/* Common subexpression elimination for GNU compiler.
Copyright (C) 1987, 1988, 1989 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 1, or (at your option)
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, 675 Mass Ave, Cambridge, MA 02139, USA. */
#include "hard-reg-set.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
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.
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.
Regs are preferred to constants as they are to everything else,
but 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
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.
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
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,
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
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.
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. */
/* Length of vectors indexed by quantity number.
We know in advance we will not need a quantity number this big. */
/* Next quantity number to be allocated.
This is 1 + the largest number needed so far. */
/* Indexed by quantity number, gives the first (or last) (pseudo) register
in the chain of registers that currently contain this quantity. */
static int *qty_first_reg
;
static int *qty_last_reg
;
/* 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. */
/* Indexed by qty number, gives the insn that stored the constant value
recorded in `qty_const'. */
static rtx
*qty_const_insn
;
/* Value stored in CC0 by previous insn:
0 if previous insn didn't store in CC0.
else 0100 + (M&7)<<3 + (N&7)
where M is 1, 0 or -1 if result was >, == or < as signed number
and N is 1, 0 or -1 if result was >, == or < as unsigned number.
0200 bit may also be set, meaning that only == and != comparisons
static int prev_insn_cc0
;
/* For machines where CC0 is one bit, we may see CC0 assigned a
constant value (after fold_rtx).
Record here the value stored in the previous insn (0 if none). */
static rtx prev_insn_explicit_cc0
;
/* Previous actual insn. 0 if at first insn of basic block. */
/* Insn being scanned. */
/* Index by (pseudo) register number, gives the quantity number
of the register's current contents. */
/* Index by (pseudo) register number, gives the number of the next
(pseudo) register in the chain of registers sharing the same value.
Or -1 if this register is at the end of the chain. */
static int *reg_next_eqv
;
/* Index by (pseudo) register number, gives the number of the previous
(pseudo) register in the chain of registers sharing the same value.
Or -1 if this register is at the beginning of the chain. */
static int *reg_prev_eqv
;
/* Index by (pseudo) register number, gives the latest rtx
to use to insert a ref to that register. */
/* Index by (pseudo) register number, gives the number of times
that register has been altered in the current basic block. */
/* Index by (pseudo) 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
static int *reg_in_table
;
/* Two vectors of max_reg ints:
one containing all -1's; in the other, element i contains i.
These are used to initialize various other vectors fast. */
static int *all_minus_one
;
/* Set nonzero in cse_insn to tell cse_basic_block to skip immediately
to the next basic block and treat it as a continuation of this one. */
static int cse_skip_to_next_block
;
/* 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 monononically always.
We use them to see whether a reg is used outside a given basic block. */
/* 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
;
/* canon_hash stores 1 in do_not_record
if it notices a reference to CC0, CC1 or PC. */
static int do_not_record
;
/* 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 `equivalence_only' field means that this expression came from a
REG_EQUIV or REG_EQUAL note; it is not valid for substitution into an insn.
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
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
*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
;
#define HASH(x, m) (canon_hash (x, m) % NBUCKETS)
/* 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. */
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
;
/* 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
Here is how the bits are set.
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. */
int var
: 1; /* Invalidate variable addresses. */
int nonscalar
: 1; /* Invalidate all but scalar variables. */
int all
: 1; /* Invalidate all memory refs. */
/* Nonzero if X has the form (PLUS frame-pointer integer). */
#define FIXED_BASE_PLUS_P(X) \
(GET_CODE (X) == PLUS && GET_CODE (XEXP (X, 1)) == CONST_INT \
&& (XEXP (X, 0) == frame_pointer_rtx || XEXP (X, 0) == arg_pointer_rtx))
static struct table_elt
*lookup ();
static void free_element ();
static void remove_invalid_refs ();
static int exp_equiv_p ();
static void invalidate_from_clobbers ();
static int canon_hash ();
static rtx
equiv_constant ();
static int get_integer_term ();
static rtx
get_related_value ();
static void note_mem_written ();
static int cse_rtx_addr_varies_p ();
/* Return an estimate of the cost of computing rtx X.
The only use of this is to compare the costs of two expressions
to decide whether to replace one with the other. */
register enum rtx_code code
;
total
= 2 * GET_MODE_SIZE (GET_MODE (x
)) / UNITS_PER_WORD
; /* Sum the costs of the sub-rtx's, plus 2 just put in. */
fmt
= GET_RTX_FORMAT (code
); for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
total
+= rtx_cost (XEXP (x
, i
)); for (j
= 0; j
< XVECLEN (x
, i
); j
++)
total
+= rtx_cost (XVECEXP (x
, i
, j
));/* Clear the hash table and initialize each register with its own quantity,
for a new basic block. */
register int vecsize
= max_reg
* sizeof (rtx
);
bzero (reg_rtx
, vecsize
);
bzero (reg_tick
, vecsize
);
bcopy (all_minus_one
, reg_in_table
, vecsize
);
bcopy (all_minus_one
, reg_next_eqv
, vecsize
);
bcopy (all_minus_one
, reg_prev_eqv
, vecsize
);
bcopy (consec_ints
, reg_qty
, vecsize
);
for (i
= 0; i
< max_qty
; i
++)
for (i
= 0; i
< NBUCKETS
; i
++)
register struct table_elt
*this, *next
;
for (this = table
[i
]; this; this = next
)
next
= this->next_same_hash
; bzero (table
, sizeof table
);
prev_insn_explicit_cc0
= 0;/* Say that register REG contains a quantity not in any register before. */
q
= reg_qty
[reg
] = next_qty
++;/* Make reg NEW equivalent to reg OLD.
OLD is not changing; NEW is. */
register int lastr
, firstr
;
register int q
= reg_qty
[old
];
/* Nothing should become eqv until it has a "non-invalid" qty number. */
firstr
= qty_first_reg
[q
]; /* Prefer pseudo regs to hard regs with the same value.
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 (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
; /* If NEW is a hard reg, insert at end.
Otherwise, insert before any hard regs that are at the end. */
while (lastr
< FIRST_PSEUDO_REGISTER
&& 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; reg_next_eqv
[lastr
] = new; reg_prev_eqv
[new] = lastr
;/* Discard the records of what is in register REG. */
register int n
= reg_next_eqv
[reg
];
register int p
= reg_prev_eqv
[reg
];
register int q
= reg_qty
[reg
];
/* Save time if already invalid */
/* It shouldn't be linked to anything if it's invalid. */
if (reg_prev_eqv
[q
] != -1)
if (reg_next_eqv
[q
] != -1)
qty_first_reg
[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. */
register enum rtx_code code
;
register int regno
= REGNO (x
);
if (reg_in_table
[regno
] >= 0 && reg_in_table
[regno
] != reg_tick
[regno
])
remove_invalid_refs (regno
);
reg_in_table
[regno
] = reg_tick
[regno
]; fmt
= GET_RTX_FORMAT (code
); for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
mention_regs (XEXP (x
, i
));
for (j
= 0; j
< XVECLEN (x
, i
); j
++)
mention_regs (XVECEXP (x
, i
, j
));
/* Update the register quantities for inserting X into the hash table
with a value equivalent to CLASSP.
(If CLASSP is not a REG or a SUBREG, it is irrelevant.)
If MODIFIED is nonzero, X is a destination; it is being modified.
Note that reg_invalidate 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. */
insert_regs (x
, classp
, modified
)
struct table_elt
*classp
;
register int regno
= REGNO (x
);
if (modified
|| reg_qty
[regno
] == regno
)
if (classp
&& GET_CODE (classp
->exp
) == REG
)
make_regs_eqv (regno
, REGNO (classp
->exp
));
/* Make sure reg_rtx is set up even for regs
not explicitly set (such as function value). */
reg_rtx
[REGNO (classp
->exp
)] = classp
->exp
; /* Copying a subreg into a subreg makes the regs equivalent,
but only if the entire regs' mode is within one word.
Copying one reg of a DImode into one reg of another DImode
does not make them equivalent. */
else if (GET_CODE (x
) == SUBREG
&& GET_CODE (SUBREG_REG (x
)) == REG
&& GET_MODE_SIZE (GET_MODE (SUBREG_REG (x
))) <= UNITS_PER_WORD
|| reg_qty
[REGNO (SUBREG_REG (x
))] == REGNO (SUBREG_REG (x
))))
if (classp
&& GET_CODE (classp
->exp
) == SUBREG
&& GET_CODE (SUBREG_REG (classp
->exp
)) == REG
&& GET_MODE (SUBREG_REG (classp
->exp
)) == GET_MODE (SUBREG_REG (x
)))
int oregno
= REGNO (SUBREG_REG (classp
->exp
));
make_regs_eqv (REGNO (SUBREG_REG (x
)), oregno
);
/* Make sure reg_rtx is set up even for regs
not explicitly set (such as function value). */
reg_rtx
[oregno
] = SUBREG_REG (classp
->exp
); make_new_qty (REGNO (SUBREG_REG (x
)));
/* Look in or update the hash table. */
/* Put the element ELT on the list of free elements. */
elt
->next_same_hash
= free_element_chain
; free_element_chain
= elt
;/* Return an element that is free for use. */
static struct table_elt
*
struct table_elt
*elt
= free_element_chain
;
free_element_chain
= elt
->next_same_hash
; 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. */
register struct table_elt
*elt
;
/* 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
;
prev
->next_same_value
= next
; register struct table_elt
*newfirst
= 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
;
prev
->next_same_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
->related_value
= elt
->related_value
; if (p
->related_value
== p
)
/* 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
static struct table_elt
*
register struct table_elt
*p
;
for (p
= table
[hash
]; p
; p
= p
->next_same_hash
)
if (mode
== p
->mode
&& (x
== p
->exp
|| exp_equiv_p (x
, p
->exp
, 1)))
/* 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
)
register struct table_elt
*p
;
/* 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
)
for (p
= table
[hash
]; p
; p
= p
->next_same_hash
)
if (mode
== p
->mode
&& (x
== p
->exp
|| exp_equiv_p (x
, p
->exp
, 0)))
/* Look for an expression equivalent to X and with code CODE.
If one is found, return that expression. */
lookup_as_function (x
, code
)
register struct table_elt
*p
= lookup (x
, safe_hash (x
, 0) % NBUCKETS
,
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 (XEXP (p
->exp
, 0), XEXP (p
->exp
, 0), 1)))
/* Insert X in the hash table, assuming HASH is its hash code
and CLASSP is the current first 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 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. */
(((X)->cost < (Y)->cost) || \
((X)->cost == (Y)->cost \
&& GET_CODE ((X)->exp) == REG && GET_CODE ((Y)->exp) == REG \
&& (uid_cuid[regno_last_uid[REGNO ((X)->exp)]] > cse_basic_block_end \
|| uid_cuid[regno_first_uid[REGNO ((X)->exp)]] < cse_basic_block_start) \
&& (uid_cuid[regno_last_uid[REGNO ((X)->exp)]] \
> uid_cuid[regno_last_uid[REGNO ((Y)->exp)]])))
static struct table_elt
*
insert (x
, classp
, hash
, mode
)
register struct table_elt
*classp
;
register struct table_elt
*elt
;
/* Put an element for X into the right hash bucket. */
elt
->cost
= rtx_cost (x
) * 2; /* Make pseudo regs a little cheaper than hard regs. */
if (GET_CODE (x
) == REG
&& REGNO (x
) >= FIRST_PSEUDO_REGISTER
)
elt
->next_same_value
= 0; elt
->prev_same_value
= 0; elt
->next_same_hash
= table
[hash
]; elt
->equivalence_only
= 0; table
[hash
]->prev_same_hash
= elt
; /* Put it into the proper value-class. */
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
; /* 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
);
/* Put it after P and before NEXT. */
elt
->next_same_value
= next
; next
->prev_same_value
= elt
; elt
->prev_same_value
= p
; p
->next_same_value
= elt
; elt
->first_same_value
= classp
; elt
->first_same_value
= elt
; if ((CONSTANT_P (x
) || GET_CODE (x
) == CONST_DOUBLE
|| FIXED_BASE_PLUS_P (x
))
&& GET_CODE (elt
->first_same_value
->exp
) == REG
)
qty_const
[reg_qty
[REGNO (elt
->first_same_value
->exp
)]] = x
; qty_const_insn
[reg_qty
[REGNO (elt
->first_same_value
->exp
)]] = this_insn
; if (elt
->next_same_value
!= 0
&& (CONSTANT_P (elt
->next_same_value
->exp
)
|| GET_CODE (elt
->next_same_value
->exp
) == CONST_DOUBLE
|| FIXED_BASE_PLUS_P (elt
->next_same_value
->exp
)))
qty_const
[reg_qty
[REGNO (x
)]] = elt
->next_same_value
->exp
; qty_const_insn
[reg_qty
[REGNO (x
)]] = this_insn
; if (CONSTANT_P (elt
->first_same_value
->exp
)
|| GET_CODE (elt
->first_same_value
->exp
) == CONST_DOUBLE
|| FIXED_BASE_PLUS_P (elt
->first_same_value
->exp
))
qty_const
[reg_qty
[REGNO (x
)]] = elt
->first_same_value
->exp
; 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
); struct table_elt
*subelt
, *subelt_prev
;
/* Get the integer-free subexpression in the hash table. */
subhash
= safe_hash (subexp
, mode
) % NBUCKETS
; subelt
= lookup (subexp
, subhash
, mode
); subelt
= insert (subexp
, 0, 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. */
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
;/* 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).
A nonvarying address may be just a register or just
a symbol reference, or it may be either of those plus
register struct table_elt
*p
;
/* 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,
register int hash
= HASH (x
, 0);
reg_invalidate (REGNO (x
));
remove (lookup_for_remove (x
, hash
, GET_MODE (x
)), hash
);
if (GET_CODE (x
) == SUBREG
)
if (GET_CODE (SUBREG_REG (x
)) != REG
)
invalidate (SUBREG_REG (x
));
/* 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. */
/* Registers with nonvarying addresses usually have constant equivalents;
but the frame pointer register is also possible. */
if (GET_CODE (base
) == REG
&& qty_const
[reg_qty
[REGNO (base
)]] != 0)
base
= qty_const
[reg_qty
[REGNO (base
)]]; if (GET_CODE (base
) == CONST
)
if (GET_CODE (base
) == PLUS
&& GET_CODE (XEXP (base
, 1)) == CONST_INT
)
start
= INTVAL (XEXP (base
, 1)); end
= start
+ GET_MODE_SIZE (GET_MODE (x
)); 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 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. */
remove_invalid_refs (regno
)
register struct table_elt
*p
, *next
;
register rtx x
= reg_rtx
[regno
];
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_p (p
->exp
, x
))
/* Remove from the hash table all expressions that reference memory,
or some of them as specified by *WRITES. */
invalidate_memory (writes
)
struct write_data
*writes
;
register struct table_elt
*p
, *next
;
int nonscalar
= writes
->nonscalar
;
for (i
= 0; i
< NBUCKETS
; i
++)
for (p
= table
[i
]; p
; p
= next
)
next
= p
->next_same_hash
; || (nonscalar
&& p
->in_struct
)
|| cse_rtx_addr_varies_p (p
->exp
)))
/* Return the value of the integer term in X, if one is apparent;
We do not check extremely carefully for the presence of integer terms
but rather consider only the cases that `insert' notices
for the `related_value' field. */
if (GET_CODE (x
) == CONST
)
if (GET_CODE (x
) == MINUS
&& GET_CODE (XEXP (x
, 1)) == CONST_INT
)
return - INTVAL (XEXP (x
, 1));
if (GET_CODE (x
) != PLUS
)
if (GET_CODE (XEXP (x
, 0)) == CONST_INT
)
return INTVAL (XEXP (x
, 0));
if (GET_CODE (XEXP (x
, 1)) == CONST_INT
)
return INTVAL (XEXP (x
, 1));
if (GET_CODE (x
) != CONST
)
if (GET_CODE (x
) == PLUS
)
if (GET_CODE (XEXP (x
, 0)) == CONST_INT
)
if (GET_CODE (XEXP (x
, 1)) == CONST_INT
)
else if (GET_CODE (x
) == MINUS
&& GET_CODE (XEXP (x
, 1)) == CONST_INT
)
/* 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 or it would not be a valid address, return 0. */
use_related_value (x
, elt
)
register struct table_elt
*relt
= 0;
register struct table_elt
*p
;
/* 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)
else if (elt
== 0 && GET_CODE (x
) == CONST
)
rtx subexp
= get_related_value (x
); safe_hash (subexp
, GET_MODE (subexp
)) % NBUCKETS
,
/* Search all related table entries for one that has an
if (p
->first_same_value
!= 0
&& GET_CODE (p
->first_same_value
->exp
) == REG
)
/* We went all the way around, so there is nothing to be found.
/* Perhaps RELT was in the table for some other reason and
it has no related values recorded. */
/* Note: OFFSET may be 0 if P->xexp and X are related by commutativity. */
offset
= (get_integer_term (x
) - get_integer_term (p
->exp
)); addr
= plus_constant (p
->first_same_value
->exp
, offset
); if (memory_address_p (QImode
, addr
))
/* 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.
It also knows it can use HASHREG to get the hash code of (REG n). */
((((int) REG << 7) + reg_qty[REGNO (RTX)]) % NBUCKETS)
register enum rtx_code code
;
/* repeat is used to turn tail-recursion into iteration. */
/* We do not invalidate anything on pushing or popping
because they cannot change anything but the stack pointer;
but that means we must consider the stack pointer volatile
since it can be changed "mysteriously". */
register int regno
= REGNO (x
);
if (regno
== STACK_POINTER_REGNUM
|| (regno
< FIRST_PSEUDO_REGISTER
&& global_regs
[regno
]))
return hash
+ ((int) REG
<< 7) + reg_qty
[regno
];
hash
+= ((int) mode
+ ((int) CONST_INT
<< 7) + INTVAL (x
) + (INTVAL (x
) >> HASHBITS
));
return ((1 << HASHBITS
) - 1) & hash
;
/* This is like the general case, except that it only counts
the first two elements. */
hash
+= (int) code
+ (int) GET_MODE (x
); for (i
= 2; i
< GET_RTX_LENGTH (CONST_DOUBLE
); i
++)
hash
+= ((1 << HASHBITS
) - 1) & (tem
+ (tem
>> HASHBITS
)); /* Assume there is only one rtx object for any given label. */
/* Use `and' to ensure a positive number. */
return (hash
+ ((int) LABEL_REF
<< 7)
+ ((int) XEXP (x
, 0) & ((1 << HASHBITS
) - 1)));
return (hash
+ ((int) SYMBOL_REF
<< 7)
+ ((int) XEXP (x
, 0) & ((1 << HASHBITS
) - 1)));
if (! RTX_UNCHANGING_P (x
))
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. */
i
= GET_RTX_LENGTH (code
) - 1; hash
+= (int) code
+ (int) GET_MODE (x
); fmt
= GET_RTX_FORMAT (code
); /* 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. */
hash
+= canon_hash (XEXP (x
, i
), 0); for (j
= 0; j
< XVECLEN (x
, i
); j
++)
hash
+= canon_hash (XVECEXP (x
, i
, j
), 0); register char *p
= XSTR (x
, i
);
hash
+= ((1 << HASHBITS
) - 1) & (tem
+ (tem
>> HASHBITS
)); register int tem
= XINT (x
, i
);
hash
+= ((1 << HASHBITS
) - 1) & (tem
+ (tem
>> HASHBITS
));/* Like canon_hash but with no side effects. */
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 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 1 iff X and Y would canonicalize into the same thing,
without actually constructing the canonicalization of either one.
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. */
exp_equiv_p (x
, y
, validate
)
register enum rtx_code code
;
/* Note: it is incorrect to assume an expression is equivalent to itself
if VALIDATE is nonzero. */
if (code
!= GET_CODE (y
))
return XINT (x
, 0) == XINT (y
, 0);
return XEXP (x
, 0) == XEXP (y
, 0);
return (reg_qty
[REGNO (x
)] == reg_qty
[REGNO (y
)]
|| reg_in_table
[REGNO (y
)] == reg_tick
[REGNO (y
)]));
/* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. */
if (GET_MODE (x
) != GET_MODE (y
))
/* 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
--)
if (! exp_equiv_p (XEXP (x
, i
), XEXP (y
, i
), validate
))
if (XVECLEN (x
, i
) != XVECLEN (y
, i
))
for (j
= 0; j
< XVECLEN (x
, i
); j
++)
if (! exp_equiv_p (XVECEXP (x
, i
, j
), XVECEXP (y
, i
, j
), validate
))
if (strcmp (XSTR (x
, i
), XSTR (y
, i
)))
if (XINT (x
, i
) != XINT (y
, i
))
/* 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. */
register enum rtx_code code
;
/* If X as a whole has the same code as Y, they may match.
if (code
== GET_CODE (y
))
if (exp_equiv_p (x
, y
, 0))
/* X does not match, so try its subexpressions. */
fmt
= GET_RTX_FORMAT (code
); for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
if (refers_to_p (XEXP (x
, i
), y
))
for (j
= 0; j
< XVECLEN (x
, i
); j
++)
if (refers_to_p (XVECEXP (x
, i
, j
), y
))
/* Return 1 iff any subexpression of X refers to memory
at an address of REG plus some offset
such that any of the bytes' offsets fall between START (inclusive)
The value is undefined if X is a varying address.
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. */
refers_to_mem_p (x
, reg
, start
, end
)
register enum rtx_code code
;
register rtx addr
= XEXP (x
, 0); /* Get the address. */
if (GET_CODE (addr
) == REG
/* qty_const is 0 when outside the cse pass;
at such times, this info is not available. */
&& qty_const
[reg_qty
[REGNO (addr
)]] != 0)
addr
= qty_const
[reg_qty
[REGNO (addr
)]]; if (GET_CODE (addr
) == CONST
)
/* If ADDR is BASE, or BASE plus an integer, put
else if (GET_CODE (addr
) == PLUS
&& GET_CODE (XEXP (addr
, 1)) == CONST_INT
)
i
= INTVAL (XEXP (addr
, 1)); myend
= i
+ GET_MODE_SIZE (GET_MODE (x
)); return myend
> start
&& i
< 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 (refers_to_mem_p (XEXP (x
, i
), reg
, start
, end
))
for (j
= 0; j
< XVECLEN (x
, i
); j
++)
if (refers_to_mem_p (XVECEXP (x
, i
, j
), reg
, start
, end
))
/* 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. */
cse_rtx_addr_varies_p (x
)
&& GET_CODE (XEXP (x
, 0)) == REG
&& qty_const
[reg_qty
[REGNO (XEXP (x
, 0))]] != 0)
return rtx_addr_varies_p (x
);
/* Canonicalize an expression:
replace each register reference inside it
with the "oldest" equivalent register. */
register enum rtx_code code
;
/* 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. */
if (REGNO (x
) < FIRST_PSEUDO_REGISTER
)
new = reg_rtx
[qty_first_reg
[reg_qty
[REGNO (x
)]]];
fmt
= GET_RTX_FORMAT (code
); for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
XEXP (x
, i
) = canon_reg (XEXP (x
, i
));
for (j
= 0; j
< XVECLEN (x
, i
); j
++)
XVECEXP (x
, i
, j
) = canon_reg (XVECEXP (x
, i
, j
));
/* 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.
Otherwise, return X, possibly with one or more operands
modified by recursive calls to this function.
If X is a register whose contents are known, we do NOT
return those contents. This is because an instruction that
uses a register is usually faster than one that uses a constant.
COPYFLAG is nonzero for memory addresses and subexpressions thereof.
If COPYFLAG is nonzero, we avoid altering X itself
by creating new structure when necessary. In this case we
can risk creating invalid structure because it will be tested.
If COPYFLAG is zero, be careful not to substitute constants
into expressions that cannot be simplified. */
register enum rtx_code code
;
/* Constant equivalents of first three operands of X;
0 when no such equivalent is known. */
width
= GET_MODE_BITSIZE (GET_MODE (x
)); /* No use simplifying an EXPR_LIST
since they are used only for lists of args
in a function call's REG_EQUAL note. */
/* We must be careful when folding a memory address
to avoid making it invalid. So fold nondestructively
and use the result only if it's valid. */
rtx newaddr
= fold_rtx (XEXP (x
, 0), 1); /* Save time if no change was made. */
if (XEXP (x
, 0) == newaddr
)
if (! memory_address_p (GET_MODE (x
), newaddr
)
&& memory_address_p (GET_MODE (x
), XEXP (x
, 0)))
/* Don't replace a value with a more expensive one. */
if (rtx_cost (XEXP (x
, 0)) < rtx_cost (newaddr
))
return gen_rtx (MEM
, GET_MODE (x
), newaddr
);
/* Try folding our operands.
Then see which ones have constant values known. */
fmt
= GET_RTX_FORMAT (code
); for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
register rtx tem
= fold_rtx (XEXP (x
, i
), copyflag
);
/* If an operand has changed under folding, and we are not supposed to
alter the original structure, copy X if we haven't yet done so. */
if (! copied
&& tem
!= XEXP (x
, i
))
rtx
new = rtx_alloc (code
); PUT_MODE (new, GET_MODE (x
));
for (j
= 0; j
< GET_RTX_LENGTH (code
); j
++)
XINT (new, j
) = XINT (x
, j
);
/* Install the possibly altered folded operand. */
/* For the first three operands, see if the operand
is constant or equivalent to a constant. */
rtx const_arg
= equiv_constant (tem
); /* Don't try to fold inside of a vector of expressions.
Doing nothing is is harmless. */
/* If a commutative operation, place a constant integer as the second
operand unless the first operand is also a constant integer. Otherwise,
place any constant second unless the first operand is also a constant. */
if (const_arg0
&& const_arg0
== XEXP (x
, 0)
&& (! (const_arg1
&& const_arg1
== XEXP (x
, 1))
|| (GET_CODE (const_arg0
) == CONST_INT
&& GET_CODE (const_arg1
) != CONST_INT
)))
copied
= 1, x
= copy_rtx (x
); tem
= XEXP (x
, 0); XEXP (x
, 0) = XEXP (x
, 1); XEXP (x
, 1) = tem
; tem
= const_arg0
; const_arg0
= const_arg1
; const_arg1
= tem
; /* Now decode the kind of rtx X is
and then return X (if nothing can be done)
or store a value in VAL and drop through
(to return a CONST_INT for the integer VAL). */
if (GET_RTX_LENGTH (code
) == 1)
if (GET_CODE (const_arg0
) == CONST_INT
)
register int arg0
= INTVAL (const_arg0
);
enum machine_mode mode
= GET_MODE (XEXP (x
, 0));
if (GET_MODE_BITSIZE (mode
) < HOST_BITS_PER_INT
)
val
= arg0
& ~((-1) << GET_MODE_BITSIZE (mode
)); enum machine_mode mode
= GET_MODE (XEXP (x
, 0));
if (GET_MODE_BITSIZE (mode
) < HOST_BITS_PER_INT
)
val
= arg0
& ~((-1) << GET_MODE_BITSIZE (mode
)); if (val
& (1 << (GET_MODE_BITSIZE (mode
) - 1)))
val
-= 1 << GET_MODE_BITSIZE (mode
);#if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
else if (GET_CODE (const_arg0
) == CONST_DOUBLE
&& GET_MODE_CLASS (GET_MODE (x
)) == MODE_FLOAT
)
register REAL_VALUE_TYPE arg0
;
warning ("floating point trap in constant folding");
set_float_handler (handler
);
bcopy (&CONST_DOUBLE_LOW (const_arg0
), &u
, sizeof u
);
u
.d
= REAL_VALUE_NEGATE (arg0
); x
= immed_real_const_1 (u
.d
, GET_MODE (x
)); else if (GET_RTX_LENGTH (code
) == 2)
register int arg0
, arg1
, arg0s
, arg1s
;
/* If 1st arg is the condition codes, 2nd must be zero
and this must be a comparison.
Decode the info on how the previous insn set the cc0
and use that to deduce result of comparison. */
if (XEXP (x
, 0) == cc0_rtx
|| GET_CODE (XEXP (x
, 0)) == COMPARE
)
if (XEXP (x
, 0) == cc0_rtx
)
arg0
= fold_cc0 (VOIDmode
, XEXP (x
, 0)); || const_arg1
!= const0_rtx
/* 0200 bit in arg0 means only zeroness is known,
and sign is not known. */
|| ((arg0
& 0200) != 0 && code
!= EQ
&& code
!= NE
))
/* Extract either the signed or the unsigned digit from ARG0. */
if (code
== LEU
|| code
== LTU
|| code
== GEU
|| code
== GTU
)
if (arg0
== 7) arg0
= -1;
return (arg0
<= 0) ? const1_rtx
: const0_rtx
;
return (arg0
< 0) ? const1_rtx
: const0_rtx
;
return (arg0
>= 0) ? const1_rtx
: const0_rtx
;
return (arg0
> 0) ? const1_rtx
: const0_rtx
;
return (arg0
!= 0) ? const1_rtx
: const0_rtx
;
return (arg0
== 0) ? const1_rtx
: const0_rtx
;
if (const_arg0
== 0 || const_arg1
== 0
|| GET_CODE (const_arg0
) != CONST_INT
|| GET_CODE (const_arg1
) != CONST_INT
)
/* Even if we can't compute a constant result,
there are some cases worth simplifying. */
/* Note that we cannot rely on constant args to come last,
even for commutative operators,
because that happens only when the constant is explicit. */
if (const_arg0
== const0_rtx
|| const_arg0
== fconst0_rtx
|| const_arg0
== dconst0_rtx
)
if (const_arg1
== const0_rtx
|| const_arg1
== fconst0_rtx
|| const_arg1
== dconst0_rtx
)
/* Handle both-operands-constant cases. */
if (const_arg0
!= 0 && const_arg1
!= 0
&& GET_CODE (const_arg0
) != CONST_DOUBLE
&& GET_CODE (const_arg1
) != CONST_DOUBLE
&& GET_MODE_CLASS (GET_MODE (x
)) == MODE_INT
)
if (GET_CODE (const_arg1
) == CONST_INT
)
new = plus_constant (const_arg0
, INTVAL (const_arg1
));
new = gen_rtx (PLUS
, GET_MODE (x
), const0_rtx
, const0_rtx
);
XEXP (new, 0) = const_arg0
;
if (GET_CODE (const_arg0
) == CONST
)
XEXP (new, 0) = XEXP (const_arg0
, 0);
XEXP (new, 1) = const_arg1
;
if (GET_CODE (const_arg1
) == CONST
)
XEXP (new, 1) = XEXP (const_arg1
, 0);
new = gen_rtx (CONST
, GET_MODE (new), new);
&& GET_CODE (const_arg1
) == CONST_INT
&& GET_CODE (XEXP (x
, 0)) == PLUS
&& (CONSTANT_P (XEXP (XEXP (x
, 0), 0))
|| CONSTANT_P (XEXP (XEXP (x
, 0), 1))))
/* constant + (variable + constant)
can result if an index register is made constant.
We simplify this by adding the constants.
If we did not, it would become an invalid address. */
new = plus_constant (XEXP (x
, 0),
if (const_arg1
== const0_rtx
)
if (XEXP (x
, 0) == XEXP (x
, 1)
|| (const_arg0
!= 0 && const_arg0
== const_arg1
))
/* We can't assume x-x is 0 with IEEE floating point. */
if (GET_MODE_CLASS (GET_MODE (x
)) == MODE_INT
)
if (const_arg1
== const0_rtx
|| const_arg1
== fconst0_rtx
|| const_arg1
== dconst0_rtx
)
if (XEXP (x
, 0) == XEXP (x
, 1)
|| (const_arg0
!= 0 && const_arg0
== const_arg1
))
/* We can't assume x-x is 0 with IEEE floating point. */
if (GET_MODE_CLASS (GET_MODE (x
)) == MODE_INT
)
/* Change subtraction from zero into negation. */
if (const_arg0
== const0_rtx
)
return gen_rtx (NEG
, GET_MODE (x
), XEXP (x
, 1));
/* Don't let a relocatable value get a negative coeff. */
if (const_arg0
!= 0 && const_arg1
!= 0
&& GET_CODE (const_arg1
) == CONST_INT
)
new = plus_constant (const_arg0
, - INTVAL (const_arg1
));
if (const_arg1
&& GET_CODE (const_arg1
) == CONST_INT
&& INTVAL (const_arg1
) == -1
/* Don't do this in the case of widening multiplication. */
&& GET_MODE (XEXP (x
, 0)) == GET_MODE (x
))
return gen_rtx (NEG
, GET_MODE (x
), XEXP (x
, 0));
if (const_arg0
&& GET_CODE (const_arg0
) == CONST_INT
&& INTVAL (const_arg0
) == -1
&& GET_MODE (XEXP (x
, 1)) == GET_MODE (x
))
return gen_rtx (NEG
, GET_MODE (x
), XEXP (x
, 1));
if (const_arg1
== const0_rtx
|| const_arg0
== const0_rtx
)
if (const_arg1
== fconst0_rtx
|| const_arg0
== fconst0_rtx
)
if (const_arg1
== dconst0_rtx
|| const_arg0
== dconst0_rtx
)
if (const_arg1
== const1_rtx
)
if (const_arg0
== const1_rtx
)
if (const_arg1
== const0_rtx
)
if (const_arg0
== const0_rtx
)
if (const_arg1
&& GET_CODE (const_arg1
) == CONST_INT
&& (INTVAL (const_arg1
) & GET_MODE_MASK (GET_MODE (x
)))
== GET_MODE_MASK (GET_MODE (x
)))
if (const_arg0
&& GET_CODE (const_arg0
) == CONST_INT
&& (INTVAL (const_arg0
) & GET_MODE_MASK (GET_MODE (x
)))
== GET_MODE_MASK (GET_MODE (x
)))
if (const_arg1
== const0_rtx
)
if (const_arg0
== const0_rtx
)
if (const_arg1
&& GET_CODE (const_arg1
) == CONST_INT
&& (INTVAL (const_arg1
) & GET_MODE_MASK (GET_MODE (x
)))
== GET_MODE_MASK (GET_MODE (x
)))
return gen_rtx (NOT
, GET_MODE (x
), XEXP (x
, 0));
if (const_arg0
&& GET_CODE (const_arg0
) == CONST_INT
&& (INTVAL (const_arg0
) & GET_MODE_MASK (GET_MODE (x
)))
== GET_MODE_MASK (GET_MODE (x
)))
return gen_rtx (NOT
, GET_MODE (x
), XEXP (x
, 1));
if (const_arg1
== const0_rtx
|| const_arg0
== const0_rtx
)
if (const_arg1
&& GET_CODE (const_arg1
) == CONST_INT
&& (INTVAL (const_arg1
) & GET_MODE_MASK (GET_MODE (x
)))
== GET_MODE_MASK (GET_MODE (x
)))
if (const_arg0
&& GET_CODE (const_arg0
) == CONST_INT
&& (INTVAL (const_arg0
) & GET_MODE_MASK (GET_MODE (x
)))
== GET_MODE_MASK (GET_MODE (x
)))
if (const_arg1
== const1_rtx
)
if (const_arg0
== const0_rtx
)
if (const_arg0
== const0_rtx
|| const_arg1
== const1_rtx
)
if (const_arg1
== const0_rtx
)
if (const_arg0
== const0_rtx
)
if (new != 0 && LEGITIMATE_CONSTANT_P (new))
if (GET_MODE (XEXP (x
, 0)) != VOIDmode
)
arithwidth
= GET_MODE_BITSIZE (GET_MODE (XEXP (x
, 0))); if (GET_MODE (XEXP (x
, 1)) != VOIDmode
)
arithwidth
= GET_MODE_BITSIZE (GET_MODE (XEXP (x
, 1))); /* Get the integer argument values in two forms:
zero-extended in ARG0, ARG1 and sign-extended in ARG0S, ARG1S. */
arg0
= INTVAL (const_arg0
); arg1
= INTVAL (const_arg1
); if (arithwidth
< HOST_BITS_PER_INT
&& arithwidth
> 0)
arg0
&= (1 << arithwidth
) - 1; arg1
&= (1 << arithwidth
) - 1; if (arg0s
& (1 << (arithwidth
- 1)))
arg0s
|= ((-1) << arithwidth
); if (arg1s
& (1 << (arithwidth
- 1)))
arg1s
|= ((-1) << arithwidth
); /* Compute the value of the arithmetic. */
val
= (unsigned) arg0
* arg1
; val
= (unsigned) arg0
/ arg1
; val
= (unsigned) arg0
% arg1
; val
= ((unsigned) arg0
) <= ((unsigned) arg1
); val
= ((unsigned) arg0
) < ((unsigned) arg1
); val
= ((unsigned) arg0
) >= ((unsigned) arg1
); val
= ((unsigned) arg0
) > ((unsigned) arg1
); /* If target machine uses negative shift counts
but host machine does not, simulate them. */
val
= ((unsigned) arg0
) >> -arg1
; val
= ((unsigned) arg0
) << arg1
; int size
= GET_MODE_SIZE (GET_MODE (x
)) * BITS_PER_UNIT
;
val
= ((((unsigned) arg0
) << arg1
) | (((unsigned) arg0
) >> (size
- arg1
)));
val
= ((((unsigned) arg0
) >> arg1
) | (((unsigned) arg0
) << (size
- arg1
)));
/* If target machine uses negative shift counts
but host machine does not, simulate them. */
val
= ((unsigned) arg0
) << -arg1
; val
= ((unsigned) arg0
) >> arg1
; else if (code
== IF_THEN_ELSE
&& const_arg0
!= 0
&& GET_CODE (const_arg0
) == CONST_INT
)
return XEXP (x
, ((INTVAL (const_arg0
) != 0) ? 1 : 2));
else if (code
== IF_THEN_ELSE
&& XEXP (x
, 0) == cc0_rtx
&& prev_insn_explicit_cc0
!= 0)
return XEXP (x
, ((INTVAL (prev_insn_explicit_cc0
) != 0) ? 1 : 2));
else if (code
== SIGN_EXTRACT
|| code
== ZERO_EXTRACT
)
if (const_arg0
!= 0 && const_arg1
!= 0 && const_arg2
!= 0
&& GET_CODE (const_arg0
) == CONST_INT
&& GET_CODE (const_arg1
) == CONST_INT
&& GET_CODE (const_arg2
) == CONST_INT
)
/* Extracting a bit-field from a constant */
val
= INTVAL (const_arg0
); val
>>= (GET_MODE_BITSIZE (GET_MODE (XEXP (x
, 0))) - INTVAL (const_arg2
) - INTVAL (const_arg1
));
val
>>= INTVAL (const_arg2
); if (HOST_BITS_PER_INT
!= INTVAL (const_arg1
))
val
&= (1 << INTVAL (const_arg1
)) - 1; /* If desired, propagate sign bit. */
&& (val
& (1 << (INTVAL (const_arg1
) - 1))))
val
|= ~ (1 << INTVAL (const_arg1
)); /* Clear the bits that don't belong in our mode,
unless they and our sign bit are all one.
So we get either a reasonable negative value or a reasonable
unsigned value for this mode. */
if (width
< HOST_BITS_PER_INT
&& width
> 0)
if ((val
& ((-1) << (width
- 1)))
!= ((-1) << (width
- 1)))
/* Now make the new constant. */
rtx
new = gen_rtx (CONST_INT
, VOIDmode
, val
); return LEGITIMATE_CONSTANT_P (new) ? new : x
;
/* Return a constant value currently equivalent to X.
Return 0 if we don't know one. */
if (CONSTANT_P (x
) || GET_CODE (x
) == CONST_DOUBLE
)
else if (GET_CODE (x
) == REG
&& (tem1
= qty_const
[reg_qty
[REGNO (x
)]]) != 0
/* Make sure it is really a constant */
&& GET_CODE (tem1
) != REG
&& GET_CODE (tem1
) != PLUS
)
/* If integer truncation is being done with SUBREG,
we can compute the result. */
else if (GET_CODE (x
) == SUBREG
&& SUBREG_WORD (x
) == 0
&& (tem1
= qty_const
[reg_qty
[REGNO (SUBREG_REG (x
))]]) != 0
/* Make sure it is a known integer. */
&& GET_CODE (tem1
) == CONST_INT
&& GET_MODE_SIZE (GET_MODE (x
)) <= HOST_BITS_PER_INT
/* Make sure this SUBREG is truncation. */
&& GET_MODE_SIZE (GET_MODE (x
)) < GET_MODE_SIZE (GET_MODE (SUBREG_REG (x
))))
int value
= INTVAL (tem1
);
if (GET_MODE_BITSIZE (GET_MODE (x
)) != HOST_BITS_PER_INT
)
value
&= (1 << GET_MODE_BITSIZE (GET_MODE (x
))) - 1; if (value
== INTVAL (tem1
))
return gen_rtx (CONST_INT
, VOIDmode
, value
);
/* Given an expression X which is used to set CC0,
return an integer recording (in the encoding used for prev_insn_cc0)
how the condition codes would be set by that expression.
Return 0 if the value is not constant
or if there is any doubt what condition codes result from it.
MODE is the machine mode to use to interpret X if it is a CONST_INT. */
if (GET_CODE (x
) == COMPARE
)
rtx y0
= fold_rtx (XEXP (x
, 0), 0); rtx y1
= fold_rtx (XEXP (x
, 1), 0); tem
= equiv_constant (y0
); tem
= equiv_constant (y1
); /* Compare floats; report the result only for signed compares
since that's all there are for floats. */
if (GET_CODE (y0
) == CONST_DOUBLE
&& GET_CODE (y1
) == CONST_DOUBLE
&& GET_MODE_CLASS (GET_MODE (y0
)) == MODE_FLOAT
)
union real_extract u0
, u1
;
warning ("floating point trap in constant folding");
set_float_handler (handler
);
bcopy (&CONST_DOUBLE_LOW (y0
), &u0
, sizeof u0
);
bcopy (&CONST_DOUBLE_LOW (y1
), &u1
, sizeof u1
);
value
= 0100 + (REAL_VALUES_LESS (u0
.d
, u1
.d
) ? 7 << 3 : REAL_VALUES_LESS (u1
.d
, u0
.d
) ? 1 << 3 : 0);
/* Aside from that, demand explicit integers. */
if (GET_CODE (y0
) != CONST_INT
)
if (GET_CODE (y1
) != CONST_INT
)
int width
= GET_MODE_BITSIZE (m
);
if (width
< HOST_BITS_PER_INT
)
s0
= u0
&= ~ ((-1) << width
); s1
= u1
&= ~ ((-1) << width
); if (u0
& (1 << (width
- 1)))
if (u1
& (1 << (width
- 1)))
return 0100 + ((s0
< s1
? 7 : s0
> s1
) << 3)
+ (((unsigned) u0
< (unsigned) u1
) ? 7
: ((unsigned) u0
> (unsigned) u1
));
if (GET_CODE (y0
) == REG
)
y0
= qty_const
[reg_qty
[REGNO (y0
)]]; /* Register had no constant equivalent? We can't do anything. */
/* If we don't know the mode, we can't test the sign. */
/* Value is frame-pointer plus a constant? Or non-explicit constant?
That isn't zero, but we don't know its sign. */
if (FIXED_BASE_PLUS_P (y0
)
|| GET_CODE (y0
) == SYMBOL_REF
|| GET_CODE (y0
) == CONST
|| GET_CODE (y0
) == LABEL_REF
)
return 0300 + (1<<3) + 1;
/* Otherwise, only integers enable us to optimize. */
if (GET_CODE (y0
) != CONST_INT
)
int width
= GET_MODE_BITSIZE (m
);
if (width
< HOST_BITS_PER_INT
)
s0
= u0
&= ~ ((-1) << GET_MODE_BITSIZE (m
)); if (u0
& (1 << (GET_MODE_BITSIZE (m
) - 1)))
s0
|= ((-1) << GET_MODE_BITSIZE (m
)); return 0100 + ((s0
< 0 ? 7 : s0
> 0) << 3) + (u0
!= 0);
/* Attempt to prove that a loop will be executed >= 1 times,
or prove it will be executed 0 times.
If either can be proved, delete some of the code. */
predecide_loop_entry (insn
)
register rtx jump
= NEXT_INSN (insn
);
register rtx loop_top_label
= NEXT_INSN (jump
);
enum anon1
{ UNK
, DELETE_LOOP
, DELETE_JUMP
} disposition
= UNK
;
/* Give up if we don't find a jump that enters the loop. */
if (! simplejump_p (jump
))
/* Find the label at the top of the loop. */
while (GET_CODE (loop_top_label
) == BARRIER
|| GET_CODE (loop_top_label
) == NOTE
)
loop_top_label
= NEXT_INSN (loop_top_label
); if (GET_CODE (loop_top_label
) != CODE_LABEL
)
/* Find the label at which the loop is entered. */
p
= XEXP (SET_SRC (PATTERN (jump
)), 0); if (GET_CODE (p
) != CODE_LABEL
)
/* Trace the flow of control through the end test,
propagating constants, to see if result is determined. */
prev_insn_explicit_cc0
= 0; /* Avoid infinite loop if we find a cycle of jumps. */
/* At end of function? Means rtl is inconsistent,
but this can happen when stmt.c gets confused
/* Arriving at end of loop means endtest will drop out. */
&& NOTE_LINE_NUMBER (p
) == NOTE_INSN_LOOP_END
)
disposition
= DELETE_LOOP
; else if (GET_CODE (p
) == CODE_LABEL
|| GET_CODE (p
) == NOTE
)
/* We only know how to handle two kinds of insns:
conditional jumps, and those that set the condition codes. */
else if (GET_CODE (p
) == INSN
&& GET_CODE (PATTERN (p
)) == SET
&& SET_DEST (PATTERN (p
)) == cc0_rtx
)
prev_insn_cc0
= fold_cc0 (GET_MODE (SET_SRC (PATTERN (p
))), copy_rtx (SET_SRC (PATTERN (p
))));
if (GET_CODE (SET_SRC (PATTERN (p
))) == CONST_INT
)
prev_insn_explicit_cc0
= SET_SRC (PATTERN (p
)); else if (GET_CODE (p
) == JUMP_INSN
&& GET_CODE (PATTERN (p
)) == SET
&& SET_DEST (PATTERN (p
)) == pc_rtx
)
= fold_rtx (SET_SRC (PATTERN (p
)), 1);
if (GET_CODE (target
) == LABEL_REF
)
else if (target
!= pc_rtx
)
/* If destination of jump is not fixed, give up. */
/* Any other kind of insn means we don't know
what result the test will have. */
/* Arriving at top of loop means we can drop straight in.
Check here because we can arrive only via a jump insn
which would have changed P above. */
disposition
= DELETE_JUMP
; /* We went past one insn; consider the next. */
if (disposition
== DELETE_JUMP
)
/* We know the loop test will succeed the first time,
so delete the jump to the test; drop right into loop.
Note that one call to delete_insn gets the BARRIER as well. */
if (disposition
== DELETE_LOOP
)
/* We know the endtest will fail and drop right out of the loop,
but it isn't safe to delete the loop here.
There could be jumps into it from outside.
So make the entry-jump jump around the loop.
This will cause find_basic_blocks to delete it if appropriate. */
register rtx label
= gen_label_rtx ();
emit_label_after (label
, p
);
redirect_jump (jump
, label
);
/* CSE processing for one instruction.
First simplify sources and addresses of all assignments
in the instruction, using previously-computed equivalents values.
Then install the new sources and destinations in the table
/* Data on one SET contained in the instruction. */
/* The SET rtx itself. */
/* The hash-table element for the SET_SRC of the SET. */
struct table_elt
*src_elt
;
/* Hash code for the SET_SRC. */
/* Hash code for the SET_DEST. */
/* The SET_DEST, with SUBREG, etc., stripped. */
/* Place where the pointer to the INNER_DEST was found. */
/* Nonzero if the SET_SRC is in memory. */
/* Nonzero if the SET_SRC is in a structure. */
/* Nonzero if the SET_SRC contains something
whose value cannot be predicted and understood. */
/* Original machine mode, in case it becomes a CONST_INT. */
register rtx x
= PATTERN (insn
);
/* Records what this insn does to set CC0,
using same encoding used for prev_insn_cc0. */
/* Likewise, what to store in prev_insn_explicit_cc0. */
rtx this_insn_explicit_cc0
= 0; struct write_data writes_memory
;
static struct write_data init
= {0, 0, 0};
struct table_elt
*src_eqv_elt
= 0;
/* Find all the SETs and CLOBBERs in this instruction.
Record all the SETs in the array `set' and count them.
Also determine whether there is a CLOBBER that invalidates
all memory references, or all references at varying addresses. */
sets
= (struct set
*) alloca (sizeof (struct set
)); if (REG_NOTES (insn
) != 0)
/* Store the equivalent value (re REG_EQUAL or REG_EQUIV) in SRC_EQV. */
tem
= find_reg_note (insn
, REG_EQUIV
, 0); tem
= find_reg_note (insn
, REG_EQUAL
, 0); if (tem
) src_eqv
= XEXP (tem
, 0);
/* Ignore the REG_EQUAL or REG_EQUIV note if its contents
are the same as the source. */
if (src_eqv
&& rtx_equal_p (src_eqv
, SET_SRC (x
)))
/* Return now for unconditional jumps.
They never need cse processing, so this does not hurt.
The reason is not efficiency but rather
so that we can test at the end for instructions
that have been simplified to unconditional jumps
and not be misled by unchanged instructions
that were unconditional jumps to begin with. */
if (SET_DEST (x
) == pc_rtx
&& GET_CODE (SET_SRC (x
)) == LABEL_REF
)
/* Return now for call-insns, (set (reg 0) (call ...)).
The hard function value register is used only once, to copy to
someplace else, so it isn't worth cse'ing (and on 80386 is unsafe)! */
if (GET_CODE (SET_SRC (x
)) == CALL
)
else if (GET_CODE (x
) == PARALLEL
)
register int lim
= XVECLEN (x
, 0);
sets
= (struct set
*) alloca (lim
* sizeof (struct set
)); /* Find all regs explicitly clobbered in this insn,
and ensure they are not replaced with any other regs
When a reg that is clobbered is also used for input,
we should presume that that is for a reason,
and we should not substitute some other register
which is not supposed to be clobbered. */
for (i
= 0; i
< lim
; i
++)
register rtx y
= XVECEXP (x
, 0, i
);
if (GET_CODE (y
) == CLOBBER
&& GET_CODE (XEXP (y
, 0)) == REG
)
invalidate (XEXP (y
, 0));
for (i
= 0; i
< lim
; i
++)
register rtx y
= XVECEXP (x
, 0, i
);
else if (GET_CODE (y
) == CLOBBER
)
/* If we clobber memory, take note of that,
This does nothing when a register is clobbered
because we have already invalidated the reg. */
note_mem_written (XEXP (y
, 0), &writes_memory
);
else if (GET_CODE (y
) == USE
&& ! (GET_CODE (XEXP (y
, 0)) == REG
&& REGNO (XEXP (y
, 0)) < FIRST_PSEUDO_REGISTER
))
else if (GET_CODE (y
) == CALL
)
else if (GET_CODE (x
) == CLOBBER
)
note_mem_written (XEXP (x
, 0), &writes_memory
);
else if (GET_CODE (x
) == CALL
)
invalidate_from_clobbers (&writes_memory
, x
);
/* Canonicalize sources and addresses of destinations.
set sets[i].src_elt to the class each source belongs to.
Detect assignments from or to volatile things
and set set[i] to zero so they will be ignored
in the rest of this function.
Nothing in this loop changes the hash table or the register chains. */
for (i
= 0; i
< n_sets
; i
++)
register struct table_elt
*elt
;
dest
= SET_DEST (sets
[i
].rtl
); src
= SET_SRC (sets
[i
].rtl
); /* If SRC is a constant that has no machine mode,
hash it with the destination's machine mode.
This way we can keep different modes separate. */
mode
= GET_MODE (src
) == VOIDmode
? GET_MODE (dest
) : GET_MODE (src
); /* Replace each registers in SRC with oldest equivalent register,
but if DEST is a register do not replace it if it appears in SRC. */
if (GET_CODE (dest
) == REG
)
int tem
= reg_qty
[REGNO (dest
)];
reg_qty
[REGNO (dest
)] = REGNO (dest
); src_eqv
= canon_reg (src_eqv
); reg_qty
[REGNO (dest
)] = tem
; src_eqv
= canon_reg (src_eqv
); enum machine_mode eqvmode
= mode
;
if (GET_CODE (dest
) == STRICT_LOW_PART
)
eqvmode
= GET_MODE (SUBREG_REG (XEXP (dest
, 0))); src_eqv
= fold_rtx (src_eqv
, 0); src_eqv_hash_code
= HASH (src_eqv
, eqvmode
); /* Replace the src_eqv with its cheapest equivalent. */
elt
= lookup (src_eqv
, src_eqv_hash_code
, eqvmode
); if (elt
&& elt
!= elt
->first_same_value
)
elt
= elt
->first_same_value
; /* Find the cheapest one that is still valid. */
while ((GET_CODE (elt
->exp
) != REG
&& !exp_equiv_p (elt
->exp
, elt
->exp
, 1))
|| elt
->equivalence_only
)
elt
= elt
->next_same_value
; src_eqv
= copy_rtx (elt
->exp
); src_eqv_hash_code
= HASH (src_eqv
, elt
->mode
); src_eqv_in_memory
= hash_arg_in_memory
; src_eqv_in_struct
= hash_arg_in_struct
; /* Compute SRC's hash code, and also notice if it
should not be recorded at all. In that case,
prevent any further processing of this assignment. */
/* If SRC is a subreg of a reg with a known value,
perform the truncation now. */
if (GET_CODE (src
) == SUBREG
)
rtx temp
= equiv_constant (src
); /* If we have (NOT Y), see if Y is known to be (NOT Z).
If so, (NOT Y) simplifies to Z. */
if (GET_CODE (src
) == NOT
|| GET_CODE (src
) == NEG
)
rtx y
= lookup_as_function (XEXP (src
, 0), GET_CODE (src
)); src
= copy_rtx (XEXP (y
, 0)); /* If storing a constant value in a register that
previously held the constant value 0,
record this fact with a REG_WAS_0 note on this insn. */
if (GET_CODE (src
) == CONST_INT
&& GET_CODE (dest
) == REG
&& qty_const
[reg_qty
[REGNO (dest
)]] == const0_rtx
)
REG_NOTES (insn
) = gen_rtx (INSN_LIST
, REG_WAS_0
,
qty_const_insn
[reg_qty
[REGNO (dest
)]], sets
[i
].src_hash_code
= HASH (src
, mode
); sets
[i
].src_volatile
= do_not_record
; /* This code caused multiple hash-table entries
to be created for registers. Invalidation
would only get one, leaving others that didn't belong.
I don't know what good this ever did. */
if (GET_CODE (src
) == REG
)
sets
[i
].src_in_memory
= 0; /* If source is a perverse subreg (such as QI treated as an SI),
treat it as volatile. It may do the work of an SI in one context
where the extra bits are not being used, but cannot replace an SI
if (GET_CODE (src
) == SUBREG
&& (GET_MODE_SIZE (GET_MODE (src
))
> GET_MODE_SIZE (GET_MODE (SUBREG_REG (src
)))))
sets
[i
].src_volatile
= 1; else if (!sets
[i
].src_volatile
)
/* Replace the source with its cheapest equivalent. */
elt
= lookup (src
, sets
[i
].src_hash_code
, mode
); if (elt
&& elt
!= elt
->first_same_value
)
elt
= elt
->first_same_value
; /* Find the cheapest one that is still valid. */
while ((GET_CODE (elt
->exp
) != REG
&& !exp_equiv_p (elt
->exp
, elt
->exp
, 1))
|| elt
->equivalence_only
)
elt
= elt
->next_same_value
; /* Don't replace with things that are not likely to be valid,
such as arithmetic expressions, unless the destination is
if (general_operand (elt
->exp
, VOIDmode
)
|| GET_CODE (dest
) == REG
)
src
= copy_rtx (elt
->exp
); sets
[i
].src_hash_code
= HASH (src
, elt
->mode
); /* If ELT is a constant, is there a register
linearly related to it? If so, replace it
with the sum of that register plus an offset. */
if (GET_CODE (src
) == CONST
&& n_sets
== 1
&& SET_DEST (sets
[i
].rtl
) != cc0_rtx
)
rtx newsrc
= use_related_value (src
, elt
); if (newsrc
== 0 && src_eqv
!= 0)
newsrc
= use_related_value (src_eqv
, src_eqv_elt
); sets
[i
].src_hash_code
= HASH (src
, GET_MODE (src
)); /* The new expression for the SRC has the same value
as the previous one; so if the previous one is in
the hash table, put the new one in as equivalent. */
elt
= insert (src
, elt
->first_same_value
, sets
[i
].src_hash_code
, /* Maybe the new expression is in the table already. */
elt
= lookup (src
, sets
[i
].src_hash_code
, mode
); /* And maybe a register contains the same value. */
if (elt
&& elt
!= elt
->first_same_value
)
elt
= elt
->first_same_value
; /* Find the cheapest one that is still valid. */
while ((GET_CODE (elt
->exp
) != REG
&& !exp_equiv_p (elt
->exp
, elt
->exp
, 1))
|| elt
->equivalence_only
)
elt
= elt
->next_same_value
; src
= copy_rtx (elt
->exp
); sets
[i
].src_hash_code
= HASH (src
, elt
->mode
); /* This would normally be inhibited by the REG_EQUIV
note we are about to make. */
/* Deleted because the inhibition was deleted. */
SET_SRC (sets
[i
].rtl
) = src
;
/* Record the actual constant value
in a REG_EQUIV or REG_EQUAL note. */
if (GET_CODE (SET_DEST (sets
[i
].rtl
)) == REG
)
/* A REG_EQUIV note means the dest never changes.
Don't put one on unless there is already one. */
rtx note
= find_reg_note (insn
, REG_EQUIV
, 0); REG_NOTES (insn
) = gen_rtx (EXPR_LIST
, REG_EQUAL
,
oldsrc
, REG_NOTES (insn
)); sets
[i
].src_in_memory
= hash_arg_in_memory
; sets
[i
].src_in_struct
= hash_arg_in_struct
; /* Either canon_reg or the copy_rtx may have changed this. */
/* Note it is not safe to replace the sources if there
is more than one set. We could get an insn
[(set (reg) (reg)) (set (reg) (reg))], which is probably
not in the machine description.
This case we could handle by breaking into several insns.
Cases of partial substitution cannot win at all. */
/* Also, if this insn is setting a "constant" register,
we may not replace the value that is given to it. */
/* Now that the REG_EQUIV contains the constant instead of the reg,
it should be ok to modify the insn's actual source. */
if (REG_NOTES (insn
) == 0
|| REG_NOTE_KIND (REG_NOTES (insn
)) != REG_EQUIV
)
SET_SRC (sets
[0].rtl
) = src
;
sets
[i
].inner_dest_loc
= &SET_DEST (sets
[0].rtl
); /* Look within any SIGN_EXTRACT or ZERO_EXTRACT
to the MEM or REG within it. */
if (GET_CODE (dest
) == SIGN_EXTRACT
|| GET_CODE (dest
) == ZERO_EXTRACT
)
XEXP (dest
, 1) = canon_reg (XEXP (dest
, 1));
XEXP (dest
, 2) = canon_reg (XEXP (dest
, 2));
sets
[i
].inner_dest_loc
= &XEXP (dest
, 0); else if (GET_CODE (dest
) == SUBREG
|| GET_CODE (dest
) == STRICT_LOW_PART
)
sets
[i
].inner_dest_loc
= &XEXP (dest
, 0); sets
[i
].inner_dest
= dest
; /* If storing into memory, do cse on the memory address.
Also compute the hash code of the destination now,
before the effects of this instruction are recorded,
since the register values used in the address computation
are those before this instruction. */
if (GET_CODE (dest
) == MEM
)
dest
= fold_rtx (dest
, 0); /* Pushing or popping does not invalidate anything. */
if ((GET_CODE (addr
) == PRE_DEC
|| GET_CODE (addr
) == PRE_INC
|| GET_CODE (addr
) == POST_DEC
|| GET_CODE (addr
) == POST_INC
)
&& GET_CODE (XEXP (addr
, 0)) == REG
&& REGNO (XEXP (addr
, 0)) == STACK_POINTER_REGNUM
)
/* Otherwise, decide whether we invalidate
everything in memory, or just things at non-fixed places.
Writing a large aggregate must invalidate everything
because we don't know how long it is. */
note_mem_written (dest
, &writes_memory
);
/* Do not try to replace addresses of local and argument slots.
The MEM expressions for args and non-register local variables
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. It also doesn't do any good! */
if ((GET_CODE (addr
) == PLUS
&& GET_CODE (XEXP (addr
, 0)) == REG
&& GET_CODE (XEXP (addr
, 1)) == CONST_INT
&& (hash
= REGNO (XEXP (addr
, 0)),
hash
== FRAME_POINTER_REGNUM
|| hash
== ARG_POINTER_REGNUM
)) || (GET_CODE (addr
) == REG
hash
== FRAME_POINTER_REGNUM
|| hash
== ARG_POINTER_REGNUM
))) sets
[i
].dest_hash_code
= ((int)MEM
+ canon_hash (addr
, GET_MODE (dest
))) % NBUCKETS
; /* Look for a simpler equivalent for the destination address. */
hash
= HASH (addr
, Pmode
); elt
= lookup (addr
, hash
, Pmode
); sets
[i
].dest_hash_code
= ((int) MEM
+ hash
) % NBUCKETS
; if (elt
&& elt
!= elt
->first_same_value
)
elt
= elt
->first_same_value
; /* Find the cheapest one that is still valid. */
while ((GET_CODE (elt
->exp
) != REG
&& !exp_equiv_p (elt
->exp
, elt
->exp
, 1))
|| elt
->equivalence_only
)
elt
= elt
->next_same_value
; addr
= copy_rtx (elt
->exp
); /* Create a new MEM rtx, in case the old one
is shared somewhere else. */
dest
= gen_rtx (MEM
, GET_MODE (dest
), addr
); = MEM_VOLATILE_P (sets
[i
].inner_dest
);
= MEM_IN_STRUCT_P (sets
[i
].inner_dest
);
*sets
[i
].inner_dest_loc
= dest
;
sets
[i
].inner_dest
= dest
; /* Don't enter a bit-field in the hash table
because the value in it after the store
may not equal what was stored, due to truncation. */
if (GET_CODE (SET_DEST (sets
[i
].rtl
)) == ZERO_EXTRACT
|| GET_CODE (SET_DEST (sets
[i
].rtl
)) == SIGN_EXTRACT
)
rtx width
= XEXP (SET_DEST (sets
[i
].rtl
), 1); rtx value
= equiv_constant (SET_SRC (sets
[i
].rtl
)); if (value
!= 0 && GET_CODE (value
) == CONST_INT
&& GET_CODE (width
) == CONST_INT
&& INTVAL (width
) < HOST_BITS_PER_INT
&& ! (INTVAL (value
) & (-1) << INTVAL (width
)))
/* Exception: if the value is constant,
we can tell whether truncation would change it. */
sets
[i
].src_volatile
= 1, src_eqv
= 0; /* No further processing for this assignment
if destination is volatile or if the source and destination
|| (GET_CODE (dest
) == REG
? REGNO (dest
) == STACK_POINTER_REGNUM
: GET_CODE (dest
) != MEM
)
|| rtx_equal_p (SET_SRC (sets
[i
].rtl
), SET_DEST (sets
[i
].rtl
)))
if (sets
[i
].rtl
!= 0 && dest
!= SET_DEST (sets
[i
].rtl
))
sets
[i
].dest_hash_code
= HASH (SET_DEST (sets
[i
].rtl
), mode
); && (GET_CODE (src
) == COMPARE
|| GET_CODE (src
) == REG
))
this_insn_cc0
= fold_cc0 (sets
[i
].mode
, src
); if (dest
== cc0_rtx
&& GET_CODE (src
) == CONST_INT
)
this_insn_explicit_cc0
= src
; /* Now enter all non-volatile source expressions in the hash table
if they are not already present.
Record in src_elt the heads of their equivalence classes.
This way we can insert the corresponding destinations into
the same classes even if the actual sources are no longer in them
(having been invalidated). */
if (src_eqv
&& src_eqv_elt
== 0 && sets
[0].rtl
!= 0)
register struct table_elt
*elt
;
rtx dest
= SET_DEST (sets
[0].rtl
); enum machine_mode eqvmode
= GET_MODE (dest
);
if (GET_CODE (dest
) == STRICT_LOW_PART
)
eqvmode
= GET_MODE (SUBREG_REG (XEXP (dest
, 0))); if (insert_regs (src_eqv
, 0, 0))
src_eqv_hash_code
= HASH (src_eqv
, eqvmode
); elt
= insert (src_eqv
, 0, src_eqv_hash_code
, eqvmode
); elt
->in_memory
= src_eqv_in_memory
; elt
->in_struct
= src_eqv_in_struct
; elt
->equivalence_only
= 1; src_eqv_elt
= elt
->first_same_value
; for (i
= 0; i
< n_sets
; i
++)
if (sets
[i
].rtl
&& ! sets
[i
].src_volatile
)
if (GET_CODE (SET_DEST (sets
[i
].rtl
)) == STRICT_LOW_PART
)
/* REG_EQUAL in setting a STRICT_LOW_PART
gives an equivalent for the entire destination register,
not just for the subreg being stored in now.
This is a more interesting equivalent, so we arrange later
to treat the entire reg as the destination. */
sets
[i
].src_elt
= src_eqv_elt
; sets
[i
].src_hash_code
= src_eqv_hash_code
; else if (sets
[i
].src_elt
== 0)
register rtx src
= SET_SRC (sets
[i
].rtl
);
register rtx dest
= SET_DEST (sets
[i
].rtl
);
register struct table_elt
*elt
;
= GET_MODE (src
) == VOIDmode
? GET_MODE (dest
) : GET_MODE (src
);
/* Note that these insert_regs calls cannot remove
any of the src_elt's, because they would have failed to match
if (insert_regs (src
, 0, 0))
sets
[i
].src_hash_code
= HASH (src
, mode
); elt
= insert (src
, src_eqv_elt
, sets
[i
].src_hash_code
, mode
); elt
->in_memory
= sets
[i
].src_in_memory
; elt
->in_struct
= sets
[i
].src_in_struct
; sets
[i
].src_elt
= elt
->first_same_value
; invalidate_from_clobbers (&writes_memory
, x
);
/* Now invalidate everything set by this instruction.
If a SUBREG or other funny destination is being set,
sets[i].rtl is still nonzero, so here we invalidate the reg
a part of which is being set. */
for (i
= 0; i
< n_sets
; i
++)
register rtx dest
= sets
[i
].inner_dest
;
/* Needed for registers to remove the register from its
previous quantity's chain.
Needed for memory if this is a nonvarying address, unless
we have just done an invalidate_memory that covers even those. */
if (GET_CODE (dest
) == REG
|| GET_CODE (dest
) == SUBREG
|| (! writes_memory
.all
&& ! cse_rtx_addr_varies_p (dest
)))
/* Make sure registers mentioned in destinations
are safe for use in an expression to be inserted.
This removes from the hash table
any invalid entry that refers to one of these registers. */
for (i
= 0; i
< n_sets
; i
++)
if (sets
[i
].rtl
&& GET_CODE (SET_DEST (sets
[i
].rtl
)) != REG
)
mention_regs (SET_DEST (sets
[i
].rtl
));
/* 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. */
for (i
= 0; i
< n_sets
; i
++)
/* If the source is volatile, its destination goes in
if (sets
[i
].src_volatile
)
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. */
register struct table_elt
*elt
= sets
[i
].src_elt
;
while (elt
&& elt
->first_same_value
== 0)
elt
= elt
->next_same_value
; sets
[i
].src_elt
= elt
? elt
->first_same_value
: 0; /* Now insert the destinations into their equivalence classes. */
for (i
= 0; i
< n_sets
; i
++)
register rtx dest
= SET_DEST (sets
[i
].rtl
);
register struct table_elt
*elt
;
&& GET_CODE (dest
) == MEM
&& (GET_MODE (dest
) == SFmode
|| GET_MODE (dest
) == DFmode
))
/* STRICT_LOW_PART isn't part of the value BEING set,
and neither is the SUBREG inside it.
Note that in this case SETS[I].SRC_ELT is really SRC_EQV_ELT. */
if (GET_CODE (dest
) == STRICT_LOW_PART
)
dest
= SUBREG_REG (XEXP (dest
, 0)); if (GET_CODE (dest
) == REG
)
/* Registers must also be inserted into chains for quantities. */
if (insert_regs (dest
, sets
[i
].src_elt
, 1))
/* If `insert_regs' changes something, the hash code must be
sets
[i
].dest_hash_code
= HASHREG (dest
); if (GET_CODE (dest
) == SUBREG
)
/* Registers must also be inserted into chains for quantities. */
if (insert_regs (dest
, sets
[i
].src_elt
, 1))
/* If `insert_regs' changes something, the hash code must be
= canon_hash (dest
, GET_MODE (dest
)) % NBUCKETS
;
elt
= insert (dest
, sets
[i
].src_elt
, sets
[i
].dest_hash_code
, GET_MODE (dest
)); elt
->in_memory
= GET_CODE (sets
[i
].inner_dest
) == MEM
; elt
->in_struct
= (MEM_IN_STRUCT_P (sets
[i
].inner_dest
) || sets
[i
].inner_dest
!= SET_DEST (sets
[i
].rtl
));
/* Special handling for (set REG0 REG1)
where REG0 is the "cheapest", cheaper than REG1.
After cse, REG1 will probably not be used in the sequel,
so (if easily done) change this insn to (set REG1 REG0) and
replace REG1 with REG0 in the previous insn that computed their value.
Then REG1 will become a dead store and won't cloud the situation
for later optimizations. */
if (n_sets
== 1 && sets
[0].rtl
&& GET_CODE (SET_DEST (sets
[0].rtl
)) == REG
&& GET_CODE (SET_SRC (sets
[0].rtl
)) == REG
&& rtx_equal_p (canon_reg (SET_SRC (sets
[0].rtl
)), SET_DEST (sets
[0].rtl
)))
rtx prev
= PREV_INSN (insn
); while (prev
&& GET_CODE (prev
) == NOTE
)
if (prev
&& GET_CODE (prev
) == INSN
&& GET_CODE (PATTERN (prev
)) == SET
&& SET_DEST (PATTERN (prev
)) == SET_SRC (sets
[0].rtl
))
rtx dest
= SET_DEST (sets
[0].rtl
); rtx note
= find_reg_note (prev
, REG_EQUIV
, 0); SET_DEST (PATTERN (prev
)) = dest
;
SET_DEST (sets
[0].rtl
) = SET_SRC (sets
[0].rtl
);
SET_SRC (sets
[0].rtl
) = dest
;
/* If REG1 was equivalent to a constant, REG0 is not. */
PUT_MODE (note
, REG_EQUAL
);
/* Did this insn become an unconditional branch or become a no-op? */
if (GET_CODE (insn
) == JUMP_INSN
&& SET_DEST (x
) == pc_rtx
)
if (SET_SRC (x
) == pc_rtx
)
NOTE_LINE_NUMBER (insn
) = NOTE_INSN_DELETED
;
NOTE_SOURCE_FILE (insn
) = 0;
/* If previous insn just set CC0 for us, delete it too. */
if (prev_insn_cc0
!= 0 || prev_insn_explicit_cc0
!= 0)
PUT_CODE (prev_insn
, NOTE
);
NOTE_LINE_NUMBER (prev_insn
) = NOTE_INSN_DELETED
;
NOTE_SOURCE_FILE (prev_insn
) = 0;
/* One less use of the label this insn used to jump to. */
--LABEL_NUSES (JUMP_LABEL (insn
));
else if (GET_CODE (SET_SRC (x
)) == LABEL_REF
)
emit_barrier_after (insn
);
/* If previous insn just set CC0 for us, delete it too. */
if (prev_insn_cc0
!= 0 || prev_insn_explicit_cc0
!= 0)
PUT_CODE (prev_insn
, NOTE
);
NOTE_LINE_NUMBER (prev_insn
) = NOTE_INSN_DELETED
;
NOTE_SOURCE_FILE (prev_insn
) = 0;
/* If jump target is the following label, and this is only use of it,
skip direct to that label and continue optimizing there. */
while (label
!= 0 && GET_CODE (label
) != CODE_LABEL
)
label
= NEXT_INSN (label
); if (label
== XEXP (SET_SRC (x
), 0)
&& LABEL_NUSES (label
) == 1)
cse_skip_to_next_block
= 1; /* If this insn used to store a value based on CC0 but now value is constant,
and the previous insn just set CC0 for us, delete previous insn.
Here we use the fact that nothing expects CC0 to be valid over an insn,
which is true until the final pass. */
if (GET_CODE (x
) == SET
&& prev_insn_cc0
&& CONSTANT_P (SET_SRC (x
)))
PUT_CODE (prev_insn
, NOTE
);
NOTE_LINE_NUMBER (prev_insn
) = NOTE_INSN_DELETED
;
NOTE_SOURCE_FILE (prev_insn
) = 0;
prev_insn_explicit_cc0
= this_insn_explicit_cc0
; prev_insn_cc0
= this_insn_cc0
;/* Store 1 in *WRITES_PTR for those categories of memory ref
that must be invalidated when the expression WRITTEN is stored in.
If WRITTEN is null, say everything must be invalidated. */
note_mem_written (written
, writes_ptr
)
struct write_data
*writes_ptr
;
static struct write_data everything
= {1, 1, 1};
*writes_ptr
= everything
;
else if (GET_CODE (written
) == MEM
)
/* Pushing or popping the stack invalidates nothing. */
rtx addr
= XEXP (written
, 0); if ((GET_CODE (addr
) == PRE_DEC
|| GET_CODE (addr
) == PRE_INC
|| GET_CODE (addr
) == POST_DEC
|| GET_CODE (addr
) == POST_INC
)
&& GET_CODE (XEXP (addr
, 0)) == REG
&& REGNO (XEXP (addr
, 0)) == STACK_POINTER_REGNUM
)
if (GET_MODE (written
) == BLKmode
)
*writes_ptr
= everything
;
else if (cse_rtx_addr_varies_p (written
))
/* A varying address that is a sum indicates an array element,
and that's just as good as a structure element
in implying that we need not invalidate scalar variables. */
if (!(MEM_IN_STRUCT_P (written
)
|| GET_CODE (XEXP (written
, 0)) == PLUS
))
writes_ptr
->nonscalar
= 1;/* Perform invalidation on the basis of everything about an insn
except for invalidating the actual places that are SET in it.
This includes the places CLOBBERed, and anything that might
alias with something that is SET or CLOBBERed.
W points to the writes_memory for this insn, a struct write_data
saying which kinds of memory references must be invalidated.
X is the pattern of the insn. */
invalidate_from_clobbers (w
, x
)
/* If W->var is not set, W specifies no action.
If W->all is set, this step gets all memory refs
so they can be ignored in the rest of this function. */
if (GET_CODE (x
) == CLOBBER
)
&& (GET_CODE (ref
) == REG
|| GET_CODE (ref
) == SUBREG
|| (GET_CODE (ref
) == MEM
&& ! w
->all
)))
else if (GET_CODE (x
) == PARALLEL
)
for (i
= XVECLEN (x
, 0) - 1; i
>= 0; i
--)
register rtx y
= XVECEXP (x
, 0, i
);
if (GET_CODE (y
) == CLOBBER
)
&&(GET_CODE (ref
) == REG
|| GET_CODE (ref
) == SUBREG
|| (GET_CODE (ref
) == MEM
&& !w
->all
)))
/* Find the end of INSN's basic block, and return the cuid of its last insn
and the total number of SETs in all the insns of the block. */
struct cse_basic_block_data
{ int cuid
, nsets
; rtx last
; };
static struct cse_basic_block_data
cse_end_of_basic_block (insn
)
struct cse_basic_block_data val
;
/* Scan to end of this basic block. */
while (p
&& GET_CODE (p
) != CODE_LABEL
)
/* Don't cse out the end of a loop. This makes a difference
only for the unusual loops that always execute at least once;
all other loops have labels there so we will stop in any case.
Cse'ing out the end of the loop is dangerous because it
might cause an invariant expression inside the loop
to be reused after the end of the loop. This would make it
hard to move the expression out of the loop in loop.c,
especially if it is one of several equivalent expressions
and loop.c would like to eliminate it.
The occasional optimizations lost by this will all come back
if loop and cse are made to work alternatingly. */
&& NOTE_LINE_NUMBER (p
) == NOTE_INSN_LOOP_END
)
/* Don't cse over a call to setjmp; on some machines (eg vax)
the regs restored by the longjmp come from
a later time than the setjmp. */
&& NOTE_LINE_NUMBER (p
) == NOTE_INSN_SETJMP
)
/* A PARALLEL can have lots of SETs in it,
especially if it is really an ASM_OPERANDS. */
if (GET_CODE (p
) == INSN
&& GET_CODE (PATTERN (p
)) == PARALLEL
)
nsets
+= XVECLEN (PATTERN (p
), 0); val
.cuid
= uid_cuid
[last_uid
];static rtx
cse_basic_block ();
/* Perform cse on the instructions of a function.
F is the first instruction.
NREGS is one plus the highest pseudo-reg number used in the instruction.
Returns 1 if jump_optimize should be redone due to simplifications
in conditional jump instructions. */
/* f is the first instruction of a chain of insns for one function */
/* nregs is the total number of registers used in it */
all_minus_one
= (int *) alloca (nregs
* sizeof (int)); consec_ints
= (int *) alloca (nregs
* sizeof (int)); for (i
= 0; i
< nregs
; i
++)
reg_next_eqv
= (int *) alloca (nregs
* sizeof (int)); reg_prev_eqv
= (int *) alloca (nregs
* sizeof (int)); reg_qty
= (int *) alloca (nregs
* sizeof (int)); reg_rtx
= (rtx
*) alloca (nregs
* sizeof (rtx
)); reg_in_table
= (int *) alloca (nregs
* sizeof (int)); reg_tick
= (int *) alloca (nregs
* sizeof (int)); /* Discard all the free elements of the previous function
since they are allocated in the temporarily obstack. */
bzero (table
, sizeof table
);
/* Find the largest uid. */
for (insn
= f
, i
= 0; insn
; insn
= NEXT_INSN (insn
))
uid_cuid
= (short *) alloca ((i
+ 1) * sizeof (short)); bzero (uid_cuid
, (i
+ 1) * sizeof (short));
/* Compute the mapping from uids to cuids.
CUIDs are numbers assigned to insns, like uids,
except that cuids increase monotonically through the code.
Don't assign cuids to line-number NOTEs, so that the distance in cuids
between two insns is not affected by -g. */
for (insn
= f
, i
= 0; insn
; insn
= NEXT_INSN (insn
))
if (GET_CODE (insn
) != NOTE
|| NOTE_LINE_NUMBER (insn
) < 0)
/* Give a line number note the same cuid as preceding insn. */
/* Loop over basic blocks.
Compute the maximum number of qty's needed for each basic block
(which is 2 for each SET). */
struct cse_basic_block_data val
;
val
= cse_end_of_basic_block (insn
); cse_basic_block_end
= val
.cuid
; cse_basic_block_start
= INSN_CUID (insn
); /* Make MAX_QTY bigger to give us room to optimize
past the end of this basic block, if that should prove useful. */
insn
= cse_basic_block (insn
, val
.last
); /* Tell refers_to_mem_p that qty_const info is not available. */
if (max_elements_made
< n_elements_made
)
max_elements_made
= n_elements_made
; return cse_jumps_altered
;
cse_basic_block (from
, to
)
int *qv1
= (int *) alloca (max_qty
* sizeof (int));
int *qv2
= (int *) alloca (max_qty
* sizeof (int));
rtx
*qv3
= (rtx
*) alloca (max_qty
* sizeof (rtx
)); qty_const_insn
= (rtx
*) alloca (max_qty
* sizeof (rtx
)); cse_skip_to_next_block
= 0; for (insn
= from
; insn
!= to
; insn
= NEXT_INSN (insn
))
register enum rtx_code code
;
if (code
== INSN
|| code
== JUMP_INSN
|| code
== CALL_INSN
)
/* Memory, and some registers, are invalidate by subroutine calls. */
static struct write_data everything
= {1, 1, 1};
invalidate_memory (&everything
);
for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
if (call_used_regs
[i
] && reg_rtx
[i
]
&& i
!= FRAME_POINTER_REGNUM
&& i
!= ARG_POINTER_REGNUM
)
/* Loop beginnings are often followed by jumps
(that enter the loop above the endtest).
See if we can prove the loop will be executed at least once;
if so, delete the jump. Also perhaps we can prove loop
will never be executed and delete the entire thing. */
&& NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_BEG
&& GET_CODE (NEXT_INSN (insn
)) == JUMP_INSN
)
predecide_loop_entry (insn
);
/* Whether that jump was deleted or not,
it certainly is the end of the basic block.
Since the jump is unconditional,
it requires no further processing here. */
/* See if it is ok to keep on going past the label
which used to end our basic block. */
if (cse_skip_to_next_block
|| (to
!= 0 && NEXT_INSN (insn
) == to
&& LABEL_NUSES (to
) == 0))
struct cse_basic_block_data val
;
/* Skip the remaining insns in this block. */
cse_skip_to_next_block
= 0; /* Find the end of the following block. */
val
= cse_end_of_basic_block (NEXT_INSN (insn
)); /* If the tables we allocated have enough space left
to handle all the SETs in the next basic block,
continue through it. Otherwise, return,
and that block will be scanned individually. */
if (val
.nsets
* 2 + next_qty
> max_qty
)
cse_basic_block_end
= val
.cuid
; return to
? NEXT_INSN (to
) : 0;
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