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/* Common subexpression elimination for GNU compiler.
Copyright (C) 1987, 88, 89, 92-6, 1997 Free Software Foundation, Inc.
This file is part of GNU CC.
GNU CC 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 2, or (at your option)
any later version.
GNU CC 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 GNU CC; see the file COPYING. If not, write to
the Free Software Foundation, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include "config.h"
/* Must precede rtl.h for FFS. */
#include <stdio.h>
#include "rtl.h"
#include "regs.h"
#include "hard-reg-set.h"
#include "flags.h"
#include "real.h"
#include "insn-config.h"
#include "recog.h"
#include <setjmp.h>
/* The basic idea of common subexpression elimination is to go
through the code, keeping a record of expressions that would
have the same value at the current scan point, and replacing
expressions encountered with the cheapest equivalent expression.
It is too complicated to keep track of the different possibilities
when control paths merge; so, at each label, we forget all that is
known and start fresh. This can be described as processing each
basic block separately. Note, however, that these are not quite
the same as the basic blocks found by a later pass and used for
data flow analysis and register packing. We do not need to start fresh
after a conditional jump instruction if there is no label there.
We use two data structures to record the equivalent expressions:
a hash table for most expressions, and several vectors together
with "quantity numbers" to record equivalent (pseudo) registers.
The use of the special data structure for registers is desirable
because it is faster. It is possible because registers references
contain a fairly small number, the register number, taken from
a contiguously allocated series, and two register references are
identical if they have the same number. General expressions
do not have any such thing, so the only way to retrieve the
information recorded on an expression other than a register
is to keep it in a hash table.
Registers and "quantity numbers":
At the start of each basic block, all of the (hardware and pseudo)
registers used in the function are given distinct quantity
numbers to indicate their contents. During scan, when the code
copies one register into another, we copy the quantity number.
When a register is loaded in any other way, we allocate a new
quantity number to describe the value generated by this operation.
`reg_qty' records what quantity a register is currently thought
of as containing.
All real quantity numbers are greater than or equal to `max_reg'.
If register N has not been assigned a quantity, reg_qty[N] will equal N.
Quantity numbers below `max_reg' do not exist and none of the `qty_...'
variables should be referenced with an index below `max_reg'.
We also maintain a bidirectional chain of registers for each
quantity number. `qty_first_reg', `qty_last_reg',
`reg_next_eqv' and `reg_prev_eqv' hold these chains.
The first register in a chain is the one whose lifespan is least local.
Among equals, it is the one that was seen first.
We replace any equivalent register with that one.
If two registers have the same quantity number, it must be true that
REG expressions with `qty_mode' must be in the hash table for both
registers and must be in the same class.
The converse is not true. Since hard registers may be referenced in
any mode, two REG expressions might be equivalent in the hash table
but not have the same quantity number if the quantity number of one
of the registers is not the same mode as those expressions.
Constants and quantity numbers
When a quantity has a known constant value, that value is stored
in the appropriate element of qty_const. This is in addition to
putting the constant in the hash table as is usual for non-regs.
Whether a reg or a constant is preferred is determined by the configuration
macro CONST_COSTS and will often depend on the constant value. In any
event, expressions containing constants can be simplified, by fold_rtx.
When a quantity has a known nearly constant value (such as an address
of a stack slot), that value is stored in the appropriate element
of qty_const.
Integer constants don't have a machine mode. However, cse
determines the intended machine mode from the destination
of the instruction that moves the constant. The machine mode
is recorded in the hash table along with the actual RTL
constant expression so that different modes are kept separate.
Other expressions:
To record known equivalences among expressions in general
we use a hash table called `table'. It has a fixed number of buckets
that contain chains of `struct table_elt' elements for expressions.
These chains connect the elements whose expressions have the same
hash codes.
Other chains through the same elements connect the elements which
currently have equivalent values.
Register references in an expression are canonicalized before hashing
the expression. This is done using `reg_qty' and `qty_first_reg'.
The hash code of a register reference is computed using the quantity
number, not the register number.
When the value of an expression changes, it is necessary to remove from the
hash table not just that expression but all expressions whose values
could be different as a result.
1. If the value changing is in memory, except in special cases
ANYTHING referring to memory could be changed. That is because
nobody knows where a pointer does not point.
The function `invalidate_memory' removes what is necessary.
The special cases are when the address is constant or is
a constant plus a fixed register such as the frame pointer
or a static chain pointer. When such addresses are stored in,
we can tell exactly which other such addresses must be invalidated
due to overlap. `invalidate' does this.
All expressions that refer to non-constant
memory addresses are also invalidated. `invalidate_memory' does this.
2. If the value changing is a register, all expressions
containing references to that register, and only those,
must be removed.
Because searching the entire hash table for expressions that contain
a register is very slow, we try to figure out when it isn't necessary.
Precisely, this is necessary only when expressions have been
entered in the hash table using this register, and then the value has
changed, and then another expression wants to be added to refer to
the register's new value. This sequence of circumstances is rare
within any one basic block.
The vectors `reg_tick' and `reg_in_table' are used to detect this case.
reg_tick[i] is incremented whenever a value is stored in register i.
reg_in_table[i] holds -1 if no references to register i have been
entered in the table; otherwise, it contains the value reg_tick[i] had
when the references were entered. If we want to enter a reference
and reg_in_table[i] != reg_tick[i], we must scan and remove old references.
Until we want to enter a new entry, the mere fact that the two vectors
don't match makes the entries be ignored if anyone tries to match them.
Registers themselves are entered in the hash table as well as in
the equivalent-register chains. However, the vectors `reg_tick'
and `reg_in_table' do not apply to expressions which are simple
register references. These expressions are removed from the table
immediately when they become invalid, and this can be done even if
we do not immediately search for all the expressions that refer to
the register.
A CLOBBER rtx in an instruction invalidates its operand for further
reuse. A CLOBBER or SET rtx whose operand is a MEM:BLK
invalidates everything that resides in memory.
Related expressions:
Constant expressions that differ only by an additive integer
are called related. When a constant expression is put in
the table, the related expression with no constant term
is also entered. These are made to point at each other
so that it is possible to find out if there exists any
register equivalent to an expression related to a given expression. */
/* One plus largest register number used in this function. */
static int max_reg;
/* Length of vectors indexed by quantity number.
We know in advance we will not need a quantity number this big. */
static int max_qty;
/* Next quantity number to be allocated.
This is 1 + the largest number needed so far. */
static int next_qty;
/* Indexed by quantity number, gives the first (or last) register
in the chain of registers that currently contain this quantity. */
static int *qty_first_reg;
static int *qty_last_reg;
/* Index by quantity number, gives the mode of the quantity. */
static enum machine_mode *qty_mode;
/* Indexed by quantity number, gives the rtx of the constant value of the
quantity, or zero if it does not have a known value.
A sum of the frame pointer (or arg pointer) plus a constant
can also be entered here. */
static rtx *qty_const;
/* Indexed by qty number, gives the insn that stored the constant value
recorded in `qty_const'. */
static rtx *qty_const_insn;
/* The next three variables are used to track when a comparison between a
quantity and some constant or register has been passed. In that case, we
know the results of the comparison in case we see it again. These variables
record a comparison that is known to be true. */
/* Indexed by qty number, gives the rtx code of a comparison with a known
result involving this quantity. If none, it is UNKNOWN. */
static enum rtx_code *qty_comparison_code;
/* Indexed by qty number, gives the constant being compared against in a
comparison of known result. If no such comparison, it is undefined.
If the comparison is not with a constant, it is zero. */
static rtx *qty_comparison_const;
/* Indexed by qty number, gives the quantity being compared against in a
comparison of known result. If no such comparison, if it undefined.
If the comparison is not with a register, it is -1. */
static int *qty_comparison_qty;
#ifdef HAVE_cc0
/* For machines that have a CC0, we do not record its value in the hash
table since its use is guaranteed to be the insn immediately following
its definition and any other insn is presumed to invalidate it.
Instead, we store below the value last assigned to CC0. If it should
happen to be a constant, it is stored in preference to the actual
assigned value. In case it is a constant, we store the mode in which
the constant should be interpreted. */
static rtx prev_insn_cc0;
static enum machine_mode prev_insn_cc0_mode;
#endif
/* Previous actual insn. 0 if at first insn of basic block. */
static rtx prev_insn;
/* Insn being scanned. */
static rtx this_insn;
/* Index by register number, gives the quantity number
of the register's current contents. */
static int *reg_qty;
/* Index by register number, gives the number of the next (or
previous) register in the chain of registers sharing the same
value.
Or -1 if this register is at the end of the chain.
If reg_qty[N] == N, reg_next_eqv[N] is undefined. */
static int *reg_next_eqv;
static int *reg_prev_eqv;
/* Index by register number, gives the number of times
that register has been altered in the current basic block. */
static int *reg_tick;
/* Index by register number, gives the reg_tick value at which
rtx's containing this register are valid in the hash table.
If this does not equal the current reg_tick value, such expressions
existing in the hash table are invalid.
If this is -1, no expressions containing this register have been
entered in the table. */
static int *reg_in_table;
/* A HARD_REG_SET containing all the hard registers for which there is
currently a REG expression in the hash table. Note the difference
from the above variables, which indicate if the REG is mentioned in some
expression in the table. */
static HARD_REG_SET hard_regs_in_table;
/* A HARD_REG_SET containing all the hard registers that are invalidated
by a CALL_INSN. */
static HARD_REG_SET regs_invalidated_by_call;
/* Two vectors of ints:
one containing max_reg -1's; the other max_reg + 500 (an approximation
for max_qty) elements where element i contains i.
These are used to initialize various other vectors fast. */
static int *all_minus_one;
static int *consec_ints;
/* CUID of insn that starts the basic block currently being cse-processed. */
static int cse_basic_block_start;
/* CUID of insn that ends the basic block currently being cse-processed. */
static int cse_basic_block_end;
/* Vector mapping INSN_UIDs to cuids.
The cuids are like uids but increase monotonically always.
We use them to see whether a reg is used outside a given basic block. */
static int *uid_cuid;
/* Highest UID in UID_CUID. */
static int max_uid;
/* Get the cuid of an insn. */
#define INSN_CUID(INSN) (uid_cuid[INSN_UID (INSN)])
/* Nonzero if cse has altered conditional jump insns
in such a way that jump optimization should be redone. */
static int cse_jumps_altered;
/* Nonzero if we put a LABEL_REF into the hash table. Since we may have put
it into an INSN without a REG_LABEL, we have to rerun jump after CSE
to put in the note. */
static int recorded_label_ref;
/* canon_hash stores 1 in do_not_record
if it notices a reference to CC0, PC, or some other volatile
subexpression. */
static int do_not_record;
#ifdef LOAD_EXTEND_OP
/* Scratch rtl used when looking for load-extended copy of a MEM. */
static rtx memory_extend_rtx;
#endif
/* canon_hash stores 1 in hash_arg_in_memory
if it notices a reference to memory within the expression being hashed. */
static int hash_arg_in_memory;
/* canon_hash stores 1 in hash_arg_in_struct
if it notices a reference to memory that's part of a structure. */
static int hash_arg_in_struct;
/* The hash table contains buckets which are chains of `struct table_elt's,
each recording one expression's information.
That expression is in the `exp' field.
Those elements with the same hash code are chained in both directions
through the `next_same_hash' and `prev_same_hash' fields.
Each set of expressions with equivalent values
are on a two-way chain through the `next_same_value'
and `prev_same_value' fields, and all point with
the `first_same_value' field at the first element in
that chain. The chain is in order of increasing cost.
Each element's cost value is in its `cost' field.
The `in_memory' field is nonzero for elements that
involve any reference to memory. These elements are removed
whenever a write is done to an unidentified location in memory.
To be safe, we assume that a memory address is unidentified unless
the address is either a symbol constant or a constant plus
the frame pointer or argument pointer.
The `in_struct' field is nonzero for elements that
involve any reference to memory inside a structure or array.
The `related_value' field is used to connect related expressions
(that differ by adding an integer).
The related expressions are chained in a circular fashion.
`related_value' is zero for expressions for which this
chain is not useful.
The `cost' field stores the cost of this element's expression.
The `is_const' flag is set if the element is a constant (including
a fixed address).
The `flag' field is used as a temporary during some search routines.
The `mode' field is usually the same as GET_MODE (`exp'), but
if `exp' is a CONST_INT and has no machine mode then the `mode'
field is the mode it was being used as. Each constant is
recorded separately for each mode it is used with. */
struct table_elt
{
rtx exp;
struct table_elt *next_same_hash;
struct table_elt *prev_same_hash;
struct table_elt *next_same_value;
struct table_elt *prev_same_value;
struct table_elt *first_same_value;
struct table_elt *related_value;
int cost;
enum machine_mode mode;
char in_memory;
char in_struct;
char is_const;
char flag;
};
/* We don't want a lot of buckets, because we rarely have very many
things stored in the hash table, and a lot of buckets slows
down a lot of loops that happen frequently. */
#define NBUCKETS 31
/* Compute hash code of X in mode M. Special-case case where X is a pseudo
register (hard registers may require `do_not_record' to be set). */
#define HASH(X, M) \
(GET_CODE (X) == REG && REGNO (X) >= FIRST_PSEUDO_REGISTER \
? (((unsigned) REG << 7) + (unsigned) reg_qty[REGNO (X)]) % NBUCKETS \
: canon_hash (X, M) % NBUCKETS)
/* Determine whether register number N is considered a fixed register for CSE.
It is desirable to replace other regs with fixed regs, to reduce need for
non-fixed hard regs.
A reg wins if it is either the frame pointer or designated as fixed,
but not if it is an overlapping register. */
#ifdef OVERLAPPING_REGNO_P
#define FIXED_REGNO_P(N) \
(((N) == FRAME_POINTER_REGNUM || (N) == HARD_FRAME_POINTER_REGNUM \
|| fixed_regs[N] || global_regs[N]) \
&& ! OVERLAPPING_REGNO_P ((N)))
#else
#define FIXED_REGNO_P(N) \
((N) == FRAME_POINTER_REGNUM || (N) == HARD_FRAME_POINTER_REGNUM \
|| fixed_regs[N] || global_regs[N])
#endif
/* Compute cost of X, as stored in the `cost' field of a table_elt. Fixed
hard registers and pointers into the frame are the cheapest with a cost
of 0. Next come pseudos with a cost of one and other hard registers with
a cost of 2. Aside from these special cases, call `rtx_cost'. */
#define CHEAP_REGNO(N) \
((N) == FRAME_POINTER_REGNUM || (N) == HARD_FRAME_POINTER_REGNUM \
|| (N) == STACK_POINTER_REGNUM || (N) == ARG_POINTER_REGNUM \
|| ((N) >= FIRST_VIRTUAL_REGISTER && (N) <= LAST_VIRTUAL_REGISTER) \
|| ((N) < FIRST_PSEUDO_REGISTER \
&& FIXED_REGNO_P (N) && REGNO_REG_CLASS (N) != NO_REGS))
/* A register is cheap if it is a user variable assigned to the register
or if its register number always corresponds to a cheap register. */
#define CHEAP_REG(N) \
((REG_USERVAR_P (N) && REGNO (N) < FIRST_PSEUDO_REGISTER) \
|| CHEAP_REGNO (REGNO (N)))
#define COST(X) \
(GET_CODE (X) == REG \
? (CHEAP_REG (X) ? 0 \
: REGNO (X) >= FIRST_PSEUDO_REGISTER ? 1 \
: 2) \
: notreg_cost(X))
/* Determine if the quantity number for register X represents a valid index
into the `qty_...' variables. */
#define REGNO_QTY_VALID_P(N) (reg_qty[N] != (N))
static struct table_elt *table[NBUCKETS];
/* Chain of `struct table_elt's made so far for this function
but currently removed from the table. */
static struct table_elt *free_element_chain;
/* Number of `struct table_elt' structures made so far for this function. */
static int n_elements_made;
/* Maximum value `n_elements_made' has had so far in this compilation
for functions previously processed. */
static int max_elements_made;
/* Surviving equivalence class when two equivalence classes are merged
by recording the effects of a jump in the last insn. Zero if the
last insn was not a conditional jump. */
static struct table_elt *last_jump_equiv_class;
/* Set to the cost of a constant pool reference if one was found for a
symbolic constant. If this was found, it means we should try to
convert constants into constant pool entries if they don't fit in
the insn. */
static int constant_pool_entries_cost;
/* Bits describing what kind of values in memory must be invalidated
for a particular instruction. If all three bits are zero,
no memory refs need to be invalidated. Each bit is more powerful
than the preceding ones, and if a bit is set then the preceding
bits are also set.
Here is how the bits are set:
Pushing onto the stack invalidates only the stack pointer,
writing at a fixed address invalidates only variable addresses,
writing in a structure element at variable address
invalidates all but scalar variables,
and writing in anything else at variable address invalidates everything. */
struct write_data
{
int sp : 1; /* Invalidate stack pointer. */
int var : 1; /* Invalidate variable addresses. */
int nonscalar : 1; /* Invalidate all but scalar variables. */
int all : 1; /* Invalidate all memory refs. */
};
/* Define maximum length of a branch path. */
#define PATHLENGTH 10
/* This data describes a block that will be processed by cse_basic_block. */
struct cse_basic_block_data {
/* Lowest CUID value of insns in block. */
int low_cuid;
/* Highest CUID value of insns in block. */
int high_cuid;
/* Total number of SETs in block. */
int nsets;
/* Last insn in the block. */
rtx last;
/* Size of current branch path, if any. */
int path_size;
/* Current branch path, indicating which branches will be taken. */
struct branch_path {
/* The branch insn. */
rtx branch;
/* Whether it should be taken or not. AROUND is the same as taken
except that it is used when the destination label is not preceded
by a BARRIER. */
enum taken {TAKEN, NOT_TAKEN, AROUND} status;
} path[PATHLENGTH];
};
/* Nonzero if X has the form (PLUS frame-pointer integer). We check for
virtual regs here because the simplify_*_operation routines are called
by integrate.c, which is called before virtual register instantiation. */
#define FIXED_BASE_PLUS_P(X) \
((X) == frame_pointer_rtx || (X) == hard_frame_pointer_rtx \
|| (X) == arg_pointer_rtx \
|| (X) == virtual_stack_vars_rtx \
|| (X) == virtual_incoming_args_rtx \
|| (GET_CODE (X) == PLUS && GET_CODE (XEXP (X, 1)) == CONST_INT \
&& (XEXP (X, 0) == frame_pointer_rtx \
|| XEXP (X, 0) == hard_frame_pointer_rtx \
|| XEXP (X, 0) == arg_pointer_rtx \
|| XEXP (X, 0) == virtual_stack_vars_rtx \
|| XEXP (X, 0) == virtual_incoming_args_rtx)))
/* Similar, but also allows reference to the stack pointer.
This used to include FIXED_BASE_PLUS_P, however, we can't assume that
arg_pointer_rtx by itself is nonzero, because on at least one machine,
the i960, the arg pointer is zero when it is unused. */
#define NONZERO_BASE_PLUS_P(X) \
((X) == frame_pointer_rtx || (X) == hard_frame_pointer_rtx \
|| (X) == virtual_stack_vars_rtx \
|| (X) == virtual_incoming_args_rtx \
|| (GET_CODE (X) == PLUS && GET_CODE (XEXP (X, 1)) == CONST_INT \
&& (XEXP (X, 0) == frame_pointer_rtx \
|| XEXP (X, 0) == hard_frame_pointer_rtx \
|| XEXP (X, 0) == arg_pointer_rtx \
|| XEXP (X, 0) == virtual_stack_vars_rtx \
|| XEXP (X, 0) == virtual_incoming_args_rtx)) \
|| (X) == stack_pointer_rtx \
|| (X) == virtual_stack_dynamic_rtx \
|| (X) == virtual_outgoing_args_rtx \
|| (GET_CODE (X) == PLUS && GET_CODE (XEXP (X, 1)) == CONST_INT \
&& (XEXP (X, 0) == stack_pointer_rtx \
|| XEXP (X, 0) == virtual_stack_dynamic_rtx \
|| XEXP (X, 0) == virtual_outgoing_args_rtx)))
static int notreg_cost PROTO((rtx));
static void new_basic_block PROTO((void));
static void make_new_qty PROTO((int));
static void make_regs_eqv PROTO((int, int));
static void delete_reg_equiv PROTO((int));
static int mention_regs PROTO((rtx));
static int insert_regs PROTO((rtx, struct table_elt *, int));
static void free_element PROTO((struct table_elt *));
static void remove_from_table PROTO((struct table_elt *, unsigned));
static struct table_elt *get_element PROTO((void));
static struct table_elt *lookup PROTO((rtx, unsigned, enum machine_mode)),
*lookup_for_remove PROTO((rtx, unsigned, enum machine_mode));
static rtx lookup_as_function PROTO((rtx, enum rtx_code));
static struct table_elt *insert PROTO((rtx, struct table_elt *, unsigned,
enum machine_mode));
static void merge_equiv_classes PROTO((struct table_elt *,
struct table_elt *));
static void invalidate PROTO((rtx, enum machine_mode));
static void remove_invalid_refs PROTO((int));
static void rehash_using_reg PROTO((rtx));
static void invalidate_memory PROTO((struct write_data *));
static void invalidate_for_call PROTO((void));
static rtx use_related_value PROTO((rtx, struct table_elt *));
static unsigned canon_hash PROTO((rtx, enum machine_mode));
static unsigned safe_hash PROTO((rtx, enum machine_mode));
static int exp_equiv_p PROTO((rtx, rtx, int, int));
static void set_nonvarying_address_components PROTO((rtx, int, rtx *,
HOST_WIDE_INT *,
HOST_WIDE_INT *));
static int refers_to_p PROTO((rtx, rtx));
static int refers_to_mem_p PROTO((rtx, rtx, HOST_WIDE_INT,
HOST_WIDE_INT));
static int cse_rtx_addr_varies_p PROTO((rtx));
static rtx canon_reg PROTO((rtx, rtx));
static void find_best_addr PROTO((rtx, rtx *));
static enum rtx_code find_comparison_args PROTO((enum rtx_code, rtx *, rtx *,
enum machine_mode *,
enum machine_mode *));
static rtx cse_gen_binary PROTO((enum rtx_code, enum machine_mode,
rtx, rtx));
static rtx simplify_plus_minus PROTO((enum rtx_code, enum machine_mode,
rtx, rtx));
static rtx fold_rtx PROTO((rtx, rtx));
static rtx equiv_constant PROTO((rtx));
static void record_jump_equiv PROTO((rtx, int));
static void record_jump_cond PROTO((enum rtx_code, enum machine_mode,
rtx, rtx, int));
static void cse_insn PROTO((rtx, int));
static void note_mem_written PROTO((rtx, struct write_data *));
static void invalidate_from_clobbers PROTO((struct write_data *, rtx));
static rtx cse_process_notes PROTO((rtx, rtx));
static void cse_around_loop PROTO((rtx));
static void invalidate_skipped_set PROTO((rtx, rtx));
static void invalidate_skipped_block PROTO((rtx));
static void cse_check_loop_start PROTO((rtx, rtx));
static void cse_set_around_loop PROTO((rtx, rtx, rtx));
static rtx cse_basic_block PROTO((rtx, rtx, struct branch_path *, int));
static void count_reg_usage PROTO((rtx, int *, rtx, int));
extern int rtx_equal_function_value_matters;
/* Return an estimate of the cost of computing rtx X.
One use is in cse, to decide which expression to keep in the hash table.
Another is in rtl generation, to pick the cheapest way to multiply.
Other uses like the latter are expected in the future. */
/* Internal function, to compute cost when X is not a register; called
from COST macro to keep it simple. */
static int
notreg_cost (x)
rtx x;
{
return ((GET_CODE (x) == SUBREG
&& GET_CODE (SUBREG_REG (x)) == REG
&& GET_MODE_CLASS (GET_MODE (x)) == MODE_INT
&& GET_MODE_CLASS (GET_MODE (SUBREG_REG (x))) == MODE_INT
&& (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)))))
? (CHEAP_REG (SUBREG_REG (x)) ? 0
: (REGNO (SUBREG_REG (x)) >= FIRST_PSEUDO_REGISTER ? 1
: 2))
: rtx_cost (x, SET) * 2);
}
/* Return the right cost to give to an operation
to make the cost of the corresponding register-to-register instruction
N times that of a fast register-to-register instruction. */
#define COSTS_N_INSNS(N) ((N) * 4 - 2)
int
rtx_cost (x, outer_code)
rtx x;
enum rtx_code outer_code;
{
register int i, j;
register enum rtx_code code;
register char *fmt;
register int total;
if (x == 0)
return 0;
/* Compute the default costs of certain things.
Note that RTX_COSTS can override the defaults. */
code = GET_CODE (x);
switch (code)
{
case MULT:
/* Count multiplication by 2**n as a shift,
because if we are considering it, we would output it as a shift. */
if (GET_CODE (XEXP (x, 1)) == CONST_INT
&& exact_log2 (INTVAL (XEXP (x, 1))) >= 0)
total = 2;
else
total = COSTS_N_INSNS (5);
break;
case DIV:
case UDIV:
case MOD:
case UMOD:
total = COSTS_N_INSNS (7);
break;
case USE:
/* Used in loop.c and combine.c as a marker. */
total = 0;
break;
case ASM_OPERANDS:
/* We don't want these to be used in substitutions because
we have no way of validating the resulting insn. So assign
anything containing an ASM_OPERANDS a very high cost. */
total = 1000;
break;
default:
total = 2;
}
switch (code)
{
case REG:
return ! CHEAP_REG (x);
case SUBREG:
/* If we can't tie these modes, make this expensive. The larger
the mode, the more expensive it is. */
if (! MODES_TIEABLE_P (GET_MODE (x), GET_MODE (SUBREG_REG (x))))
return COSTS_N_INSNS (2
+ GET_MODE_SIZE (GET_MODE (x)) / UNITS_PER_WORD);
return 2;
#ifdef RTX_COSTS
RTX_COSTS (x, code, outer_code);
#endif
CONST_COSTS (x, code, outer_code);
}
/* Sum the costs of the sub-rtx's, plus cost of this operation,
which is already in total. */
fmt = GET_RTX_FORMAT (code);
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
if (fmt[i] == 'e')
total += rtx_cost (XEXP (x, i), code);
else if (fmt[i] == 'E')
for (j = 0; j < XVECLEN (x, i); j++)
total += rtx_cost (XVECEXP (x, i, j), code);
return total;
}
/* Clear the hash table and initialize each register with its own quantity,
for a new basic block. */
static void
new_basic_block ()
{
register int i;
next_qty = max_reg;
bzero ((char *) reg_tick, max_reg * sizeof (int));
bcopy ((char *) all_minus_one, (char *) reg_in_table,
max_reg * sizeof (int));
bcopy ((char *) consec_ints, (char *) reg_qty, max_reg * sizeof (int));
CLEAR_HARD_REG_SET (hard_regs_in_table);
/* The per-quantity values used to be initialized here, but it is
much faster to initialize each as it is made in `make_new_qty'. */
for (i = 0; i < NBUCKETS; i++)
{
register struct table_elt *this, *next;
for (this = table[i]; this; this = next)
{
next = this->next_same_hash;
free_element (this);
}
}
bzero ((char *) table, sizeof table);
prev_insn = 0;
#ifdef HAVE_cc0
prev_insn_cc0 = 0;
#endif
}
/* Say that register REG contains a quantity not in any register before
and initialize that quantity. */
static void
make_new_qty (reg)
register int reg;
{
register int q;
if (next_qty >= max_qty)
abort ();
q = reg_qty[reg] = next_qty++;
qty_first_reg[q] = reg;
qty_last_reg[q] = reg;
qty_const[q] = qty_const_insn[q] = 0;
qty_comparison_code[q] = UNKNOWN;
reg_next_eqv[reg] = reg_prev_eqv[reg] = -1;
}
/* Make reg NEW equivalent to reg OLD.
OLD is not changing; NEW is. */
static void
make_regs_eqv (new, old)
register int new, old;
{
register int lastr, firstr;
register int q = reg_qty[old];
/* Nothing should become eqv until it has a "non-invalid" qty number. */
if (! REGNO_QTY_VALID_P (old))
abort ();
reg_qty[new] = q;
firstr = qty_first_reg[q];
lastr = qty_last_reg[q];
/* Prefer fixed hard registers to anything. Prefer pseudo regs to other
hard regs. Among pseudos, if NEW will live longer than any other reg
of the same qty, and that is beyond the current basic block,
make it the new canonical replacement for this qty. */
if (! (firstr < FIRST_PSEUDO_REGISTER && FIXED_REGNO_P (firstr))
/* Certain fixed registers might be of the class NO_REGS. This means
that not only can they not be allocated by the compiler, but
they cannot be used in substitutions or canonicalizations
either. */
&& (new >= FIRST_PSEUDO_REGISTER || REGNO_REG_CLASS (new) != NO_REGS)
&& ((new < FIRST_PSEUDO_REGISTER && FIXED_REGNO_P (new))
|| (new >= FIRST_PSEUDO_REGISTER
&& (firstr < FIRST_PSEUDO_REGISTER
|| ((uid_cuid[REGNO_LAST_UID (new)] > cse_basic_block_end
|| (uid_cuid[REGNO_FIRST_UID (new)]
< cse_basic_block_start))
&& (uid_cuid[REGNO_LAST_UID (new)]
> uid_cuid[REGNO_LAST_UID (firstr)]))))))
{
reg_prev_eqv[firstr] = new;
reg_next_eqv[new] = firstr;
reg_prev_eqv[new] = -1;
qty_first_reg[q] = new;
}
else
{
/* If NEW is a hard reg (known to be non-fixed), insert at end.
Otherwise, insert before any non-fixed hard regs that are at the
end. Registers of class NO_REGS cannot be used as an
equivalent for anything. */
while (lastr < FIRST_PSEUDO_REGISTER && reg_prev_eqv[lastr] >= 0
&& (REGNO_REG_CLASS (lastr) == NO_REGS || ! FIXED_REGNO_P (lastr))
&& new >= FIRST_PSEUDO_REGISTER)
lastr = reg_prev_eqv[lastr];
reg_next_eqv[new] = reg_next_eqv[lastr];
if (reg_next_eqv[lastr] >= 0)
reg_prev_eqv[reg_next_eqv[lastr]] = new;
else
qty_last_reg[q] = new;
reg_next_eqv[lastr] = new;
reg_prev_eqv[new] = lastr;
}
}
/* Remove REG from its equivalence class. */
static void
delete_reg_equiv (reg)
register int reg;
{
register int q = reg_qty[reg];
register int p, n;
/* If invalid, do nothing. */
if (q == reg)
return;
p = reg_prev_eqv[reg];
n = reg_next_eqv[reg];
if (n != -1)
reg_prev_eqv[n] = p;
else
qty_last_reg[q] = p;
if (p != -1)
reg_next_eqv[p] = n;
else
qty_first_reg[q] = n;
reg_qty[reg] = reg;
}
/* Remove any invalid expressions from the hash table
that refer to any of the registers contained in expression X.
Make sure that newly inserted references to those registers
as subexpressions will be considered valid.
mention_regs is not called when a register itself
is being stored in the table.
Return 1 if we have done something that may have changed the hash code
of X. */
static int
mention_regs (x)
rtx x;
{
register enum rtx_code code;
register int i, j;
register char *fmt;
register int changed = 0;
if (x == 0)
return 0;
code = GET_CODE (x);
if (code == REG)
{
register int regno = REGNO (x);
register int endregno
= regno + (regno >= FIRST_PSEUDO_REGISTER ? 1
: HARD_REGNO_NREGS (regno, GET_MODE (x)));
int i;
for (i = regno; i < endregno; i++)
{
if (reg_in_table[i] >= 0 && reg_in_table[i] != reg_tick[i])
remove_invalid_refs (i);
reg_in_table[i] = reg_tick[i];
}
return 0;
}
/* If X is a comparison or a COMPARE and either operand is a register
that does not have a quantity, give it one. This is so that a later
call to record_jump_equiv won't cause X to be assigned a different
hash code and not found in the table after that call.
It is not necessary to do this here, since rehash_using_reg can
fix up the table later, but doing this here eliminates the need to
call that expensive function in the most common case where the only
use of the register is in the comparison. */
if (code == COMPARE || GET_RTX_CLASS (code) == '<')
{
if (GET_CODE (XEXP (x, 0)) == REG
&& ! REGNO_QTY_VALID_P (REGNO (XEXP (x, 0))))
if (insert_regs (XEXP (x, 0), NULL_PTR, 0))
{
rehash_using_reg (XEXP (x, 0));
changed = 1;
}
if (GET_CODE (XEXP (x, 1)) == REG
&& ! REGNO_QTY_VALID_P (REGNO (XEXP (x, 1))))
if (insert_regs (XEXP (x, 1), NULL_PTR, 0))
{
rehash_using_reg (XEXP (x, 1));
changed = 1;
}
}
fmt = GET_RTX_FORMAT (code);
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
if (fmt[i] == 'e')
changed |= mention_regs (XEXP (x, i));
else if (fmt[i] == 'E')
for (j = 0; j < XVECLEN (x, i); j++)
changed |= mention_regs (XVECEXP (x, i, j));
return changed;
}
/* Update the register quantities for inserting X into the hash table
with a value equivalent to CLASSP.
(If the class does not contain a REG, it is irrelevant.)
If MODIFIED is nonzero, X is a destination; it is being modified.
Note that delete_reg_equiv should be called on a register
before insert_regs is done on that register with MODIFIED != 0.
Nonzero value means that elements of reg_qty have changed
so X's hash code may be different. */
static int
insert_regs (x, classp, modified)
rtx x;
struct table_elt *classp;
int modified;
{
if (GET_CODE (x) == REG)
{
register int regno = REGNO (x);
/* If REGNO is in the equivalence table already but is of the
wrong mode for that equivalence, don't do anything here. */
if (REGNO_QTY_VALID_P (regno)
&& qty_mode[reg_qty[regno]] != GET_MODE (x))
return 0;
if (modified || ! REGNO_QTY_VALID_P (regno))
{
if (classp)
for (classp = classp->first_same_value;
classp != 0;
classp = classp->next_same_value)
if (GET_CODE (classp->exp) == REG
&& GET_MODE (classp->exp) == GET_MODE (x))
{
make_regs_eqv (regno, REGNO (classp->exp));
return 1;
}
make_new_qty (regno);
qty_mode[reg_qty[regno]] = GET_MODE (x);
return 1;
}
return 0;
}
/* If X is a SUBREG, we will likely be inserting the inner register in the
table. If that register doesn't have an assigned quantity number at
this point but does later, the insertion that we will be doing now will
not be accessible because its hash code will have changed. So assign
a quantity number now. */
else if (GET_CODE (x) == SUBREG && GET_CODE (SUBREG_REG (x)) == REG
&& ! REGNO_QTY_VALID_P (REGNO (SUBREG_REG (x))))
{
insert_regs (SUBREG_REG (x), NULL_PTR, 0);
mention_regs (SUBREG_REG (x));
return 1;
}
else
return mention_regs (x);
}
/* Look in or update the hash table. */
/* Put the element ELT on the list of free elements. */
static void
free_element (elt)
struct table_elt *elt;
{
elt->next_same_hash = free_element_chain;
free_element_chain = elt;
}
/* Return an element that is free for use. */
static struct table_elt *
get_element ()
{
struct table_elt *elt = free_element_chain;
if (elt)
{
free_element_chain = elt->next_same_hash;
return elt;
}
n_elements_made++;
return (struct table_elt *) oballoc (sizeof (struct table_elt));
}
/* Remove table element ELT from use in the table.
HASH is its hash code, made using the HASH macro.
It's an argument because often that is known in advance
and we save much time not recomputing it. */
static void
remove_from_table (elt, hash)
register struct table_elt *elt;
unsigned hash;
{
if (elt == 0)
return;
/* Mark this element as removed. See cse_insn. */
elt->first_same_value = 0;
/* Remove the table element from its equivalence class. */
{
register struct table_elt *prev = elt->prev_same_value;
register struct table_elt *next = elt->next_same_value;
if (next) next->prev_same_value = prev;
if (prev)
prev->next_same_value = next;
else
{
register struct table_elt *newfirst = next;
while (next)
{
next->first_same_value = newfirst;
next = next->next_same_value;
}
}
}
/* Remove the table element from its hash bucket. */
{
register struct table_elt *prev = elt->prev_same_hash;
register struct table_elt *next = elt->next_same_hash;
if (next) next->prev_same_hash = prev;
if (prev)
prev->next_same_hash = next;
else if (table[hash] == elt)
table[hash] = next;
else
{
/* This entry is not in the proper hash bucket. This can happen
when two classes were merged by `merge_equiv_classes'. Search
for the hash bucket that it heads. This happens only very
rarely, so the cost is acceptable. */
for (hash = 0; hash < NBUCKETS; hash++)
if (table[hash] == elt)
table[hash] = next;
}
}
/* Remove the table element from its related-value circular chain. */
if (elt->related_value != 0 && elt->related_value != elt)
{
register struct table_elt *p = elt->related_value;
while (p->related_value != elt)
p = p->related_value;
p->related_value = elt->related_value;
if (p->related_value == p)
p->related_value = 0;
}
free_element (elt);
}
/* Look up X in the hash table and return its table element,
or 0 if X is not in the table.
MODE is the machine-mode of X, or if X is an integer constant
with VOIDmode then MODE is the mode with which X will be used.
Here we are satisfied to find an expression whose tree structure
looks like X. */
static struct table_elt *
lookup (x, hash, mode)
rtx x;
unsigned hash;
enum machine_mode mode;
{
register struct table_elt *p;
for (p = table[hash]; p; p = p->next_same_hash)
if (mode == p->mode && ((x == p->exp && GET_CODE (x) == REG)
|| exp_equiv_p (x, p->exp, GET_CODE (x) != REG, 0)))
return p;
return 0;
}
/* Like `lookup' but don't care whether the table element uses invalid regs.
Also ignore discrepancies in the machine mode of a register. */
static struct table_elt *
lookup_for_remove (x, hash, mode)
rtx x;
unsigned hash;
enum machine_mode mode;
{
register struct table_elt *p;
if (GET_CODE (x) == REG)
{
int regno = REGNO (x);
/* Don't check the machine mode when comparing registers;
invalidating (REG:SI 0) also invalidates (REG:DF 0). */
for (p = table[hash]; p; p = p->next_same_hash)
if (GET_CODE (p->exp) == REG
&& REGNO (p->exp) == regno)
return p;
}
else
{
for (p = table[hash]; p; p = p->next_same_hash)
if (mode == p->mode && (x == p->exp || exp_equiv_p (x, p->exp, 0, 0)))
return p;
}
return 0;
}
/* Look for an expression equivalent to X and with code CODE.
If one is found, return that expression. */
static rtx
lookup_as_function (x, code)
rtx x;
enum rtx_code code;
{
register struct table_elt *p = lookup (x, safe_hash (x, VOIDmode) % NBUCKETS,
GET_MODE (x));
if (p == 0)
return 0;
for (p = p->first_same_value; p; p = p->next_same_value)
{
if (GET_CODE (p->exp) == code
/* Make sure this is a valid entry in the table. */
&& exp_equiv_p (p->exp, p->exp, 1, 0))
return p->exp;
}
return 0;
}
/* Insert X in the hash table, assuming HASH is its hash code
and CLASSP is an element of the class it should go in
(or 0 if a new class should be made).
It is inserted at the proper position to keep the class in
the order cheapest first.
MODE is the machine-mode of X, or if X is an integer constant
with VOIDmode then MODE is the mode with which X will be used.
For elements of equal cheapness, the most recent one
goes in front, except that the first element in the list
remains first unless a cheaper element is added. The order of
pseudo-registers does not matter, as canon_reg will be called to
find the cheapest when a register is retrieved from the table.
The in_memory field in the hash table element is set to 0.
The caller must set it nonzero if appropriate.
You should call insert_regs (X, CLASSP, MODIFY) before calling here,
and if insert_regs returns a nonzero value
you must then recompute its hash code before calling here.
If necessary, update table showing constant values of quantities. */
#define CHEAPER(X,Y) ((X)->cost < (Y)->cost)
static struct table_elt *
insert (x, classp, hash, mode)
register rtx x;
register struct table_elt *classp;
unsigned hash;
enum machine_mode mode;
{
register struct table_elt *elt;
/* If X is a register and we haven't made a quantity for it,
something is wrong. */
if (GET_CODE (x) == REG && ! REGNO_QTY_VALID_P (REGNO (x)))
abort ();
/* If X is a hard register, show it is being put in the table. */
if (GET_CODE (x) == REG && REGNO (x) < FIRST_PSEUDO_REGISTER)
{
int regno = REGNO (x);
int endregno = regno + HARD_REGNO_NREGS (regno, GET_MODE (x));
int i;
for (i = regno; i < endregno; i++)
SET_HARD_REG_BIT (hard_regs_in_table, i);
}
/* If X is a label, show we recorded it. */
if (GET_CODE (x) == LABEL_REF
|| (GET_CODE (x) == CONST && GET_CODE (XEXP (x, 0)) == PLUS
&& GET_CODE (XEXP (XEXP (x, 0), 0)) == LABEL_REF))
recorded_label_ref = 1;
/* Put an element for X into the right hash bucket. */
elt = get_element ();
elt->exp = x;
elt->cost = COST (x);
elt->next_same_value = 0;
elt->prev_same_value = 0;
elt->next_same_hash = table[hash];
elt->prev_same_hash = 0;
elt->related_value = 0;
elt->in_memory = 0;
elt->mode = mode;
elt->is_const = (CONSTANT_P (x)
/* GNU C++ takes advantage of this for `this'
(and other const values). */
|| (RTX_UNCHANGING_P (x)
&& GET_CODE (x) == REG
&& REGNO (x) >= FIRST_PSEUDO_REGISTER)
|| FIXED_BASE_PLUS_P (x));
if (table[hash])
table[hash]->prev_same_hash = elt;
table[hash] = elt;
/* Put it into the proper value-class. */
if (classp)
{
classp = classp->first_same_value;
if (CHEAPER (elt, classp))
/* Insert at the head of the class */
{
register struct table_elt *p;
elt->next_same_value = classp;
classp->prev_same_value = elt;
elt->first_same_value = elt;
for (p = classp; p; p = p->next_same_value)
p->first_same_value = elt;
}
else
{
/* Insert not at head of the class. */
/* Put it after the last element cheaper than X. */
register struct table_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;
if (next)
next->prev_same_value = elt;
elt->prev_same_value = p;
p->next_same_value = elt;
elt->first_same_value = classp;
}
}
else
elt->first_same_value = elt;
/* If this is a constant being set equivalent to a register or a register
being set equivalent to a constant, note the constant equivalence.
If this is a constant, it cannot be equivalent to a different constant,
and a constant is the only thing that can be cheaper than a register. So
we know the register is the head of the class (before the constant was
inserted).
If this is a register that is not already known equivalent to a
constant, we must check the entire class.
If this is a register that is already known equivalent to an insn,
update `qty_const_insn' to show that `this_insn' is the latest
insn making that quantity equivalent to the constant. */
if (elt->is_const && classp && GET_CODE (classp->exp) == REG
&& GET_CODE (x) != REG)
{
qty_const[reg_qty[REGNO (classp->exp)]]
= gen_lowpart_if_possible (qty_mode[reg_qty[REGNO (classp->exp)]], x);
qty_const_insn[reg_qty[REGNO (classp->exp)]] = this_insn;
}
else if (GET_CODE (x) == REG && classp && ! qty_const[reg_qty[REGNO (x)]]
&& ! elt->is_const)
{
register struct table_elt *p;
for (p = classp; p != 0; p = p->next_same_value)
{
if (p->is_const && GET_CODE (p->exp) != REG)
{
qty_const[reg_qty[REGNO (x)]]
= gen_lowpart_if_possible (GET_MODE (x), p->exp);
qty_const_insn[reg_qty[REGNO (x)]] = this_insn;
break;
}
}
}
else if (GET_CODE (x) == REG && qty_const[reg_qty[REGNO (x)]]
&& GET_MODE (x) == qty_mode[reg_qty[REGNO (x)]])
qty_const_insn[reg_qty[REGNO (x)]] = this_insn;
/* If this is a constant with symbolic value,
and it has a term with an explicit integer value,
link it up with related expressions. */
if (GET_CODE (x) == CONST)
{
rtx subexp = get_related_value (x);
unsigned subhash;
struct table_elt *subelt, *subelt_prev;
if (subexp != 0)
{
/* Get the integer-free subexpression in the hash table. */
subhash = safe_hash (subexp, mode) % NBUCKETS;
subelt = lookup (subexp, subhash, mode);
if (subelt == 0)
subelt = insert (subexp, NULL_PTR, subhash, mode);
/* Initialize SUBELT's circular chain if it has none. */
if (subelt->related_value == 0)
subelt->related_value = subelt;
/* Find the element in the circular chain that precedes SUBELT. */
subelt_prev = subelt;
while (subelt_prev->related_value != subelt)
subelt_prev = subelt_prev->related_value;
/* Put new ELT into SUBELT's circular chain just before SUBELT.
This way the element that follows SUBELT is the oldest one. */
elt->related_value = subelt_prev->related_value;
subelt_prev->related_value = elt;
}
}
return elt;
}
/* Given two equivalence classes, CLASS1 and CLASS2, put all the entries from
CLASS2 into CLASS1. This is done when we have reached an insn which makes
the two classes equivalent.
CLASS1 will be the surviving class; CLASS2 should not be used after this
call.
Any invalid entries in CLASS2 will not be copied. */
static void
merge_equiv_classes (class1, class2)
struct table_elt *class1, *class2;
{
struct table_elt *elt, *next, *new;
/* Ensure we start with the head of the classes. */
class1 = class1->first_same_value;
class2 = class2->first_same_value;
/* If they were already equal, forget it. */
if (class1 == class2)
return;
for (elt = class2; elt; elt = next)
{
unsigned hash;
rtx exp = elt->exp;
enum machine_mode mode = elt->mode;
next = elt->next_same_value;
/* Remove old entry, make a new one in CLASS1's class.
Don't do this for invalid entries as we cannot find their
hash code (it also isn't necessary). */
if (GET_CODE (exp) == REG || exp_equiv_p (exp, exp, 1, 0))
{
hash_arg_in_memory = 0;
hash_arg_in_struct = 0;
hash = HASH (exp, mode);
if (GET_CODE (exp) == REG)
delete_reg_equiv (REGNO (exp));
remove_from_table (elt, hash);
if (insert_regs (exp, class1, 0))
{
rehash_using_reg (exp);
hash = HASH (exp, mode);
}
new = insert (exp, class1, hash, mode);
new->in_memory = hash_arg_in_memory;
new->in_struct = hash_arg_in_struct;
}
}
}
/* Remove from the hash table, or mark as invalid,
all expressions whose values could be altered by storing in X.
X is a register, a subreg, or a memory reference with nonvarying address
(because, when a memory reference with a varying address is stored in,
all memory references are removed by invalidate_memory
so specific invalidation is superfluous).
FULL_MODE, if not VOIDmode, indicates that this much should be invalidated
instead of just the amount indicated by the mode of X. This is only used
for bitfield stores into memory.
A nonvarying address may be just a register or just
a symbol reference, or it may be either of those plus
a numeric offset. */
static void
invalidate (x, full_mode)
rtx x;
enum machine_mode full_mode;
{
register int i;
register struct table_elt *p;
rtx base;
HOST_WIDE_INT start, end;
/* If X is a register, dependencies on its contents
are recorded through the qty number mechanism.
Just change the qty number of the register,
mark it as invalid for expressions that refer to it,
and remove it itself. */
if (GET_CODE (x) == REG)
{
register int regno = REGNO (x);
register unsigned hash = HASH (x, GET_MODE (x));
/* Remove REGNO from any quantity list it might be on and indicate
that it's value might have changed. If it is a pseudo, remove its
entry from the hash table.
For a hard register, we do the first two actions above for any
additional hard registers corresponding to X. Then, if any of these
registers are in the table, we must remove any REG entries that
overlap these registers. */
delete_reg_equiv (regno);
reg_tick[regno]++;
if (regno >= FIRST_PSEUDO_REGISTER)
{
/* Because a register can be referenced in more than one mode,
we might have to remove more than one table entry. */
struct table_elt *elt;
while (elt = lookup_for_remove (x, hash, GET_MODE (x)))
remove_from_table (elt, hash);
}
else
{
HOST_WIDE_INT in_table
= TEST_HARD_REG_BIT (hard_regs_in_table, regno);
int endregno = regno + HARD_REGNO_NREGS (regno, GET_MODE (x));
int tregno, tendregno;
register struct table_elt *p, *next;
CLEAR_HARD_REG_BIT (hard_regs_in_table, regno);
for (i = regno + 1; i < endregno; i++)
{
in_table |= TEST_HARD_REG_BIT (hard_regs_in_table, i);
CLEAR_HARD_REG_BIT (hard_regs_in_table, i);
delete_reg_equiv (i);
reg_tick[i]++;
}
if (in_table)
for (hash = 0; hash < NBUCKETS; hash++)
for (p = table[hash]; p; p = next)
{
next = p->next_same_hash;
if (GET_CODE (p->exp) != REG
|| REGNO (p->exp) >= FIRST_PSEUDO_REGISTER)
continue;
tregno = REGNO (p->exp);
tendregno
= tregno + HARD_REGNO_NREGS (tregno, GET_MODE (p->exp));
if (tendregno > regno && tregno < endregno)
remove_from_table (p, hash);
}
}
return;
}
if (GET_CODE (x) == SUBREG)
{
if (GET_CODE (SUBREG_REG (x)) != REG)
abort ();
invalidate (SUBREG_REG (x), VOIDmode);
return;
}
/* X is not a register; it must be a memory reference with
a nonvarying address. Remove all hash table elements
that refer to overlapping pieces of memory. */
if (GET_CODE (x) != MEM)
abort ();
if (full_mode == VOIDmode)
full_mode = GET_MODE (x);
set_nonvarying_address_components (XEXP (x, 0), GET_MODE_SIZE (full_mode),
&base, &start, &end);
for (i = 0; i < NBUCKETS; i++)
{
register struct table_elt *next;
for (p = table[i]; p; p = next)
{
next = p->next_same_hash;
if (refers_to_mem_p (p->exp, base, start, end))
remove_from_table (p, i);
}
}
}
/* Remove all expressions that refer to register REGNO,
since they are already invalid, and we are about to
mark that register valid again and don't want the old
expressions to reappear as valid. */
static void
remove_invalid_refs (regno)
int regno;
{
register int i;
register struct table_elt *p, *next;
for (i = 0; i < NBUCKETS; i++)
for (p = table[i]; p; p = next)
{
next = p->next_same_hash;
if (GET_CODE (p->exp) != REG
&& refers_to_regno_p (regno, regno + 1, p->exp, NULL_PTR))
remove_from_table (p, i);
}
}
/* Recompute the hash codes of any valid entries in the hash table that
reference X, if X is a register, or SUBREG_REG (X) if X is a SUBREG.
This is called when we make a jump equivalence. */
static void
rehash_using_reg (x)
rtx x;
{
int i;
struct table_elt *p, *next;
unsigned hash;
if (GET_CODE (x) == SUBREG)
x = SUBREG_REG (x);
/* If X is not a register or if the register is known not to be in any
valid entries in the table, we have no work to do. */
if (GET_CODE (x) != REG
|| reg_in_table[REGNO (x)] < 0
|| reg_in_table[REGNO (x)] != reg_tick[REGNO (x)])
return;
/* Scan all hash chains looking for valid entries that mention X.
If we find one and it is in the wrong hash chain, move it. We can skip
objects that are registers, since they are handled specially. */
for (i = 0; i < NBUCKETS; i++)
for (p = table[i]; p; p = next)
{
next = p->next_same_hash;
if (GET_CODE (p->exp) != REG && reg_mentioned_p (x, p->exp)
&& exp_equiv_p (p->exp, p->exp, 1, 0)
&& i != (hash = safe_hash (p->exp, p->mode) % NBUCKETS))
{
if (p->next_same_hash)
p->next_same_hash->prev_same_hash = p->prev_same_hash;
if (p->prev_same_hash)
p->prev_same_hash->next_same_hash = p->next_same_hash;
else
table[i] = p->next_same_hash;
p->next_same_hash = table[hash];
p->prev_same_hash = 0;
if (table[hash])
table[hash]->prev_same_hash = p;
table[hash] = p;
}
}
}
/* Remove from the hash table all expressions that reference memory,
or some of them as specified by *WRITES. */
static void
invalidate_memory (writes)
struct write_data *writes;
{
register int i;
register struct table_elt *p, *next;
int all = writes->all;
int nonscalar = writes->nonscalar;
for (i = 0; i < NBUCKETS; i++)
for (p = table[i]; p; p = next)
{
next = p->next_same_hash;
if (p->in_memory
&& (all
|| (nonscalar && p->in_struct)
|| cse_rtx_addr_varies_p (p->exp)))
remove_from_table (p, i);
}
}
/* Remove from the hash table any expression that is a call-clobbered
register. Also update their TICK values. */
static void
invalidate_for_call ()
{
int regno, endregno;
int i;
unsigned hash;
struct table_elt *p, *next;
int in_table = 0;
/* Go through all the hard registers. For each that is clobbered in
a CALL_INSN, remove the register from quantity chains and update
reg_tick if defined. Also see if any of these registers is currently
in the table. */
for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
if (TEST_HARD_REG_BIT (regs_invalidated_by_call, regno))
{
delete_reg_equiv (regno);
if (reg_tick[regno] >= 0)
reg_tick[regno]++;
in_table |= (TEST_HARD_REG_BIT (hard_regs_in_table, regno) != 0);
}
/* In the case where we have no call-clobbered hard registers in the
table, we are done. Otherwise, scan the table and remove any
entry that overlaps a call-clobbered register. */
if (in_table)
for (hash = 0; hash < NBUCKETS; hash++)
for (p = table[hash]; p; p = next)
{
next = p->next_same_hash;
if (GET_CODE (p->exp) != REG
|| REGNO (p->exp) >= FIRST_PSEUDO_REGISTER)
continue;
regno = REGNO (p->exp);
endregno = regno + HARD_REGNO_NREGS (regno, GET_MODE (p->exp));
for (i = regno; i < endregno; i++)
if (TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
{
remove_from_table (p, hash);
break;
}
}
}
/* Given an expression X of type CONST,
and ELT which is its table entry (or 0 if it
is not in the hash table),
return an alternate expression for X as a register plus integer.
If none can be found, return 0. */
static rtx
use_related_value (x, elt)
rtx x;
struct table_elt *elt;
{
register struct table_elt *relt = 0;
register struct table_elt *p, *q;
HOST_WIDE_INT offset;
/* First, is there anything related known?
If we have a table element, we can tell from that.
Otherwise, must look it up. */
if (elt != 0 && elt->related_value != 0)
relt = elt;
else if (elt == 0 && GET_CODE (x) == CONST)
{
rtx subexp = get_related_value (x);
if (subexp != 0)
relt = lookup (subexp,
safe_hash (subexp, GET_MODE (subexp)) % NBUCKETS,
GET_MODE (subexp));
}
if (relt == 0)
return 0;
/* Search all related table entries for one that has an
equivalent register. */
p = relt;
while (1)
{
/* This loop is strange in that it is executed in two different cases.
The first is when X is already in the table. Then it is searching
the RELATED_VALUE list of X's class (RELT). The second case is when
X is not in the table. Then RELT points to a class for the related
value.
Ensure that, whatever case we are in, that we ignore classes that have
the same value as X. */
if (rtx_equal_p (x, p->exp))
q = 0;
else
for (q = p->first_same_value; q; q = q->next_same_value)
if (GET_CODE (q->exp) == REG)
break;
if (q)
break;
p = p->related_value;
/* We went all the way around, so there is nothing to be found.
Alternatively, perhaps RELT was in the table for some other reason
and it has no related values recorded. */
if (p == relt || p == 0)
break;
}
if (q == 0)
return 0;
offset = (get_integer_term (x) - get_integer_term (p->exp));
/* Note: OFFSET may be 0 if P->xexp and X are related by commutativity. */
return plus_constant (q->exp, offset);
}
/* Hash an rtx. We are careful to make sure the value is never negative.
Equivalent registers hash identically.
MODE is used in hashing for CONST_INTs only;
otherwise the mode of X is used.
Store 1 in do_not_record if any subexpression is volatile.
Store 1 in hash_arg_in_memory if X contains a MEM rtx
which does not have the RTX_UNCHANGING_P bit set.
In this case, also store 1 in hash_arg_in_struct
if there is a MEM rtx which has the MEM_IN_STRUCT_P bit 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. */
static unsigned
canon_hash (x, mode)
rtx x;
enum machine_mode mode;
{
register int i, j;
register unsigned hash = 0;
register enum rtx_code code;
register char *fmt;
/* repeat is used to turn tail-recursion into iteration. */
repeat:
if (x == 0)
return hash;
code = GET_CODE (x);
switch (code)
{
case REG:
{
register int regno = REGNO (x);
/* On some machines, we can't record any non-fixed hard register,
because extending its life will cause reload problems. We
consider ap, fp, and sp to be fixed for this purpose.
On all machines, we can't record any global registers. */
if (regno < FIRST_PSEUDO_REGISTER
&& (global_regs[regno]
#ifdef SMALL_REGISTER_CLASSES
|| (SMALL_REGISTER_CLASSES
&& ! fixed_regs[regno]
&& regno != FRAME_POINTER_REGNUM
&& regno != HARD_FRAME_POINTER_REGNUM
&& regno != ARG_POINTER_REGNUM
&& regno != STACK_POINTER_REGNUM)
#endif
))
{
do_not_record = 1;
return 0;
}
hash += ((unsigned) REG << 7) + (unsigned) reg_qty[regno];
return hash;
}
case CONST_INT:
{
unsigned HOST_WIDE_INT tem = INTVAL (x);
hash += ((unsigned) CONST_INT << 7) + (unsigned) mode + tem;
return hash;
}
case CONST_DOUBLE:
/* This is like the general case, except that it only counts
the integers representing the constant. */
hash += (unsigned) code + (unsigned) GET_MODE (x);
if (GET_MODE (x) != VOIDmode)
for (i = 2; i < GET_RTX_LENGTH (CONST_DOUBLE); i++)
{
unsigned tem = XINT (x, i);
hash += tem;
}
else
hash += ((unsigned) CONST_DOUBLE_LOW (x)
+ (unsigned) CONST_DOUBLE_HIGH (x));
return hash;
/* Assume there is only one rtx object for any given label. */
case LABEL_REF:
hash
+= ((unsigned) LABEL_REF << 7) + (unsigned HOST_WIDE_INT) XEXP (x, 0);
return hash;
case SYMBOL_REF:
hash
+= ((unsigned) SYMBOL_REF << 7) + (unsigned HOST_WIDE_INT) XSTR (x, 0);
return hash;
case MEM:
if (MEM_VOLATILE_P (x))
{
do_not_record = 1;
return 0;
}
if (! RTX_UNCHANGING_P (x) || FIXED_BASE_PLUS_P (XEXP (x, 0)))
{
hash_arg_in_memory = 1;
if (MEM_IN_STRUCT_P (x)) hash_arg_in_struct = 1;
}
/* Now that we have already found this special case,
might as well speed it up as much as possible. */
hash += (unsigned) MEM;
x = XEXP (x, 0);
goto repeat;
case PRE_DEC:
case PRE_INC:
case POST_DEC:
case POST_INC:
case PC:
case CC0:
case CALL:
case UNSPEC_VOLATILE:
do_not_record = 1;
return 0;
case ASM_OPERANDS:
if (MEM_VOLATILE_P (x))
{
do_not_record = 1;
return 0;
}
}
i = GET_RTX_LENGTH (code) - 1;
hash += (unsigned) code + (unsigned) GET_MODE (x);
fmt = GET_RTX_FORMAT (code);
for (; i >= 0; i--)
{
if (fmt[i] == 'e')
{
rtx tem = XEXP (x, i);
/* If we are about to do the last recursive call
needed at this level, change it into iteration.
This function is called enough to be worth it. */
if (i == 0)
{
x = tem;
goto repeat;
}
hash += canon_hash (tem, 0);
}
else if (fmt[i] == 'E')
for (j = 0; j < XVECLEN (x, i); j++)
hash += canon_hash (XVECEXP (x, i, j), 0);
else if (fmt[i] == 's')
{
register unsigned char *p = (unsigned char *) XSTR (x, i);
if (p)
while (*p)
hash += *p++;
}
else if (fmt[i] == 'i')
{
register unsigned tem = XINT (x, i);
hash += tem;
}
else
abort ();
}
return hash;
}
/* Like canon_hash but with no side effects. */
static unsigned
safe_hash (x, mode)
rtx x;
enum machine_mode mode;
{
int save_do_not_record = do_not_record;
int save_hash_arg_in_memory = hash_arg_in_memory;
int save_hash_arg_in_struct = hash_arg_in_struct;
unsigned hash = canon_hash (x, mode);
hash_arg_in_memory = save_hash_arg_in_memory;
hash_arg_in_struct = save_hash_arg_in_struct;
do_not_record = save_do_not_record;
return hash;
}
/* Return 1 iff X and Y would canonicalize into the same thing,
without actually constructing the canonicalization of either one.
If VALIDATE is nonzero,
we assume X is an expression being processed from the rtl
and Y was found in the hash table. We check register refs
in Y for being marked as valid.
If EQUAL_VALUES is nonzero, we allow a register to match a constant value
that is known to be in the register. Ordinarily, we don't allow them
to match, because letting them match would cause unpredictable results
in all the places that search a hash table chain for an equivalent
for a given value. A possible equivalent that has different structure
has its hash code computed from different data. Whether the hash code
is the same as that of the the given value is pure luck. */
static int
exp_equiv_p (x, y, validate, equal_values)
rtx x, y;
int validate;
int equal_values;
{
register int i, j;
register enum rtx_code code;
register char *fmt;
/* Note: it is incorrect to assume an expression is equivalent to itself
if VALIDATE is nonzero. */
if (x == y && !validate)
return 1;
if (x == 0 || y == 0)
return x == y;
code = GET_CODE (x);
if (code != GET_CODE (y))
{
if (!equal_values)
return 0;
/* If X is a constant and Y is a register or vice versa, they may be
equivalent. We only have to validate if Y is a register. */
if (CONSTANT_P (x) && GET_CODE (y) == REG
&& REGNO_QTY_VALID_P (REGNO (y))
&& GET_MODE (y) == qty_mode[reg_qty[REGNO (y)]]
&& rtx_equal_p (x, qty_const[reg_qty[REGNO (y)]])
&& (! validate || reg_in_table[REGNO (y)] == reg_tick[REGNO (y)]))
return 1;
if (CONSTANT_P (y) && code == REG
&& REGNO_QTY_VALID_P (REGNO (x))
&& GET_MODE (x) == qty_mode[reg_qty[REGNO (x)]]
&& rtx_equal_p (y, qty_const[reg_qty[REGNO (x)]]))
return 1;
return 0;
}
/* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. */
if (GET_MODE (x) != GET_MODE (y))
return 0;
switch (code)
{
case PC:
case CC0:
return x == y;
case CONST_INT:
return INTVAL (x) == INTVAL (y);
case LABEL_REF:
return XEXP (x, 0) == XEXP (y, 0);
case SYMBOL_REF:
return XSTR (x, 0) == XSTR (y, 0);
case REG:
{
int regno = REGNO (y);
int endregno
= regno + (regno >= FIRST_PSEUDO_REGISTER ? 1
: HARD_REGNO_NREGS (regno, GET_MODE (y)));
int i;
/* If the quantities are not the same, the expressions are not
equivalent. If there are and we are not to validate, they
are equivalent. Otherwise, ensure all regs are up-to-date. */
if (reg_qty[REGNO (x)] != reg_qty[regno])
return 0;
if (! validate)
return 1;
for (i = regno; i < endregno; i++)
if (reg_in_table[i] != reg_tick[i])
return 0;
return 1;
}
/* For commutative operations, check both orders. */
case PLUS:
case MULT:
case AND:
case IOR:
case XOR:
case NE:
case EQ:
return ((exp_equiv_p (XEXP (x, 0), XEXP (y, 0), validate, equal_values)
&& exp_equiv_p (XEXP (x, 1), XEXP (y, 1),
validate, equal_values))
|| (exp_equiv_p (XEXP (x, 0), XEXP (y, 1),
validate, equal_values)
&& exp_equiv_p (XEXP (x, 1), XEXP (y, 0),
validate, equal_values)));
}
/* Compare the elements. If any pair of corresponding elements
fail to match, return 0 for the whole things. */
fmt = GET_RTX_FORMAT (code);
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
{
switch (fmt[i])
{
case 'e':
if (! exp_equiv_p (XEXP (x, i), XEXP (y, i), validate, equal_values))
return 0;
break;
case 'E':
if (XVECLEN (x, i) != XVECLEN (y, i))
return 0;
for (j = 0; j < XVECLEN (x, i); j++)
if (! exp_equiv_p (XVECEXP (x, i, j), XVECEXP (y, i, j),
validate, equal_values))
return 0;
break;
case 's':
if (strcmp (XSTR (x, i), XSTR (y, i)))
return 0;
break;
case 'i':
if (XINT (x, i) != XINT (y, i))
return 0;
break;
case 'w':
if (XWINT (x, i) != XWINT (y, i))
return 0;
break;
case '0':
break;
default:
abort ();
}
}
return 1;
}
/* Return 1 iff any subexpression of X matches Y.
Here we do not require that X or Y be valid (for registers referred to)
for being in the hash table. */
static int
refers_to_p (x, y)
rtx x, y;
{
register int i;
register enum rtx_code code;
register char *fmt;
repeat:
if (x == y)
return 1;
if (x == 0 || y == 0)
return 0;
code = GET_CODE (x);
/* If X as a whole has the same code as Y, they may match.
If so, return 1. */
if (code == GET_CODE (y))
{
if (exp_equiv_p (x, y, 0, 1))
return 1;
}
/* X does not match, so try its subexpressions. */
fmt = GET_RTX_FORMAT (code);
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
if (fmt[i] == 'e')
{
if (i == 0)
{
x = XEXP (x, 0);
goto repeat;
}
else
if (refers_to_p (XEXP (x, i), y))
return 1;
}
else if (fmt[i] == 'E')
{
int j;
for (j = 0; j < XVECLEN (x, i); j++)
if (refers_to_p (XVECEXP (x, i, j), y))
return 1;
}
return 0;
}
/* Given ADDR and SIZE (a memory address, and the size of the memory reference),
set PBASE, PSTART, and PEND which correspond to the base of the address,
the starting offset, and ending offset respectively.
ADDR is known to be a nonvarying address. */
/* ??? Despite what the comments say, this function is in fact frequently
passed varying addresses. This does not appear to cause any problems. */
static void
set_nonvarying_address_components (addr, size, pbase, pstart, pend)
rtx addr;
int size;
rtx *pbase;
HOST_WIDE_INT *pstart, *pend;
{
rtx base;
HOST_WIDE_INT start, end;
base = addr;
start = 0;
end = 0;
/* Registers with nonvarying addresses usually have constant equivalents;
but the frame pointer register is also possible. */
if (GET_CODE (base) == REG
&& qty_const != 0
&& REGNO_QTY_VALID_P (REGNO (base))
&& qty_mode[reg_qty[REGNO (base)]] == GET_MODE (base)
&& qty_const[reg_qty[REGNO (base)]] != 0)
base = qty_const[reg_qty[REGNO (base)]];
else if (GET_CODE (base) == PLUS
&& GET_CODE (XEXP (base, 1)) == CONST_INT
&& GET_CODE (XEXP (base, 0)) == REG
&& qty_const != 0
&& REGNO_QTY_VALID_P (REGNO (XEXP (base, 0)))
&& (qty_mode[reg_qty[REGNO (XEXP (base, 0))]]
== GET_MODE (XEXP (base, 0)))
&& qty_const[reg_qty[REGNO (XEXP (base, 0))]])
{
start = INTVAL (XEXP (base, 1));
base = qty_const[reg_qty[REGNO (XEXP (base, 0))]];
}
/* This can happen as the result of virtual register instantiation,
if the initial offset is too large to be a valid address. */
else if (GET_CODE (base) == PLUS
&& GET_CODE (XEXP (base, 0)) == REG
&& GET_CODE (XEXP (base, 1)) == REG
&& qty_const != 0
&& REGNO_QTY_VALID_P (REGNO (XEXP (base, 0)))
&& (qty_mode[reg_qty[REGNO (XEXP (base, 0))]]
== GET_MODE (XEXP (base, 0)))
&& qty_const[reg_qty[REGNO (XEXP (base, 0))]]
&& REGNO_QTY_VALID_P (REGNO (XEXP (base, 1)))
&& (qty_mode[reg_qty[REGNO (XEXP (base, 1))]]
== GET_MODE (XEXP (base, 1)))
&& qty_const[reg_qty[REGNO (XEXP (base, 1))]])
{
rtx tem = qty_const[reg_qty[REGNO (XEXP (base, 1))]];
base = qty_const[reg_qty[REGNO (XEXP (base, 0))]];
/* One of the two values must be a constant. */
if (GET_CODE (base) != CONST_INT)
{
if (GET_CODE (tem) != CONST_INT)
abort ();
start = INTVAL (tem);
}
else
{
start = INTVAL (base);
base = tem;
}
}
/* Handle everything that we can find inside an address that has been
viewed as constant. */
while (1)
{
/* If no part of this switch does a "continue", the code outside
will exit this loop. */
switch (GET_CODE (base))
{
case LO_SUM:
/* By definition, operand1 of a LO_SUM is the associated constant
address. Use the associated constant address as the base
instead. */
base = XEXP (base, 1);
continue;
case CONST:
/* Strip off CONST. */
base = XEXP (base, 0);
continue;
case PLUS:
if (GET_CODE (XEXP (base, 1)) == CONST_INT)
{
start += INTVAL (XEXP (base, 1));
base = XEXP (base, 0);
continue;
}
break;
case AND:
/* Handle the case of an AND which is the negative of a power of
two. This is used to represent unaligned memory operations. */
if (GET_CODE (XEXP (base, 1)) == CONST_INT
&& exact_log2 (- INTVAL (XEXP (base, 1))) > 0)
{
set_nonvarying_address_components (XEXP (base, 0), size,
pbase, pstart, pend);
/* Assume the worst misalignment. START is affected, but not
END, so compensate but adjusting SIZE. Don't lose any
constant we already had. */
size = *pend - *pstart - INTVAL (XEXP (base, 1)) - 1;
start += *pstart + INTVAL (XEXP (base, 1)) + 1;
end += *pend;
base = *pbase;
}
break;
}
break;
}
if (GET_CODE (base) == CONST_INT)
{
start += INTVAL (base);
base = const0_rtx;
}
end = start + size;
/* Set the return values. */
*pbase = base;
*pstart = start;
*pend = end;
}
/* Return 1 iff any subexpression of X refers to memory
at an address of BASE plus some offset
such that any of the bytes' offsets fall between START (inclusive)
and END (exclusive).
The value is undefined if X is a varying address (as determined by
cse_rtx_addr_varies_p). This function is not used in such cases.
When used in the cse pass, `qty_const' is nonzero, and it is used
to treat an address that is a register with a known constant value
as if it were that constant value.
In the loop pass, `qty_const' is zero, so this is not done. */
static int
refers_to_mem_p (x, base, start, end)
rtx x, base;
HOST_WIDE_INT start, end;
{
register HOST_WIDE_INT i;
register enum rtx_code code;
register char *fmt;
repeat:
if (x == 0)
return 0;
code = GET_CODE (x);
if (code == MEM)
{
register rtx addr = XEXP (x, 0); /* Get the address. */
rtx mybase;
HOST_WIDE_INT mystart, myend;
set_nonvarying_address_components (addr, GET_MODE_SIZE (GET_MODE (x)),
&mybase, &mystart, &myend);
/* refers_to_mem_p is never called with varying addresses.
If the base addresses are not equal, there is no chance
of the memory addresses conflicting. */
if (! rtx_equal_p (mybase, base))
return 0;
return myend > start && mystart < end;
}
/* X does not match, so try its subexpressions. */
fmt = GET_RTX_FORMAT (code);
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
if (fmt[i] == 'e')
{
if (i == 0)
{
x = XEXP (x, 0);
goto repeat;
}
else
if (refers_to_mem_p (XEXP (x, i), base, start, end))
return 1;
}
else if (fmt[i] == 'E')
{
int j;
for (j = 0; j < XVECLEN (x, i); j++)
if (refers_to_mem_p (XVECEXP (x, i, j), base, start, end))
return 1;
}
return 0;
}
/* Nonzero if X refers to memory at a varying address;
except that a register which has at the moment a known constant value
isn't considered variable. */
static int
cse_rtx_addr_varies_p (x)
rtx x;
{
/* 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 (GET_CODE (x) == MEM
&& GET_CODE (XEXP (x, 0)) == REG
&& REGNO_QTY_VALID_P (REGNO (XEXP (x, 0)))
&& GET_MODE (XEXP (x, 0)) == qty_mode[reg_qty[REGNO (XEXP (x, 0))]]
&& qty_const[reg_qty[REGNO (XEXP (x, 0))]] != 0)
return 0;
if (GET_CODE (x) == MEM
&& GET_CODE (XEXP (x, 0)) == PLUS
&& GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT
&& GET_CODE (XEXP (XEXP (x, 0), 0)) == REG
&& REGNO_QTY_VALID_P (REGNO (XEXP (XEXP (x, 0), 0)))
&& (GET_MODE (XEXP (XEXP (x, 0), 0))
== qty_mode[reg_qty[REGNO (XEXP (XEXP (x, 0), 0))]])
&& qty_const[reg_qty[REGNO (XEXP (XEXP (x, 0), 0))]])
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) == MEM
&& GET_CODE (XEXP (x, 0)) == PLUS
&& GET_CODE (XEXP (XEXP (x, 0), 0)) == REG
&& GET_CODE (XEXP (XEXP (x, 0), 1)) == REG
&& REGNO_QTY_VALID_P (REGNO (XEXP (XEXP (x, 0), 0)))
&& (GET_MODE (XEXP (XEXP (x, 0), 0))
== qty_mode[reg_qty[REGNO (XEXP (XEXP (x, 0), 0))]])
&& qty_const[reg_qty[REGNO (XEXP (XEXP (x, 0), 0))]]
&& REGNO_QTY_VALID_P (REGNO (XEXP (XEXP (x, 0), 1)))
&& (GET_MODE (XEXP (XEXP (x, 0), 1))
== qty_mode[reg_qty[REGNO (XEXP (XEXP (x, 0), 1))]])
&& qty_const[reg_qty[REGNO (XEXP (XEXP (x, 0), 1))]])
return 0;
return rtx_addr_varies_p (x);
}
/* Canonicalize an expression:
replace each register reference inside it
with the "oldest" equivalent register.
If INSN is non-zero and we are replacing a pseudo with a hard register
or vice versa, validate_change is used to ensure that INSN remains valid
after we make our substitution. The calls are made with IN_GROUP non-zero
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
generally be discarded since the changes we are making are optional. */
static rtx
canon_reg (x, insn)
rtx x;
rtx insn;
{
register int i;
register enum rtx_code code;
register char *fmt;
if (x == 0)
return x;
code = GET_CODE (x);
switch (code)
{
case PC:
case CC0:
case CONST:
case CONST_INT:
case CONST_DOUBLE:
case SYMBOL_REF:
case LABEL_REF:
case ADDR_VEC:
case ADDR_DIFF_VEC:
return x;
case REG:
{
register int first;
/* Never replace a hard reg, because hard regs can appear
in more than one machine mode, and we must preserve the mode
of each occurrence. Also, some hard regs appear in
MEMs that are shared and mustn't be altered. Don't try to
replace any reg that maps to a reg of class NO_REGS. */
if (REGNO (x) < FIRST_PSEUDO_REGISTER
|| ! REGNO_QTY_VALID_P (REGNO (x)))
return x;
first = qty_first_reg[reg_qty[REGNO (x)]];
return (first >= FIRST_PSEUDO_REGISTER ? regno_reg_rtx[first]
: REGNO_REG_CLASS (first) == NO_REGS ? x
: gen_rtx (REG, qty_mode[reg_qty[REGNO (x)]], first));
}
}
fmt = GET_RTX_FORMAT (code);
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
{
register int j;
if (fmt[i] == 'e')
{
rtx new = canon_reg (XEXP (x, i), 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
&& GET_CODE (new) == REG && GET_CODE (XEXP (x, i)) == REG
&& (((REGNO (new) < FIRST_PSEUDO_REGISTER)
!= (REGNO (XEXP (x, i)) < FIRST_PSEUDO_REGISTER))
|| (insn_code = recog_memoized (insn)) < 0
|| insn_n_dups[insn_code] > 0))
validate_change (insn, &XEXP (x, i), new, 1);
else
XEXP (x, i) = new;
}
else if (fmt[i] == 'E')
for (j = 0; j < XVECLEN (x, i); j++)
XVECEXP (x, i, j) = canon_reg (XVECEXP (x, i, j), insn);
}
return x;
}
/* LOC is a location within INSN that is an operand address (the contents of
a MEM). Find the best equivalent address to use that is valid for this
insn.
On most CISC machines, complicated address modes are costly, and rtx_cost
is a good approximation for that cost. However, most RISC machines have
only a few (usually only one) memory reference formats. If an address is
valid at all, it is often just as cheap as any other address. Hence, for
RISC machines, we use the configuration macro `ADDRESS_COST' to compare the
costs of various addresses. For two addresses of equal cost, choose the one
with the highest `rtx_cost' value as that has the potential of eliminating
the most insns. For equal costs, we choose the first in the equivalence
class. Note that we ignore the fact that pseudo registers are cheaper
than hard registers here because we would also prefer the pseudo registers.
*/
static void
find_best_addr (insn, loc)
rtx insn;
rtx *loc;
{
struct table_elt *elt, *p;
rtx addr = *loc;
int our_cost;
int found_better = 1;
int save_do_not_record = do_not_record;
int save_hash_arg_in_memory = hash_arg_in_memory;
int save_hash_arg_in_struct = hash_arg_in_struct;
int addr_volatile;
int regno;
unsigned hash;
/* Do not try to replace constant addresses or addresses of local and
argument slots. These MEM expressions are made only once and inserted
in many instructions, as well as being used to control symbol table
output. It is not safe to clobber them.
There are some uncommon cases where the address is already in a register
for some reason, but we cannot take advantage of that because we have
no easy way to unshare the MEM. In addition, looking up all stack
addresses is costly. */
if ((GET_CODE (addr) == PLUS
&& GET_CODE (XEXP (addr, 0)) == REG
&& GET_CODE (XEXP (addr, 1)) == CONST_INT
&& (regno = REGNO (XEXP (addr, 0)),
regno == FRAME_POINTER_REGNUM || regno == HARD_FRAME_POINTER_REGNUM
|| regno == ARG_POINTER_REGNUM))
|| (GET_CODE (addr) == REG
&& (regno = REGNO (addr), regno == FRAME_POINTER_REGNUM
|| regno == HARD_FRAME_POINTER_REGNUM
|| regno == ARG_POINTER_REGNUM))
|| CONSTANT_ADDRESS_P (addr))
return;
/* If this address is not simply a register, try to fold it. This will
sometimes simplify the expression. Many simplifications
will not be valid, but some, usually applying the associative rule, will
be valid and produce better code. */
if (GET_CODE (addr) != REG)
{
rtx folded = fold_rtx (copy_rtx (addr), NULL_RTX);
if (1
#ifdef ADDRESS_COST
&& (ADDRESS_COST (folded) < ADDRESS_COST (addr)
|| (ADDRESS_COST (folded) == ADDRESS_COST (addr)
&& rtx_cost (folded, MEM) > rtx_cost (addr, MEM)))
#else
&& rtx_cost (folded, MEM) < rtx_cost (addr, MEM)
#endif
&& validate_change (insn, loc, folded, 0))
addr = folded;
}
/* If this address is not in the hash table, we can't look for equivalences
of the whole address. Also, ignore if volatile. */
do_not_record = 0;
hash = HASH (addr, Pmode);
addr_volatile = do_not_record;
do_not_record = save_do_not_record;
hash_arg_in_memory = save_hash_arg_in_memory;
hash_arg_in_struct = save_hash_arg_in_struct;
if (addr_volatile)
return;
elt = lookup (addr, hash, Pmode);
#ifndef ADDRESS_COST
if (elt)
{
our_cost = elt->cost;
/* Find the lowest cost below ours that works. */
for (elt = elt->first_same_value; elt; elt = elt->next_same_value)
if (elt->cost < our_cost
&& (GET_CODE (elt->exp) == REG
|| exp_equiv_p (elt->exp, elt->exp, 1, 0))
&& validate_change (insn, loc,
canon_reg (copy_rtx (elt->exp), NULL_RTX), 0))
return;
}
#else
if (elt)
{
/* We need to find the best (under the criteria documented above) entry
in the class that is valid. We use the `flag' field to indicate
choices that were invalid and iterate until we can't find a better
one that hasn't already been tried. */
for (p = elt->first_same_value; p; p = p->next_same_value)
p->flag = 0;
while (found_better)
{
int best_addr_cost = ADDRESS_COST (*loc);
int best_rtx_cost = (elt->cost + 1) >> 1;
struct table_elt *best_elt = elt;
found_better = 0;
for (p = elt->first_same_value; p; p = p->next_same_value)
if (! p->flag
&& (GET_CODE (p->exp) == REG
|| exp_equiv_p (p->exp, p->exp, 1, 0))
&& (ADDRESS_COST (p->exp) < best_addr_cost
|| (ADDRESS_COST (p->exp) == best_addr_cost
&& (p->cost + 1) >> 1 > best_rtx_cost)))
{
found_better = 1;
best_addr_cost = ADDRESS_COST (p->exp);
best_rtx_cost = (p->cost + 1) >> 1;
best_elt = p;
}
if (found_better)
{
if (validate_change (insn, loc,
canon_reg (copy_rtx (best_elt->exp),
NULL_RTX), 0))
return;
else
best_elt->flag = 1;
}
}
}
/* If the address is a binary operation with the first operand a register
and the second a constant, do the same as above, but looking for
equivalences of the register. Then try to simplify before checking for
the best address to use. This catches a few cases: First is when we
have REG+const and the register is another REG+const. We can often merge
the constants and eliminate one insn and one register. It may also be
that a machine has a cheap REG+REG+const. Finally, this improves the
code on the Alpha for unaligned byte stores. */
if (flag_expensive_optimizations
&& (GET_RTX_CLASS (GET_CODE (*loc)) == '2'
|| GET_RTX_CLASS (GET_CODE (*loc)) == 'c')
&& GET_CODE (XEXP (*loc, 0)) == REG
&& GET_CODE (XEXP (*loc, 1)) == CONST_INT)
{
rtx c = XEXP (*loc, 1);
do_not_record = 0;
hash = HASH (XEXP (*loc, 0), Pmode);
do_not_record = save_do_not_record;
hash_arg_in_memory = save_hash_arg_in_memory;
hash_arg_in_struct = save_hash_arg_in_struct;
elt = lookup (XEXP (*loc, 0), hash, Pmode);
if (elt == 0)
return;
/* We need to find the best (under the criteria documented above) entry
in the class that is valid. We use the `flag' field to indicate
choices that were invalid and iterate until we can't find a better
one that hasn't already been tried. */
for (p = elt->first_same_value; p; p = p->next_same_value)
p->flag = 0;
while (found_better)
{
int best_addr_cost = ADDRESS_COST (*loc);
int best_rtx_cost = (COST (*loc) + 1) >> 1;
struct table_elt *best_elt = elt;
rtx best_rtx = *loc;
int count;
/* This is at worst case an O(n^2) algorithm, so limit our search
to the first 32 elements on the list. This avoids trouble
compiling code with very long basic blocks that can easily
call cse_gen_binary so many times that we run out of memory. */
found_better = 0;
for (p = elt->first_same_value, count = 0;
p && count < 32;
p = p->next_same_value, count++)
if (! p->flag
&& (GET_CODE (p->exp) == REG
|| exp_equiv_p (p->exp, p->exp, 1, 0)))
{
rtx new = cse_gen_binary (GET_CODE (*loc), Pmode, p->exp, c);
if ((ADDRESS_COST (new) < best_addr_cost
|| (ADDRESS_COST (new) == best_addr_cost
&& (COST (new) + 1) >> 1 > best_rtx_cost)))
{
found_better = 1;
best_addr_cost = ADDRESS_COST (new);
best_rtx_cost = (COST (new) + 1) >> 1;
best_elt = p;
best_rtx = new;
}
}
if (found_better)
{
if (validate_change (insn, loc,
canon_reg (copy_rtx (best_rtx),
NULL_RTX), 0))
return;
else
best_elt->flag = 1;
}
}
}
#endif
}
/* Given an operation (CODE, *PARG1, *PARG2), where code is a comparison
operation (EQ, NE, GT, etc.), follow it back through the hash table and
what values are being compared.
*PARG1 and *PARG2 are updated to contain the rtx representing the values
actually being compared. For example, if *PARG1 was (cc0) and *PARG2
was (const_int 0), *PARG1 and *PARG2 will be set to the objects that were
compared to produce cc0.
The return value is the comparison operator and is either the code of
A or the code corresponding to the inverse of the comparison. */
static enum rtx_code
find_comparison_args (code, parg1, parg2, pmode1, pmode2)
enum rtx_code code;
rtx *parg1, *parg2;
enum machine_mode *pmode1, *pmode2;
{
rtx arg1, arg2;
arg1 = *parg1, arg2 = *parg2;
/* If ARG2 is const0_rtx, see what ARG1 is equivalent to. */
while (arg2 == CONST0_RTX (GET_MODE (arg1)))
{
/* Set non-zero when we find something of interest. */
rtx x = 0;
int reverse_code = 0;
struct table_elt *p = 0;
/* If arg1 is a COMPARE, extract the comparison arguments from it.
On machines with CC0, this is the only case that can occur, since
fold_rtx will return the COMPARE or item being compared with zero
when given CC0. */
if (GET_CODE (arg1) == COMPARE && arg2 == const0_rtx)
x = arg1;
/* If ARG1 is a comparison operator and CODE is testing for
STORE_FLAG_VALUE, get the inner arguments. */
else if (GET_RTX_CLASS (GET_CODE (arg1)) == '<')
{
if (code == NE
|| (GET_MODE_CLASS (GET_MODE (arg1)) == MODE_INT
&& code == LT && STORE_FLAG_VALUE == -1)
#ifdef FLOAT_STORE_FLAG_VALUE
|| (GET_MODE_CLASS (GET_MODE (arg1)) == MODE_FLOAT
&& FLOAT_STORE_FLAG_VALUE < 0)
#endif
)
x = arg1;
else if (code == EQ
|| (GET_MODE_CLASS (GET_MODE (arg1)) == MODE_INT
&& code == GE && STORE_FLAG_VALUE == -1)
#ifdef FLOAT_STORE_FLAG_VALUE
|| (GET_MODE_CLASS (GET_MODE (arg1)) == MODE_FLOAT
&& FLOAT_STORE_FLAG_VALUE < 0)
#endif
)
x = arg1, reverse_code = 1;
}
/* ??? We could also check for
(ne (and (eq (...) (const_int 1))) (const_int 0))
and related forms, but let's wait until we see them occurring. */
if (x == 0)
/* Look up ARG1 in the hash table and see if it has an equivalence
that lets us see what is being compared. */
p = lookup (arg1, safe_hash (arg1, GET_MODE (arg1)) % NBUCKETS,
GET_MODE (arg1));
if (p) p = p->first_same_value;
for (; p; p = p->next_same_value)
{
enum machine_mode inner_mode = GET_MODE (p->exp);
/* If the entry isn't valid, skip it. */
if (! exp_equiv_p (p->exp, p->exp, 1, 0))
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
be equivalent to a comparison operation that would set ARG1 to
either STORE_FLAG_VALUE or zero. If this is an NE operation,
ORIG_CODE is the actual comparison being done; if it is an EQ,
we must reverse ORIG_CODE. On machine with a negative value
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))))
#ifdef FLOAT_STORE_FLAG_VALUE
|| (code == LT
&& GET_MODE_CLASS (inner_mode) == MODE_FLOAT
&& FLOAT_STORE_FLAG_VALUE < 0)
#endif
)
&& GET_RTX_CLASS (GET_CODE (p->exp)) == '<'))
{
x = p->exp;
break;
}
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))))
#ifdef FLOAT_STORE_FLAG_VALUE
|| (code == GE
&& GET_MODE_CLASS (inner_mode) == MODE_FLOAT
&& FLOAT_STORE_FLAG_VALUE < 0)
#endif
)
&& GET_RTX_CLASS (GET_CODE (p->exp)) == '<')
{
reverse_code = 1;
x = p->exp;
break;
}
/* If this is fp + constant, the equivalent is a better operand since
it may let us predict the value of the comparison. */
else if (NONZERO_BASE_PLUS_P (p->exp))
{
arg1 = p->exp;
continue;
}
}
/* If we didn't find a useful equivalence for ARG1, we are done.
Otherwise, set up for the next iteration. */
if (x == 0)
break;
arg1 = XEXP (x, 0), arg2 = XEXP (x, 1);
if (GET_RTX_CLASS (GET_CODE (x)) == '<')
code = GET_CODE (x);
if (reverse_code)
code = reverse_condition (code);
}
/* Return our results. Return the modes from before fold_rtx
because fold_rtx might produce const_int, and then it's too late. */
*pmode1 = GET_MODE (arg1), *pmode2 = GET_MODE (arg2);
*parg1 = fold_rtx (arg1, 0), *parg2 = fold_rtx (arg2, 0);
return code;
}
/* Try to simplify a unary operation CODE whose output mode is to be
MODE with input operand OP whose mode was originally OP_MODE.
Return zero if no simplification can be made. */
rtx
simplify_unary_operation (code, mode, op, op_mode)
enum rtx_code code;
enum machine_mode mode;
rtx op;
enum machine_mode op_mode;
{
register int width = GET_MODE_BITSIZE (mode);
/* The order of these tests is critical so that, for example, we don't
check the wrong mode (input vs. output) for a conversion operation,
such as FIX. At some point, this should be simplified. */
#if !defined(REAL_IS_NOT_DOUBLE) || defined(REAL_ARITHMETIC)
if (code == FLOAT && GET_MODE (op) == VOIDmode
&& (GET_CODE (op) == CONST_DOUBLE || GET_CODE (op) == CONST_INT))
{
HOST_WIDE_INT hv, lv;
REAL_VALUE_TYPE d;
if (GET_CODE (op) == CONST_INT)
lv = INTVAL (op), hv = INTVAL (op) < 0 ? -1 : 0;
else
lv = CONST_DOUBLE_LOW (op), hv = CONST_DOUBLE_HIGH (op);
#ifdef REAL_ARITHMETIC
REAL_VALUE_FROM_INT (d, lv, hv, mode);
#else
if (hv < 0)
{
d = (double) (~ hv);
d *= ((double) ((HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2))
* (double) ((HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2)));
d += (double) (unsigned HOST_WIDE_INT) (~ lv);
d = (- d - 1.0);
}
else
{
d = (double) hv;
d *= ((double) ((HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2))
* (double) ((HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2)));
d += (double) (unsigned HOST_WIDE_INT) lv;
}
#endif /* REAL_ARITHMETIC */
d = real_value_truncate (mode, d);
return CONST_DOUBLE_FROM_REAL_VALUE (d, mode);
}
else if (code == UNSIGNED_FLOAT && GET_MODE (op) == VOIDmode
&& (GET_CODE (op) == CONST_DOUBLE || GET_CODE (op) == CONST_INT))
{
HOST_WIDE_INT hv, lv;
REAL_VALUE_TYPE d;
if (GET_CODE (op) == CONST_INT)
lv = INTVAL (op), hv = INTVAL (op) < 0 ? -1 : 0;
else
lv = CONST_DOUBLE_LOW (op), hv = CONST_DOUBLE_HIGH (op);
if (op_mode == VOIDmode)
{
/* We don't know how to interpret negative-looking numbers in
this case, so don't try to fold those. */
if (hv < 0)
return 0;
}
else if (GET_MODE_BITSIZE (op_mode) >= HOST_BITS_PER_WIDE_INT * 2)
;
else
hv = 0, lv &= GET_MODE_MASK (op_mode);
#ifdef REAL_ARITHMETIC
REAL_VALUE_FROM_UNSIGNED_INT (d, lv, hv, mode);
#else
d = (double) (unsigned HOST_WIDE_INT) hv;
d *= ((double) ((HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2))
* (double) ((HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2)));
d += (double) (unsigned HOST_WIDE_INT) lv;
#endif /* REAL_ARITHMETIC */
d = real_value_truncate (mode, d);
return CONST_DOUBLE_FROM_REAL_VALUE (d, mode);
}
#endif
if (GET_CODE (op) == CONST_INT
&& width <= HOST_BITS_PER_WIDE_INT && width > 0)
{
register HOST_WIDE_INT arg0 = INTVAL (op);
register HOST_WIDE_INT val;
switch (code)