re PR middle-end/31150 (Not promoting an whole array to be static const)
PR middle-end/31150
* dse.c (struct store_info): Add const_rhs field.
(clear_rhs_from_active_local_stores): Clear also const_rhs.
(record_store): Try also cselib_expand_value_rtx to get a constant.
(find_shift_sequence, get_stored_val): Use const_rhs instead of
rhs if worthwhile.
* cselib.c (cselib_record_sets): If !cselib_record_memory and
there is just one set from read-only MEM, look at REG_EQUAL or
REG_EQUIV note.
* dse.c (struct store_info): Add redundant_reason field.
(record_store): When storing the same constant as has been
stored by an earlier store, set redundant_reason field
to the earlier store's insn_info_t. Don't delete cannot_delete
insns.
(find_shift_sequence): Remove read_info argument, add read_mode
and require_cst arguments. Return early if require_cst and
constant wouldn't be returned.
(get_stored_val): New function.
(replace_read): Use it.
(scan_insn): Put even cannot_delete insns with exactly 1 store
into active_local_stores.
(dse_step1): Don't delete cannot_delete insns. Remove redundant
constant stores if contains_cselib_groups and earlier store storing
the same value hasn't been eliminated.
(dse_step6): Renamed to dse_step7. New function.
(dse_step7): Renamed from dse_step6.
(rest_of_handle_dse): Call dse_step6 and dse_step7 at the end.
* cselib.c (cselib_expand_value_rtx): Don't wrap CONST_INTs
into CONST unless really necessary. Handle SUBREG, unary,
ternary, bitfield and compares specially, to be able to simplify
operations on constants.
(expand_loc): Try to optimize LO_SUM.
* dse.c (get_call_args): New function.
(scan_insn): Don't handle BUILT_IN_BZERO. For memset, attempt
to get call arguments and if successful and both len and val are
constants, handle the call as (mem:BLK) (const_int) store.
* dse.c (struct store_info): Add is_large bool field, change
positions_needed into a union of a bitmask and bitmap + count.
(free_store_info): Free bitmap if is_large.
(set_usage_bits): Don't look at stores where
offset + width >= MAX_OFFSET.
(set_position_unneeded, set_all_positions_unneeded,
any_positions_needed_p, all_positions_needed_p): New static inline
functions.
(record_store): Handle BLKmode stores of CONST_INT, if
MEM_SIZE is set on the MEM. Use the new positions_needed
accessor inlines.
(replace_read): Handle reads from BLKmode CONST_INT stores.
(check_mem_read_rtx): Use all_positions_needed_p function.
(dse_step1): Free large positions_needed bitmaps and clear is_large.
* dse.c (struct store_info): Change begin and end types to
HOST_WIDE_INT.
* dse.c (record_store): Fix check for unused store.
* expr.c (block_clear_fn): No longer static.
* expr.h (block_clear_fn): Declare.
* dse.c (scan_insn): Memset and bzero can just read their
arguments.
* gcc.c-torture/execute/
20081218-1.c: New test.
From-SVN: r142892