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combine.c (struct reg_stat): Add new fields truncation_label and truncated_to_mode.
* combine.c (struct reg_stat): Add new fields truncation_label and truncated_to_mode. (record_value_for_reg): Reset truncated_to_mode. (record_truncated_value): New function. (check_promoted_subreg): Call it. Rename to check_conversions. (combine_instructions): Rename check_promoted_subreg to check_conversions. (reg_truncated_to_mode): New function. (make_extraction): Use it. Check TRULY_NOOP_TRUNCATION. (gen_lowpart_or_truncate): New function. (force_to_mode): Use it instead of gen_lowpart. From-SVN: r109679
This commit is contained in:
Adam Nemet
Adam Nemet
parent
c460314601
commit
4df8acd3c8
@ -1,3 +1,17 @@
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2006-01-13 Adam Nemet <anemet@caviumnetworks.com>
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* combine.c (struct reg_stat): Add new fields truncation_label and
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truncated_to_mode.
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(record_value_for_reg): Reset truncated_to_mode.
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(record_truncated_value): New function.
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(check_promoted_subreg): Call it. Rename to check_conversions.
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(combine_instructions): Rename check_promoted_subreg to
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check_conversions.
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(reg_truncated_to_mode): New function.
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(make_extraction): Use it. Check TRULY_NOOP_TRUNCATION.
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(gen_lowpart_or_truncate): New function.
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(force_to_mode): Use it instead of gen_lowpart.
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2006-01-13 Diego Novillo <dnovillo@redhat.com>
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* tree-ssa-alias.c (add_type_alias): Fix typo. Test whether
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161
gcc/combine.c
161
gcc/combine.c
@ -220,7 +220,7 @@ struct reg_stat {
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unsigned HOST_WIDE_INT last_set_nonzero_bits;
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char last_set_sign_bit_copies;
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ENUM_BITFIELD(machine_mode) last_set_mode : 8;
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ENUM_BITFIELD(machine_mode) last_set_mode : 8;
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/* Set nonzero if references to register n in expressions should not be
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used. last_set_invalid is set nonzero when this register is being
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@ -243,6 +243,19 @@ struct reg_stat {
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unsigned char sign_bit_copies;
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unsigned HOST_WIDE_INT nonzero_bits;
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/* Record the value of the label_tick when the last truncation
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happened. The field truncated_to_mode is only valid if
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truncation_label == label_tick. */
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int truncation_label;
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/* Record the last truncation seen for this register. If truncation
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is not a nop to this mode we might be able to save an explicit
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truncation if we know that value already contains a truncated
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value. */
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ENUM_BITFIELD(machine_mode) truncated_to_mode : 8;
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};
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static struct reg_stat *reg_stat;
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@ -407,7 +420,7 @@ static rtx gen_lowpart_for_combine (enum machine_mode, rtx);
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static enum rtx_code simplify_comparison (enum rtx_code, rtx *, rtx *);
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static void update_table_tick (rtx);
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static void record_value_for_reg (rtx, rtx, rtx);
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static void check_promoted_subreg (rtx, rtx);
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static void check_conversions (rtx, rtx);
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static void record_dead_and_set_regs_1 (rtx, rtx, void *);
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static void record_dead_and_set_regs (rtx);
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static int get_last_value_validate (rtx *, rtx, int, int);
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@ -424,6 +437,9 @@ static int insn_cuid (rtx);
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static void record_promoted_value (rtx, rtx);
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static int unmentioned_reg_p_1 (rtx *, void *);
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static bool unmentioned_reg_p (rtx, rtx);
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static void record_truncated_value (rtx);
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static bool reg_truncated_to_mode (enum machine_mode, rtx);
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static rtx gen_lowpart_or_truncate (enum machine_mode, rtx);
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/* It is not safe to use ordinary gen_lowpart in combine.
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@ -790,7 +806,7 @@ combine_instructions (rtx f, unsigned int nregs)
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{
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/* See if we know about function return values before this
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insn based upon SUBREG flags. */
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check_promoted_subreg (insn, PATTERN (insn));
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check_conversions (insn, PATTERN (insn));
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/* Try this insn with each insn it links back to. */
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@ -5989,6 +6005,11 @@ make_extraction (enum machine_mode mode, rtx inner, HOST_WIDE_INT pos,
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&& ! (spans_byte && inner_mode != tmode)
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&& ((pos_rtx == 0 && (pos % BITS_PER_WORD) == 0
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&& !MEM_P (inner)
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&& (inner_mode == tmode
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|| !REG_P (inner)
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|| TRULY_NOOP_TRUNCATION (GET_MODE_BITSIZE (tmode),
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GET_MODE_BITSIZE (inner_mode))
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|| reg_truncated_to_mode (tmode, inner))
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&& (! in_dest
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|| (REG_P (inner)
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&& have_insn_for (STRICT_LOW_PART, tmode))))
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@ -6758,6 +6779,22 @@ canon_reg_for_combine (rtx x, rtx reg)
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return x;
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}
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/* Return X converted to MODE. If the value is already truncated to
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MODE we can just return a subreg even though in the general case we
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would need an explicit truncation. */
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static rtx
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gen_lowpart_or_truncate (enum machine_mode mode, rtx x)
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{
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if (GET_MODE_SIZE (GET_MODE (x)) <= GET_MODE_SIZE (mode)
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|| TRULY_NOOP_TRUNCATION (GET_MODE_BITSIZE (mode),
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GET_MODE_BITSIZE (GET_MODE (x)))
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|| (REG_P (x) && reg_truncated_to_mode (mode, x)))
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return gen_lowpart (mode, x);
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else
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return gen_rtx_TRUNCATE (mode, x);
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}
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/* See if X can be simplified knowing that we will only refer to it in
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MODE and will only refer to those bits that are nonzero in MASK.
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If other bits are being computed or if masking operations are done
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@ -7023,11 +7060,11 @@ force_to_mode (rtx x, enum machine_mode mode, unsigned HOST_WIDE_INT mask,
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/* For most binary operations, just propagate into the operation and
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change the mode if we have an operation of that mode. */
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op0 = gen_lowpart (op_mode,
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force_to_mode (XEXP (x, 0), mode, mask,
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next_select));
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op1 = gen_lowpart (op_mode,
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force_to_mode (XEXP (x, 1), mode, mask,
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op0 = gen_lowpart_or_truncate (op_mode,
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force_to_mode (XEXP (x, 0), mode, mask,
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next_select));
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op1 = gen_lowpart_or_truncate (op_mode,
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force_to_mode (XEXP (x, 1), mode, mask,
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next_select));
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if (op_mode != GET_MODE (x) || op0 != XEXP (x, 0) || op1 != XEXP (x, 1))
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@ -7060,9 +7097,9 @@ force_to_mode (rtx x, enum machine_mode mode, unsigned HOST_WIDE_INT mask,
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else
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mask = fuller_mask;
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op0 = gen_lowpart (op_mode,
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force_to_mode (XEXP (x, 0), op_mode,
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mask, next_select));
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op0 = gen_lowpart_or_truncate (op_mode,
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force_to_mode (XEXP (x, 0), op_mode,
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mask, next_select));
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if (op_mode != GET_MODE (x) || op0 != XEXP (x, 0))
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x = simplify_gen_binary (code, op_mode, op0, XEXP (x, 1));
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@ -7266,9 +7303,9 @@ force_to_mode (rtx x, enum machine_mode mode, unsigned HOST_WIDE_INT mask,
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mask = fuller_mask;
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unop:
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op0 = gen_lowpart (op_mode,
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force_to_mode (XEXP (x, 0), mode, mask,
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next_select));
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op0 = gen_lowpart_or_truncate (op_mode,
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force_to_mode (XEXP (x, 0), mode, mask,
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next_select));
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if (op_mode != GET_MODE (x) || op0 != XEXP (x, 0))
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x = simplify_gen_unary (code, op_mode, op0, op_mode);
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break;
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@ -7291,11 +7328,13 @@ force_to_mode (rtx x, enum machine_mode mode, unsigned HOST_WIDE_INT mask,
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written in a narrower mode. We play it safe and do not do so. */
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SUBST (XEXP (x, 1),
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gen_lowpart (GET_MODE (x), force_to_mode (XEXP (x, 1), mode,
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mask, next_select)));
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gen_lowpart_or_truncate (GET_MODE (x),
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force_to_mode (XEXP (x, 1), mode,
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mask, next_select)));
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SUBST (XEXP (x, 2),
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gen_lowpart (GET_MODE (x), force_to_mode (XEXP (x, 2), mode,
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mask, next_select)));
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gen_lowpart_or_truncate (GET_MODE (x),
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force_to_mode (XEXP (x, 2), mode,
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mask, next_select)));
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break;
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default:
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@ -7303,7 +7342,7 @@ force_to_mode (rtx x, enum machine_mode mode, unsigned HOST_WIDE_INT mask,
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}
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/* Ensure we return a value of the proper mode. */
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return gen_lowpart (mode, x);
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return gen_lowpart_or_truncate (mode, x);
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}
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/* Return nonzero if X is an expression that has one of two values depending on
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@ -10871,6 +10910,7 @@ record_value_for_reg (rtx reg, rtx insn, rtx value)
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reg_stat[i].last_set_nonzero_bits = 0;
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reg_stat[i].last_set_sign_bit_copies = 0;
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reg_stat[i].last_death = 0;
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reg_stat[i].truncated_to_mode = 0;
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}
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/* Mark registers that are being referenced in this value. */
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@ -11004,6 +11044,7 @@ record_dead_and_set_regs (rtx insn)
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reg_stat[i].last_set_nonzero_bits = 0;
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reg_stat[i].last_set_sign_bit_copies = 0;
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reg_stat[i].last_death = 0;
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reg_stat[i].truncated_to_mode = 0;
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}
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last_call_cuid = mem_last_set = INSN_CUID (insn);
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@ -11067,15 +11108,81 @@ record_promoted_value (rtx insn, rtx subreg)
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}
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}
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/* Scan X for promoted SUBREGs. For each one found,
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note what it implies to the registers used in it. */
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/* Check if X, a register, is known to contain a value already
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truncated to MODE. In this case we can use a subreg to refer to
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the truncated value even though in the generic case we would need
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an explicit truncation. */
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static bool
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reg_truncated_to_mode (enum machine_mode mode, rtx x)
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{
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enum machine_mode truncated = reg_stat[REGNO (x)].truncated_to_mode;
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if (truncated == 0 || reg_stat[REGNO (x)].truncation_label != label_tick)
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return false;
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if (GET_MODE_SIZE (truncated) <= GET_MODE_SIZE (mode))
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return true;
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if (TRULY_NOOP_TRUNCATION (GET_MODE_BITSIZE (mode),
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GET_MODE_BITSIZE (truncated)))
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return true;
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return false;
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}
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/* X is a REG or a SUBREG. If X is some sort of a truncation record
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it. For non-TRULY_NOOP_TRUNCATION targets we might be able to turn
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a truncate into a subreg using this information. */
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static void
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check_promoted_subreg (rtx insn, rtx x)
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record_truncated_value (rtx x)
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{
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if (GET_CODE (x) == SUBREG && SUBREG_PROMOTED_VAR_P (x)
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&& REG_P (SUBREG_REG (x)))
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record_promoted_value (insn, x);
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enum machine_mode truncated_mode;
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if (GET_CODE (x) == SUBREG && REG_P (SUBREG_REG (x)))
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{
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enum machine_mode original_mode = GET_MODE (SUBREG_REG (x));
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truncated_mode = GET_MODE (x);
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if (GET_MODE_SIZE (original_mode) <= GET_MODE_SIZE (truncated_mode))
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return;
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if (TRULY_NOOP_TRUNCATION (GET_MODE_BITSIZE (truncated_mode),
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GET_MODE_BITSIZE (original_mode)))
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return;
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x = SUBREG_REG (x);
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}
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/* ??? For hard-regs we now record everthing. We might be able to
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optimize this using last_set_mode. */
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else if (REG_P (x) && REGNO (x) < FIRST_PSEUDO_REGISTER)
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truncated_mode = GET_MODE (x);
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else
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return;
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if (reg_stat[REGNO (x)].truncated_to_mode == 0
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|| reg_stat[REGNO (x)].truncation_label < label_tick
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|| (GET_MODE_SIZE (truncated_mode)
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< GET_MODE_SIZE (reg_stat[REGNO (x)].truncated_to_mode)))
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{
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reg_stat[REGNO (x)].truncated_to_mode = truncated_mode;
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reg_stat[REGNO (x)].truncation_label = label_tick;
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}
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}
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/* Scan X for promoted SUBREGs and truncated REGs. For each one
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found, note what it implies to the registers used in it. */
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static void
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check_conversions (rtx insn, rtx x)
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{
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if (GET_CODE (x) == SUBREG || REG_P (x))
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{
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if (GET_CODE (x) == SUBREG
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&& SUBREG_PROMOTED_VAR_P (x)
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&& REG_P (SUBREG_REG (x)))
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record_promoted_value (insn, x);
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record_truncated_value (x);
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}
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else
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{
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const char *format = GET_RTX_FORMAT (GET_CODE (x));
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@ -11085,13 +11192,13 @@ check_promoted_subreg (rtx insn, rtx x)
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switch (format[i])
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{
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case 'e':
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check_promoted_subreg (insn, XEXP (x, i));
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check_conversions (insn, XEXP (x, i));
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break;
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case 'V':
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case 'E':
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if (XVEC (x, i) != 0)
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for (j = 0; j < XVECLEN (x, i); j++)
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check_promoted_subreg (insn, XVECEXP (x, i, j));
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check_conversions (insn, XVECEXP (x, i, j));
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break;
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}
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}
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