         * config/frv/frv.c (frv_dwarf_store, frv_expand_prologue)
>         (frv_expand_block_move, frv_expand_block_clear, frv_return_addr_rtx)
>         (frv_index_memory, unspec_got_name, frv_find_base_term)
>         (frv_output_dwarf_dtprel): Likewise.
> 
>         * config/h8300/h8300.c (h8300_push_pop, h8300_return_addr_rtx)
>         (h8300_swap_into_er6, h8300_swap_out_of_er6): Likewise.
> 
>         * config/i386/i386.h (RETURN_ADDR_RTX): Likewise.
>         * config/i386/i386.c (setup_incoming_varargs_64)
>         (setup_incoming_varargs_ms_64, choose_baseaddr)
>         (ix86_emit_save_reg_using_mov, ix86_adjust_stack_and_probe)
>         (ix86_emit_probe_stack_range, ix86_expand_prologue)
>         (ix86_emit_restore_reg_using_pop, ix86_emit_leave)
>         (ix86_expand_epilogue, legitimize_pic_address, ix86_legitimize_address)
>         (ix86_split_long_move, ix86_expand_movmem, ix86_expand_setmem)
>         (ix86_static_chain, ix86_trampoline_init, x86_this_parameter)
>         (x86_output_mi_thunk): Likewise.
>         * config/i386/i386.md: Likewise.
> 
>         * config/ia64/ia64.c (ia64_expand_load_address)
>         (ia64_expand_tls_address, ia64_expand_move, ia64_split_tmode)
>         (do_spill, ia64_trampoline_init): Likewise.
> 
>         * config/iq2000/iq2000.c (iq2000_va_start)
>         (iq2000_emit_frame_related_store, iq2000_expand_prologue)
>         (iq2000_expand_eh_return, iq2000_setup_incoming_varargs)
>         (iq2000_print_operand, iq2000_legitimize_address): Likewise.
> 
>         * config/lm32/lm32.c (lm32_setup_incoming_varargs): Likewise.
> 
>         * config/m32c/m32c.c (m32c_return_addr_rtx)
>         (m32c_expand_insv): Likewise.
> 
>         * config/m32r/m32r.c (m32r_setup_incoming_varargs)
>         (m32r_legitimize_pic_address, m32r_print_operand)
>         (m32r_print_operand_address): Likewise.
> 
>         * config/m68k/linux.h (FINALIZE_TRAMPOLINE): Likewise.
>         * config/m68k/m68k.h (RETURN_ADDR_RTX): Likewise.
>         (EH_RETURN_HANDLER_RTX): Likewise.
>         * config/m68k/m68k.c (m68k_emit_movem, m68k_expand_prologue)
>         (m68k_expand_epilogue, legitimize_pic_address)
>         (m68k_output_mi_thunk): Likewise.
>         * config/m68k/m68k.md: Likewise.
> 
>         * config/mcore/mcore.c (mcore_expand_prolog): Likewise.
>         (mcore_expand_epilog): Likewise.
>         * config/mcore/mcore.md: Likewise.
> 
>         * config/mep/mep.c (mep_allocate_initial_value)
>         (mep_expand_prologue, mep_expand_epilogue): Likewise.
> 
>         * config/microblaze/microblaze.c (double_memory_operand)
>         (microblaze_block_move_loop): Likewise.
> 
>         * config/mips/mips.c (mips_strip_unspec_address, mips_add_offset)
>         (mips_setup_incoming_varargs, mips_va_start, mips_block_move_loop)
>         (mips_print_operand, mips16e_save_restore_reg, mips_save_restore_reg)
>         (mips_expand_prologue, mips_epilogue_set_cfa)
>         (mips_expand_epilogue): Likewise.
>         * config/mips/mips.md: Likewise.
> 
>         * config/mmix/mmix.c (mmix_dynamic_chain_address, mmix_return_addr_rtx)
>         (mmix_expand_prologue, mmix_expand_epilogue): Likewise.
> 
>         * config/mn10300/mn10300.c (mn10300_gen_multiple_store)
>         (mn10300_builtin_saveregs, mn10300_trampoline_init): Likewise.
> 
>         * config/moxie/moxie.h (INCOMING_RETURN_ADDR_RTX): Likewise.
>         (EH_RETURN_HANDLER_RTX): Likewise.
>         * config/moxie/moxie.c (moxie_static_chain): Likewise.
> 
>         * config/pa/pa.c (legitimize_pic_address, hppa_legitimize_address)
>         (store_reg, set_reg_plus_d, pa_expand_prologue, load_reg)
>         (pa_return_addr_rtx, hppa_builtin_saveregs)
>         (pa_trampoline_init): Likewise.
>         * config/pa/pa.md: Likewise.
> 
>         * config/pdp11/pdp11.c (pdp11_expand_epilogue): Likewise.
> 
>         * config/picochip/picochip.c (picochip_static_chain): Likewise.
> 
>         * config/rs6000/rs6000.h (RS6000_SAVE_TOC): Likewise.
>         * config/rs6000/rs6000.c (rs6000_legitimize_address)
>         (setup_incoming_varargs, print_operand, rs6000_return_addr)
>         (rs6000_emit_eh_reg_restore, rs6000_emit_probe_stack_range)
>         (rs6000_emit_epilogue)
>         (rs6000_machopic_legitimize_pic_address): Likewise.
> 
>         * config/rx/rx.c (gen_rx_rtsd_vector, gen_rx_popm_vector): Likewise.
> 
>         * config/s390/s390.h (INITIAL_FRAME_ADDRESS_RTX): Likewise.
>         (DYNAMIC_CHAIN_ADDRESS): Likewise.
>         * config/s390/s390.c (s390_decompose_address, legitimize_pic_address)
>         (s390_delegitimize_address, print_operand, annotate_constant_pool_refs)
>         (replace_constant_pool_ref, s390_return_addr_rtx, s390_back_chain_rtx)
>         (save_fpr, restore_fpr, save_gprs, restore_gprs, s390_emit_prologue)
>         (s390_emit_epilogue, s390_function_profiler): Likewise.
>         * config/s390/s390.md: Likewise.
> 
>         * config/score/score.c (score_add_offset, score_prologue): Likewise.
> 
>         * config/sh/sh.c (expand_block_move, push_regs, sh_builtin_saveregs)
>         (sh_output_mi_thunk): Likewise.
>         * config/sh/sh.md: Likewise.
> 
>         * config/sparc/sparc.h (DYNAMIC_CHAIN_ADDRESS, FRAME_ADDR_RTX)
>         (RETURN_ADDR_RTX, INCOMING_RETURN_ADDR_RTX): Likewise.
>         * config/sparc/sparc.c (sparc_legitimize_pic_address)
>         (sparc_emit_probe_stack_range, emit_save_or_restore_regs)
>         (emit_window_save, sparc_flat_expand_prologue, sparc_struct_value_rtx)
>         (emit_and_preserve): Likewise.
>         * config/sparc/sparc.md: Likewise.
> 
>         * config/spu/spu.h (DYNAMIC_CHAIN_ADDRESS): Likewise.
>         * config/spu/spu.c (spu_expand_insv, spu_machine_dependent_reorg)
>         (spu_setup_incoming_varargs, ea_load_store_inline)
>         (spu_expand_load): Likewise.
> 
>         * config/stormy16/stormy16.c (xstormy16_expand_prologue)
>         (combine_bnp): Likewise.
> 
>         * config/tilegx/tilegx.h (DYNAMIC_CHAIN_ADDRESS): Likewise.
>         * config/tilegx/tilegx.c (tilegx_setup_incoming_varargs)
>         (tilegx_expand_unaligned_load, tilegx_trampoline_init): Likewise.
> 
>         * config/tilepro/tilepro.h (DYNAMIC_CHAIN_ADDRESS): Likewise.
>         * config/tilepro/tilepro.c (tilepro_setup_incoming_varargs)
>         (tilepro_expand_unaligned_load, tilepro_trampoline_init): Likewise.
> 
>         * config/v850/v850.c (expand_prologue, expand_epilogue): Likewise.
>         * config/v850/v850.md: Likewise.
> 
>         * config/vax/elf.h (EH_RETURN_STACKADJ_RTX): Likewise.
>         (EH_RETURN_HANDLER_RTX): Likewise.
>         * config/vax/vax.h (DYNAMIC_CHAIN_ADDRESS, RETURN_ADDR_RTX): Likewise.
>         * config/vax/vax.c (vax_add_reg_cfa_offset, vax_expand_prologue)
>         (print_operand_address, vax_trampoline_init): Likewise.
> 
>         * config/xtensa/xtensa.c (xtensa_expand_prologue, xtensa_return_addr)
>         (xtensa_function_value_regno_p): Likewise.