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tree-ssa-sccvn.c
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tree-ssa-sccvn.c
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/* SCC value numbering for trees
Copyright (C) 2006, 2007, 2008, 2009, 2010
Free Software Foundation, Inc.
Contributed by Daniel Berlin <dan@dberlin.org>
This file is part of GCC.
GCC 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 3, or (at your option)
any later version.
GCC 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 GCC; see the file COPYING3. If not see
<http://www.gnu.org/licenses/>. */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "tree.h"
#include "basic-block.h"
#include "tree-pretty-print.h"
#include "gimple-pretty-print.h"
#include "tree-inline.h"
#include "tree-flow.h"
#include "gimple.h"
#include "tree-dump.h"
#include "timevar.h"
#include "fibheap.h"
#include "hashtab.h"
#include "tree-iterator.h"
#include "alloc-pool.h"
#include "tree-pass.h"
#include "flags.h"
#include "bitmap.h"
#include "langhooks.h"
#include "cfgloop.h"
#include "params.h"
#include "tree-ssa-propagate.h"
#include "tree-ssa-sccvn.h"
#include "gimple-fold.h"
/* This algorithm is based on the SCC algorithm presented by Keith
Cooper and L. Taylor Simpson in "SCC-Based Value numbering"
(http://citeseer.ist.psu.edu/41805.html). In
straight line code, it is equivalent to a regular hash based value
numbering that is performed in reverse postorder.
For code with cycles, there are two alternatives, both of which
require keeping the hashtables separate from the actual list of
value numbers for SSA names.
1. Iterate value numbering in an RPO walk of the blocks, removing
all the entries from the hashtable after each iteration (but
keeping the SSA name->value number mapping between iterations).
Iterate until it does not change.
2. Perform value numbering as part of an SCC walk on the SSA graph,
iterating only the cycles in the SSA graph until they do not change
(using a separate, optimistic hashtable for value numbering the SCC
operands).
The second is not just faster in practice (because most SSA graph
cycles do not involve all the variables in the graph), it also has
some nice properties.
One of these nice properties is that when we pop an SCC off the
stack, we are guaranteed to have processed all the operands coming from
*outside of that SCC*, so we do not need to do anything special to
ensure they have value numbers.
Another nice property is that the SCC walk is done as part of a DFS
of the SSA graph, which makes it easy to perform combining and
simplifying operations at the same time.
The code below is deliberately written in a way that makes it easy
to separate the SCC walk from the other work it does.
In order to propagate constants through the code, we track which
expressions contain constants, and use those while folding. In
theory, we could also track expressions whose value numbers are
replaced, in case we end up folding based on expression
identities.
In order to value number memory, we assign value numbers to vuses.
This enables us to note that, for example, stores to the same
address of the same value from the same starting memory states are
equivalent.
TODO:
1. We can iterate only the changing portions of the SCC's, but
I have not seen an SCC big enough for this to be a win.
2. If you differentiate between phi nodes for loops and phi nodes
for if-then-else, you can properly consider phi nodes in different
blocks for equivalence.
3. We could value number vuses in more cases, particularly, whole
structure copies.
*/
/* The set of hashtables and alloc_pool's for their items. */
typedef struct vn_tables_s
{
htab_t nary;
htab_t phis;
htab_t references;
struct obstack nary_obstack;
alloc_pool phis_pool;
alloc_pool references_pool;
} *vn_tables_t;
static htab_t constant_to_value_id;
static bitmap constant_value_ids;
/* Valid hashtables storing information we have proven to be
correct. */
static vn_tables_t valid_info;
/* Optimistic hashtables storing information we are making assumptions about
during iterations. */
static vn_tables_t optimistic_info;
/* Pointer to the set of hashtables that is currently being used.
Should always point to either the optimistic_info, or the
valid_info. */
static vn_tables_t current_info;
/* Reverse post order index for each basic block. */
static int *rpo_numbers;
#define SSA_VAL(x) (VN_INFO ((x))->valnum)
/* This represents the top of the VN lattice, which is the universal
value. */
tree VN_TOP;
/* Unique counter for our value ids. */
static unsigned int next_value_id;
/* Next DFS number and the stack for strongly connected component
detection. */
static unsigned int next_dfs_num;
static VEC (tree, heap) *sccstack;
DEF_VEC_P(vn_ssa_aux_t);
DEF_VEC_ALLOC_P(vn_ssa_aux_t, heap);
/* Table of vn_ssa_aux_t's, one per ssa_name. The vn_ssa_aux_t objects
are allocated on an obstack for locality reasons, and to free them
without looping over the VEC. */
static VEC (vn_ssa_aux_t, heap) *vn_ssa_aux_table;
static struct obstack vn_ssa_aux_obstack;
/* Return the value numbering information for a given SSA name. */
vn_ssa_aux_t
VN_INFO (tree name)
{
vn_ssa_aux_t res = VEC_index (vn_ssa_aux_t, vn_ssa_aux_table,
SSA_NAME_VERSION (name));
gcc_checking_assert (res);
return res;
}
/* Set the value numbering info for a given SSA name to a given
value. */
static inline void
VN_INFO_SET (tree name, vn_ssa_aux_t value)
{
VEC_replace (vn_ssa_aux_t, vn_ssa_aux_table,
SSA_NAME_VERSION (name), value);
}
/* Initialize the value numbering info for a given SSA name.
This should be called just once for every SSA name. */
vn_ssa_aux_t
VN_INFO_GET (tree name)
{
vn_ssa_aux_t newinfo;
newinfo = XOBNEW (&vn_ssa_aux_obstack, struct vn_ssa_aux);
memset (newinfo, 0, sizeof (struct vn_ssa_aux));
if (SSA_NAME_VERSION (name) >= VEC_length (vn_ssa_aux_t, vn_ssa_aux_table))
VEC_safe_grow (vn_ssa_aux_t, heap, vn_ssa_aux_table,
SSA_NAME_VERSION (name) + 1);
VEC_replace (vn_ssa_aux_t, vn_ssa_aux_table,
SSA_NAME_VERSION (name), newinfo);
return newinfo;
}
/* Get the representative expression for the SSA_NAME NAME. Returns
the representative SSA_NAME if there is no expression associated with it. */
tree
vn_get_expr_for (tree name)
{
vn_ssa_aux_t vn = VN_INFO (name);
gimple def_stmt;
tree expr = NULL_TREE;
enum tree_code code;
if (vn->valnum == VN_TOP)
return name;
/* If the value-number is a constant it is the representative
expression. */
if (TREE_CODE (vn->valnum) != SSA_NAME)
return vn->valnum;
/* Get to the information of the value of this SSA_NAME. */
vn = VN_INFO (vn->valnum);
/* If the value-number is a constant it is the representative
expression. */
if (TREE_CODE (vn->valnum) != SSA_NAME)
return vn->valnum;
/* Else if we have an expression, return it. */
if (vn->expr != NULL_TREE)
return vn->expr;
/* Otherwise use the defining statement to build the expression. */
def_stmt = SSA_NAME_DEF_STMT (vn->valnum);
/* If the value number is not an assignment use it directly. */
if (!is_gimple_assign (def_stmt))
return vn->valnum;
/* FIXME tuples. This is incomplete and likely will miss some
simplifications. */
code = gimple_assign_rhs_code (def_stmt);
switch (TREE_CODE_CLASS (code))
{
case tcc_reference:
if ((code == REALPART_EXPR
|| code == IMAGPART_EXPR
|| code == VIEW_CONVERT_EXPR)
&& TREE_CODE (TREE_OPERAND (gimple_assign_rhs1 (def_stmt),
0)) == SSA_NAME)
expr = fold_build1 (code,
gimple_expr_type (def_stmt),
TREE_OPERAND (gimple_assign_rhs1 (def_stmt), 0));
break;
case tcc_unary:
expr = fold_build1 (code,
gimple_expr_type (def_stmt),
gimple_assign_rhs1 (def_stmt));
break;
case tcc_binary:
expr = fold_build2 (code,
gimple_expr_type (def_stmt),
gimple_assign_rhs1 (def_stmt),
gimple_assign_rhs2 (def_stmt));
break;
case tcc_exceptional:
if (code == CONSTRUCTOR
&& TREE_CODE
(TREE_TYPE (gimple_assign_rhs1 (def_stmt))) == VECTOR_TYPE)
expr = gimple_assign_rhs1 (def_stmt);
break;
default:;
}
if (expr == NULL_TREE)
return vn->valnum;
/* Cache the expression. */
vn->expr = expr;
return expr;
}
/* Free a phi operation structure VP. */
static void
free_phi (void *vp)
{
vn_phi_t phi = (vn_phi_t) vp;
VEC_free (tree, heap, phi->phiargs);
}
/* Free a reference operation structure VP. */
static void
free_reference (void *vp)
{
vn_reference_t vr = (vn_reference_t) vp;
VEC_free (vn_reference_op_s, heap, vr->operands);
}
/* Hash table equality function for vn_constant_t. */
static int
vn_constant_eq (const void *p1, const void *p2)
{
const struct vn_constant_s *vc1 = (const struct vn_constant_s *) p1;
const struct vn_constant_s *vc2 = (const struct vn_constant_s *) p2;
if (vc1->hashcode != vc2->hashcode)
return false;
return vn_constant_eq_with_type (vc1->constant, vc2->constant);
}
/* Hash table hash function for vn_constant_t. */
static hashval_t
vn_constant_hash (const void *p1)
{
const struct vn_constant_s *vc1 = (const struct vn_constant_s *) p1;
return vc1->hashcode;
}
/* Lookup a value id for CONSTANT and return it. If it does not
exist returns 0. */
unsigned int
get_constant_value_id (tree constant)
{
void **slot;
struct vn_constant_s vc;
vc.hashcode = vn_hash_constant_with_type (constant);
vc.constant = constant;
slot = htab_find_slot_with_hash (constant_to_value_id, &vc,
vc.hashcode, NO_INSERT);
if (slot)
return ((vn_constant_t)*slot)->value_id;
return 0;
}
/* Lookup a value id for CONSTANT, and if it does not exist, create a
new one and return it. If it does exist, return it. */
unsigned int
get_or_alloc_constant_value_id (tree constant)
{
void **slot;
struct vn_constant_s vc;
vn_constant_t vcp;
vc.hashcode = vn_hash_constant_with_type (constant);
vc.constant = constant;
slot = htab_find_slot_with_hash (constant_to_value_id, &vc,
vc.hashcode, INSERT);
if (*slot)
return ((vn_constant_t)*slot)->value_id;
vcp = XNEW (struct vn_constant_s);
vcp->hashcode = vc.hashcode;
vcp->constant = constant;
vcp->value_id = get_next_value_id ();
*slot = (void *) vcp;
bitmap_set_bit (constant_value_ids, vcp->value_id);
return vcp->value_id;
}
/* Return true if V is a value id for a constant. */
bool
value_id_constant_p (unsigned int v)
{
return bitmap_bit_p (constant_value_ids, v);
}
/* Compare two reference operands P1 and P2 for equality. Return true if
they are equal, and false otherwise. */
static int
vn_reference_op_eq (const void *p1, const void *p2)
{
const_vn_reference_op_t const vro1 = (const_vn_reference_op_t) p1;
const_vn_reference_op_t const vro2 = (const_vn_reference_op_t) p2;
return (vro1->opcode == vro2->opcode
/* We do not care for differences in type qualification. */
&& (vro1->type == vro2->type
|| (vro1->type && vro2->type
&& types_compatible_p (TYPE_MAIN_VARIANT (vro1->type),
TYPE_MAIN_VARIANT (vro2->type))))
&& expressions_equal_p (vro1->op0, vro2->op0)
&& expressions_equal_p (vro1->op1, vro2->op1)
&& expressions_equal_p (vro1->op2, vro2->op2));
}
/* Compute the hash for a reference operand VRO1. */
static hashval_t
vn_reference_op_compute_hash (const vn_reference_op_t vro1, hashval_t result)
{
result = iterative_hash_hashval_t (vro1->opcode, result);
if (vro1->op0)
result = iterative_hash_expr (vro1->op0, result);
if (vro1->op1)
result = iterative_hash_expr (vro1->op1, result);
if (vro1->op2)
result = iterative_hash_expr (vro1->op2, result);
return result;
}
/* Return the hashcode for a given reference operation P1. */
static hashval_t
vn_reference_hash (const void *p1)
{
const_vn_reference_t const vr1 = (const_vn_reference_t) p1;
return vr1->hashcode;
}
/* Compute a hash for the reference operation VR1 and return it. */
hashval_t
vn_reference_compute_hash (const vn_reference_t vr1)
{
hashval_t result = 0;
int i;
vn_reference_op_t vro;
HOST_WIDE_INT off = -1;
bool deref = false;
FOR_EACH_VEC_ELT (vn_reference_op_s, vr1->operands, i, vro)
{
if (vro->opcode == MEM_REF)
deref = true;
else if (vro->opcode != ADDR_EXPR)
deref = false;
if (vro->off != -1)
{
if (off == -1)
off = 0;
off += vro->off;
}
else
{
if (off != -1
&& off != 0)
result = iterative_hash_hashval_t (off, result);
off = -1;
if (deref
&& vro->opcode == ADDR_EXPR)
{
if (vro->op0)
{
tree op = TREE_OPERAND (vro->op0, 0);
result = iterative_hash_hashval_t (TREE_CODE (op), result);
result = iterative_hash_expr (op, result);
}
}
else
result = vn_reference_op_compute_hash (vro, result);
}
}
if (vr1->vuse)
result += SSA_NAME_VERSION (vr1->vuse);
return result;
}
/* Return true if reference operations P1 and P2 are equivalent. This
means they have the same set of operands and vuses. */
int
vn_reference_eq (const void *p1, const void *p2)
{
unsigned i, j;
const_vn_reference_t const vr1 = (const_vn_reference_t) p1;
const_vn_reference_t const vr2 = (const_vn_reference_t) p2;
if (vr1->hashcode != vr2->hashcode)
return false;
/* Early out if this is not a hash collision. */
if (vr1->hashcode != vr2->hashcode)
return false;
/* The VOP needs to be the same. */
if (vr1->vuse != vr2->vuse)
return false;
/* If the operands are the same we are done. */
if (vr1->operands == vr2->operands)
return true;
if (!expressions_equal_p (TYPE_SIZE (vr1->type), TYPE_SIZE (vr2->type)))
return false;
if (INTEGRAL_TYPE_P (vr1->type)
&& INTEGRAL_TYPE_P (vr2->type))
{
if (TYPE_PRECISION (vr1->type) != TYPE_PRECISION (vr2->type))
return false;
}
else if (INTEGRAL_TYPE_P (vr1->type)
&& (TYPE_PRECISION (vr1->type)
!= TREE_INT_CST_LOW (TYPE_SIZE (vr1->type))))
return false;
else if (INTEGRAL_TYPE_P (vr2->type)
&& (TYPE_PRECISION (vr2->type)
!= TREE_INT_CST_LOW (TYPE_SIZE (vr2->type))))
return false;
i = 0;
j = 0;
do
{
HOST_WIDE_INT off1 = 0, off2 = 0;
vn_reference_op_t vro1, vro2;
vn_reference_op_s tem1, tem2;
bool deref1 = false, deref2 = false;
for (; VEC_iterate (vn_reference_op_s, vr1->operands, i, vro1); i++)
{
if (vro1->opcode == MEM_REF)
deref1 = true;
if (vro1->off == -1)
break;
off1 += vro1->off;
}
for (; VEC_iterate (vn_reference_op_s, vr2->operands, j, vro2); j++)
{
if (vro2->opcode == MEM_REF)
deref2 = true;
if (vro2->off == -1)
break;
off2 += vro2->off;
}
if (off1 != off2)
return false;
if (deref1 && vro1->opcode == ADDR_EXPR)
{
memset (&tem1, 0, sizeof (tem1));
tem1.op0 = TREE_OPERAND (vro1->op0, 0);
tem1.type = TREE_TYPE (tem1.op0);
tem1.opcode = TREE_CODE (tem1.op0);
vro1 = &tem1;
deref1 = false;
}
if (deref2 && vro2->opcode == ADDR_EXPR)
{
memset (&tem2, 0, sizeof (tem2));
tem2.op0 = TREE_OPERAND (vro2->op0, 0);
tem2.type = TREE_TYPE (tem2.op0);
tem2.opcode = TREE_CODE (tem2.op0);
vro2 = &tem2;
deref2 = false;
}
if (deref1 != deref2)
return false;
if (!vn_reference_op_eq (vro1, vro2))
return false;
++j;
++i;
}
while (VEC_length (vn_reference_op_s, vr1->operands) != i
|| VEC_length (vn_reference_op_s, vr2->operands) != j);
return true;
}
/* Copy the operations present in load/store REF into RESULT, a vector of
vn_reference_op_s's. */
void
copy_reference_ops_from_ref (tree ref, VEC(vn_reference_op_s, heap) **result)
{
if (TREE_CODE (ref) == TARGET_MEM_REF)
{
vn_reference_op_s temp;
memset (&temp, 0, sizeof (temp));
temp.type = TREE_TYPE (ref);
temp.opcode = TREE_CODE (ref);
temp.op0 = TMR_INDEX (ref);
temp.op1 = TMR_STEP (ref);
temp.op2 = TMR_OFFSET (ref);
temp.off = -1;
VEC_safe_push (vn_reference_op_s, heap, *result, &temp);
memset (&temp, 0, sizeof (temp));
temp.type = NULL_TREE;
temp.opcode = ERROR_MARK;
temp.op0 = TMR_INDEX2 (ref);
temp.off = -1;
VEC_safe_push (vn_reference_op_s, heap, *result, &temp);
memset (&temp, 0, sizeof (temp));
temp.type = NULL_TREE;
temp.opcode = TREE_CODE (TMR_BASE (ref));
temp.op0 = TMR_BASE (ref);
temp.off = -1;
VEC_safe_push (vn_reference_op_s, heap, *result, &temp);
return;
}
/* For non-calls, store the information that makes up the address. */
while (ref)
{
vn_reference_op_s temp;
memset (&temp, 0, sizeof (temp));
temp.type = TREE_TYPE (ref);
temp.opcode = TREE_CODE (ref);
temp.off = -1;
switch (temp.opcode)
{
case WITH_SIZE_EXPR:
temp.op0 = TREE_OPERAND (ref, 1);
temp.off = 0;
break;
case MEM_REF:
/* The base address gets its own vn_reference_op_s structure. */
temp.op0 = TREE_OPERAND (ref, 1);
if (host_integerp (TREE_OPERAND (ref, 1), 0))
temp.off = TREE_INT_CST_LOW (TREE_OPERAND (ref, 1));
break;
case BIT_FIELD_REF:
/* Record bits and position. */
temp.op0 = TREE_OPERAND (ref, 1);
temp.op1 = TREE_OPERAND (ref, 2);
break;
case COMPONENT_REF:
/* The field decl is enough to unambiguously specify the field,
a matching type is not necessary and a mismatching type
is always a spurious difference. */
temp.type = NULL_TREE;
temp.op0 = TREE_OPERAND (ref, 1);
temp.op1 = TREE_OPERAND (ref, 2);
{
tree this_offset = component_ref_field_offset (ref);
if (this_offset
&& TREE_CODE (this_offset) == INTEGER_CST)
{
tree bit_offset = DECL_FIELD_BIT_OFFSET (TREE_OPERAND (ref, 1));
if (TREE_INT_CST_LOW (bit_offset) % BITS_PER_UNIT == 0)
{
double_int off
= double_int_add (tree_to_double_int (this_offset),
double_int_rshift
(tree_to_double_int (bit_offset),
BITS_PER_UNIT == 8
? 3 : exact_log2 (BITS_PER_UNIT),
HOST_BITS_PER_DOUBLE_INT, true));
if (double_int_fits_in_shwi_p (off))
temp.off = off.low;
}
}
}
break;
case ARRAY_RANGE_REF:
case ARRAY_REF:
/* Record index as operand. */
temp.op0 = TREE_OPERAND (ref, 1);
/* Always record lower bounds and element size. */
temp.op1 = array_ref_low_bound (ref);
temp.op2 = array_ref_element_size (ref);
if (TREE_CODE (temp.op0) == INTEGER_CST
&& TREE_CODE (temp.op1) == INTEGER_CST
&& TREE_CODE (temp.op2) == INTEGER_CST)
{
double_int off = tree_to_double_int (temp.op0);
off = double_int_add (off,
double_int_neg
(tree_to_double_int (temp.op1)));
off = double_int_mul (off, tree_to_double_int (temp.op2));
if (double_int_fits_in_shwi_p (off))
temp.off = off.low;
}
break;
case VAR_DECL:
if (DECL_HARD_REGISTER (ref))
{
temp.op0 = ref;
break;
}
/* Fallthru. */
case PARM_DECL:
case CONST_DECL:
case RESULT_DECL:
/* Canonicalize decls to MEM[&decl] which is what we end up with
when valueizing MEM[ptr] with ptr = &decl. */
temp.opcode = MEM_REF;
temp.op0 = build_int_cst (build_pointer_type (TREE_TYPE (ref)), 0);
temp.off = 0;
VEC_safe_push (vn_reference_op_s, heap, *result, &temp);
temp.opcode = ADDR_EXPR;
temp.op0 = build_fold_addr_expr (ref);
temp.type = TREE_TYPE (temp.op0);
temp.off = -1;
break;
case STRING_CST:
case INTEGER_CST:
case COMPLEX_CST:
case VECTOR_CST:
case REAL_CST:
case FIXED_CST:
case CONSTRUCTOR:
case SSA_NAME:
temp.op0 = ref;
break;
case ADDR_EXPR:
if (is_gimple_min_invariant (ref))
{
temp.op0 = ref;
break;
}
/* Fallthrough. */
/* These are only interesting for their operands, their
existence, and their type. They will never be the last
ref in the chain of references (IE they require an
operand), so we don't have to put anything
for op* as it will be handled by the iteration */
case REALPART_EXPR:
case VIEW_CONVERT_EXPR:
temp.off = 0;
break;
case IMAGPART_EXPR:
/* This is only interesting for its constant offset. */
temp.off = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (TREE_TYPE (ref)));
break;
default:
gcc_unreachable ();
}
VEC_safe_push (vn_reference_op_s, heap, *result, &temp);
if (REFERENCE_CLASS_P (ref)
|| TREE_CODE (ref) == WITH_SIZE_EXPR
|| (TREE_CODE (ref) == ADDR_EXPR
&& !is_gimple_min_invariant (ref)))
ref = TREE_OPERAND (ref, 0);
else
ref = NULL_TREE;
}
}
/* Build a alias-oracle reference abstraction in *REF from the vn_reference
operands in *OPS, the reference alias set SET and the reference type TYPE.
Return true if something useful was produced. */
bool
ao_ref_init_from_vn_reference (ao_ref *ref,
alias_set_type set, tree type,
VEC (vn_reference_op_s, heap) *ops)
{
vn_reference_op_t op;
unsigned i;
tree base = NULL_TREE;
tree *op0_p = &base;
HOST_WIDE_INT offset = 0;
HOST_WIDE_INT max_size;
HOST_WIDE_INT size = -1;
tree size_tree = NULL_TREE;
alias_set_type base_alias_set = -1;
/* First get the final access size from just the outermost expression. */
op = VEC_index (vn_reference_op_s, ops, 0);
if (op->opcode == COMPONENT_REF)
size_tree = DECL_SIZE (op->op0);
else if (op->opcode == BIT_FIELD_REF)
size_tree = op->op0;
else
{
enum machine_mode mode = TYPE_MODE (type);
if (mode == BLKmode)
size_tree = TYPE_SIZE (type);
else
size = GET_MODE_BITSIZE (mode);
}
if (size_tree != NULL_TREE)
{
if (!host_integerp (size_tree, 1))
size = -1;
else
size = TREE_INT_CST_LOW (size_tree);
}
/* Initially, maxsize is the same as the accessed element size.
In the following it will only grow (or become -1). */
max_size = size;
/* Compute cumulative bit-offset for nested component-refs and array-refs,
and find the ultimate containing object. */
FOR_EACH_VEC_ELT (vn_reference_op_s, ops, i, op)
{
switch (op->opcode)
{
/* These may be in the reference ops, but we cannot do anything
sensible with them here. */
case ADDR_EXPR:
/* Apart from ADDR_EXPR arguments to MEM_REF. */
if (base != NULL_TREE
&& TREE_CODE (base) == MEM_REF
&& op->op0
&& DECL_P (TREE_OPERAND (op->op0, 0)))
{
vn_reference_op_t pop = VEC_index (vn_reference_op_s, ops, i-1);
base = TREE_OPERAND (op->op0, 0);
if (pop->off == -1)
{
max_size = -1;
offset = 0;
}
else
offset += pop->off * BITS_PER_UNIT;
op0_p = NULL;
break;
}
/* Fallthru. */
case CALL_EXPR:
return false;
/* Record the base objects. */
case MEM_REF:
base_alias_set = get_deref_alias_set (op->op0);
*op0_p = build2 (MEM_REF, op->type,
NULL_TREE, op->op0);
op0_p = &TREE_OPERAND (*op0_p, 0);
break;
case VAR_DECL:
case PARM_DECL:
case RESULT_DECL:
case SSA_NAME:
*op0_p = op->op0;
op0_p = NULL;
break;
/* And now the usual component-reference style ops. */
case BIT_FIELD_REF:
offset += tree_low_cst (op->op1, 0);
break;
case COMPONENT_REF:
{
tree field = op->op0;
/* We do not have a complete COMPONENT_REF tree here so we
cannot use component_ref_field_offset. Do the interesting
parts manually. */
if (op->op1
|| !host_integerp (DECL_FIELD_OFFSET (field), 1))
max_size = -1;
else
{
offset += (TREE_INT_CST_LOW (DECL_FIELD_OFFSET (field))
* BITS_PER_UNIT);
offset += TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (field));
}
break;
}
case ARRAY_RANGE_REF:
case ARRAY_REF:
/* We recorded the lower bound and the element size. */
if (!host_integerp (op->op0, 0)
|| !host_integerp (op->op1, 0)
|| !host_integerp (op->op2, 0))
max_size = -1;
else
{
HOST_WIDE_INT hindex = TREE_INT_CST_LOW (op->op0);
hindex -= TREE_INT_CST_LOW (op->op1);
hindex *= TREE_INT_CST_LOW (op->op2);
hindex *= BITS_PER_UNIT;
offset += hindex;
}
break;
case REALPART_EXPR:
break;
case IMAGPART_EXPR:
offset += size;
break;
case VIEW_CONVERT_EXPR:
break;
case STRING_CST:
case INTEGER_CST:
case COMPLEX_CST:
case VECTOR_CST:
case REAL_CST:
case CONSTRUCTOR:
case CONST_DECL:
return false;
default:
return false;
}
}
if (base == NULL_TREE)
return false;
ref->ref = NULL_TREE;
ref->base = base;
ref->offset = offset;
ref->size = size;
ref->max_size = max_size;
ref->ref_alias_set = set;
if (base_alias_set != -1)
ref->base_alias_set = base_alias_set;
else
ref->base_alias_set = get_alias_set (base);
/* We discount volatiles from value-numbering elsewhere. */
ref->volatile_p = false;
return true;
}
/* Copy the operations present in load/store/call REF into RESULT, a vector of
vn_reference_op_s's. */
void
copy_reference_ops_from_call (gimple call,
VEC(vn_reference_op_s, heap) **result)
{
vn_reference_op_s temp;
unsigned i;
/* Copy the type, opcode, function being called and static chain. */
memset (&temp, 0, sizeof (temp));
temp.type = gimple_call_return_type (call);
temp.opcode = CALL_EXPR;
temp.op0 = gimple_call_fn (call);
temp.op1 = gimple_call_chain (call);
temp.off = -1;
VEC_safe_push (vn_reference_op_s, heap, *result, &temp);
/* Copy the call arguments. As they can be references as well,
just chain them together. */
for (i = 0; i < gimple_call_num_args (call); ++i)
{
tree callarg = gimple_call_arg (call, i);
copy_reference_ops_from_ref (callarg, result);
}
}
/* Create a vector of vn_reference_op_s structures from REF, a
REFERENCE_CLASS_P tree. The vector is not shared. */
static VEC(vn_reference_op_s, heap) *
create_reference_ops_from_ref (tree ref)
{
VEC (vn_reference_op_s, heap) *result = NULL;
copy_reference_ops_from_ref (ref, &result);
return result;
}
/* Create a vector of vn_reference_op_s structures from CALL, a
call statement. The vector is not shared. */
static VEC(vn_reference_op_s, heap) *
create_reference_ops_from_call (gimple call)
{
VEC (vn_reference_op_s, heap) *result = NULL;
copy_reference_ops_from_call (call, &result);
return result;
}
/* Fold *& at position *I_P in a vn_reference_op_s vector *OPS. Updates
*I_P to point to the last element of the replacement. */
void
vn_reference_fold_indirect (VEC (vn_reference_op_s, heap) **ops,
unsigned int *i_p)
{
unsigned int i = *i_p;
vn_reference_op_t op = VEC_index (vn_reference_op_s, *ops, i);
vn_reference_op_t mem_op = VEC_index (vn_reference_op_s, *ops, i - 1);
tree addr_base;
HOST_WIDE_INT addr_offset;
/* The only thing we have to do is from &OBJ.foo.bar add the offset