| /* Code for RTL register eliminations. |
| Copyright (C) 2010-2020 Free Software Foundation, Inc. |
| Contributed by Vladimir Makarov <vmakarov@redhat.com>. |
| |
| This file is part of GCC. |
| |
| GCC is free software; you can redistribute it and/or modify it under |
| the terms of the GNU General Public License as published by the Free |
| Software Foundation; either version 3, or (at your option) any later |
| version. |
| |
| GCC is distributed in the hope that it will be useful, but WITHOUT ANY |
| WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GCC; see the file COPYING3. If not see |
| <http://www.gnu.org/licenses/>. */ |
| |
| /* Eliminable registers (like a soft argument or frame pointer) are |
| widely used in RTL. These eliminable registers should be replaced |
| by real hard registers (like the stack pointer or hard frame |
| pointer) plus some offset. The offsets usually change whenever the |
| stack is expanded. We know the final offsets only at the very end |
| of LRA. |
| |
| Within LRA, we usually keep the RTL in such a state that the |
| eliminable registers can be replaced by just the corresponding hard |
| register (without any offset). To achieve this we should add the |
| initial elimination offset at the beginning of LRA and update the |
| offsets whenever the stack is expanded. We need to do this before |
| every constraint pass because the choice of offset often affects |
| whether a particular address or memory constraint is satisfied. |
| |
| We keep RTL code at most time in such state that the virtual |
| registers can be changed by just the corresponding hard registers |
| (with zero offsets) and we have the right RTL code. To achieve this |
| we should add initial offset at the beginning of LRA work and update |
| offsets after each stack expanding. But actually we update virtual |
| registers to the same virtual registers + corresponding offsets |
| before every constraint pass because it affects constraint |
| satisfaction (e.g. an address displacement became too big for some |
| target). |
| |
| The final change of eliminable registers to the corresponding hard |
| registers are done at the very end of LRA when there were no change |
| in offsets anymore: |
| |
| fp + 42 => sp + 42 |
| |
| */ |
| |
| #include "config.h" |
| #include "system.h" |
| #include "coretypes.h" |
| #include "backend.h" |
| #include "target.h" |
| #include "rtl.h" |
| #include "tree.h" |
| #include "df.h" |
| #include "memmodel.h" |
| #include "tm_p.h" |
| #include "optabs.h" |
| #include "regs.h" |
| #include "ira.h" |
| #include "recog.h" |
| #include "output.h" |
| #include "rtl-error.h" |
| #include "lra-int.h" |
| |
| /* This structure is used to record information about hard register |
| eliminations. */ |
| class lra_elim_table |
| { |
| public: |
| /* Hard register number to be eliminated. */ |
| int from; |
| /* Hard register number used as replacement. */ |
| int to; |
| /* Difference between values of the two hard registers above on |
| previous iteration. */ |
| poly_int64 previous_offset; |
| /* Difference between the values on the current iteration. */ |
| poly_int64 offset; |
| /* Nonzero if this elimination can be done. */ |
| bool can_eliminate; |
| /* CAN_ELIMINATE since the last check. */ |
| bool prev_can_eliminate; |
| /* REG rtx for the register to be eliminated. We cannot simply |
| compare the number since we might then spuriously replace a hard |
| register corresponding to a pseudo assigned to the reg to be |
| eliminated. */ |
| rtx from_rtx; |
| /* REG rtx for the replacement. */ |
| rtx to_rtx; |
| }; |
| |
| /* The elimination table. Each array entry describes one possible way |
| of eliminating a register in favor of another. If there is more |
| than one way of eliminating a particular register, the most |
| preferred should be specified first. */ |
| static class lra_elim_table *reg_eliminate = 0; |
| |
| /* This is an intermediate structure to initialize the table. It has |
| exactly the members provided by ELIMINABLE_REGS. */ |
| static const struct elim_table_1 |
| { |
| const int from; |
| const int to; |
| } reg_eliminate_1[] = |
| |
| ELIMINABLE_REGS; |
| |
| #define NUM_ELIMINABLE_REGS ARRAY_SIZE (reg_eliminate_1) |
| |
| /* Print info about elimination table to file F. */ |
| static void |
| print_elim_table (FILE *f) |
| { |
| class lra_elim_table *ep; |
| |
| for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++) |
| { |
| fprintf (f, "%s eliminate %d to %d (offset=", |
| ep->can_eliminate ? "Can" : "Can't", ep->from, ep->to); |
| print_dec (ep->offset, f); |
| fprintf (f, ", prev_offset="); |
| print_dec (ep->previous_offset, f); |
| fprintf (f, ")\n"); |
| } |
| } |
| |
| /* Print info about elimination table to stderr. */ |
| void |
| lra_debug_elim_table (void) |
| { |
| print_elim_table (stderr); |
| } |
| |
| /* Setup possibility of elimination in elimination table element EP to |
| VALUE. Setup FRAME_POINTER_NEEDED if elimination from frame |
| pointer to stack pointer is not possible anymore. */ |
| static void |
| setup_can_eliminate (class lra_elim_table *ep, bool value) |
| { |
| ep->can_eliminate = ep->prev_can_eliminate = value; |
| if (! value |
| && ep->from == FRAME_POINTER_REGNUM && ep->to == STACK_POINTER_REGNUM) |
| frame_pointer_needed = 1; |
| if (!frame_pointer_needed) |
| REGNO_POINTER_ALIGN (HARD_FRAME_POINTER_REGNUM) = 0; |
| } |
| |
| /* Map: eliminable "from" register -> its current elimination, |
| or NULL if none. The elimination table may contain more than |
| one elimination for the same hard register, but this map specifies |
| the one that we are currently using. */ |
| static class lra_elim_table *elimination_map[FIRST_PSEUDO_REGISTER]; |
| |
| /* When an eliminable hard register becomes not eliminable, we use the |
| following special structure to restore original offsets for the |
| register. */ |
| static class lra_elim_table self_elim_table; |
| |
| /* Offsets should be used to restore original offsets for eliminable |
| hard register which just became not eliminable. Zero, |
| otherwise. */ |
| static poly_int64_pod self_elim_offsets[FIRST_PSEUDO_REGISTER]; |
| |
| /* Map: hard regno -> RTL presentation. RTL presentations of all |
| potentially eliminable hard registers are stored in the map. */ |
| static rtx eliminable_reg_rtx[FIRST_PSEUDO_REGISTER]; |
| |
| /* Set up ELIMINATION_MAP of the currently used eliminations. */ |
| static void |
| setup_elimination_map (void) |
| { |
| int i; |
| class lra_elim_table *ep; |
| |
| for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
| elimination_map[i] = NULL; |
| for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++) |
| if (ep->can_eliminate && elimination_map[ep->from] == NULL) |
| elimination_map[ep->from] = ep; |
| } |
| |
| |
| |
| /* Compute the sum of X and Y, making canonicalizations assumed in an |
| address, namely: sum constant integers, surround the sum of two |
| constants with a CONST, put the constant as the second operand, and |
| group the constant on the outermost sum. |
| |
| This routine assumes both inputs are already in canonical form. */ |
| static rtx |
| form_sum (rtx x, rtx y) |
| { |
| machine_mode mode = GET_MODE (x); |
| poly_int64 offset; |
| |
| if (mode == VOIDmode) |
| mode = GET_MODE (y); |
| |
| if (mode == VOIDmode) |
| mode = Pmode; |
| |
| if (poly_int_rtx_p (x, &offset)) |
| return plus_constant (mode, y, offset); |
| else if (poly_int_rtx_p (y, &offset)) |
| return plus_constant (mode, x, offset); |
| else if (CONSTANT_P (x)) |
| std::swap (x, y); |
| |
| if (GET_CODE (x) == PLUS && CONSTANT_P (XEXP (x, 1))) |
| return form_sum (XEXP (x, 0), form_sum (XEXP (x, 1), y)); |
| |
| /* Note that if the operands of Y are specified in the opposite |
| order in the recursive calls below, infinite recursion will |
| occur. */ |
| if (GET_CODE (y) == PLUS && CONSTANT_P (XEXP (y, 1))) |
| return form_sum (form_sum (x, XEXP (y, 0)), XEXP (y, 1)); |
| |
| /* If both constant, encapsulate sum. Otherwise, just form sum. A |
| constant will have been placed second. */ |
| if (CONSTANT_P (x) && CONSTANT_P (y)) |
| { |
| if (GET_CODE (x) == CONST) |
| x = XEXP (x, 0); |
| if (GET_CODE (y) == CONST) |
| y = XEXP (y, 0); |
| |
| return gen_rtx_CONST (VOIDmode, gen_rtx_PLUS (mode, x, y)); |
| } |
| |
| return gen_rtx_PLUS (mode, x, y); |
| } |
| |
| /* Return the current substitution hard register of the elimination of |
| HARD_REGNO. If HARD_REGNO is not eliminable, return itself. */ |
| int |
| lra_get_elimination_hard_regno (int hard_regno) |
| { |
| class lra_elim_table *ep; |
| |
| if (hard_regno < 0 || hard_regno >= FIRST_PSEUDO_REGISTER) |
| return hard_regno; |
| if ((ep = elimination_map[hard_regno]) == NULL) |
| return hard_regno; |
| return ep->to; |
| } |
| |
| /* Return elimination which will be used for hard reg REG, NULL |
| otherwise. */ |
| static class lra_elim_table * |
| get_elimination (rtx reg) |
| { |
| int hard_regno; |
| class lra_elim_table *ep; |
| |
| lra_assert (REG_P (reg)); |
| if ((hard_regno = REGNO (reg)) < 0 || hard_regno >= FIRST_PSEUDO_REGISTER) |
| return NULL; |
| if ((ep = elimination_map[hard_regno]) != NULL) |
| return ep->from_rtx != reg ? NULL : ep; |
| poly_int64 offset = self_elim_offsets[hard_regno]; |
| if (known_eq (offset, 0)) |
| return NULL; |
| /* This is an iteration to restore offsets just after HARD_REGNO |
| stopped to be eliminable. */ |
| self_elim_table.from = self_elim_table.to = hard_regno; |
| self_elim_table.from_rtx |
| = self_elim_table.to_rtx |
| = eliminable_reg_rtx[hard_regno]; |
| lra_assert (self_elim_table.from_rtx != NULL); |
| self_elim_table.offset = offset; |
| return &self_elim_table; |
| } |
| |
| /* Transform (subreg (plus reg const)) to (plus (subreg reg) const) |
| when it is possible. Return X or the transformation result if the |
| transformation is done. */ |
| static rtx |
| move_plus_up (rtx x) |
| { |
| rtx subreg_reg; |
| machine_mode x_mode, subreg_reg_mode; |
| |
| if (GET_CODE (x) != SUBREG || !subreg_lowpart_p (x)) |
| return x; |
| subreg_reg = SUBREG_REG (x); |
| x_mode = GET_MODE (x); |
| subreg_reg_mode = GET_MODE (subreg_reg); |
| if (!paradoxical_subreg_p (x) |
| && GET_CODE (subreg_reg) == PLUS |
| && CONSTANT_P (XEXP (subreg_reg, 1)) |
| && GET_MODE_CLASS (x_mode) == MODE_INT |
| && GET_MODE_CLASS (subreg_reg_mode) == MODE_INT) |
| { |
| rtx cst = simplify_subreg (x_mode, XEXP (subreg_reg, 1), subreg_reg_mode, |
| subreg_lowpart_offset (x_mode, |
| subreg_reg_mode)); |
| if (cst && CONSTANT_P (cst)) |
| return gen_rtx_PLUS (x_mode, lowpart_subreg (x_mode, |
| XEXP (subreg_reg, 0), |
| subreg_reg_mode), cst); |
| } |
| return x; |
| } |
| |
| /* Scan X and replace any eliminable registers (such as fp) with a |
| replacement (such as sp) if SUBST_P, plus an offset. The offset is |
| a change in the offset between the eliminable register and its |
| substitution if UPDATE_P, or the full offset if FULL_P, or |
| otherwise zero. If FULL_P, we also use the SP offsets for |
| elimination to SP. If UPDATE_P, use UPDATE_SP_OFFSET for updating |
| offsets of register elimnable to SP. If UPDATE_SP_OFFSET is |
| non-zero, don't use difference of the offset and the previous |
| offset. |
| |
| MEM_MODE is the mode of an enclosing MEM. We need this to know how |
| much to adjust a register for, e.g., PRE_DEC. Also, if we are |
| inside a MEM, we are allowed to replace a sum of a hard register |
| and the constant zero with the hard register, which we cannot do |
| outside a MEM. In addition, we need to record the fact that a |
| hard register is referenced outside a MEM. |
| |
| If we make full substitution to SP for non-null INSN, add the insn |
| sp offset. */ |
| rtx |
| lra_eliminate_regs_1 (rtx_insn *insn, rtx x, machine_mode mem_mode, |
| bool subst_p, bool update_p, |
| poly_int64 update_sp_offset, bool full_p) |
| { |
| enum rtx_code code = GET_CODE (x); |
| class lra_elim_table *ep; |
| rtx new_rtx; |
| int i, j; |
| const char *fmt; |
| int copied = 0; |
| |
| lra_assert (!update_p || !full_p); |
| lra_assert (known_eq (update_sp_offset, 0) |
| || (!subst_p && update_p && !full_p)); |
| if (! current_function_decl) |
| return x; |
| |
| switch (code) |
| { |
| CASE_CONST_ANY: |
| case CONST: |
| case SYMBOL_REF: |
| case CODE_LABEL: |
| case PC: |
| case CC0: |
| case ASM_INPUT: |
| case ADDR_VEC: |
| case ADDR_DIFF_VEC: |
| case RETURN: |
| return x; |
| |
| case REG: |
| /* First handle the case where we encounter a bare hard register |
| that is eliminable. Replace it with a PLUS. */ |
| if ((ep = get_elimination (x)) != NULL) |
| { |
| rtx to = subst_p ? ep->to_rtx : ep->from_rtx; |
| |
| if (maybe_ne (update_sp_offset, 0)) |
| { |
| if (ep->to_rtx == stack_pointer_rtx) |
| return plus_constant (Pmode, to, update_sp_offset); |
| return to; |
| } |
| else if (update_p) |
| return plus_constant (Pmode, to, ep->offset - ep->previous_offset); |
| else if (full_p) |
| return plus_constant (Pmode, to, |
| ep->offset |
| - (insn != NULL_RTX |
| && ep->to_rtx == stack_pointer_rtx |
| ? lra_get_insn_recog_data (insn)->sp_offset |
| : 0)); |
| else |
| return to; |
| } |
| return x; |
| |
| case PLUS: |
| /* If this is the sum of an eliminable register and a constant, rework |
| the sum. */ |
| if (REG_P (XEXP (x, 0)) && CONSTANT_P (XEXP (x, 1))) |
| { |
| if ((ep = get_elimination (XEXP (x, 0))) != NULL) |
| { |
| poly_int64 offset, curr_offset; |
| rtx to = subst_p ? ep->to_rtx : ep->from_rtx; |
| |
| if (! update_p && ! full_p) |
| return gen_rtx_PLUS (Pmode, to, XEXP (x, 1)); |
| |
| if (maybe_ne (update_sp_offset, 0)) |
| offset = ep->to_rtx == stack_pointer_rtx ? update_sp_offset : 0; |
| else |
| offset = (update_p |
| ? ep->offset - ep->previous_offset : ep->offset); |
| if (full_p && insn != NULL_RTX && ep->to_rtx == stack_pointer_rtx) |
| offset -= lra_get_insn_recog_data (insn)->sp_offset; |
| if (poly_int_rtx_p (XEXP (x, 1), &curr_offset) |
| && known_eq (curr_offset, -offset)) |
| return to; |
| else |
| return gen_rtx_PLUS (Pmode, to, |
| plus_constant (Pmode, |
| XEXP (x, 1), offset)); |
| } |
| |
| /* If the hard register is not eliminable, we are done since |
| the other operand is a constant. */ |
| return x; |
| } |
| |
| /* If this is part of an address, we want to bring any constant |
| to the outermost PLUS. We will do this by doing hard |
| register replacement in our operands and seeing if a constant |
| shows up in one of them. |
| |
| Note that there is no risk of modifying the structure of the |
| insn, since we only get called for its operands, thus we are |
| either modifying the address inside a MEM, or something like |
| an address operand of a load-address insn. */ |
| |
| { |
| rtx new0 = lra_eliminate_regs_1 (insn, XEXP (x, 0), mem_mode, |
| subst_p, update_p, |
| update_sp_offset, full_p); |
| rtx new1 = lra_eliminate_regs_1 (insn, XEXP (x, 1), mem_mode, |
| subst_p, update_p, |
| update_sp_offset, full_p); |
| |
| new0 = move_plus_up (new0); |
| new1 = move_plus_up (new1); |
| if (new0 != XEXP (x, 0) || new1 != XEXP (x, 1)) |
| return form_sum (new0, new1); |
| } |
| return x; |
| |
| case MULT: |
| /* If this is the product of an eliminable hard register and a |
| constant, apply the distribute law and move the constant out |
| so that we have (plus (mult ..) ..). This is needed in order |
| to keep load-address insns valid. This case is pathological. |
| We ignore the possibility of overflow here. */ |
| if (REG_P (XEXP (x, 0)) && CONST_INT_P (XEXP (x, 1)) |
| && (ep = get_elimination (XEXP (x, 0))) != NULL) |
| { |
| rtx to = subst_p ? ep->to_rtx : ep->from_rtx; |
| |
| if (maybe_ne (update_sp_offset, 0)) |
| { |
| if (ep->to_rtx == stack_pointer_rtx) |
| return plus_constant (Pmode, |
| gen_rtx_MULT (Pmode, to, XEXP (x, 1)), |
| update_sp_offset * INTVAL (XEXP (x, 1))); |
| return gen_rtx_MULT (Pmode, to, XEXP (x, 1)); |
| } |
| else if (update_p) |
| return plus_constant (Pmode, |
| gen_rtx_MULT (Pmode, to, XEXP (x, 1)), |
| (ep->offset - ep->previous_offset) |
| * INTVAL (XEXP (x, 1))); |
| else if (full_p) |
| { |
| poly_int64 offset = ep->offset; |
| |
| if (insn != NULL_RTX && ep->to_rtx == stack_pointer_rtx) |
| offset -= lra_get_insn_recog_data (insn)->sp_offset; |
| return |
| plus_constant (Pmode, |
| gen_rtx_MULT (Pmode, to, XEXP (x, 1)), |
| offset * INTVAL (XEXP (x, 1))); |
| } |
| else |
| return gen_rtx_MULT (Pmode, to, XEXP (x, 1)); |
| } |
| |
| /* fall through */ |
| |
| case CALL: |
| case COMPARE: |
| /* See comments before PLUS about handling MINUS. */ |
| case MINUS: |
| case DIV: case UDIV: |
| case MOD: case UMOD: |
| case AND: case IOR: case XOR: |
| case ROTATERT: case ROTATE: |
| case ASHIFTRT: case LSHIFTRT: case ASHIFT: |
| case NE: case EQ: |
| case GE: case GT: case GEU: case GTU: |
| case LE: case LT: case LEU: case LTU: |
| { |
| rtx new0 = lra_eliminate_regs_1 (insn, XEXP (x, 0), mem_mode, |
| subst_p, update_p, |
| update_sp_offset, full_p); |
| rtx new1 = XEXP (x, 1) |
| ? lra_eliminate_regs_1 (insn, XEXP (x, 1), mem_mode, |
| subst_p, update_p, |
| update_sp_offset, full_p) : 0; |
| |
| if (new0 != XEXP (x, 0) || new1 != XEXP (x, 1)) |
| return gen_rtx_fmt_ee (code, GET_MODE (x), new0, new1); |
| } |
| return x; |
| |
| case EXPR_LIST: |
| /* If we have something in XEXP (x, 0), the usual case, |
| eliminate it. */ |
| if (XEXP (x, 0)) |
| { |
| new_rtx = lra_eliminate_regs_1 (insn, XEXP (x, 0), mem_mode, |
| subst_p, update_p, |
| update_sp_offset, full_p); |
| if (new_rtx != XEXP (x, 0)) |
| { |
| /* If this is a REG_DEAD note, it is not valid anymore. |
| Using the eliminated version could result in creating a |
| REG_DEAD note for the stack or frame pointer. */ |
| if (REG_NOTE_KIND (x) == REG_DEAD) |
| return (XEXP (x, 1) |
| ? lra_eliminate_regs_1 (insn, XEXP (x, 1), mem_mode, |
| subst_p, update_p, |
| update_sp_offset, full_p) |
| : NULL_RTX); |
| |
| x = alloc_reg_note (REG_NOTE_KIND (x), new_rtx, XEXP (x, 1)); |
| } |
| } |
| |
| /* fall through */ |
| |
| case INSN_LIST: |
| case INT_LIST: |
| /* Now do eliminations in the rest of the chain. If this was |
| an EXPR_LIST, this might result in allocating more memory than is |
| strictly needed, but it simplifies the code. */ |
| if (XEXP (x, 1)) |
| { |
| new_rtx = lra_eliminate_regs_1 (insn, XEXP (x, 1), mem_mode, |
| subst_p, update_p, |
| update_sp_offset, full_p); |
| if (new_rtx != XEXP (x, 1)) |
| return |
| gen_rtx_fmt_ee (GET_CODE (x), GET_MODE (x), |
| XEXP (x, 0), new_rtx); |
| } |
| return x; |
| |
| case PRE_INC: |
| case POST_INC: |
| case PRE_DEC: |
| case POST_DEC: |
| /* We do not support elimination of a register that is modified. |
| elimination_effects has already make sure that this does not |
| happen. */ |
| return x; |
| |
| case PRE_MODIFY: |
| case POST_MODIFY: |
| /* We do not support elimination of a hard register that is |
| modified. LRA has already make sure that this does not |
| happen. The only remaining case we need to consider here is |
| that the increment value may be an eliminable register. */ |
| if (GET_CODE (XEXP (x, 1)) == PLUS |
| && XEXP (XEXP (x, 1), 0) == XEXP (x, 0)) |
| { |
| rtx new_rtx = lra_eliminate_regs_1 (insn, XEXP (XEXP (x, 1), 1), |
| mem_mode, subst_p, update_p, |
| update_sp_offset, full_p); |
| |
| if (new_rtx != XEXP (XEXP (x, 1), 1)) |
| return gen_rtx_fmt_ee (code, GET_MODE (x), XEXP (x, 0), |
| gen_rtx_PLUS (GET_MODE (x), |
| XEXP (x, 0), new_rtx)); |
| } |
| return x; |
| |
| case STRICT_LOW_PART: |
| case NEG: case NOT: |
| case SIGN_EXTEND: case ZERO_EXTEND: |
| case TRUNCATE: case FLOAT_EXTEND: case FLOAT_TRUNCATE: |
| case FLOAT: case FIX: |
| case UNSIGNED_FIX: case UNSIGNED_FLOAT: |
| case ABS: |
| case SQRT: |
| case FFS: |
| case CLZ: |
| case CTZ: |
| case POPCOUNT: |
| case PARITY: |
| case BSWAP: |
| new_rtx = lra_eliminate_regs_1 (insn, XEXP (x, 0), mem_mode, |
| subst_p, update_p, |
| update_sp_offset, full_p); |
| if (new_rtx != XEXP (x, 0)) |
| return gen_rtx_fmt_e (code, GET_MODE (x), new_rtx); |
| return x; |
| |
| case SUBREG: |
| new_rtx = lra_eliminate_regs_1 (insn, SUBREG_REG (x), mem_mode, |
| subst_p, update_p, |
| update_sp_offset, full_p); |
| |
| if (new_rtx != SUBREG_REG (x)) |
| { |
| if (MEM_P (new_rtx) && !paradoxical_subreg_p (x)) |
| { |
| SUBREG_REG (x) = new_rtx; |
| alter_subreg (&x, false); |
| return x; |
| } |
| else if (! subst_p) |
| { |
| /* LRA can transform subregs itself. So don't call |
| simplify_gen_subreg until LRA transformations are |
| finished. Function simplify_gen_subreg can do |
| non-trivial transformations (like truncation) which |
| might make LRA work to fail. */ |
| SUBREG_REG (x) = new_rtx; |
| return x; |
| } |
| else |
| return simplify_gen_subreg (GET_MODE (x), new_rtx, |
| GET_MODE (new_rtx), SUBREG_BYTE (x)); |
| } |
| |
| return x; |
| |
| case MEM: |
| /* Our only special processing is to pass the mode of the MEM to our |
| recursive call and copy the flags. While we are here, handle this |
| case more efficiently. */ |
| return |
| replace_equiv_address_nv |
| (x, |
| lra_eliminate_regs_1 (insn, XEXP (x, 0), GET_MODE (x), |
| subst_p, update_p, update_sp_offset, full_p)); |
| |
| case USE: |
| /* Handle insn_list USE that a call to a pure function may generate. */ |
| new_rtx = lra_eliminate_regs_1 (insn, XEXP (x, 0), VOIDmode, |
| subst_p, update_p, update_sp_offset, full_p); |
| if (new_rtx != XEXP (x, 0)) |
| return gen_rtx_USE (GET_MODE (x), new_rtx); |
| return x; |
| |
| case CLOBBER: |
| case SET: |
| gcc_unreachable (); |
| |
| default: |
| break; |
| } |
| |
| /* Process each of our operands recursively. If any have changed, make a |
| copy of the rtx. */ |
| fmt = GET_RTX_FORMAT (code); |
| for (i = 0; i < GET_RTX_LENGTH (code); i++, fmt++) |
| { |
| if (*fmt == 'e') |
| { |
| new_rtx = lra_eliminate_regs_1 (insn, XEXP (x, i), mem_mode, |
| subst_p, update_p, |
| update_sp_offset, full_p); |
| if (new_rtx != XEXP (x, i) && ! copied) |
| { |
| x = shallow_copy_rtx (x); |
| copied = 1; |
| } |
| XEXP (x, i) = new_rtx; |
| } |
| else if (*fmt == 'E') |
| { |
| int copied_vec = 0; |
| for (j = 0; j < XVECLEN (x, i); j++) |
| { |
| new_rtx = lra_eliminate_regs_1 (insn, XVECEXP (x, i, j), mem_mode, |
| subst_p, update_p, |
| update_sp_offset, full_p); |
| if (new_rtx != XVECEXP (x, i, j) && ! copied_vec) |
| { |
| rtvec new_v = gen_rtvec_v (XVECLEN (x, i), |
| XVEC (x, i)->elem); |
| if (! copied) |
| { |
| x = shallow_copy_rtx (x); |
| copied = 1; |
| } |
| XVEC (x, i) = new_v; |
| copied_vec = 1; |
| } |
| XVECEXP (x, i, j) = new_rtx; |
| } |
| } |
| } |
| |
| return x; |
| } |
| |
| /* This function is used externally in subsequent passes of GCC. It |
| always does a full elimination of X. */ |
| rtx |
| lra_eliminate_regs (rtx x, machine_mode mem_mode, |
| rtx insn ATTRIBUTE_UNUSED) |
| { |
| return lra_eliminate_regs_1 (NULL, x, mem_mode, true, false, 0, true); |
| } |
| |
| /* Stack pointer offset before the current insn relative to one at the |
| func start. RTL insns can change SP explicitly. We keep the |
| changes from one insn to another through this variable. */ |
| static poly_int64 curr_sp_change; |
| |
| /* Scan rtx X for references to elimination source or target registers |
| in contexts that would prevent the elimination from happening. |
| Update the table of eliminables to reflect the changed state. |
| MEM_MODE is the mode of an enclosing MEM rtx, or VOIDmode if not |
| within a MEM. */ |
| static void |
| mark_not_eliminable (rtx x, machine_mode mem_mode) |
| { |
| enum rtx_code code = GET_CODE (x); |
| class lra_elim_table *ep; |
| int i, j; |
| const char *fmt; |
| poly_int64 offset = 0; |
| |
| switch (code) |
| { |
| case PRE_INC: |
| case POST_INC: |
| case PRE_DEC: |
| case POST_DEC: |
| case POST_MODIFY: |
| case PRE_MODIFY: |
| if (XEXP (x, 0) == stack_pointer_rtx |
| && ((code != PRE_MODIFY && code != POST_MODIFY) |
| || (GET_CODE (XEXP (x, 1)) == PLUS |
| && XEXP (x, 0) == XEXP (XEXP (x, 1), 0) |
| && poly_int_rtx_p (XEXP (XEXP (x, 1), 1), &offset)))) |
| { |
| poly_int64 size = GET_MODE_SIZE (mem_mode); |
| |
| #ifdef PUSH_ROUNDING |
| /* If more bytes than MEM_MODE are pushed, account for |
| them. */ |
| size = PUSH_ROUNDING (size); |
| #endif |
| if (code == PRE_DEC || code == POST_DEC) |
| curr_sp_change -= size; |
| else if (code == PRE_INC || code == POST_INC) |
| curr_sp_change += size; |
| else if (code == PRE_MODIFY || code == POST_MODIFY) |
| curr_sp_change += offset; |
| } |
| else if (REG_P (XEXP (x, 0)) |
| && REGNO (XEXP (x, 0)) >= FIRST_PSEUDO_REGISTER) |
| { |
| /* If we modify the source of an elimination rule, disable |
| it. Do the same if it is the destination and not the |
| hard frame register. */ |
| for (ep = reg_eliminate; |
| ep < ®_eliminate[NUM_ELIMINABLE_REGS]; |
| ep++) |
| if (ep->from_rtx == XEXP (x, 0) |
| || (ep->to_rtx == XEXP (x, 0) |
| && ep->to_rtx != hard_frame_pointer_rtx)) |
| setup_can_eliminate (ep, false); |
| } |
| return; |
| |
| case USE: |
| if (REG_P (XEXP (x, 0)) && REGNO (XEXP (x, 0)) < FIRST_PSEUDO_REGISTER) |
| /* If using a hard register that is the source of an eliminate |
| we still think can be performed, note it cannot be |
| performed since we don't know how this hard register is |
| used. */ |
| for (ep = reg_eliminate; |
| ep < ®_eliminate[NUM_ELIMINABLE_REGS]; |
| ep++) |
| if (ep->from_rtx == XEXP (x, 0) |
| && ep->to_rtx != hard_frame_pointer_rtx) |
| setup_can_eliminate (ep, false); |
| return; |
| |
| case CLOBBER: |
| if (REG_P (XEXP (x, 0)) && REGNO (XEXP (x, 0)) < FIRST_PSEUDO_REGISTER) |
| /* If clobbering a hard register that is the replacement |
| register for an elimination we still think can be |
| performed, note that it cannot be performed. Otherwise, we |
| need not be concerned about it. */ |
| for (ep = reg_eliminate; |
| ep < ®_eliminate[NUM_ELIMINABLE_REGS]; |
| ep++) |
| if (ep->to_rtx == XEXP (x, 0) |
| && ep->to_rtx != hard_frame_pointer_rtx) |
| setup_can_eliminate (ep, false); |
| return; |
| |
| case SET: |
| if (SET_DEST (x) == stack_pointer_rtx |
| && GET_CODE (SET_SRC (x)) == PLUS |
| && XEXP (SET_SRC (x), 0) == SET_DEST (x) |
| && poly_int_rtx_p (XEXP (SET_SRC (x), 1), &offset)) |
| { |
| curr_sp_change += offset; |
| return; |
| } |
| if (! REG_P (SET_DEST (x)) |
| || REGNO (SET_DEST (x)) >= FIRST_PSEUDO_REGISTER) |
| mark_not_eliminable (SET_DEST (x), mem_mode); |
| else |
| { |
| /* See if this is setting the replacement hard register for |
| an elimination. |
| |
| If DEST is the hard frame pointer, we do nothing because |
| we assume that all assignments to the frame pointer are |
| for non-local gotos and are being done at a time when |
| they are valid and do not disturb anything else. Some |
| machines want to eliminate a fake argument pointer (or |
| even a fake frame pointer) with either the real frame |
| pointer or the stack pointer. Assignments to the hard |
| frame pointer must not prevent this elimination. */ |
| for (ep = reg_eliminate; |
| ep < ®_eliminate[NUM_ELIMINABLE_REGS]; |
| ep++) |
| if (ep->to_rtx == SET_DEST (x) |
| && SET_DEST (x) != hard_frame_pointer_rtx) |
| setup_can_eliminate (ep, false); |
| } |
| |
| mark_not_eliminable (SET_SRC (x), mem_mode); |
| return; |
| |
| case MEM: |
| /* Our only special processing is to pass the mode of the MEM to |
| our recursive call. */ |
| mark_not_eliminable (XEXP (x, 0), GET_MODE (x)); |
| return; |
| |
| default: |
| break; |
| } |
| |
| fmt = GET_RTX_FORMAT (code); |
| for (i = 0; i < GET_RTX_LENGTH (code); i++, fmt++) |
| { |
| if (*fmt == 'e') |
| mark_not_eliminable (XEXP (x, i), mem_mode); |
| else if (*fmt == 'E') |
| for (j = 0; j < XVECLEN (x, i); j++) |
| mark_not_eliminable (XVECEXP (x, i, j), mem_mode); |
| } |
| } |
| |
| |
| |
| /* Scan INSN and eliminate all eliminable hard registers in it. |
| |
| If REPLACE_P is true, do the replacement destructively. Also |
| delete the insn as dead it if it is setting an eliminable register. |
| |
| If REPLACE_P is false, just update the offsets while keeping the |
| base register the same. If FIRST_P, use the sp offset for |
| elimination to sp. Otherwise, use UPDATE_SP_OFFSET for this. If |
| UPDATE_SP_OFFSET is non-zero, don't use difference of the offset |
| and the previous offset. Attach the note about used elimination |
| for insns setting frame pointer to update elimination easy (without |
| parsing already generated elimination insns to find offset |
| previously used) in future. */ |
| |
| void |
| eliminate_regs_in_insn (rtx_insn *insn, bool replace_p, bool first_p, |
| poly_int64 update_sp_offset) |
| { |
| int icode = recog_memoized (insn); |
| rtx set, old_set = single_set (insn); |
| bool validate_p; |
| int i; |
| rtx substed_operand[MAX_RECOG_OPERANDS]; |
| rtx orig_operand[MAX_RECOG_OPERANDS]; |
| class lra_elim_table *ep; |
| rtx plus_src, plus_cst_src; |
| lra_insn_recog_data_t id; |
| struct lra_static_insn_data *static_id; |
| |
| if (icode < 0 && asm_noperands (PATTERN (insn)) < 0 && ! DEBUG_INSN_P (insn)) |
| { |
| lra_assert (GET_CODE (PATTERN (insn)) == USE |
| || GET_CODE (PATTERN (insn)) == CLOBBER |
| || GET_CODE (PATTERN (insn)) == ASM_INPUT); |
| return; |
| } |
| |
| /* We allow one special case which happens to work on all machines we |
| currently support: a single set with the source or a REG_EQUAL |
| note being a PLUS of an eliminable register and a constant. */ |
| plus_src = plus_cst_src = 0; |
| poly_int64 offset = 0; |
| if (old_set && REG_P (SET_DEST (old_set))) |
| { |
| if (GET_CODE (SET_SRC (old_set)) == PLUS) |
| plus_src = SET_SRC (old_set); |
| /* First see if the source is of the form (plus (...) CST). */ |
| if (plus_src && poly_int_rtx_p (XEXP (plus_src, 1), &offset)) |
| plus_cst_src = plus_src; |
| /* Check that the first operand of the PLUS is a hard reg or |
| the lowpart subreg of one. */ |
| if (plus_cst_src) |
| { |
| rtx reg = XEXP (plus_cst_src, 0); |
| |
| if (GET_CODE (reg) == SUBREG && subreg_lowpart_p (reg)) |
| reg = SUBREG_REG (reg); |
| |
| if (!REG_P (reg) || REGNO (reg) >= FIRST_PSEUDO_REGISTER) |
| plus_cst_src = 0; |
| } |
| } |
| if (plus_cst_src) |
| { |
| rtx reg = XEXP (plus_cst_src, 0); |
| |
| if (GET_CODE (reg) == SUBREG) |
| reg = SUBREG_REG (reg); |
| |
| if (REG_P (reg) && (ep = get_elimination (reg)) != NULL) |
| { |
| rtx to_rtx = replace_p ? ep->to_rtx : ep->from_rtx; |
| |
| if (! replace_p) |
| { |
| if (known_eq (update_sp_offset, 0)) |
| offset += (ep->offset - ep->previous_offset); |
| if (ep->to_rtx == stack_pointer_rtx) |
| { |
| if (first_p) |
| offset -= lra_get_insn_recog_data (insn)->sp_offset; |
| else |
| offset += update_sp_offset; |
| } |
| offset = trunc_int_for_mode (offset, GET_MODE (plus_cst_src)); |
| } |
| |
| if (GET_CODE (XEXP (plus_cst_src, 0)) == SUBREG) |
| to_rtx = gen_lowpart (GET_MODE (XEXP (plus_cst_src, 0)), to_rtx); |
| /* If we have a nonzero offset, and the source is already a |
| simple REG, the following transformation would increase |
| the cost of the insn by replacing a simple REG with (plus |
| (reg sp) CST). So try only when we already had a PLUS |
| before. */ |
| if (known_eq (offset, 0) || plus_src) |
| { |
| rtx new_src = plus_constant (GET_MODE (to_rtx), to_rtx, offset); |
| |
| old_set = single_set (insn); |
| |
| /* First see if this insn remains valid when we make the |
| change. If not, try to replace the whole pattern |
| with a simple set (this may help if the original insn |
| was a PARALLEL that was only recognized as single_set |
| due to REG_UNUSED notes). If this isn't valid |
| either, keep the INSN_CODE the same and let the |
| constraint pass fix it up. */ |
| if (! validate_change (insn, &SET_SRC (old_set), new_src, 0)) |
| { |
| rtx new_pat = gen_rtx_SET (SET_DEST (old_set), new_src); |
| |
| if (! validate_change (insn, &PATTERN (insn), new_pat, 0)) |
| SET_SRC (old_set) = new_src; |
| } |
| lra_update_insn_recog_data (insn); |
| /* This can't have an effect on elimination offsets, so skip |
| right to the end. */ |
| return; |
| } |
| } |
| } |
| |
| /* Eliminate all eliminable registers occurring in operands that |
| can be handled by the constraint pass. */ |
| id = lra_get_insn_recog_data (insn); |
| static_id = id->insn_static_data; |
| validate_p = false; |
| for (i = 0; i < static_id->n_operands; i++) |
| { |
| orig_operand[i] = *id->operand_loc[i]; |
| substed_operand[i] = *id->operand_loc[i]; |
| |
| /* For an asm statement, every operand is eliminable. */ |
| if (icode < 0 || insn_data[icode].operand[i].eliminable) |
| { |
| /* Check for setting a hard register that we know about. */ |
| if (static_id->operand[i].type != OP_IN |
| && REG_P (orig_operand[i])) |
| { |
| /* If we are assigning to a hard register that can be |
| eliminated, it must be as part of a PARALLEL, since |
| the code above handles single SETs. This reg cannot |
| be longer eliminated -- it is forced by |
| mark_not_eliminable. */ |
| for (ep = reg_eliminate; |
| ep < ®_eliminate[NUM_ELIMINABLE_REGS]; |
| ep++) |
| lra_assert (ep->from_rtx != orig_operand[i] |
| || ! ep->can_eliminate); |
| } |
| |
| /* Companion to the above plus substitution, we can allow |
| invariants as the source of a plain move. */ |
| substed_operand[i] |
| = lra_eliminate_regs_1 (insn, *id->operand_loc[i], VOIDmode, |
| replace_p, ! replace_p && ! first_p, |
| update_sp_offset, first_p); |
| if (substed_operand[i] != orig_operand[i]) |
| validate_p = true; |
| } |
| } |
| |
| if (! validate_p) |
| return; |
| |
| /* Substitute the operands; the new values are in the substed_operand |
| array. */ |
| for (i = 0; i < static_id->n_operands; i++) |
| *id->operand_loc[i] = substed_operand[i]; |
| for (i = 0; i < static_id->n_dups; i++) |
| *id->dup_loc[i] = substed_operand[(int) static_id->dup_num[i]]; |
| |
| /* Transform plus (plus (hard reg, const), pseudo) to plus (plus (pseudo, |
| const), hard reg) in order to keep insn containing eliminated register |
| after all reloads calculating its offset. This permits to keep register |
| pressure under control and helps to avoid LRA cycling in patalogical |
| cases. */ |
| if (! replace_p && (set = single_set (insn)) != NULL |
| && GET_CODE (SET_SRC (set)) == PLUS |
| && GET_CODE (XEXP (SET_SRC (set), 0)) == PLUS) |
| { |
| rtx reg1, reg2, op1, op2; |
| |
| reg1 = op1 = XEXP (XEXP (SET_SRC (set), 0), 0); |
| reg2 = op2 = XEXP (SET_SRC (set), 1); |
| if (GET_CODE (reg1) == SUBREG) |
| reg1 = SUBREG_REG (reg1); |
| if (GET_CODE (reg2) == SUBREG) |
| reg2 = SUBREG_REG (reg2); |
| if (REG_P (reg1) && REG_P (reg2) |
| && REGNO (reg1) < FIRST_PSEUDO_REGISTER |
| && REGNO (reg2) >= FIRST_PSEUDO_REGISTER |
| && GET_MODE (reg1) == Pmode |
| && !have_addptr3_insn (lra_pmode_pseudo, reg1, |
| XEXP (XEXP (SET_SRC (set), 0), 1))) |
| { |
| XEXP (XEXP (SET_SRC (set), 0), 0) = op2; |
| XEXP (SET_SRC (set), 1) = op1; |
| } |
| } |
| |
| /* If we had a move insn but now we don't, re-recognize it. |
| This will cause spurious re-recognition if the old move had a |
| PARALLEL since the new one still will, but we can't call |
| single_set without having put new body into the insn and the |
| re-recognition won't hurt in this rare case. */ |
| lra_update_insn_recog_data (insn); |
| } |
| |
| /* Spill pseudos which are assigned to hard registers in SET. Add |
| affected insns for processing in the subsequent constraint |
| pass. */ |
| static void |
| spill_pseudos (HARD_REG_SET set) |
| { |
| int i; |
| bitmap_head to_process; |
| rtx_insn *insn; |
| |
| if (hard_reg_set_empty_p (set)) |
| return; |
| if (lra_dump_file != NULL) |
| { |
| fprintf (lra_dump_file, " Spilling non-eliminable hard regs:"); |
| for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
| if (TEST_HARD_REG_BIT (set, i)) |
| fprintf (lra_dump_file, " %d", i); |
| fprintf (lra_dump_file, "\n"); |
| } |
| bitmap_initialize (&to_process, ®_obstack); |
| for (i = FIRST_PSEUDO_REGISTER; i < max_reg_num (); i++) |
| if (lra_reg_info[i].nrefs != 0 && reg_renumber[i] >= 0 |
| && overlaps_hard_reg_set_p (set, |
| PSEUDO_REGNO_MODE (i), reg_renumber[i])) |
| { |
| if (lra_dump_file != NULL) |
| fprintf (lra_dump_file, " Spilling r%d(%d)\n", |
| i, reg_renumber[i]); |
| reg_renumber[i] = -1; |
| bitmap_ior_into (&to_process, &lra_reg_info[i].insn_bitmap); |
| } |
| lra_no_alloc_regs |= set; |
| for (insn = get_insns (); insn != NULL_RTX; insn = NEXT_INSN (insn)) |
| if (bitmap_bit_p (&to_process, INSN_UID (insn))) |
| { |
| lra_push_insn (insn); |
| lra_set_used_insn_alternative (insn, LRA_UNKNOWN_ALT); |
| } |
| bitmap_clear (&to_process); |
| } |
| |
| /* Update all offsets and possibility for elimination on eliminable |
| registers. Spill pseudos assigned to registers which are |
| uneliminable, update LRA_NO_ALLOC_REGS and ELIMINABLE_REG_SET. Add |
| insns to INSNS_WITH_CHANGED_OFFSETS containing eliminable hard |
| registers whose offsets should be changed. Return true if any |
| elimination offset changed. */ |
| static bool |
| update_reg_eliminate (bitmap insns_with_changed_offsets) |
| { |
| bool prev, result; |
| class lra_elim_table *ep, *ep1; |
| HARD_REG_SET temp_hard_reg_set; |
| |
| targetm.compute_frame_layout (); |
| |
| /* Clear self elimination offsets. */ |
| for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++) |
| self_elim_offsets[ep->from] = 0; |
| for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++) |
| { |
| /* If it is a currently used elimination: update the previous |
| offset. */ |
| if (elimination_map[ep->from] == ep) |
| ep->previous_offset = ep->offset; |
| |
| prev = ep->prev_can_eliminate; |
| setup_can_eliminate (ep, targetm.can_eliminate (ep->from, ep->to)); |
| if (ep->can_eliminate && ! prev) |
| { |
| /* It is possible that not eliminable register becomes |
| eliminable because we took other reasons into account to |
| set up eliminable regs in the initial set up. Just |
| ignore new eliminable registers. */ |
| setup_can_eliminate (ep, false); |
| continue; |
| } |
| if (ep->can_eliminate != prev && elimination_map[ep->from] == ep) |
| { |
| /* We cannot use this elimination anymore -- find another |
| one. */ |
| if (lra_dump_file != NULL) |
| fprintf (lra_dump_file, |
| " Elimination %d to %d is not possible anymore\n", |
| ep->from, ep->to); |
| /* If after processing RTL we decides that SP can be used as |
| a result of elimination, it cannot be changed. */ |
| gcc_assert ((ep->to_rtx != stack_pointer_rtx) |
| || (ep->from < FIRST_PSEUDO_REGISTER |
| && fixed_regs [ep->from])); |
| /* Mark that is not eliminable anymore. */ |
| elimination_map[ep->from] = NULL; |
| for (ep1 = ep + 1; ep1 < ®_eliminate[NUM_ELIMINABLE_REGS]; ep1++) |
| if (ep1->can_eliminate && ep1->from == ep->from) |
| break; |
| if (ep1 < ®_eliminate[NUM_ELIMINABLE_REGS]) |
| { |
| if (lra_dump_file != NULL) |
| fprintf (lra_dump_file, " Using elimination %d to %d now\n", |
| ep1->from, ep1->to); |
| lra_assert (known_eq (ep1->previous_offset, 0)); |
| ep1->previous_offset = ep->offset; |
| } |
| else |
| { |
| /* There is no elimination anymore just use the hard |
| register `from' itself. Setup self elimination |
| offset to restore the original offset values. */ |
| if (lra_dump_file != NULL) |
| fprintf (lra_dump_file, " %d is not eliminable at all\n", |
| ep->from); |
| self_elim_offsets[ep->from] = -ep->offset; |
| if (maybe_ne (ep->offset, 0)) |
| bitmap_ior_into (insns_with_changed_offsets, |
| &lra_reg_info[ep->from].insn_bitmap); |
| } |
| } |
| |
| INITIAL_ELIMINATION_OFFSET (ep->from, ep->to, ep->offset); |
| } |
| setup_elimination_map (); |
| result = false; |
| CLEAR_HARD_REG_SET (temp_hard_reg_set); |
| for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++) |
| if (elimination_map[ep->from] == NULL) |
| add_to_hard_reg_set (&temp_hard_reg_set, Pmode, ep->from); |
| else if (elimination_map[ep->from] == ep) |
| { |
| /* Prevent the hard register into which we eliminate from |
| the usage for pseudos. */ |
| if (ep->from != ep->to) |
| add_to_hard_reg_set (&temp_hard_reg_set, Pmode, ep->to); |
| if (maybe_ne (ep->previous_offset, ep->offset)) |
| { |
| bitmap_ior_into (insns_with_changed_offsets, |
| &lra_reg_info[ep->from].insn_bitmap); |
| |
| /* Update offset when the eliminate offset have been |
| changed. */ |
| lra_update_reg_val_offset (lra_reg_info[ep->from].val, |
| ep->offset - ep->previous_offset); |
| result = true; |
| } |
| } |
| lra_no_alloc_regs |= temp_hard_reg_set; |
| eliminable_regset &= ~temp_hard_reg_set; |
| spill_pseudos (temp_hard_reg_set); |
| return result; |
| } |
| |
| /* Initialize the table of hard registers to eliminate. |
| Pre-condition: global flag frame_pointer_needed has been set before |
| calling this function. */ |
| static void |
| init_elim_table (void) |
| { |
| class lra_elim_table *ep; |
| bool value_p; |
| const struct elim_table_1 *ep1; |
| |
| if (!reg_eliminate) |
| reg_eliminate = XCNEWVEC (class lra_elim_table, NUM_ELIMINABLE_REGS); |
| |
| memset (self_elim_offsets, 0, sizeof (self_elim_offsets)); |
| /* Initiate member values which will be never changed. */ |
| self_elim_table.can_eliminate = self_elim_table.prev_can_eliminate = true; |
| self_elim_table.previous_offset = 0; |
| |
| for (ep = reg_eliminate, ep1 = reg_eliminate_1; |
| ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++, ep1++) |
| { |
| ep->offset = ep->previous_offset = 0; |
| ep->from = ep1->from; |
| ep->to = ep1->to; |
| value_p = (targetm.can_eliminate (ep->from, ep->to) |
| && ! (ep->to == STACK_POINTER_REGNUM |
| && frame_pointer_needed |
| && (! SUPPORTS_STACK_ALIGNMENT |
| || ! stack_realign_fp))); |
| setup_can_eliminate (ep, value_p); |
| } |
| |
| /* Build the FROM and TO REG rtx's. Note that code in gen_rtx_REG |
| will cause, e.g., gen_rtx_REG (Pmode, STACK_POINTER_REGNUM) to |
| equal stack_pointer_rtx. We depend on this. Threfore we switch |
| off that we are in LRA temporarily. */ |
| lra_in_progress = 0; |
| for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++) |
| { |
| ep->from_rtx = gen_rtx_REG (Pmode, ep->from); |
| ep->to_rtx = gen_rtx_REG (Pmode, ep->to); |
| eliminable_reg_rtx[ep->from] = ep->from_rtx; |
| } |
| lra_in_progress = 1; |
| } |
| |
| /* Function for initialization of elimination once per function. It |
| sets up sp offset for each insn. */ |
| static void |
| init_elimination (void) |
| { |
| bool stop_to_sp_elimination_p; |
| basic_block bb; |
| rtx_insn *insn; |
| class lra_elim_table *ep; |
| |
| init_elim_table (); |
| FOR_EACH_BB_FN (bb, cfun) |
| { |
| curr_sp_change = 0; |
| stop_to_sp_elimination_p = false; |
| FOR_BB_INSNS (bb, insn) |
| if (INSN_P (insn)) |
| { |
| lra_get_insn_recog_data (insn)->sp_offset = curr_sp_change; |
| if (NONDEBUG_INSN_P (insn)) |
| { |
| mark_not_eliminable (PATTERN (insn), VOIDmode); |
| if (maybe_ne (curr_sp_change, 0) |
| && find_reg_note (insn, REG_LABEL_OPERAND, NULL_RTX)) |
| stop_to_sp_elimination_p = true; |
| } |
| } |
| if (! frame_pointer_needed |
| && (maybe_ne (curr_sp_change, 0) || stop_to_sp_elimination_p) |
| && bb->succs && bb->succs->length () != 0) |
| for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++) |
| if (ep->to == STACK_POINTER_REGNUM) |
| setup_can_eliminate (ep, false); |
| } |
| setup_elimination_map (); |
| } |
| |
| /* Eliminate hard reg given by its location LOC. */ |
| void |
| lra_eliminate_reg_if_possible (rtx *loc) |
| { |
| int regno; |
| class lra_elim_table *ep; |
| |
| lra_assert (REG_P (*loc)); |
| if ((regno = REGNO (*loc)) >= FIRST_PSEUDO_REGISTER |
| || ! TEST_HARD_REG_BIT (lra_no_alloc_regs, regno)) |
| return; |
| if ((ep = get_elimination (*loc)) != NULL) |
| *loc = ep->to_rtx; |
| } |
| |
| /* Do (final if FINAL_P or first if FIRST_P) elimination in INSN. Add |
| the insn for subsequent processing in the constraint pass, update |
| the insn info. */ |
| static void |
| process_insn_for_elimination (rtx_insn *insn, bool final_p, bool first_p) |
| { |
| eliminate_regs_in_insn (insn, final_p, first_p, 0); |
| if (! final_p) |
| { |
| /* Check that insn changed its code. This is a case when a move |
| insn becomes an add insn and we do not want to process the |
| insn as a move anymore. */ |
| int icode = recog (PATTERN (insn), insn, 0); |
| |
| if (icode >= 0 && icode != INSN_CODE (insn)) |
| { |
| if (INSN_CODE (insn) >= 0) |
| /* Insn code is changed. It may change its operand type |
| from IN to INOUT. Inform the subsequent assignment |
| subpass about this situation. */ |
| check_and_force_assignment_correctness_p = true; |
| INSN_CODE (insn) = icode; |
| lra_update_insn_recog_data (insn); |
| } |
| lra_update_insn_regno_info (insn); |
| lra_push_insn (insn); |
| lra_set_used_insn_alternative (insn, LRA_UNKNOWN_ALT); |
| } |
| } |
| |
| /* Entry function to do final elimination if FINAL_P or to update |
| elimination register offsets (FIRST_P if we are doing it the first |
| time). */ |
| void |
| lra_eliminate (bool final_p, bool first_p) |
| { |
| unsigned int uid; |
| bitmap_head insns_with_changed_offsets; |
| bitmap_iterator bi; |
| class lra_elim_table *ep; |
| |
| gcc_assert (! final_p || ! first_p); |
| |
| timevar_push (TV_LRA_ELIMINATE); |
| |
| if (first_p) |
| init_elimination (); |
| |
| bitmap_initialize (&insns_with_changed_offsets, ®_obstack); |
| if (final_p) |
| { |
| if (flag_checking) |
| { |
| update_reg_eliminate (&insns_with_changed_offsets); |
| gcc_assert (bitmap_empty_p (&insns_with_changed_offsets)); |
| } |
| /* We change eliminable hard registers in insns so we should do |
| this for all insns containing any eliminable hard |
| register. */ |
| for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++) |
| if (elimination_map[ep->from] != NULL) |
| bitmap_ior_into (&insns_with_changed_offsets, |
| &lra_reg_info[ep->from].insn_bitmap); |
| } |
| else if (! update_reg_eliminate (&insns_with_changed_offsets)) |
| goto lra_eliminate_done; |
| if (lra_dump_file != NULL) |
| { |
| fprintf (lra_dump_file, "New elimination table:\n"); |
| print_elim_table (lra_dump_file); |
| } |
| EXECUTE_IF_SET_IN_BITMAP (&insns_with_changed_offsets, 0, uid, bi) |
| /* A dead insn can be deleted in process_insn_for_elimination. */ |
| if (lra_insn_recog_data[uid] != NULL) |
| process_insn_for_elimination (lra_insn_recog_data[uid]->insn, |
| final_p, first_p); |
| bitmap_clear (&insns_with_changed_offsets); |
| |
| lra_eliminate_done: |
| timevar_pop (TV_LRA_ELIMINATE); |
| } |