/* Common subexpression elimination for GNU compiler.
Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998
- 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
- Free Software Foundation, Inc.
+ 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
+ 2011 Free Software Foundation, Inc.
This file is part of GCC.
<http://www.gnu.org/licenses/>. */
#include "config.h"
-/* stdio.h must precede rtl.h for FFS. */
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "regs.h"
#include "basic-block.h"
#include "flags.h"
-#include "real.h"
#include "insn-config.h"
#include "recog.h"
#include "function.h"
#include "expr.h"
+#include "diagnostic-core.h"
#include "toplev.h"
#include "output.h"
#include "ggc.h"
|| (HARD_REGISTER_NUM_P (N) \
&& FIXED_REGNO_P (N) && REGNO_REG_CLASS (N) != NO_REGS))
-#define COST(X) (REG_P (X) ? 0 : notreg_cost (X, SET))
-#define COST_IN(X,OUTER) (REG_P (X) ? 0 : notreg_cost (X, OUTER))
+#define COST(X) (REG_P (X) ? 0 : notreg_cost (X, SET, 1))
+#define COST_IN(X, OUTER, OPNO) (REG_P (X) ? 0 : notreg_cost (X, OUTER, OPNO))
/* Get the number of times this register has been updated in this
basic block. */
static sbitmap cse_visited_basic_blocks;
static bool fixed_base_plus_p (rtx x);
-static int notreg_cost (rtx, enum rtx_code);
+static int notreg_cost (rtx, enum rtx_code, int);
static int approx_reg_cost_1 (rtx *, void *);
static int approx_reg_cost (rtx);
static int preferable (int, int, int, int);
enum machine_mode);
static void merge_equiv_classes (struct table_elt *, struct table_elt *);
static void invalidate (rtx, enum machine_mode);
-static bool cse_rtx_varies_p (const_rtx, bool);
static void remove_invalid_refs (unsigned int);
static void remove_invalid_subreg_refs (unsigned int, unsigned int,
enum machine_mode);
{
if (regno < FIRST_PSEUDO_REGISTER)
{
- if (SMALL_REGISTER_CLASSES)
+ if (targetm.small_register_classes_for_mode_p (GET_MODE (x)))
return 1;
*cost_p += 2;
}
from COST macro to keep it simple. */
static int
-notreg_cost (rtx x, enum rtx_code outer)
+notreg_cost (rtx x, enum rtx_code outer, int opno)
{
return ((GET_CODE (x) == SUBREG
&& REG_P (SUBREG_REG (x))
&& (GET_MODE_SIZE (GET_MODE (x))
< GET_MODE_SIZE (GET_MODE (SUBREG_REG (x))))
&& subreg_lowpart_p (x)
- && TRULY_NOOP_TRUNCATION (GET_MODE_BITSIZE (GET_MODE (x)),
- GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x)))))
+ && TRULY_NOOP_TRUNCATION_MODES_P (GET_MODE (x),
+ GET_MODE (SUBREG_REG (x))))
? 0
- : rtx_cost (x, outer, optimize_this_for_speed_p) * 2);
+ : rtx_cost (x, outer, opno, optimize_this_for_speed_p) * 2);
}
\f
}
/* Reallocate the table with NEW_SIZE entries. */
- if (cse_reg_info_table)
- free (cse_reg_info_table);
+ free (cse_reg_info_table);
cse_reg_info_table = XNEWVEC (struct cse_reg_info, new_size);
cse_reg_info_table_size = new_size;
cse_reg_info_table_first_uninitialized = 0;
/* Put it after the last element cheaper than X. */
struct table_elt *p, *next;
- for (p = classp; (next = p->next_same_value) && CHEAPER (next, elt);
- p = next);
+ for (p = classp;
+ (next = p->next_same_value) && CHEAPER (next, elt);
+ p = next)
+ ;
/* Put it after P and before NEXT. */
elt->next_same_value = next;
{
struct check_dependence_data *d = (struct check_dependence_data *) data;
if (*x && MEM_P (*x))
- return canon_true_dependence (d->exp, d->mode, d->addr, *x, NULL_RTX,
- cse_rtx_varies_p);
+ return canon_true_dependence (d->exp, d->mode, d->addr, *x, NULL_RTX);
else
return 0;
}
On all machines, we can't record any global registers.
Nor should we record any register that is in a small
- class, as defined by CLASS_LIKELY_SPILLED_P. */
+ class, as defined by TARGET_CLASS_LIKELY_SPILLED_P. */
bool record;
if (regno >= FIRST_PSEUDO_REGISTER)
record = true;
else if (GET_MODE_CLASS (GET_MODE (x)) == MODE_CC)
record = true;
- else if (SMALL_REGISTER_CLASSES)
+ else if (targetm.small_register_classes_for_mode_p (GET_MODE (x)))
record = false;
- else if (CLASS_LIKELY_SPILLED_P (REGNO_REG_CLASS (regno)))
+ else if (targetm.class_likely_spilled_p (REGNO_REG_CLASS (regno)))
record = false;
else
record = true;
Store 1 in DO_NOT_RECORD_P if any subexpression is volatile.
If HASH_ARG_IN_MEMORY_P is not NULL, store 1 in it if X contains
- a MEM rtx which does not have the RTX_UNCHANGING_P bit set.
+ a MEM rtx which does not have the MEM_READONLY_P flag set.
Note that cse_insn knows that the hash code of a MEM expression
is just (int) MEM plus the hash code of the address. */
/* Hash an rtx X for cse via hash_rtx.
Stores 1 in do_not_record if any subexpression is volatile.
Stores 1 in hash_arg_in_memory if X contains a mem rtx which
- does not have the RTX_UNCHANGING_P bit set. */
+ does not have the MEM_READONLY_P flag set. */
static inline unsigned
canon_hash (rtx x, enum machine_mode mode)
return 1;
}
\f
-/* Return 1 if X has a value that can vary even between two
- executions of the program. 0 means X can be compared reliably
- against certain constants or near-constants. */
-
-static bool
-cse_rtx_varies_p (const_rtx x, bool from_alias)
-{
- /* We need not check for X and the equivalence class being of the same
- mode because if X is equivalent to a constant in some mode, it
- doesn't vary in any mode. */
-
- if (REG_P (x)
- && REGNO_QTY_VALID_P (REGNO (x)))
- {
- int x_q = REG_QTY (REGNO (x));
- struct qty_table_elem *x_ent = &qty_table[x_q];
-
- if (GET_MODE (x) == x_ent->mode
- && x_ent->const_rtx != NULL_RTX)
- return 0;
- }
-
- if (GET_CODE (x) == PLUS
- && CONST_INT_P (XEXP (x, 1))
- && REG_P (XEXP (x, 0))
- && REGNO_QTY_VALID_P (REGNO (XEXP (x, 0))))
- {
- int x0_q = REG_QTY (REGNO (XEXP (x, 0)));
- struct qty_table_elem *x0_ent = &qty_table[x0_q];
-
- if ((GET_MODE (XEXP (x, 0)) == x0_ent->mode)
- && x0_ent->const_rtx != NULL_RTX)
- return 0;
- }
-
- /* This can happen as the result of virtual register instantiation, if
- the initial constant is too large to be a valid address. This gives
- us a three instruction sequence, load large offset into a register,
- load fp minus a constant into a register, then a MEM which is the
- sum of the two `constant' registers. */
- if (GET_CODE (x) == PLUS
- && REG_P (XEXP (x, 0))
- && REG_P (XEXP (x, 1))
- && REGNO_QTY_VALID_P (REGNO (XEXP (x, 0)))
- && REGNO_QTY_VALID_P (REGNO (XEXP (x, 1))))
- {
- int x0_q = REG_QTY (REGNO (XEXP (x, 0)));
- int x1_q = REG_QTY (REGNO (XEXP (x, 1)));
- struct qty_table_elem *x0_ent = &qty_table[x0_q];
- struct qty_table_elem *x1_ent = &qty_table[x1_q];
-
- if ((GET_MODE (XEXP (x, 0)) == x0_ent->mode)
- && x0_ent->const_rtx != NULL_RTX
- && (GET_MODE (XEXP (x, 1)) == x1_ent->mode)
- && x1_ent->const_rtx != NULL_RTX)
- return 0;
- }
-
- return rtx_varies_p (x, from_alias);
-}
-\f
/* Subroutine of canon_reg. Pass *XLOC through canon_reg, and validate
the result if necessary. INSN is as for canon_reg. */
if (! exp_equiv_p (p->exp, p->exp, 1, false))
continue;
+ /* If it's the same comparison we're already looking at, skip it. */
+ if (COMPARISON_P (p->exp)
+ && XEXP (p->exp, 0) == arg1
+ && XEXP (p->exp, 1) == arg2)
+ continue;
+
if (GET_CODE (p->exp) == COMPARE
/* Another possibility is that this machine has a compare insn
that includes the comparison code. In that case, ARG1 would
for STORE_FLAG_VALUE, also look at LT and GE operations. */
|| ((code == NE
|| (code == LT
- && GET_MODE_CLASS (inner_mode) == MODE_INT
- && (GET_MODE_BITSIZE (inner_mode)
- <= HOST_BITS_PER_WIDE_INT)
- && (STORE_FLAG_VALUE
- & ((HOST_WIDE_INT) 1
- << (GET_MODE_BITSIZE (inner_mode) - 1))))
+ && val_signbit_known_set_p (inner_mode,
+ STORE_FLAG_VALUE))
#ifdef FLOAT_STORE_FLAG_VALUE
|| (code == LT
&& SCALAR_FLOAT_MODE_P (inner_mode)
}
else if ((code == EQ
|| (code == GE
- && GET_MODE_CLASS (inner_mode) == MODE_INT
- && (GET_MODE_BITSIZE (inner_mode)
- <= HOST_BITS_PER_WIDE_INT)
- && (STORE_FLAG_VALUE
- & ((HOST_WIDE_INT) 1
- << (GET_MODE_BITSIZE (inner_mode) - 1))))
+ && val_signbit_known_set_p (inner_mode,
+ STORE_FLAG_VALUE))
#ifdef FLOAT_STORE_FLAG_VALUE
|| (code == GE
&& SCALAR_FLOAT_MODE_P (inner_mode)
argument. */
if (const_arg != 0
&& const_arg != folded_arg
- && COST_IN (const_arg, code) <= COST_IN (folded_arg, code)
+ && COST_IN (const_arg, code, i) <= COST_IN (folded_arg, code, i)
/* It's not safe to substitute the operand of a conversion
operator with a constant, as the conversion's identity
enum rtx_code associate_code;
if (is_shift
- && (INTVAL (const_arg1) >= GET_MODE_BITSIZE (mode)
+ && (INTVAL (const_arg1) >= GET_MODE_PRECISION (mode)
|| INTVAL (const_arg1) < 0))
{
if (SHIFT_COUNT_TRUNCATED)
break;
if (is_shift
- && (INTVAL (inner_const) >= GET_MODE_BITSIZE (mode)
+ && (INTVAL (inner_const) >= GET_MODE_PRECISION (mode)
|| INTVAL (inner_const) < 0))
{
if (SHIFT_COUNT_TRUNCATED)
if (is_shift
&& CONST_INT_P (new_const)
- && INTVAL (new_const) >= GET_MODE_BITSIZE (mode))
+ && INTVAL (new_const) >= GET_MODE_PRECISION (mode))
{
/* As an exception, we can turn an ASHIFTRT of this
form into a shift of the number of bits - 1. */
is not worth testing for with no SUBREG). */
/* Note that GET_MODE (op0) may not equal MODE. */
- if (code == EQ && GET_CODE (op0) == SUBREG
- && (GET_MODE_SIZE (GET_MODE (op0))
- > GET_MODE_SIZE (GET_MODE (SUBREG_REG (op0)))))
+ if (code == EQ && paradoxical_subreg_p (op0))
{
enum machine_mode inner_mode = GET_MODE (SUBREG_REG (op0));
rtx tem = record_jump_cond_subreg (inner_mode, op1);
reversed_nonequality);
}
- if (code == EQ && GET_CODE (op1) == SUBREG
- && (GET_MODE_SIZE (GET_MODE (op1))
- > GET_MODE_SIZE (GET_MODE (SUBREG_REG (op1)))))
+ if (code == EQ && paradoxical_subreg_p (op1))
{
enum machine_mode inner_mode = GET_MODE (SUBREG_REG (op1));
rtx tem = record_jump_cond_subreg (inner_mode, op0);
if (MEM_P (XEXP (x, 0)))
canon_reg (XEXP (x, 0), insn);
}
-
/* Canonicalize a USE of a pseudo register or memory location. */
else if (GET_CODE (x) == USE
&& ! (REG_P (XEXP (x, 0))
&& REGNO (XEXP (x, 0)) < FIRST_PSEUDO_REGISTER))
- canon_reg (XEXP (x, 0), insn);
+ canon_reg (x, insn);
+ else if (GET_CODE (x) == ASM_OPERANDS)
+ {
+ for (i = ASM_OPERANDS_INPUT_LENGTH (x) - 1; i >= 0; i--)
+ {
+ rtx input = ASM_OPERANDS_INPUT (x, i);
+ if (!(REG_P (input) && REGNO (input) < FIRST_PSEUDO_REGISTER))
+ {
+ input = canon_reg (input, insn);
+ validate_change (insn, &ASM_OPERANDS_INPUT (x, i), input, 1);
+ }
+ }
+ }
else if (GET_CODE (x) == CALL)
{
/* The result of apply_change_group can be ignored; see canon_reg. */
treat it as volatile. It may do the work of an SI in one context
where the extra bits are not being used, but cannot replace an SI
in general. */
- if (GET_CODE (src) == SUBREG
- && (GET_MODE_SIZE (GET_MODE (src))
- > GET_MODE_SIZE (GET_MODE (SUBREG_REG (src)))))
+ if (paradoxical_subreg_p (src))
sets[i].src_volatile = 1;
#endif
if (src_const && src_related == 0 && CONST_INT_P (src_const)
&& GET_MODE_CLASS (mode) == MODE_INT
- && GET_MODE_BITSIZE (mode) < BITS_PER_WORD)
+ && GET_MODE_PRECISION (mode) < BITS_PER_WORD)
{
enum machine_mode wider_mode;
for (wider_mode = GET_MODE_WIDER_MODE (mode);
wider_mode != VOIDmode
- && GET_MODE_BITSIZE (wider_mode) <= BITS_PER_WORD
+ && GET_MODE_PRECISION (wider_mode) <= BITS_PER_WORD
&& src_related == 0;
wider_mode = GET_MODE_WIDER_MODE (wider_mode))
{
/* Also skip paradoxical subregs, unless that's what we're
looking for. */
- if (code == SUBREG
- && (GET_MODE_SIZE (GET_MODE (p->exp))
- > GET_MODE_SIZE (GET_MODE (SUBREG_REG (p->exp))))
+ if (paradoxical_subreg_p (p->exp)
&& ! (src != 0
&& GET_CODE (src) == SUBREG
&& GET_MODE (src) == GET_MODE (p->exp)
size, but later may be adjusted so that the upper bits aren't
what we want. So reject it. */
if (elt != 0
- && GET_CODE (elt->exp) == SUBREG
- && (GET_MODE_SIZE (GET_MODE (elt->exp))
- > GET_MODE_SIZE (GET_MODE (SUBREG_REG (elt->exp))))
+ && paradoxical_subreg_p (elt->exp)
/* It is okay, though, if the rtx we're trying to match
will ignore any of the bits we can't predict. */
&& ! (src != 0
dest = canon_rtx (SET_DEST (sets[i].rtl));
if (!MEM_P (src) || !MEM_P (dest)
- || !nonoverlapping_memrefs_p (src, dest))
+ || !nonoverlapping_memrefs_p (src, dest, false))
break;
}
&& CONST_INT_P (XEXP (SET_DEST (sets[i].rtl), 1))
&& CONST_INT_P (XEXP (SET_DEST (sets[i].rtl), 2))
&& REG_P (XEXP (SET_DEST (sets[i].rtl), 0))
- && (GET_MODE_BITSIZE (GET_MODE (SET_DEST (sets[i].rtl)))
+ && (GET_MODE_PRECISION (GET_MODE (SET_DEST (sets[i].rtl)))
>= INTVAL (XEXP (SET_DEST (sets[i].rtl), 1)))
&& ((unsigned) INTVAL (XEXP (SET_DEST (sets[i].rtl), 1))
+ (unsigned) INTVAL (XEXP (SET_DEST (sets[i].rtl), 2))
HOST_WIDE_INT mask;
unsigned int shift;
if (BITS_BIG_ENDIAN)
- shift = GET_MODE_BITSIZE (GET_MODE (dest_reg))
+ shift = GET_MODE_PRECISION (GET_MODE (dest_reg))
- INTVAL (pos) - INTVAL (width);
else
shift = INTVAL (pos);
some tracking to be wrong.
??? Think about this more later. */
- || (GET_CODE (dest) == SUBREG
- && (GET_MODE_SIZE (GET_MODE (dest))
- > GET_MODE_SIZE (GET_MODE (SUBREG_REG (dest))))
+ || (paradoxical_subreg_p (dest)
&& (GET_CODE (sets[i].src) == SIGN_EXTEND
|| GET_CODE (sets[i].src) == ZERO_EXTEND)))
continue;
else
e = NULL;
- if (e && e->dest != EXIT_BLOCK_PTR
+ if (e
+ && !((e->flags & EDGE_ABNORMAL_CALL) && cfun->has_nonlocal_label)
+ && e->dest != EXIT_BLOCK_PTR
&& single_pred_p (e->dest)
/* Avoid visiting basic blocks twice. The large comment
above explains why this can happen. */
}
}
+ optimize_this_for_speed_p = optimize_bb_for_speed_p (bb);
FOR_BB_INSNS (bb, insn)
{
- optimize_this_for_speed_p = optimize_bb_for_speed_p (bb);
/* If we have processed 1,000 insns, flush the hash table to
avoid extreme quadratic behavior. We must not include NOTEs
in the count since there may be more of them when generating
recorded_label_ref = true;
#ifdef HAVE_cc0
- /* If the previous insn set CC0 and this insn no longer
- references CC0, delete the previous insn. Here we use
- fact that nothing expects CC0 to be valid over an insn,
- which is true until the final pass. */
- {
- rtx prev_insn, tem;
-
- prev_insn = PREV_INSN (insn);
- if (prev_insn && NONJUMP_INSN_P (prev_insn)
- && (tem = single_set (prev_insn)) != 0
- && SET_DEST (tem) == cc0_rtx
- && ! reg_mentioned_p (cc0_rtx, PATTERN (insn)))
- delete_insn (prev_insn);
- }
-
- /* If this insn is not the last insn in the basic block,
- it will be PREV_INSN(insn) in the next iteration. If
- we recorded any CC0-related information for this insn,
- remember it. */
- if (insn != BB_END (bb))
+ if (NONDEBUG_INSN_P (insn))
{
- prev_insn_cc0 = this_insn_cc0;
- prev_insn_cc0_mode = this_insn_cc0_mode;
+ /* If the previous insn sets CC0 and this insn no
+ longer references CC0, delete the previous insn.
+ Here we use fact that nothing expects CC0 to be
+ valid over an insn, which is true until the final
+ pass. */
+ rtx prev_insn, tem;
+
+ prev_insn = prev_nonnote_nondebug_insn (insn);
+ if (prev_insn && NONJUMP_INSN_P (prev_insn)
+ && (tem = single_set (prev_insn)) != NULL_RTX
+ && SET_DEST (tem) == cc0_rtx
+ && ! reg_mentioned_p (cc0_rtx, PATTERN (insn)))
+ delete_insn (prev_insn);
+
+ /* If this insn is not the last insn in the basic
+ block, it will be PREV_INSN(insn) in the next
+ iteration. If we recorded any CC0-related
+ information for this insn, remember it. */
+ if (insn != BB_END (bb))
+ {
+ prev_insn_cc0 = this_insn_cc0;
+ prev_insn_cc0_mode = this_insn_cc0_mode;
+ }
}
#endif
}
/* With non-call exceptions, we are not always able to update
the CFG properly inside cse_insn. So clean up possibly
redundant EH edges here. */
- if (flag_non_call_exceptions && have_eh_succ_edges (bb))
+ if (cfun->can_throw_non_call_exceptions && have_eh_succ_edges (bb))
cse_cfg_altered |= purge_dead_edges (bb);
/* If we changed a conditional jump, we may have terminated
Don't count a usage of DEST, which is the SET_DEST of a SET which
contains X in its SET_SRC. This is because such a SET does not
modify the liveness of DEST.
- DEST is set to pc_rtx for a trapping insn, which means that we must count
- uses of a SET_DEST regardless because the insn can't be deleted here. */
+ DEST is set to pc_rtx for a trapping insn, or for an insn with side effects.
+ We must then count uses of a SET_DEST regardless, because the insn can't be
+ deleted here. */
static void
count_reg_usage (rtx x, int *counts, rtx dest, int incr)
case CALL_INSN:
case INSN:
case JUMP_INSN:
- /* We expect dest to be NULL_RTX here. If the insn may trap, mark
- this fact by setting DEST to pc_rtx. */
- if (insn_could_throw_p (x))
+ /* We expect dest to be NULL_RTX here. If the insn may trap,
+ or if it cannot be deleted due to side-effects, mark this fact
+ by setting DEST to pc_rtx. */
+ if (insn_could_throw_p (x) || side_effects_p (PATTERN (x)))
dest = pc_rtx;
if (code == CALL_INSN)
count_reg_usage (CALL_INSN_FUNCTION_USAGE (x), counts, dest, incr);
return;
case ASM_OPERANDS:
- /* If the asm is volatile, then this insn cannot be deleted,
- and so the inputs *must* be live. */
- if (MEM_VOLATILE_P (x))
- dest = NULL_RTX;
/* Iterate over just the inputs, not the constraints as well. */
for (i = ASM_OPERANDS_INPUT_LENGTH (x) - 1; i >= 0; i--)
count_reg_usage (ASM_OPERANDS_INPUT (x, i), counts, dest, incr);
}
}
\f
-/* Return true if a register is dead. Can be used in for_each_rtx. */
+/* Return true if X is a dead register. */
-static int
-is_dead_reg (rtx *loc, void *data)
+static inline int
+is_dead_reg (rtx x, int *counts)
{
- rtx x = *loc;
- int *counts = (int *)data;
-
return (REG_P (x)
&& REGNO (x) >= FIRST_PSEUDO_REGISTER
&& counts[REGNO (x)] == 0);
#ifdef HAVE_cc0
else if (GET_CODE (SET_DEST (set)) == CC0
&& !side_effects_p (SET_SRC (set))
- && ((tem = next_nonnote_insn (insn)) == 0
+ && ((tem = next_nonnote_nondebug_insn (insn)) == NULL_RTX
|| !INSN_P (tem)
|| !reg_referenced_p (cc0_rtx, PATTERN (tem))))
return false;
#endif
- else if (!is_dead_reg (&SET_DEST (set), counts)
+ else if (!is_dead_reg (SET_DEST (set), counts)
|| side_effects_p (SET_SRC (set)))
return true;
return false;
else if (INSN_VAR_LOCATION_DECL (insn) == INSN_VAR_LOCATION_DECL (next))
return false;
- /* If this debug insn references a dead register, drop the
- location expression for now. ??? We could try to find the
- def and see if propagation is possible. */
- if (for_each_rtx (&INSN_VAR_LOCATION_LOC (insn), is_dead_reg, counts))
- {
- INSN_VAR_LOCATION_LOC (insn) = gen_rtx_UNKNOWN_VAR_LOC ();
- df_insn_rescan (insn);
- }
-
return true;
}
else
return true;
}
+/* Count the number of stores into pseudo. Callback for note_stores. */
+
+static void
+count_stores (rtx x, const_rtx set ATTRIBUTE_UNUSED, void *data)
+{
+ int *counts = (int *) data;
+ if (REG_P (x) && REGNO (x) >= FIRST_PSEUDO_REGISTER)
+ counts[REGNO (x)]++;
+}
+
+struct dead_debug_insn_data
+{
+ int *counts;
+ rtx *replacements;
+ bool seen_repl;
+};
+
+/* Return if a DEBUG_INSN needs to be reset because some dead
+ pseudo doesn't have a replacement. Callback for for_each_rtx. */
+
+static int
+is_dead_debug_insn (rtx *loc, void *data)
+{
+ rtx x = *loc;
+ struct dead_debug_insn_data *ddid = (struct dead_debug_insn_data *) data;
+
+ if (is_dead_reg (x, ddid->counts))
+ {
+ if (ddid->replacements && ddid->replacements[REGNO (x)] != NULL_RTX)
+ ddid->seen_repl = true;
+ else
+ return 1;
+ }
+ return 0;
+}
+
+/* Replace a dead pseudo in a DEBUG_INSN with replacement DEBUG_EXPR.
+ Callback for simplify_replace_fn_rtx. */
+
+static rtx
+replace_dead_reg (rtx x, const_rtx old_rtx ATTRIBUTE_UNUSED, void *data)
+{
+ rtx *replacements = (rtx *) data;
+
+ if (REG_P (x)
+ && REGNO (x) >= FIRST_PSEUDO_REGISTER
+ && replacements[REGNO (x)] != NULL_RTX)
+ {
+ if (GET_MODE (x) == GET_MODE (replacements[REGNO (x)]))
+ return replacements[REGNO (x)];
+ return lowpart_subreg (GET_MODE (x), replacements[REGNO (x)],
+ GET_MODE (replacements[REGNO (x)]));
+ }
+ return NULL_RTX;
+}
+
/* Scan all the insns and delete any that are dead; i.e., they store a register
that is never used or they copy a register to itself.
{
int *counts;
rtx insn, prev;
+ rtx *replacements = NULL;
int ndead = 0;
timevar_push (TV_DELETE_TRIVIALLY_DEAD);
/* First count the number of times each register is used. */
- counts = XCNEWVEC (int, nreg);
- for (insn = insns; insn; insn = NEXT_INSN (insn))
- if (INSN_P (insn))
- count_reg_usage (insn, counts, NULL_RTX, 1);
-
+ if (MAY_HAVE_DEBUG_INSNS)
+ {
+ counts = XCNEWVEC (int, nreg * 3);
+ for (insn = insns; insn; insn = NEXT_INSN (insn))
+ if (DEBUG_INSN_P (insn))
+ count_reg_usage (INSN_VAR_LOCATION_LOC (insn), counts + nreg,
+ NULL_RTX, 1);
+ else if (INSN_P (insn))
+ {
+ count_reg_usage (insn, counts, NULL_RTX, 1);
+ note_stores (PATTERN (insn), count_stores, counts + nreg * 2);
+ }
+ /* If there can be debug insns, COUNTS are 3 consecutive arrays.
+ First one counts how many times each pseudo is used outside
+ of debug insns, second counts how many times each pseudo is
+ used in debug insns and third counts how many times a pseudo
+ is stored. */
+ }
+ else
+ {
+ counts = XCNEWVEC (int, nreg);
+ for (insn = insns; insn; insn = NEXT_INSN (insn))
+ if (INSN_P (insn))
+ count_reg_usage (insn, counts, NULL_RTX, 1);
+ /* If no debug insns can be present, COUNTS is just an array
+ which counts how many times each pseudo is used. */
+ }
/* Go from the last insn to the first and delete insns that only set unused
registers or copy a register to itself. As we delete an insn, remove
usage counts for registers it uses.
The first jump optimization pass may leave a real insn as the last
insn in the function. We must not skip that insn or we may end
- up deleting code that is not really dead. */
+ up deleting code that is not really dead.
+
+ If some otherwise unused register is only used in DEBUG_INSNs,
+ try to create a DEBUG_EXPR temporary and emit a DEBUG_INSN before
+ the setter. Then go through DEBUG_INSNs and if a DEBUG_EXPR
+ has been created for the unused register, replace it with
+ the DEBUG_EXPR, otherwise reset the DEBUG_INSN. */
for (insn = get_last_insn (); insn; insn = prev)
{
int live_insn = 0;
if (! live_insn && dbg_cnt (delete_trivial_dead))
{
- count_reg_usage (insn, counts, NULL_RTX, -1);
+ if (DEBUG_INSN_P (insn))
+ count_reg_usage (INSN_VAR_LOCATION_LOC (insn), counts + nreg,
+ NULL_RTX, -1);
+ else
+ {
+ rtx set;
+ if (MAY_HAVE_DEBUG_INSNS
+ && (set = single_set (insn)) != NULL_RTX
+ && is_dead_reg (SET_DEST (set), counts)
+ /* Used at least once in some DEBUG_INSN. */
+ && counts[REGNO (SET_DEST (set)) + nreg] > 0
+ /* And set exactly once. */
+ && counts[REGNO (SET_DEST (set)) + nreg * 2] == 1
+ && !side_effects_p (SET_SRC (set))
+ && asm_noperands (PATTERN (insn)) < 0)
+ {
+ rtx dval, bind;
+
+ /* Create DEBUG_EXPR (and DEBUG_EXPR_DECL). */
+ dval = make_debug_expr_from_rtl (SET_DEST (set));
+
+ /* Emit a debug bind insn before the insn in which
+ reg dies. */
+ bind = gen_rtx_VAR_LOCATION (GET_MODE (SET_DEST (set)),
+ DEBUG_EXPR_TREE_DECL (dval),
+ SET_SRC (set),
+ VAR_INIT_STATUS_INITIALIZED);
+ count_reg_usage (bind, counts + nreg, NULL_RTX, 1);
+
+ bind = emit_debug_insn_before (bind, insn);
+ df_insn_rescan (bind);
+
+ if (replacements == NULL)
+ replacements = XCNEWVEC (rtx, nreg);
+ replacements[REGNO (SET_DEST (set))] = dval;
+ }
+
+ count_reg_usage (insn, counts, NULL_RTX, -1);
+ ndead++;
+ }
delete_insn_and_edges (insn);
- ndead++;
}
}
+ if (MAY_HAVE_DEBUG_INSNS)
+ {
+ struct dead_debug_insn_data ddid;
+ ddid.counts = counts;
+ ddid.replacements = replacements;
+ for (insn = get_last_insn (); insn; insn = PREV_INSN (insn))
+ if (DEBUG_INSN_P (insn))
+ {
+ /* If this debug insn references a dead register that wasn't replaced
+ with an DEBUG_EXPR, reset the DEBUG_INSN. */
+ ddid.seen_repl = false;
+ if (for_each_rtx (&INSN_VAR_LOCATION_LOC (insn),
+ is_dead_debug_insn, &ddid))
+ {
+ INSN_VAR_LOCATION_LOC (insn) = gen_rtx_UNKNOWN_VAR_LOC ();
+ df_insn_rescan (insn);
+ }
+ else if (ddid.seen_repl)
+ {
+ INSN_VAR_LOCATION_LOC (insn)
+ = simplify_replace_fn_rtx (INSN_VAR_LOCATION_LOC (insn),
+ NULL_RTX, replace_dead_reg,
+ replacements);
+ df_insn_rescan (insn);
+ }
+ }
+ free (replacements);
+ }
+
if (dump_file && ndead)
fprintf (dump_file, "Deleted %i trivially dead insns\n",
ndead);
0, /* properties_destroyed */
0, /* todo_flags_start */
TODO_df_finish | TODO_verify_rtl_sharing |
- TODO_dump_func |
TODO_ggc_collect |
TODO_verify_flow, /* todo_flags_finish */
}
0, /* properties_destroyed */
0, /* todo_flags_start */
TODO_df_finish | TODO_verify_rtl_sharing |
- TODO_dump_func |
TODO_ggc_collect |
TODO_verify_flow /* todo_flags_finish */
}
0, /* properties_destroyed */
0, /* todo_flags_start */
TODO_df_finish | TODO_verify_rtl_sharing |
- TODO_dump_func |
TODO_ggc_collect |
TODO_verify_flow /* todo_flags_finish */
}
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