/* Reload pseudo regs into hard regs for insns that require hard regs.
Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
- 1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
+ 1999, 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
This file is part of GCC.
/* This obstack is used for allocation of rtl during register elimination.
The allocated storage can be freed once find_reloads has processed the
insn. */
-struct obstack reload_obstack;
+static struct obstack reload_obstack;
/* Points to the beginning of the reload_obstack. All insn_chain structures
are allocated first. */
-char *reload_startobj;
+static char *reload_startobj;
/* The point after all insn_chain structures. Used to quickly deallocate
memory allocated in copy_reloads during calculate_needs_all_insns. */
-char *reload_firstobj;
+static char *reload_firstobj;
/* This points before all local rtl generated by register elimination.
Used to quickly free all memory after processing one insn. */
static void update_eliminable_offsets (void);
static void mark_not_eliminable (rtx, rtx, void *);
static void set_initial_elim_offsets (void);
-static void verify_initial_elim_offsets (void);
+static bool verify_initial_elim_offsets (void);
static void set_initial_label_offsets (void);
static void set_offsets_for_label (rtx);
static void init_elim_table (void);
static void update_eliminables (HARD_REG_SET *);
static void spill_hard_reg (unsigned int, int);
static int finish_spills (int);
-static void ior_hard_reg_set (HARD_REG_SET *, HARD_REG_SET *);
static void scan_paradoxical_subregs (rtx);
static void count_pseudo (int);
static void order_regs_for_reload (struct insn_chain *);
rtx, rtx, int, int);
static int free_for_value_p (int, enum machine_mode, int, enum reload_type,
rtx, rtx, int, int);
-static int function_invariant_p (rtx);
static int reload_reg_reaches_end_p (unsigned int, int, enum reload_type);
static int allocate_reload_reg (struct insn_chain *, int, int);
static int conflicts_with_override (rtx);
static void add_auto_inc_notes (rtx, rtx);
#endif
static void copy_eh_notes (rtx, rtx);
+static int reloads_conflict (int, int);
+static rtx gen_reload (rtx, rtx, int, enum reload_type);
\f
/* Initialize the reload pass once per compilation. */
compute_use_by_pseudos (HARD_REG_SET *to, regset from)
{
unsigned int regno;
+ reg_set_iterator rsi;
- EXECUTE_IF_SET_IN_REG_SET
- (from, FIRST_PSEUDO_REGISTER, regno,
- {
- int r = reg_renumber[regno];
- int nregs;
-
- if (r < 0)
- {
- /* reload_combine uses the information from
- BASIC_BLOCK->global_live_at_start, which might still
- contain registers that have not actually been allocated
- since they have an equivalence. */
- gcc_assert (reload_completed);
- }
- else
- {
- nregs = hard_regno_nregs[r][PSEUDO_REGNO_MODE (regno)];
- while (nregs-- > 0)
- SET_HARD_REG_BIT (*to, r + nregs);
- }
- });
+ EXECUTE_IF_SET_IN_REG_SET (from, FIRST_PSEUDO_REGISTER, regno, rsi)
+ {
+ int r = reg_renumber[regno];
+ int nregs;
+
+ if (r < 0)
+ {
+ /* reload_combine uses the information from
+ BASIC_BLOCK->global_live_at_start, which might still
+ contain registers that have not actually been allocated
+ since they have an equivalence. */
+ gcc_assert (reload_completed);
+ }
+ else
+ {
+ nregs = hard_regno_nregs[r][PSEUDO_REGNO_MODE (regno)];
+ while (nregs-- > 0)
+ SET_HARD_REG_BIT (*to, r + nregs);
+ }
+ }
}
/* Replace all pseudos found in LOC with their corresponding
/* Set during calculate_needs if an insn needs register elimination. */
static int something_needs_elimination;
/* Set during calculate_needs if an insn needs an operand changed. */
-int something_needs_operands_changed;
+static int something_needs_operands_changed;
/* Nonzero means we couldn't get enough spill regs. */
static int failure;
if (! call_used_regs[i] && ! fixed_regs[i] && ! LOCAL_REGNO (i))
regs_ever_live[i] = 1;
-#ifdef NON_SAVING_SETJMP
- /* A function that calls setjmp should save and restore all the
- call-saved registers on a system where longjmp clobbers them. */
- if (NON_SAVING_SETJMP && current_function_calls_setjmp)
- {
- for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
- if (! call_used_regs[i])
- regs_ever_live[i] = 1;
- }
-#endif
-
/* Find all the pseudo registers that didn't get hard regs
but do have known equivalent constants or memory slots.
These include parameters (known equivalent to parameter slots)
that is not a legitimate memory operand. As later
stages of reload assume that all addresses found
in the reg_equiv_* arrays were originally legitimate,
- we ignore such REG_EQUIV notes. */
- if (memory_operand (x, VOIDmode))
+
+ It can also happen that a REG_EQUIV note contains a
+ readonly memory location. If the destination pseudo
+ is set from some other value (typically a different
+ pseudo), and the destination pseudo does not get a
+ hard reg, then reload will replace the destination
+ pseudo with its equivalent memory location. This
+ is horribly bad as it creates a store to a readonly
+ memory location and a runtime segfault. To avoid
+ this problem we reject readonly memory locations
+ for equivalences. This is overly conservative as
+ we could find all sets of the destination pseudo
+ and remove them as they should be redundant. */
+ if (memory_operand (x, VOIDmode) && ! MEM_READONLY_P (x))
{
/* Always unshare the equivalence, so we can
substitute into this insn without touching the
if (starting_frame_size != get_frame_size ())
something_changed = 1;
+ /* Even if the frame size remained the same, we might still have
+ changed elimination offsets, e.g. if find_reloads called
+ force_const_mem requiring the back end to allocate a constant
+ pool base register that needs to be saved on the stack. */
+ else if (!verify_initial_elim_offsets ())
+ something_changed = 1;
+
{
HARD_REG_SET to_spill;
CLEAR_HARD_REG_SET (to_spill);
gcc_assert (old_frame_size == get_frame_size ());
- if (num_eliminable)
- verify_initial_elim_offsets ();
+ gcc_assert (verify_initial_elim_offsets ());
}
/* If we were able to eliminate the frame pointer, show that it is no
CLEAR_REGNO_REG_SET (bb->global_live_at_start,
HARD_FRAME_POINTER_REGNUM);
- /* Come here (with failure set nonzero) if we can't get enough spill regs
- and we decide not to abort about it. */
+ /* Come here (with failure set nonzero) if we can't get enough spill
+ regs. */
failed:
CLEAR_REG_SET (&spilled_pseudos);
replace_pseudos_in (& XEXP (PATTERN (insn), 0),
VOIDmode, PATTERN (insn));
+ /* Discard obvious no-ops, even without -O. This optimization
+ is fast and doesn't interfere with debugging. */
+ if (NONJUMP_INSN_P (insn)
+ && GET_CODE (PATTERN (insn)) == SET
+ && REG_P (SET_SRC (PATTERN (insn)))
+ && REG_P (SET_DEST (PATTERN (insn)))
+ && (REGNO (SET_SRC (PATTERN (insn)))
+ == REGNO (SET_DEST (PATTERN (insn)))))
+ {
+ delete_insn (insn);
+ continue;
+ }
+
pnote = ®_NOTES (insn);
while (*pnote != 0)
{
if (size > STACK_CHECK_MAX_FRAME_SIZE)
{
- warning ("frame size too large for reliable stack checking");
+ warning (0, "frame size too large for reliable stack checking");
if (! verbose_warned)
{
- warning ("try reducing the number of local variables");
+ warning (0, "try reducing the number of local variables");
verbose_warned = 1;
}
}
static void
order_regs_for_reload (struct insn_chain *chain)
{
- int i;
+ unsigned i;
HARD_REG_SET used_by_pseudos;
HARD_REG_SET used_by_pseudos2;
+ reg_set_iterator rsi;
COPY_HARD_REG_SET (bad_spill_regs, fixed_reg_set);
CLEAR_REG_SET (&pseudos_counted);
EXECUTE_IF_SET_IN_REG_SET
- (&chain->live_throughout, FIRST_PSEUDO_REGISTER, i,
- {
- count_pseudo (i);
- });
+ (&chain->live_throughout, FIRST_PSEUDO_REGISTER, i, rsi)
+ {
+ count_pseudo (i);
+ }
EXECUTE_IF_SET_IN_REG_SET
- (&chain->dead_or_set, FIRST_PSEUDO_REGISTER, i,
- {
- count_pseudo (i);
- });
+ (&chain->dead_or_set, FIRST_PSEUDO_REGISTER, i, rsi)
+ {
+ count_pseudo (i);
+ }
CLEAR_REG_SET (&pseudos_counted);
}
\f
int k;
HARD_REG_SET not_usable;
HARD_REG_SET used_by_other_reload;
+ reg_set_iterator rsi;
COPY_HARD_REG_SET (not_usable, bad_spill_regs);
IOR_HARD_REG_SET (not_usable, bad_spill_regs_global);
rl->regno = best_reg;
EXECUTE_IF_SET_IN_REG_SET
- (&chain->live_throughout, FIRST_PSEUDO_REGISTER, j,
- {
- count_spilled_pseudo (best_reg, rl->nregs, j);
- });
+ (&chain->live_throughout, FIRST_PSEUDO_REGISTER, j, rsi)
+ {
+ count_spilled_pseudo (best_reg, rl->nregs, j);
+ }
EXECUTE_IF_SET_IN_REG_SET
- (&chain->dead_or_set, FIRST_PSEUDO_REGISTER, j,
- {
- count_spilled_pseudo (best_reg, rl->nregs, j);
- });
+ (&chain->dead_or_set, FIRST_PSEUDO_REGISTER, j, rsi)
+ {
+ count_spilled_pseudo (best_reg, rl->nregs, j);
+ }
for (i = 0; i < rl->nregs; i++)
{
static void
spill_failure (rtx insn, enum reg_class class)
{
- static const char *const reg_class_names[] = REG_CLASS_NAMES;
if (asm_noperands (PATTERN (insn)) >= 0)
error_for_asm (insn, "can't find a register in class %qs while "
"reloading %<asm%>",
where something illegal happened during reload_as_needed that could
cause incorrect code to be generated if we did not check for it. */
-static void
+static bool
verify_initial_elim_offsets (void)
{
HOST_WIDE_INT t;
+ if (!num_eliminable)
+ return true;
+
#ifdef ELIMINABLE_REGS
- struct elim_table *ep;
+ {
+ struct elim_table *ep;
- for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++)
- {
- INITIAL_ELIMINATION_OFFSET (ep->from, ep->to, t);
- gcc_assert (t == ep->initial_offset);
- }
+ for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++)
+ {
+ INITIAL_ELIMINATION_OFFSET (ep->from, ep->to, t);
+ if (t != ep->initial_offset)
+ return false;
+ }
+ }
#else
INITIAL_FRAME_POINTER_OFFSET (t);
- gcc_assert (t == reg_eliminate[0].initial_offset);
+ if (t != reg_eliminate[0].initial_offset)
+ return false;
#endif
+
+ return true;
}
/* Reset all offsets on eliminable registers to their initial values. */
num_not_at_initial_offset = 0;
}
+/* Subroutine of set_initial_label_offsets called via for_each_eh_label. */
+
+static void
+set_initial_eh_label_offset (rtx label)
+{
+ set_label_offsets (label, NULL_RTX, 1);
+}
+
/* Initialize the known label offsets.
Set a known offset for each forced label to be at the initial offset
of each elimination. We do this because we assume that all
for (x = forced_labels; x; x = XEXP (x, 1))
if (XEXP (x, 0))
set_label_offsets (XEXP (x, 0), NULL_RTX, 1);
+
+ for_each_eh_label (set_initial_eh_label_offset);
}
/* Set all elimination offsets to the known values for the code label given
SET_REGNO_REG_SET (&spilled_pseudos, i);
}
-/* I'm getting weird preprocessor errors if I use IOR_HARD_REG_SET
- from within EXECUTE_IF_SET_IN_REG_SET. Hence this awkwardness. */
-
-static void
-ior_hard_reg_set (HARD_REG_SET *set1, HARD_REG_SET *set2)
-{
- IOR_HARD_REG_SET (*set1, *set2);
-}
-
/* After find_reload_regs has been run for all insn that need reloads,
and/or spill_hard_regs was called, this function is used to actually
spill pseudo registers and try to reallocate them. It also sets up the
{
struct insn_chain *chain;
int something_changed = 0;
- int i;
+ unsigned i;
+ reg_set_iterator rsi;
/* Build the spill_regs array for the function. */
/* If there are some registers still to eliminate and one of the spill regs
else
spill_reg_order[i] = -1;
- EXECUTE_IF_SET_IN_REG_SET
- (&spilled_pseudos, FIRST_PSEUDO_REGISTER, i,
- {
- /* Record the current hard register the pseudo is allocated to in
- pseudo_previous_regs so we avoid reallocating it to the same
- hard reg in a later pass. */
- gcc_assert (reg_renumber[i] >= 0);
-
- SET_HARD_REG_BIT (pseudo_previous_regs[i], reg_renumber[i]);
- /* Mark it as no longer having a hard register home. */
- reg_renumber[i] = -1;
- /* We will need to scan everything again. */
- something_changed = 1;
- });
+ EXECUTE_IF_SET_IN_REG_SET (&spilled_pseudos, FIRST_PSEUDO_REGISTER, i, rsi)
+ {
+ /* Record the current hard register the pseudo is allocated to in
+ pseudo_previous_regs so we avoid reallocating it to the same
+ hard reg in a later pass. */
+ gcc_assert (reg_renumber[i] >= 0);
+
+ SET_HARD_REG_BIT (pseudo_previous_regs[i], reg_renumber[i]);
+ /* Mark it as no longer having a hard register home. */
+ reg_renumber[i] = -1;
+ /* We will need to scan everything again. */
+ something_changed = 1;
+ }
/* Retry global register allocation if possible. */
if (global)
for (chain = insns_need_reload; chain; chain = chain->next_need_reload)
{
EXECUTE_IF_SET_IN_REG_SET
- (&chain->live_throughout, FIRST_PSEUDO_REGISTER, i,
- {
- ior_hard_reg_set (pseudo_forbidden_regs + i,
- &chain->used_spill_regs);
- });
+ (&chain->live_throughout, FIRST_PSEUDO_REGISTER, i, rsi)
+ {
+ IOR_HARD_REG_SET (pseudo_forbidden_regs[i],
+ chain->used_spill_regs);
+ }
EXECUTE_IF_SET_IN_REG_SET
- (&chain->dead_or_set, FIRST_PSEUDO_REGISTER, i,
- {
- ior_hard_reg_set (pseudo_forbidden_regs + i,
- &chain->used_spill_regs);
- });
+ (&chain->dead_or_set, FIRST_PSEUDO_REGISTER, i, rsi)
+ {
+ IOR_HARD_REG_SET (pseudo_forbidden_regs[i],
+ chain->used_spill_regs);
+ }
}
/* Retry allocating the spilled pseudos. For each reg, merge the
and call retry_global_alloc.
We change spill_pseudos here to only contain pseudos that did not
get a new hard register. */
- for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
+ for (i = FIRST_PSEUDO_REGISTER; i < (unsigned)max_regno; i++)
if (reg_old_renumber[i] != reg_renumber[i])
{
HARD_REG_SET forbidden;
}
/* Let alter_reg modify the reg rtx's for the modified pseudos. */
- for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
+ for (i = FIRST_PSEUDO_REGISTER; i < (unsigned)max_regno; i++)
{
int regno = reg_renumber[i];
if (reg_old_renumber[i] == regno)
unsigned int nr;
/* note_stores does give us subregs of hard regs,
- subreg_regno_offset will abort if it is not a hard reg. */
+ subreg_regno_offset requires a hard reg. */
while (GET_CODE (x) == SUBREG)
{
/* We ignore the subreg offset when calculating the regno,
This function uses the same algorithm as reload_reg_free_p above. */
-int
+static int
reloads_conflict (int r1, int r2)
{
enum reload_type r1_type = rld[r1].when_needed;
\f
/* Indexed by reload number, 1 if incoming value
inherited from previous insns. */
-char reload_inherited[MAX_RELOADS];
+static char reload_inherited[MAX_RELOADS];
/* For an inherited reload, this is the insn the reload was inherited from,
if we know it. Otherwise, this is 0. */
-rtx reload_inheritance_insn[MAX_RELOADS];
+static rtx reload_inheritance_insn[MAX_RELOADS];
/* If nonzero, this is a place to get the value of the reload,
rather than using reload_in. */
-rtx reload_override_in[MAX_RELOADS];
+static rtx reload_override_in[MAX_RELOADS];
/* For each reload, the hard register number of the register used,
or -1 if we did not need a register for this reload. */
-int reload_spill_index[MAX_RELOADS];
+static int reload_spill_index[MAX_RELOADS];
/* Subroutine of free_for_value_p, used to check a single register.
START_REGNO is the starting regno of the full reload register
}
/* Return nonzero if the rtx X is invariant over the current function. */
-/* ??? Actually, the places where we use this expect exactly what
- * is tested here, and not everything that is function invariant. In
- * particular, the frame pointer and arg pointer are special cased;
- * pic_offset_table_rtx is not, and this will cause aborts when we
- * go to spill these things to memory. */
+/* ??? Actually, the places where we use this expect exactly what is
+ tested here, and not everything that is function invariant. In
+ particular, the frame pointer and arg pointer are special cased;
+ pic_offset_table_rtx is not, and we must not spill these things to
+ memory. */
-static int
+int
function_invariant_p (rtx x)
{
if (CONSTANT_P (x))
need_mode = mode;
else
need_mode
- = smallest_mode_for_size (GET_MODE_SIZE (mode) + byte,
+ = smallest_mode_for_size (GET_MODE_BITSIZE (mode)
+ + byte * BITS_PER_UNIT,
GET_MODE_CLASS (mode));
- if (
-#ifdef CANNOT_CHANGE_MODE_CLASS
- (!REG_CANNOT_CHANGE_MODE_P (i, GET_MODE (last_reg),
- need_mode)
- &&
-#endif
- (GET_MODE_SIZE (GET_MODE (last_reg))
+ if ((GET_MODE_SIZE (GET_MODE (last_reg))
>= GET_MODE_SIZE (need_mode))
#ifdef CANNOT_CHANGE_MODE_CLASS
- )
+ /* Verify that the register in "i" can be obtained
+ from LAST_REG. */
+ && !REG_CANNOT_CHANGE_MODE_P (REGNO (last_reg),
+ GET_MODE (last_reg),
+ mode)
#endif
&& reg_reloaded_contents[i] == regno
&& TEST_HARD_REG_BIT (reg_reloaded_valid, i)
gcc_assert (GET_CODE (equiv) == SUBREG);
regno = subreg_regno (equiv);
equiv = gen_rtx_REG (rld[r].mode, regno);
+ /* If we choose EQUIV as the reload register, but the
+ loop below decides to cancel the inheritance, we'll
+ end up reloading EQUIV in rld[r].mode, not the mode
+ it had originally. That isn't safe when EQUIV isn't
+ available as a spill register since its value might
+ still be live at this point. */
+ for (i = regno; i < regno + (int) rld[r].nregs; i++)
+ if (TEST_HARD_REG_BIT (reload_reg_unavailable, i))
+ equiv = 0;
}
}
|| rld[j].when_needed == RELOAD_FOR_INPADDR_ADDRESS)
? RELOAD_FOR_OTHER_ADDRESS : RELOAD_OTHER);
- /* Check to see if we accidentally converted two reloads
- that use the same reload register with different inputs
- to the same type. If so, the resulting code won't work,
- so abort. */
+ /* Check to see if we accidentally converted two
+ reloads that use the same reload register with
+ different inputs to the same type. If so, the
+ resulting code won't work. */
if (rld[j].reg_rtx)
for (k = 0; k < j; k++)
gcc_assert (rld[k].in == 0 || rld[k].reg_rtx == 0
|| !(set = single_set (insn))
|| rtx_equal_p (old, SET_DEST (set))
|| !reg_mentioned_p (old, SET_SRC (set))
- || !regno_clobbered_p (REGNO (old), insn, rl->mode, 0))
+ || !((REGNO (old) < FIRST_PSEUDO_REGISTER)
+ && regno_clobbered_p (REGNO (old), insn, rl->mode, 0)))
gen_reload (old, reloadreg, rl->opnum,
rl->when_needed);
}
actually no need to store the old value in it. */
if (optimize
+ /* Only attempt this for input reloads; for RELOAD_OTHER we miss
+ that there may be multiple uses of the previous output reload.
+ Restricting to RELOAD_FOR_INPUT is mostly paranoia. */
+ && rl->when_needed == RELOAD_FOR_INPUT
&& (reload_inherited[j] || reload_override_in[j])
&& rl->reg_rtx
&& REG_P (rl->reg_rtx)
Returns first insn emitted. */
-rtx
+static rtx
gen_reload (rtx out, rtx in, int opnum, enum reload_type type)
{
rtx last = get_last_insn ();
/* If the pseudo-reg we are reloading is no longer referenced
anywhere between the store into it and here,
- and no jumps or labels intervene, then the value can get
- here through the reload reg alone.
+ and we're within the same basic block, then the value can only
+ pass through the reload reg and end up here.
Otherwise, give up--return. */
for (i1 = NEXT_INSN (output_reload_insn);
i1 != insn; i1 = NEXT_INSN (i1))
{
- if (LABEL_P (i1) || JUMP_P (i1))
+ if (NOTE_INSN_BASIC_BLOCK_P (i1))
return;
if ((NONJUMP_INSN_P (i1) || CALL_P (i1))
&& reg_mentioned_p (reg, PATTERN (i1)))
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