avail_exprs_stack Class Reference

#include <tree-ssa-scopedtables.h>

Collaboration diagram for avail_exprs_stack:

Public Member Functions
	avail_exprs_stack (hash_table< expr_elt_hasher > *table)
	~avail_exprs_stack (void)
void	push_marker (void)
void	pop_to_marker (void)
void	record_expr (expr_hash_elt_t, expr_hash_elt_t, char)
hash_table< expr_elt_hasher > *	avail_exprs (void)
tree	lookup_avail_expr (gimple *, bool, bool, expr_hash_elt **=NULL)
void	record_cond (cond_equivalence *)

Private Member Functions
tree	simplify_binary_operation (gimple *, class expr_hash_elt)
avail_exprs_stack &	operator= (const avail_exprs_stack &)
	avail_exprs_stack (class avail_exprs_stack &)

Private Attributes
vec< std::pair< expr_hash_elt_t, expr_hash_elt_t > >	m_stack
hash_table< expr_elt_hasher > *	m_avail_exprs

Detailed Description

This class defines a unwindable expression equivalence table
layered on top of the expression hash table.

Essentially it's just a stack of available expression value pairs with
a special marker (NULL, NULL) to indicate unwind points.    

Constructor & Destructor Documentation

avail_exprs_stack() [1/2]

avail_exprs_stack::avail_exprs_stack ( hash_table< expr_elt_hasher > * table )

inline

References m_avail_exprs, m_stack, and table.

~avail_exprs_stack()

avail_exprs_stack::~avail_exprs_stack ( void )

inline

References m_stack.

avail_exprs_stack() [2/2]

avail_exprs_stack::avail_exprs_stack ( class avail_exprs_stack & )

private

Member Function Documentation

avail_exprs()

hash_table< expr_elt_hasher > * avail_exprs_stack::avail_exprs ( void )

inline

References m_avail_exprs.

lookup_avail_expr()

tree avail_exprs_stack::lookup_avail_expr	(	gimple *	stmt,
		bool	insert,
		bool	tbaa_p,
		expr_hash_elt **	elt = NULL )

Search for an existing instance of STMT in the AVAIL_EXPRS_STACK table.
If found, return its LHS. Otherwise insert STMT in the table and
return NULL_TREE.

Also, when an expression is first inserted in the  table, it is also
is also added to AVAIL_EXPRS_STACK, so that it can be removed when
we finish processing this block and its children.   

References dump_file, dump_flags, expr_hash_elt::expr(), EXPR_SINGLE, hash_table< Descriptor, Lazy, Allocator >::find_slot(), gimple_get_lhs(), gimple_phi_result(), gimple_vuse(), if(), insert(), is_gimple_min_invariant(), hashable_expr::kind, m_avail_exprs, NULL, NULL_TREE, hashable_expr::ops, expr_hash_elt::print(), record_expr(), hashable_expr::rhs, simplify_binary_operation(), hashable_expr::single, TDF_DETAILS, and TREE_CODE.

Referenced by eliminate_redundant_computations(), record_equivalences_from_stmt(), dom_jt_simplifier::simplify(), and dom_opt_dom_walker::test_for_singularity().

operator=()

avail_exprs_stack & avail_exprs_stack::operator= ( const avail_exprs_stack & )

private

pop_to_marker()

void avail_exprs_stack::pop_to_marker

(

void

)

Initialize local stacks for this optimizer and record equivalences
upon entry to BB.  Equivalences can come from the edge traversed to
reach BB or they may come from PHI nodes at the start of BB.   

Pop items off the unwinding stack, removing each from the hash table
until a marker is encountered.   

References hash_table< Descriptor, Lazy, Allocator >::clear_slot(), dump_file, dump_flags, hash_table< Descriptor, Lazy, Allocator >::find_slot(), gcc_assert, m_avail_exprs, m_stack, NULL, and TDF_DETAILS.

push_marker()

void avail_exprs_stack::push_marker ( void )

inline

References NULL, and record_expr().

record_cond()

void avail_exprs_stack::record_cond

(

cond_equivalence *

p

)

Enter condition equivalence P into the hash table.

This indicates that a conditional expression has a known
boolean value.   

References cond_equivalence::cond, hash_table< Descriptor, Lazy, Allocator >::find_slot_with_hash(), expr_hash_elt::hash(), m_avail_exprs, NULL, record_expr(), and cond_equivalence::value.

Referenced by record_temporary_equivalences().

record_expr()

void avail_exprs_stack::record_expr	(	expr_hash_elt_t	,
		expr_hash_elt_t	,
		char	)

Add <ELT1,ELT2> to the unwinding stack so they can be later removed
from the hash table.   

References dump_file, dump_flags, m_stack, expr_hash_elt::print(), and TDF_DETAILS.

Referenced by lookup_avail_expr(), push_marker(), and record_cond().

simplify_binary_operation()

tree avail_exprs_stack::simplify_binary_operation ( gimple * stmt, class expr_hash_elt element )

private

We looked for STMT in the hash table, but did not find it.

If STMT is an assignment from a binary operator, we may know something
about the operands relationship to each other which would allow
us to derive a constant value for the RHS of STMT.   

References ALL_FRACT_MODE_P, boolean_type_node, build_one_cst(), build_zero_cst(), expr, expr_hash_elt::expr(), EXPR_BINARY, hash_table< Descriptor, Lazy, Allocator >::find_slot(), FLOAT_TYPE_P, gcc_unreachable, gimple_assign_lhs(), gimple_assign_rhs1(), gimple_assign_rhs2(), HONOR_NANS(), integer_onep(), is_gimple_assign(), m_avail_exprs, NULL_TREE, expr::ops, tree_swap_operands_p(), TREE_TYPE, operand::type, and TYPE_MODE.

Referenced by lookup_avail_expr().

Field Documentation

m_avail_exprs

hash_table<expr_elt_hasher>* avail_exprs_stack::m_avail_exprs

private

Referenced by avail_exprs(), avail_exprs_stack(), lookup_avail_expr(), pop_to_marker(), record_cond(), and simplify_binary_operation().

m_stack

vec<std::pair<expr_hash_elt_t, expr_hash_elt_t> > avail_exprs_stack::m_stack

private

Referenced by avail_exprs_stack(), pop_to_marker(), record_expr(), and ~avail_exprs_stack().

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The documentation for this class was generated from the following files:

• tree-ssa-scopedtables.h
• tree-ssa-scopedtables.cc