static struct table_elt *table[HASH_SIZE];
+/* Number of elements in the hash table. */
+
+static unsigned int table_size;
+
/* Chain of `struct table_elt's made so far for this function
but currently removed from the table. */
}
}
+ table_size = 0;
+
#ifdef HAVE_cc0
prev_insn = 0;
prev_insn_cc0 = 0;
/* Now add it to the free element chain. */
elt->next_same_hash = free_element_chain;
free_element_chain = elt;
+
+ table_size--;
}
/* Look up X in the hash table and return its table element,
}
}
+ table_size++;
+
return elt;
}
\f
/* Note that invalidate can remove elements
after P in the current hash chain. */
if (REG_P (p->exp))
- invalidate (p->exp, p->mode);
+ invalidate (p->exp, VOIDmode);
else
remove_from_table (p, i);
}
validate_canon_reg (rtx *xloc, rtx insn)
{
rtx new = canon_reg (*xloc, insn);
- int insn_code;
/* If replacing pseudo with hard reg or vice versa, ensure the
insn remains valid. Likewise if the insn has MATCH_DUPs. */
- if (insn != 0 && new != 0
- && REG_P (new) && REG_P (*xloc)
- && (((REGNO (new) < FIRST_PSEUDO_REGISTER)
- != (REGNO (*xloc) < FIRST_PSEUDO_REGISTER))
- || GET_MODE (new) != GET_MODE (*xloc)
- || (insn_code = recog_memoized (insn)) < 0
- || insn_data[insn_code].n_dups > 0))
+ if (insn != 0 && new != 0)
validate_change (insn, xloc, new, 1);
else
*xloc = new;
replace each register reference inside it
with the "oldest" equivalent register.
- If INSN is nonzero and we are replacing a pseudo with a hard register
- or vice versa, validate_change is used to ensure that INSN remains valid
+ If INSN is nonzero validate_change is used to ensure that INSN remains valid
after we make our substitution. The calls are made with IN_GROUP nonzero
so apply_change_group must be called upon the outermost return from this
function (unless INSN is zero). The result of apply_change_group can
return x;
}
-/* Fold MEM. */
+/* Fold MEM. Not to be called directly, see fold_rtx_mem instead. */
static rtx
-fold_rtx_mem (rtx x, rtx insn)
+fold_rtx_mem_1 (rtx x, rtx insn)
{
enum machine_mode mode = GET_MODE (x);
rtx new;
}
}
+/* Fold MEM. */
+
+static rtx
+fold_rtx_mem (rtx x, rtx insn)
+{
+ /* To avoid infinite oscillations between fold_rtx and fold_rtx_mem,
+ refuse to allow recursion of the latter past n levels. This can
+ happen because fold_rtx_mem will try to fold the address of the
+ memory reference it is passed, i.e. conceptually throwing away
+ the MEM and reinjecting the bare address into fold_rtx. As a
+ result, patterns like
+
+ set (reg1)
+ (plus (reg)
+ (mem (plus (reg2) (const_int))))
+
+ set (reg2)
+ (plus (reg)
+ (mem (plus (reg1) (const_int))))
+
+ will defeat any "first-order" short-circuit put in either
+ function to prevent these infinite oscillations.
+
+ The heuristics for determining n is as follows: since each time
+ it is invoked fold_rtx_mem throws away a MEM, and since MEMs
+ are generically not nested, we assume that each invocation of
+ fold_rtx_mem corresponds to a new "top-level" operand, i.e.
+ the source or the destination of a SET. So fold_rtx_mem is
+ bound to stop or cycle before n recursions, n being the number
+ of expressions recorded in the hash table. We also leave some
+ play to account for the initial steps. */
+
+ static unsigned int depth;
+ rtx ret;
+
+ if (depth > 3 + table_size)
+ return x;
+
+ depth++;
+ ret = fold_rtx_mem_1 (x, insn);
+ depth--;
+
+ return ret;
+}
+
/* If X is a nontrivial arithmetic operation on an argument
for which a constant value can be determined, return
the result of operating on that value, as a constant.
{
int is_shift
= (code == ASHIFT || code == ASHIFTRT || code == LSHIFTRT);
- rtx y = lookup_as_function (folded_arg0, code);
- rtx inner_const;
+ rtx y, inner_const, new_const;
enum rtx_code associate_code;
- rtx new_const;
-
- if (y == 0
- || 0 == (inner_const
- = equiv_constant (fold_rtx (XEXP (y, 1), 0)))
- || GET_CODE (inner_const) != CONST_INT
- /* If we have compiled a statement like
- "if (x == (x & mask1))", and now are looking at
- "x & mask2", we will have a case where the first operand
- of Y is the same as our first operand. Unless we detect
- this case, an infinite loop will result. */
- || XEXP (y, 0) == folded_arg0)
+
+ if (is_shift
+ && (INTVAL (const_arg1) >= GET_MODE_BITSIZE (mode)
+ || INTVAL (const_arg1) < 0))
+ {
+ if (SHIFT_COUNT_TRUNCATED)
+ const_arg1 = GEN_INT (INTVAL (const_arg1)
+ & (GET_MODE_BITSIZE (mode) - 1));
+ else
+ break;
+ }
+
+ y = lookup_as_function (folded_arg0, code);
+ if (y == 0)
+ break;
+
+ /* If we have compiled a statement like
+ "if (x == (x & mask1))", and now are looking at
+ "x & mask2", we will have a case where the first operand
+ of Y is the same as our first operand. Unless we detect
+ this case, an infinite loop will result. */
+ if (XEXP (y, 0) == folded_arg0)
+ break;
+
+ inner_const = equiv_constant (fold_rtx (XEXP (y, 1), 0));
+ if (!inner_const || GET_CODE (inner_const) != CONST_INT)
break;
/* Don't associate these operations if they are a PLUS with the
&& exact_log2 (- INTVAL (const_arg1)) >= 0)))
break;
+ if (is_shift
+ && (INTVAL (inner_const) >= GET_MODE_BITSIZE (mode)
+ || INTVAL (inner_const) < 0))
+ {
+ if (SHIFT_COUNT_TRUNCATED)
+ inner_const = GEN_INT (INTVAL (inner_const)
+ & (GET_MODE_BITSIZE (mode) - 1));
+ else
+ break;
+ }
+
/* Compute the code used to compose the constants. For example,
A-C1-C2 is A-(C1 + C2), so if CODE == MINUS, we want PLUS. */
shift on a machine that does a sign-extend as a pair
of shifts. */
- if (is_shift && GET_CODE (new_const) == CONST_INT
+ if (is_shift
+ && GET_CODE (new_const) == CONST_INT
&& INTVAL (new_const) >= GET_MODE_BITSIZE (mode))
{
/* As an exception, we can turn an ASHIFTRT of this
form into a shift of the number of bits - 1. */
if (code == ASHIFTRT)
new_const = GEN_INT (GET_MODE_BITSIZE (mode) - 1);
+ else if (!side_effects_p (XEXP (y, 0)))
+ return CONST0_RTX (mode);
else
break;
}
unsigned src_const_hash;
/* Table entry for constant equivalent for SET_SRC, if any. */
struct table_elt *src_const_elt;
+ /* Table entry for the destination address. */
+ struct table_elt *dest_addr_elt;
};
static void
rtx dest = SET_DEST (sets[i].rtl);
rtx src = SET_SRC (sets[i].rtl);
rtx new = canon_reg (src, insn);
- int insn_code;
sets[i].orig_src = src;
- if ((REG_P (new) && REG_P (src)
- && ((REGNO (new) < FIRST_PSEUDO_REGISTER)
- != (REGNO (src) < FIRST_PSEUDO_REGISTER)))
- || (insn_code = recog_memoized (insn)) < 0
- || insn_data[insn_code].n_dups > 0)
- validate_change (insn, &SET_SRC (sets[i].rtl), new, 1);
- else
- SET_SRC (sets[i].rtl) = new;
+ validate_change (insn, &SET_SRC (sets[i].rtl), new, 1);
if (GET_CODE (dest) == ZERO_EXTRACT)
{
rtx addr = XEXP (dest, 0);
if (GET_RTX_CLASS (GET_CODE (addr)) == RTX_AUTOINC
&& XEXP (addr, 0) == stack_pointer_rtx)
- invalidate (stack_pointer_rtx, Pmode);
+ invalidate (stack_pointer_rtx, VOIDmode);
#endif
dest = fold_rtx (dest, insn);
}
so that the destination goes into that class. */
sets[i].src_elt = src_eqv_elt;
+ /* Record destination addresses in the hash table. This allows us to
+ check if they are invalidated by other sets. */
+ for (i = 0; i < n_sets; i++)
+ {
+ if (sets[i].rtl)
+ {
+ rtx x = sets[i].inner_dest;
+ struct table_elt *elt;
+ enum machine_mode mode;
+ unsigned hash;
+
+ if (MEM_P (x))
+ {
+ x = XEXP (x, 0);
+ mode = GET_MODE (x);
+ hash = HASH (x, mode);
+ elt = lookup (x, hash, mode);
+ if (!elt)
+ {
+ if (insert_regs (x, NULL, 0))
+ {
+ rehash_using_reg (x);
+ hash = HASH (x, mode);
+ }
+ elt = insert (x, NULL, hash, mode);
+ }
+
+ sets[i].dest_addr_elt = elt;
+ }
+ else
+ sets[i].dest_addr_elt = NULL;
+ }
+ }
+
invalidate_from_clobbers (x);
/* Some registers are invalidated by subroutine calls. Memory is
}
/* We may have just removed some of the src_elt's from the hash table.
- So replace each one with the current head of the same class. */
+ So replace each one with the current head of the same class.
+ Also check if destination addresses have been removed. */
for (i = 0; i < n_sets; i++)
if (sets[i].rtl)
{
- if (sets[i].src_elt && sets[i].src_elt->first_same_value == 0)
+ if (sets[i].dest_addr_elt
+ && sets[i].dest_addr_elt->first_same_value == 0)
+ {
+ /* The elt was removed, which means this destination is not
+ valid after this instruction. */
+ sets[i].rtl = NULL_RTX;
+ }
+ else if (sets[i].src_elt && sets[i].src_elt->first_same_value == 0)
/* If elt was removed, find current head of same class,
or 0 if nothing remains of that class. */
{
{
for (q = PREV_INSN (JUMP_LABEL (p)); q; q = PREV_INSN (q))
if ((!NOTE_P (q)
- || NOTE_LINE_NUMBER (q) == NOTE_INSN_LOOP_END
|| (PREV_INSN (q) && CALL_P (PREV_INSN (q))
&& find_reg_note (PREV_INSN (q), REG_SETJMP, NULL)))
&& (!LABEL_P (q) || LABEL_NUSES (q) != 0))
delete_dead_jumptables ();
if (tem || optimize > 1)
- cleanup_cfg (CLEANUP_EXPENSIVE | CLEANUP_PRE_LOOP);
+ cleanup_cfg (CLEANUP_EXPENSIVE);
return 0;
}
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