static bool cselib_record_memory;
static bool cselib_preserve_constants;
+static bool cselib_any_perm_equivs;
static int entry_and_rtx_equal_p (const void *, const void *);
static hashval_t get_value_hash (const void *);
static struct elt_list *new_elt_list (struct elt_list *, cselib_val *);
static inline void
promote_debug_loc (struct elt_loc_list *l)
{
- if (l->setting_insn && DEBUG_INSN_P (l->setting_insn)
+ if (l && l->setting_insn && DEBUG_INSN_P (l->setting_insn)
&& (!cselib_current_insn || !DEBUG_INSN_P (cselib_current_insn)))
{
n_debug_values--;
cselib_reset_table (1);
}
-/* Remove from hash table all VALUEs except constants
- and function invariants. */
+/* Return TRUE if V is a constant, a function invariant or a VALUE
+ equivalence; FALSE otherwise. */
-static int
-preserve_only_constants (void **x, void *info ATTRIBUTE_UNUSED)
+static bool
+invariant_or_equiv_p (cselib_val *v)
{
- cselib_val *v = (cselib_val *)*x;
struct elt_loc_list *l;
+ if (v == cfa_base_preserved_val)
+ return true;
+
+ /* Keep VALUE equivalences around. */
+ for (l = v->locs; l; l = l->next)
+ if (GET_CODE (l->loc) == VALUE)
+ return true;
+
if (v->locs != NULL
&& v->locs->next == NULL)
{
if (CONSTANT_P (v->locs->loc)
&& (GET_CODE (v->locs->loc) != CONST
|| !references_value_p (v->locs->loc, 0)))
- return 1;
+ return true;
/* Although a debug expr may be bound to different expressions,
we can preserve it as if it was constant, to get unification
and proper merging within var-tracking. */
|| GET_CODE (v->locs->loc) == DEBUG_IMPLICIT_PTR
|| GET_CODE (v->locs->loc) == ENTRY_VALUE
|| GET_CODE (v->locs->loc) == DEBUG_PARAMETER_REF)
- return 1;
- if (cfa_base_preserved_val)
- {
- if (v == cfa_base_preserved_val)
- return 1;
- if (GET_CODE (v->locs->loc) == PLUS
- && CONST_INT_P (XEXP (v->locs->loc, 1))
- && XEXP (v->locs->loc, 0) == cfa_base_preserved_val->val_rtx)
- return 1;
- }
+ return true;
+
+ /* (plus (value V) (const_int C)) is invariant iff V is invariant. */
+ if (GET_CODE (v->locs->loc) == PLUS
+ && CONST_INT_P (XEXP (v->locs->loc, 1))
+ && GET_CODE (XEXP (v->locs->loc, 0)) == VALUE
+ && invariant_or_equiv_p (CSELIB_VAL_PTR (XEXP (v->locs->loc, 0))))
+ return true;
}
- /* Keep VALUE equivalences around. */
- for (l = v->locs; l; l = l->next)
- if (GET_CODE (l->loc) == VALUE)
- return 1;
+ return false;
+}
+
+/* Remove from hash table all VALUEs except constants, function
+ invariants and VALUE equivalences. */
+
+static int
+preserve_constants_and_equivs (void **x, void *info ATTRIBUTE_UNUSED)
+{
+ cselib_val *v = (cselib_val *)*x;
- htab_clear_slot (cselib_hash_table, x);
+ if (!invariant_or_equiv_p (v))
+ htab_clear_slot (cselib_hash_table, x);
return 1;
}
}
if (cselib_preserve_constants)
- htab_traverse (cselib_hash_table, preserve_only_constants, NULL);
+ htab_traverse (cselib_hash_table, preserve_constants_and_equivs, NULL);
else
- htab_empty (cselib_hash_table);
+ {
+ htab_empty (cselib_hash_table);
+ gcc_checking_assert (!cselib_any_perm_equivs);
+ }
n_useless_values = 0;
n_useless_debug_values = 0;
unsigned int regno = UINT_MAX;
struct elt_loc_list *p_in = p;
- for (; p; p = p -> next)
+ for (; p; p = p->next)
{
+ /* Return these right away to avoid returning stack pointer based
+ expressions for frame pointer and vice versa, which is something
+ that would confuse DSE. See the comment in cselib_expand_value_rtx_1
+ for more details. */
+ if (REG_P (p->loc)
+ && (REGNO (p->loc) == STACK_POINTER_REGNUM
+ || REGNO (p->loc) == FRAME_POINTER_REGNUM
+ || REGNO (p->loc) == HARD_FRAME_POINTER_REGNUM
+ || REGNO (p->loc) == cfa_base_preserved_regno))
+ return p->loc;
/* Avoid infinite recursion trying to expand a reg into a
the same reg. */
if ((REG_P (p->loc))
return copy;
}
+/* Wrapper for cselib_subst_to_values, that indicates X is in INSN. */
+
+rtx
+cselib_subst_to_values_from_insn (rtx x, enum machine_mode memmode, rtx insn)
+{
+ rtx ret;
+ gcc_assert (!cselib_current_insn);
+ cselib_current_insn = insn;
+ ret = cselib_subst_to_values (x, memmode);
+ cselib_current_insn = NULL;
+ return ret;
+}
+
/* Look up the rtl expression X in our tables and return the value it
has. If CREATE is zero, we return NULL if we don't know the value.
Otherwise, we create a new one if possible, using mode MODE if X
}
}
\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
-cselib_rtx_varies_p (const_rtx x ATTRIBUTE_UNUSED, bool from_alias ATTRIBUTE_UNUSED)
-{
- /* We actually don't need to verify very hard. This is because
- if X has actually changed, we invalidate the memory anyway,
- so assume that all common memory addresses are
- invariant. */
- return 0;
-}
-
/* Invalidate any locations in the table which are changed because of a
store to MEM_RTX. If this is called because of a non-const call
instruction, MEM_RTX is (mem:BLK const0_rtx). */
continue;
}
if (num_mems < PARAM_VALUE (PARAM_MAX_CSELIB_MEMORY_LOCATIONS)
- && ! canon_true_dependence (mem_rtx, GET_MODE (mem_rtx), mem_addr,
- x, NULL_RTX, cselib_rtx_varies_p))
+ && ! canon_true_dependence (mem_rtx, GET_MODE (mem_rtx),
+ mem_addr, x, NULL_RTX))
{
has_mem = true;
num_mems++;
if (nelt != elt)
{
+ cselib_any_perm_equivs = true;
+
if (!PRESERVED_VALUE_P (nelt->val_rtx))
cselib_preserve_value (nelt);
cselib_current_insn = save_cselib_current_insn;
}
+/* Return TRUE if any permanent equivalences have been recorded since
+ the table was last initialized. */
+bool
+cselib_have_permanent_equivalences (void)
+{
+ return cselib_any_perm_equivs;
+}
+
/* There is no good way to determine how many elements there can be
in a PARALLEL. Since it's fairly cheap, use a really large number. */
#define MAX_SETS (FIRST_PSEUDO_REGISTER * 2)
value_pool = create_alloc_pool ("value", RTX_CODE_SIZE (VALUE), 100);
cselib_record_memory = record_what & CSELIB_RECORD_MEMORY;
cselib_preserve_constants = record_what & CSELIB_PRESERVE_CONSTANTS;
+ cselib_any_perm_equivs = false;
/* (mem:BLK (scratch)) is a special mechanism to conflict with everything,
see canon_true_dependence. This is only created once. */
{
cselib_discard_hook = NULL;
cselib_preserve_constants = false;
+ cselib_any_perm_equivs = false;
cfa_base_preserved_val = NULL;
cfa_base_preserved_regno = INVALID_REGNUM;
free_alloc_pool (elt_list_pool);
fputs (" locs:", out);
do
{
- fprintf (out, "\n from insn %i ",
- INSN_UID (l->setting_insn));
+ if (l->setting_insn)
+ fprintf (out, "\n from insn %i ",
+ INSN_UID (l->setting_insn));
+ else
+ fprintf (out, "\n ");
print_inline_rtx (out, l->loc, 4);
}
while ((l = l->next));
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