Re: [025/nnn] poly_int: SUBREG_BYTE

[Jeff Law <law@redhat.com>]

On 10/23/2017 11:10 AM, Richard Sandiford wrote:
> This patch changes SUBREG_BYTE from an int to a poly_int.
> Since valid SUBREG_BYTEs must be contained within the mode of the
> SUBREG_REG, the required range is the same as for GET_MODE_SIZE,
> i.e. unsigned short.  The patch therefore uses poly_uint16(_pod)
> for the SUBREG_BYTE.
> 
> Using poly_uint16_pod rtx fields requires a new field code ('p').
> Since there are no other uses of 'p' besides SUBREG_BYTE, the patch
> doesn't add an XPOLY or whatever; all uses should go via SUBREG_BYTE
> instead.
> 
> The patch doesn't bother implementing 'p' support for legacy
> define_peepholes, since none of the remaining ones have subregs
> in their patterns.
> 
> As it happened, the rtl documentation used SUBREG as an example of a
> code with mixed field types, accessed via XEXP (x, 0) and XINT (x, 1).
> Since there's no direct replacement for XINT, and since people should
> never use it even if there were, the patch changes the example to use
> INT_LIST instead.
> 
> The patch also changes subreg-related helper functions so that they too
> take and return polynomial offsets.  This makes the patch quite big, but
> it's mostly mechanical.  The patch generally sticks to existing choices
> wrt signedness.
> 
> 
> 2017-10-23  Richard Sandiford  <richard.sandiford@linaro.org>
> 	    Alan Hayward  <alan.hayward@arm.com>
> 	    David Sherwood  <david.sherwood@arm.com>
> 
> gcc/
> 	* doc/rtl.texi: Update documentation of SUBREG_BYTE.  Document the
> 	'p' format code.  Use INT_LIST rather than SUBREG as the example of
> 	a code with an XINT and an XEXP.  Remove the implication that
> 	accessing an rtx field using XINT is expected to work.
> 	* rtl.def (SUBREG): Change format from "ei" to "ep".
> 	* rtl.h (rtunion::rt_subreg): New field.
> 	(XCSUBREG): New macro.
> 	(SUBREG_BYTE): Use it.
> 	(subreg_shape): Change offset from an unsigned int to a poly_uint16.
> 	Update constructor accordingly.
> 	(subreg_shape::operator ==): Update accordingly.
> 	(subreg_shape::unique_id): Return an unsigned HOST_WIDE_INT rather
> 	than an unsigned int.
> 	(subreg_lsb, subreg_lowpart_offset, subreg_highpart_offset): Return
> 	a poly_uint64 rather than an unsigned int.
> 	(subreg_lsb_1): Likewise.  Take the offset as a poly_uint64 rather
> 	than an unsigned int.
> 	(subreg_size_offset_from_lsb, subreg_size_lowpart_offset)
> 	(subreg_size_highpart_offset): Return a poly_uint64 rather than
> 	an unsigned int.  Take the sizes as poly_uint64s.
> 	(subreg_offset_from_lsb): Return a poly_uint64 rather than
> 	an unsigned int.  Take the shift as a poly_uint64 rather than
> 	an unsigned int.
> 	(subreg_regno_offset, subreg_offset_representable_p): Take the offset
> 	as a poly_uint64 rather than an unsigned int.
> 	(simplify_subreg_regno): Likewise.
> 	(byte_lowpart_offset): Return the memory offset as a poly_int64
> 	rather than an int.
> 	(subreg_memory_offset): Likewise.  Take the subreg offset as a
> 	poly_uint64 rather than an unsigned int.
> 	(simplify_subreg, simplify_gen_subreg, subreg_get_info)
> 	(gen_rtx_SUBREG, validate_subreg): Take the subreg offset as a
> 	poly_uint64 rather than an unsigned int.
> 	* rtl.c (rtx_format): Describe 'p' in comment.
> 	(copy_rtx, rtx_equal_p_cb, rtx_equal_p): Handle 'p'.
> 	* emit-rtl.c (validate_subreg, gen_rtx_SUBREG): Take the subreg
> 	offset as a poly_uint64 rather than an unsigned int.
> 	(byte_lowpart_offset): Return the memory offset as a poly_int64
> 	rather than an int.
> 	(subreg_memory_offset): Likewise.  Take the subreg offset as a
> 	poly_uint64 rather than an unsigned int.
> 	(subreg_size_lowpart_offset, subreg_size_highpart_offset): Take the
> 	mode sizes as poly_uint64s rather than unsigned ints.  Return a
> 	poly_uint64 rather than an unsigned int.
> 	(subreg_lowpart_p): Treat subreg offsets as poly_ints.
> 	(copy_insn_1): Handle 'p'.
> 	* rtlanal.c (set_noop_p): Treat subregs offsets as poly_uint64s.
> 	(subreg_lsb_1): Take the subreg offset as a poly_uint64 rather than
> 	an unsigned int.  Return the shift in the same way.
> 	(subreg_lsb): Return the shift as a poly_uint64 rather than an
> 	unsigned int.
> 	(subreg_size_offset_from_lsb): Take the sizes and shift as
> 	poly_uint64s rather than unsigned ints.  Return the offset as
> 	a poly_uint64.
> 	(subreg_get_info, subreg_regno_offset, subreg_offset_representable_p)
> 	(simplify_subreg_regno): Take the offset as a poly_uint64 rather than
> 	an unsigned int.
> 	* rtlhash.c (add_rtx): Handle 'p'.
> 	* genemit.c (gen_exp): Likewise.
> 	* gengenrtl.c (type_from_format, gendef): Likewise.
> 	* gensupport.c (subst_pattern_match, get_alternatives_number)
> 	(collect_insn_data, alter_predicate_for_insn, alter_constraints)
> 	(subst_dup): Likewise.
> 	* gengtype.c (adjust_field_rtx_def): Likewise.
> 	* genrecog.c (find_operand, find_matching_operand, validate_pattern)
> 	(match_pattern_2): Likewise.
> 	(rtx_test::SUBREG_FIELD): New rtx_test::kind_enum.
> 	(rtx_test::subreg_field): New function.
> 	(operator ==, safe_to_hoist_p, transition_parameter_type)
> 	(print_nonbool_test, print_test): Handle SUBREG_FIELD.
> 	* genattrtab.c (attr_rtx_1): Say that 'p' is deliberately not handled.
> 	* genpeep.c (match_rtx): Likewise.
> 	* print-rtl.c (print_poly_int): Include if GENERATOR_FILE too.
> 	(rtx_writer::print_rtx_operand): Handle 'p'.
> 	(print_value): Handle SUBREG.
> 	* read-rtl.c (apply_int_iterator): Likewise.
> 	(rtx_reader::read_rtx_operand): Handle 'p'.
> 	* alias.c (rtx_equal_for_memref_p): Likewise.
> 	* cselib.c (rtx_equal_for_cselib_1, cselib_hash_rtx): Likewise.
> 	* caller-save.c (replace_reg_with_saved_mem): Treat subreg offsets
> 	as poly_ints.
> 	* calls.c (expand_call): Likewise.
> 	* combine.c (combine_simplify_rtx, expand_field_assignment): Likewise.
> 	(make_extraction, gen_lowpart_for_combine): Likewise.
> 	* loop-invariant.c (hash_invariant_expr_1, invariant_expr_equal_p):
> 	Likewise.
> 	* cse.c (remove_invalid_subreg_refs): Take the offset as a poly_uint64
> 	rather than an unsigned int.  Treat subreg offsets as poly_ints.
> 	(exp_equiv_p): Handle 'p'.
> 	(hash_rtx_cb): Likewise.  Treat subreg offsets as poly_ints.
> 	(equiv_constant, cse_insn): Treat subreg offsets as poly_ints.
> 	* dse.c (find_shift_sequence): Likewise.
> 	* dwarf2out.c (rtl_for_decl_location): Likewise.
> 	* expmed.c (extract_low_bits): Likewise.
> 	* expr.c (emit_group_store, undefined_operand_subword_p): Likewise.
> 	(expand_expr_real_2): Likewise.
> 	* final.c (alter_subreg): Likewise.
> 	(leaf_renumber_regs_insn): Handle 'p'.
> 	* function.c (assign_parm_find_stack_rtl, assign_parm_setup_stack):
> 	Treat subreg offsets as poly_ints.
> 	* fwprop.c (forward_propagate_and_simplify): Likewise.
> 	* ifcvt.c (noce_emit_move_insn, noce_emit_cmove): Likewise.
> 	* ira.c (get_subreg_tracking_sizes): Likewise.
> 	* ira-conflicts.c (go_through_subreg): Likewise.
> 	* ira-lives.c (process_single_reg_class_operands): Likewise.
> 	* jump.c (rtx_renumbered_equal_p): Likewise.  Handle 'p'.
> 	* lower-subreg.c (simplify_subreg_concatn): Take the subreg offset
> 	as a poly_uint64 rather than an unsigned int.
> 	(simplify_gen_subreg_concatn, resolve_simple_move): Treat
> 	subreg offsets as poly_ints.
> 	* lra-constraints.c (operands_match_p): Handle 'p'.
> 	(match_reload, curr_insn_transform): Treat subreg offsets as poly_ints.
> 	* lra-spills.c (assign_mem_slot): Likewise.
> 	* postreload.c (move2add_valid_value_p): Likewise.
> 	* recog.c (general_operand, indirect_operand): Likewise.
> 	* regcprop.c (copy_value, maybe_mode_change): Likewise.
> 	(copyprop_hardreg_forward_1): Likewise.
> 	* reginfo.c (simplifiable_subregs_hasher::hash, simplifiable_subregs)
> 	(record_subregs_of_mode): Likewise.
> 	* rtlhooks.c (gen_lowpart_general, gen_lowpart_if_possible): Likewise.
> 	* reload.c (operands_match_p): Handle 'p'.
> 	(find_reloads_subreg_address): Treat subreg offsets as poly_ints.
> 	* reload1.c (alter_reg, choose_reload_regs): Likewise.
> 	(compute_reload_subreg_offset): Likewise, and return an poly_int64.
> 	* simplify-rtx.c (simplify_truncation, simplify_binary_operation_1):
> 	(test_vector_ops_duplicate): Treat subreg offsets as poly_ints.
> 	(simplify_const_poly_int_tests<N>::run): Likewise.
> 	(simplify_subreg, simplify_gen_subreg): Take the subreg offset as
> 	a poly_uint64 rather than an unsigned int.
> 	* valtrack.c (debug_lowpart_subreg): Likewise.
> 	* var-tracking.c (var_lowpart): Likewise.
> 	(loc_cmp): Handle 'p'.
> 

> Index: gcc/rtlanal.c
[ ... Going to assume these bits are right WRT the endianness bits ...]

> -      unsigned int lower_word_part = lower_bytes & -UNITS_PER_WORD;
> -      unsigned int upper_word_part = upper_bytes & -UNITS_PER_WORD;
> +      /* When bytes and words have oppposite endianness, we must be able
Nit.  Oppposite

OK with nit fixed.

jeff