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gcc/gcc/tree-ssa-forwprop.c
Andrew Pinski 5be014d5b7 [multiple changes] 
2007-06-15  Andrew Pinski <andrew_pinski@playstation.sony.com>
            Zdenek Dvorak <dvorakz@suse.cz>
            Richard Guenther  <rguenther@suse.de>
            Kaz Kojima  <kkojima@gcc.gnu.org>

	* tree-vrp.c (compare_values_warnv): Convert val2 to
	the type of val1.
	(extract_range_from_assert): Create
	POINTER_PLUS_EXPR for pointer types.
	(extract_range_from_binary_expr): Handle
	only POINTER_PLUS_EXPR, MIN_EXPR, and MAX_EXPR
	for pointer types.
	* doc/c-tree.texi (POINTER_PLUS_EXPR): Document.
	* tree-ssa-loop-niter.c (split_to_var_and_offset): Handle
	POINTER_PLUS_EXPR as PLUS_EXPR.
	(number_of_iterations_lt_to_ne):
	For pointer types, use sizetype when
	creating MINUS_EXPR/PLUS_EXPRs.
	(assert_loop_rolls_lt): For pointer types, use sizetype when
	creating MINUS_EXPR/PLUS_EXPRs.
	(number_of_iterations_le): Likewise.
	(expand_simple_operations): POINTER_PLUS_EXPR are simple also.
	(derive_constant_upper_bound): Handle POINTER_PLUS_EXPR just
	like PLUS_EXPR and MINUS_EXPR.
	* tree-pretty-print.c (dump_generic_node): Handle
	POINTER_PLUS_EXPR.
	(op_prio): Likewise.
	(op_symbol_1): Likewise.
	* optabs.c (optab_for_tree_code): Likewise.
	* tree-ssa-loop-manip.c (create_iv): Handle pointer base
	specially.
	* tree-tailcall.c (process_assignment): Mention
	POINTER_PLUS_EXPR in a TODO comment.
	* tree.c (build2_stat): Assert when trying to use PLUS_EXPR or 
	MINUS_EXPR with a pointer. Also assert for POINTER_PLUS_EXPR
	not used with a pointer and an integer type.
	* tree-scalar-evolution.c (add_to_evolution_1): Convert the
	increment using chrec_convert_rhs instead of chrec_convert.
	(follow_ssa_edge_in_rhs): Handle POINTER_PLUS_EXPR like
	PLUS_EXPR except for the right hand side's type will be
	sizetype.
	(interpret_rhs_modify_stmt): Handle POINTER_PLUS_EXPR.
	(fold_used_pointer_cast): Kill.
	(pointer_offset_p): Kill.
	(fold_used_pointer): Kill.
	(pointer_used_p): Kill.
	(analyze_scalar_evolution_1 <case GIMPLE_MODIFY_STMT>): Don't
	call fold_used_pointer.
	(instantiate_parameters_1): Convert the increment
	using chrec_convert_rhs instead of chrec_convert.
	Handle POINTER_PLUS_EXPR as PLUS_EXPR.
	* builtins.c (get_pointer_alignment): Handle POINTER_PLUS_EXPR
	instead of PLUS_EXPR.
	(expand_builtin_strcat): Create a POINTER_PLUS_EXPR instead of
	PLUS_EXPR for pointers.
	(std_gimplify_va_arg_expr): Likewise.
	(fold_builtin_memory_op): Likewise.
	(fold_builtin_strstr): Likewise.
	(fold_builtin_strchr): Likewise.
	(fold_builtin_strrchr): Likewise.
	(fold_builtin_strpbrk): Likewise.
	(expand_builtin_memory_chk): Likewise.
	(fold_builtin_memory_chk): Likewise.
	(std_expand_builtin_va_start): Use
	sizetype for the call to make_tree and then convert
	to the pointer type.
	(fold_builtin_memchr): Use POINTER_PLUS_EXPR
	instead of PLUS_EXPR for adding to a pointer.
	(std_gimplify_va_arg_expr): Use fold_build2 for
	the creating of POINTER_PLUS_EXPR.  For the BIT_AND_EXPR, cast
	the operands to sizetype first and then cast the BIT_AND_EXPR
	back to the pointer type.
	* fold-const.c (build_range_check): Handle pointer types
	specially.
	(extract_array_ref): Look for POINTER_PLUS_EXPR instead
	of PLUS_EXPR's. Make sure the offset is converted to
	sizetype.
	(try_move_mult_to_index): Strip the NOPs from the offset.
	Remove code argument and replace all uses with PLUS_EXPR.
	(fold_to_nonsharp_ineq_using_bound): Handle pointer types
	specially. Don't use a pointer type for MINUS_EXPR.
	(fold_unary): Handle for (T1)(X op Y),
	only p+ as that is the only as that can be handled for
	binary operators now.
	(fold_binary <case POINTER_PLUS_EXPR>): Add folding of
	POINTER_PLUS_EXPR.
	<case PLUS_EXPR>: Add folding of PTR+INT into
	PTR p+ INT.
	Don't call try_move_mult_to_index.
	<case MINUS_EXPR>: Fold (PTR0 p+ A) - (PTR1 p+ B)
	into (PTR0 - PTR1) + (A - B). Fold (PTR0 p+ A) - PTR1 into
	(PTR0 - PTR1) + A iff (PTR0 - PTR1) simplifies.
	Don't call try_move_mult_to_index.
	(tree_expr_nonnegative_warnv_p): Handle POINTER_PLUS_EXPR.
	(tree_expr_nonzero_p): Likewise.
	(fold_indirect_ref_1): Look at POINTER_PLUS_EXPR instead
	of PLUS_EXPR for the complex expression folding.
	* tree-chrec.c (chrec_fold_plus_poly_poly): If the
	first chrec is a pointer type, then the second should
	be sizetype and not the first's type.
	For POINTER_PLUS_EXPR, use a different right hand side type.
	Handle POINTER_PLUS_EXPR like PLUS_EXPR.
	(chrec_fold_plus_1): For POINTER_PLUS_EXPR, use a
	different right hand side type.
	Handle POINTER_PLUS_EXPR like PLUS_EXPR.
	(chrec_fold_plus): For pointer types, use POINTER_PLUS_EXPR
	instead of PLUS_EXPR.
	When either operand is zero, convert the other operand.
	(chrec_apply): Use chrec_convert_rhs
	on the argument x instead of chrec_convert.
	(reset_evolution_in_loop): For pointer types, the new_evol
	should be sizetype.
	(convert_affine_scev): For POINTER_PLUS_EXPR, use a
	different right hand side type.
	Handle POINTER_PLUS_EXPR like PLUS_EXPR.
	(chrec_convert_rhs): New function.
	(chrec_convert_aggressive): For POINTER_PLUS_EXPR, use a
	different right hand side type.
	Handle POINTER_PLUS_EXPR like PLUS_EXPR.
	* tree-chrec.h (chrec_convert_rhs): New prototype.
	(build_polynomial_chrec): For pointer types, the right hand
	* tree-ssa-ccp.c (maybe_fold_stmt_indirect): Look for
	POINTER_PLUS_EXPR instead of PLUS_EXPR's.
	Remove subtraction case as it is always addition now.
	Make sure the offset is converted to sizetype.
	(fold_stmt_r): Don't handle PLUS_EXPR/MINUS_EXPR specially.
	Handle POINTER_PLUS_EXPR like PLUS_EXPR was handled before.
	* tree-ssa-loop-ivopts.c (determine_base_object): Abort for 
	PLUS_EXPR in pointer type.
	Handle POINTER_PLUS_EXPR.
	(tree_to_aff_combination): Likewise.
	(force_expr_to_var_cost): Likewise.
	(force_expr_to_var_cost): Likewise. Create a POINTER_PLUS_EXPR
	instead of PLUS_EXPR for pointers.
	* c-format.c (check_format_arg): Handle POINTER_PLUS_EXPR
	instead of PLUS_EXPR of pointer types.
	* tree-stdarg.c (va_list_counter_bump): Handle POINTER_PLUS_EXPR
	as PLUS_EXPR.
	(check_va_list_escapes): Likewise.
	(check_all_va_list_escapes): Likewise.
	* dwarf2out.c (loc_descriptor_from_tree_1):
	Handle POINT_PLUS_EXPR as a PLUS_EXPR.
	* expr.c (expand_expr_real_1): Handle POINTER_PLUS_EXPR.
	(string_constant): Likewise.
	* tree-ssa-address.c (tree_mem_ref_addr): When adding
	the offset to the base, use POINTER_PLUS_EXPR.
	(add_to_parts): Convert the index to sizetype.
	(create_mem_ref): Create A POINTER_PLUS_EXPR for the one case.
	* matrix-reorg.c (collect_data_for_malloc_call): Stmt
	will now only be either INDIRECT_REF and POINTER_PLUS_EXPR.
	Offset only holds something for PLUS_EXPR.
	(ssa_accessed_in_tree): Handle POINTER_PLUS_EXPR just as
	a PLUS_EXPR.
	(analyze_transpose): POINTER_PLUS_EXPR will only show up now
	and not PLUS_EXPR.
	(analyze_accesses_for_modify_stmt): Likewise.
	Remove comment about the type being integral type as it is
	wrong now.
	(can_calculate_expr_before_stmt): Handle POINTER_PLUS_EXPR as
	PLUS_EXPR.
	(transform_access_sites): POINTER_PLUS_EXPR will only show up now
	and not PLUS_EXPR.
	Correct the type which the artimentic is done in (is now
	sizetype).
	Reindent one loop.
	* tree-data-ref.c (split_constant_offset): Handle
	POINTER_PLUS_EXPR
	* tree-affine.c (tree_to_aff_combination): Likewise.
	* c-typeck.c (build_unary_op): For pointers create the increment
	as a sizetype. Create a POINTER_PLUS_EXPR instead of PLUS_EXPR
	for pointers.
	* gimplify.c (gimplify_self_mod_expr): Create a
	POINTER_PLUS_EXPR instead of PLUS_EXPR for pointers.
	(gimplify_omp_atomic_fetch_op): Handle POINTER_PLUS_EXPR.
	* tree.def (POINTER_PLUS_EXPR): New tree code.
	* tree-predcom.c (ref_at_iteration): If we have a pointer
	type do the multiplication in sizetype.
	* tree-mudflap.c (mf_xform_derefs_1): Create a
	POINTER_PLUS_EXPR instead of PLUS_EXPR for pointers.
	* tree-ssa-forwprop.c 
	(forward_propagate_addr_into_variable_array_index):
	Don't expect there to be a cast for the index as that
	does not exist anymore.
	(forward_propagate_addr_expr_1): Check for POINTER_PLUS_EXPR
	instead of PLUS_EXPR.
	Don't check for the first operand of the POINTER_PLUS_EXPR
	was the index as it cannot be.
	Call forward_propagate_addr_into_variable_array_index with
	the SSA_NAME instead of the statement.
	* varasm.c (const_hash_1): Handle POINTER_PLUS_EXPR.
	(compare_constant): Likewise.
	(copy_constant): Likewise.
	(compute_reloc_for_constant): Likewise.
	(output_addressed_constants): Likewise.
	(initializer_constant_valid_p): Likewise.
	* tree-ssa.c (tree_ssa_useless_type_conversion_1):
	Convert the MIN/MAX of the inner type to the outer
	type before comparing them.
	* tree-ssa-loop-prefetch.c (idx_analyze_ref):  Handle
	POINTER_PLUS_EXPR instead of PLUS_EXPR.
	(issue_prefetch_ref): Create a POINTER_PLUS_EXPR instead
	of PLUS_EXPR for pointers.
	* tree-inline.c (estimate_num_insns_1): Handle
	POINTER_PLUS_EXPR.
	* tree-vect-transform.c (vect_create_addr_base_for_vector_ref): 
	Create a POINTER_PLUS_EXPR instead of PLUS_EXPR for pointers.
	(bump_vector_ptr): Create a POINTER_PLUS_EXPR
	instead of PLUS_EXPR for the pointer increment statement.
	(vect_update_ivs_after_vectorizer): For pointer types, create
	POINTER_PLUS_EXPR instead of PLUS_EXPR and also create
	MULT_EXPR in sizetype.
	(vect_gen_niters_for_prolog_loop): Add a cast when creating
	byte_misalign.
	* tree-object-size.c (plus_expr_object_size): Handle
	POINTER_PLUS_EXPR instead of PLUS_EXPR.  Removing all the extra
	code which is trying to figure out which side is a pointer and 
	is the index.
	(check_for_plus_in_loops_1): Likewise.
	(check_for_plus_in_loops): Likewise.
	* c-common.c (pointer_int_sum): Create a
	POINTER_PLUS_EXPR instead of PLUS_EXPR for pointers.
	* tree-ssa-structalias.c (handle_ptr_arith): Handle
	only POINTER_PLUS_EXPR.  Removing all the extra
	code which is trying to figure out which side is a pointer and 
	is the index.
	* tree-cfg.c (verify_expr): Add extra checking for pointers and
	PLUS_EXPR and MINUS_EXPR.
	Also add checking to make sure the operands of POINTER_PLUS_EXPR
	are correct.
	* config/frv/frv.c (frv_expand_builtin_va_start): Use sizetype
	with make_tree, instead of a pointer type.
	* config/s390/s390.c (s390_va_start): Use POINTER_PLUS_EXPR
	for pointers instead of PLUS_EXPR.
	(s390_gimplify_va_arg): Likewise.
	* config/spu/spu.c (spu_va_start): Create POINTER_PLUS_EXPR
	instead of PLUS_EXPR when doing addition on pointer
	types.  Use sizetype for the second operand.
	(spu_gimplify_va_arg_expr): Likewise.
	* config/sparc/sparc.c (sparc_gimplify_va_arg): Use 
	POINTER_PLUS_EXPR instead of PLUS_EXPR when the operand was
	a pointer.  Don't create a BIT_AND_EXPR for pointer types.
	* config/i386/i386.c (ix86_va_start): Use POINTER_PLUS_EXPR
	for the pointer addition and also use size_int/sizetype
	for the offset.
	(ix86_gimplify_va_arg): Likewise.
	Perform BIT_AND_EXPR on sizetype arguments.
	* config/sh/sh.c (sh_va_start): Call make_tree with sizetype
	and convert its result to a pointer type.  Use POINTER_PLUS_EXPR
	for the pointer additions and also use size_int for the offsets.
	(sh_gimplify_va_arg_expr): Use POINTER_PLUS_EXPR for the pointer
	additions and also use size_int for the offsets.  Perform
	BIT_AND_EXPR on sizetype arguments.
	* config/ia64/ia64.c (ia64_gimplify_va_arg): Use
	POINTER_PLUS_EXPR for pointers and create the
	BIT_AND_EXPR in sizetype.
	* config/rs6000/rs6000.c (rs6000_va_start): Use POINTER_PLUS_EXPR
	instead of PLUS_EXPR for pointer addition.
	(rs6000_va_start): Likewise.
	Also use sizetype for the offset.
	* config/pa/pa.c (reloc_needed): Handle POINTER_PLUS_EXPR
	as PLUS_EXPR/MINUS_EXPR.
	(hppa_gimplify_va_arg_expr): Don't create MINUS_EXPR or
	PLUS_EXPR for pointers, instead use POINTER_PLUS_EXPR.
	Don't use BIT_AND_EXPR on a pointer type, convert the
	expression to sizetype first.
	* config/mips/mips.c (mips_va_start): Use POINTER_PLUS_EXPR
	for pointers.
	(mips_gimplify_va_arg_expr): Likewise.
	Don't create BIT_AND_EXPR in a pointer type.



2007-06-15  Andrew Pinski  <andrew_pinski@playstation.sony.com>

        * trans-intrinsic.c (gfc_conv_intrinsic_repeat): Use
        POINTER_PLUS_EXPR instead of PLUS_EXPR for pointer addition.
        * trans-expr.c (gfc_trans_string_copy): Create
        POINTER_PLUS_EXPR instead of a PLUS_EXPR
        for pointer types.

2007-06-15  Andrew Pinski  <andrew_pinski@playstation.sony.com>

	* typeck.c (build_binary_op): For templates build the
	expression in pieces to avoid the assert in build2_stat.
	(get_member_function_from_ptrfunc):
	Change over to using POINTER_PLUS_EXPR and convert
	the second operand to sizetype.
	* typeck2.c (build_m_component_ref):  Likewise.
	* init.c (expand_virtual_init): Create a POINTER_PLUS_EXPR
	instead of PLUS_EXPR for pointers.
	(build_new_1): Likewise.
	(build_vec_delete_1): Likewise.
	(build_vec_delete): Likewise.
	* class.c (build_base_path): Likewise.
	(build_base_path): Likewise.
	(convert_to_base_statically): Likewise.
	(fixed_type_or_null): Handle POINTER_PLUS_EXPR.
	(get_vtbl_decl_for_binfo): Handle POINTER_PLUS_EXPR
	instead of PLUS_EXPR.
	(dfs_accumulate_vtbl_inits): Create a POINTER_PLUS_EXPR
	instead of PLUS_EXPR for pointers.
	* call.c (build_special_member_call): Likewise.
	* rtti.c (build_headof): Likewise.
	Use sizetype instead of ptrdiff_type_node.
	(tinfo_base_init): Create a POINTER_PLUS_EXPR
	instead of PLUS_EXPR for pointers.
	* except.c (expand_start_catch_block):  Do a
	NEGATIVE and then a POINTER_PLUS_EXPR instead
	of a MINUS_EXPR.
	* cp-gimplify.c (cxx_omp_clause_apply_fn): Convert
	PLUS_EXPR on pointer types over to use
	POINTER_PLUS_EXPR and remove the conversion
	to the pointer types.
	* method.c (thunk_adjust): Use POINTER_PLUS_EXPR for
	adding to a pointer type. Use size_int instead of
	ssize_int. Convert the index to sizetype before
	adding it to the pointer.



2007-06-15  Andrew Pinski  <andrew_pinski@playstation.sony.com>

        * trans.c (Attribute_to_gnu): When subtracting an
        offset from a pointer, use POINTER_PLUS_EXPR with
        NEGATE_EXPR instead of MINUS_EXPR.
        (gnat_to_gnu): Likewise.
        * utils.c (convert): When converting between
        thin pointers, use POINTER_PLUS_EXPR and sizetype
        for the offset.
        * utils2.c (known_alignment): POINTER_PLUS_EXPR
        have the same semantics as PLUS_EXPR for alignment.
        (build_binary_op): Add support for the semantics of
        POINTER_PLUS_EXPR's operands.
        When adding an offset to a pointer, use POINTER_PLUS_EXPR.



2007-06-15 Andrew Pinski  <andrew_pinski@playstation.sony.com>

        * class.c (make_class_data): Build the index in sizetype.
        Use POINTER_PLUS_EXPR instead of PLUS_EXPR when
        adding to a pointer type.
        (build_symbol_entry): Likewise.
        * expr.c (build_java_arrayaccess): Likewise.
        (build_field_ref): Likewise.
        (build_known_method_ref): Likewise.
        (build_invokevirtual): Likewise.
        * except.c (build_exception_object_ref): Do a
        NEGATIVE and then a POINTER_PLUS_EXPR instead
        of a MINUS_EXPR.


2007-06-15  Andrew Pinski  <andrew_pinski@playstation.sony.com>

	PR tree-opt/32225
	* gcc.c-torture/compile/20070605-1.c: New test.

	* gcc.c-torture/compile/20070603-1.c: New testcase.
	* gcc.c-torture/compile/20070603-2.c: New testcase.

	* gcc.c-torture/compile/20070531-1.c: New test.

	PR tree-opt/32167
	* gcc.c-torture/compile/20070531-2.c: New test.

	PR tree-opt/32144
	* gcc.c-torture/compile/20070529-1.c: New test.

	PR tree-opt/32145
	* gcc.c-torture/compile/20070529-2.c: New test.

	PR tree-opt/32015
	* gcc.c-torture/compile/20070520-1.c: New test.

	* g++.dg/ext/java-1.C: New test.

	* gcc.dg/vect/vect-106.c: We are now able to vectorize two
	loops instead of one. Remove the "can't determine dependence"
	check.
	* gcc.dg/tree-ssa/20030815-1.c: Remove testcase which is no longer
	needed as the cast is gone in the first place.
	* gcc.dg/max-1.c: Change local variable a to be a global one.
	* gcc.dg/tree-ssa/ssa-pre-8.c: Update testcase since we don't
	have a cast which is PREd.

From-SVN: r125755
2007-06-15 22:42:36 -07:00

1371 lines
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/* Forward propagation of expressions for single use variables.
Copyright (C) 2004, 2005 Free Software Foundation, Inc.
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 2, 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 COPYING. If not, write to
the Free Software Foundation, 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA. */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "ggc.h"
#include "tree.h"
#include "rtl.h"
#include "tm_p.h"
#include "basic-block.h"
#include "timevar.h"
#include "diagnostic.h"
#include "tree-flow.h"
#include "tree-pass.h"
#include "tree-dump.h"
#include "langhooks.h"
#include "flags.h"
/* This pass propagates the RHS of assignment statements into use
sites of the LHS of the assignment. It's basically a specialized
form of tree combination. It is hoped all of this can disappear
when we have a generalized tree combiner.
Note carefully that after propagation the resulting statement
must still be a proper gimple statement. Right now we simply
only perform propagations we know will result in valid gimple
code. One day we'll want to generalize this code.
One class of common cases we handle is forward propagating a single use
variable into a COND_EXPR.
bb0:
x = a COND b;
if (x) goto ... else goto ...
Will be transformed into:
bb0:
if (a COND b) goto ... else goto ...
Similarly for the tests (x == 0), (x != 0), (x == 1) and (x != 1).
Or (assuming c1 and c2 are constants):
bb0:
x = a + c1;
if (x EQ/NEQ c2) goto ... else goto ...
Will be transformed into:
bb0:
if (a EQ/NEQ (c2 - c1)) goto ... else goto ...
Similarly for x = a - c1.
Or
bb0:
x = !a
if (x) goto ... else goto ...
Will be transformed into:
bb0:
if (a == 0) goto ... else goto ...
Similarly for the tests (x == 0), (x != 0), (x == 1) and (x != 1).
For these cases, we propagate A into all, possibly more than one,
COND_EXPRs that use X.
Or
bb0:
x = (typecast) a
if (x) goto ... else goto ...
Will be transformed into:
bb0:
if (a != 0) goto ... else goto ...
(Assuming a is an integral type and x is a boolean or x is an
integral and a is a boolean.)
Similarly for the tests (x == 0), (x != 0), (x == 1) and (x != 1).
For these cases, we propagate A into all, possibly more than one,
COND_EXPRs that use X.
In addition to eliminating the variable and the statement which assigns
a value to the variable, we may be able to later thread the jump without
adding insane complexity in the dominator optimizer.
Also note these transformations can cascade. We handle this by having
a worklist of COND_EXPR statements to examine. As we make a change to
a statement, we put it back on the worklist to examine on the next
iteration of the main loop.
A second class of propagation opportunities arises for ADDR_EXPR
nodes.
ptr = &x->y->z;
res = *ptr;
Will get turned into
res = x->y->z;
Or
ptr = &x[0];
ptr2 = ptr + <constant>;
Will get turned into
ptr2 = &x[constant/elementsize];
Or
ptr = &x[0];
offset = index * element_size;
offset_p = (pointer) offset;
ptr2 = ptr + offset_p
Will get turned into:
ptr2 = &x[index];
We also propagate casts into SWITCH_EXPR and COND_EXPR conditions to
allow us to remove the cast and {NOT_EXPR,NEG_EXPR} into a subsequent
{NOT_EXPR,NEG_EXPR}.
This will (of course) be extended as other needs arise. */
static bool forward_propagate_addr_expr (tree name, tree rhs);
/* Set to true if we delete EH edges during the optimization. */
static bool cfg_changed;
/* Get the next statement we can propagate NAME's value into skipping
trivial copies. Returns the statement that is suitable as a
propagation destination or NULL_TREE if there is no such one.
This only returns destinations in a single-use chain. FINAL_NAME_P
if non-NULL is written to the ssa name that represents the use. */
static tree
get_prop_dest_stmt (tree name, tree *final_name_p)
{
use_operand_p use;
tree use_stmt;
do {
/* If name has multiple uses, bail out. */
if (!single_imm_use (name, &use, &use_stmt))
return NULL_TREE;
/* If this is not a trivial copy, we found it. */
if (TREE_CODE (use_stmt) != GIMPLE_MODIFY_STMT
|| TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 0)) != SSA_NAME
|| GIMPLE_STMT_OPERAND (use_stmt, 1) != name)
break;
/* Continue searching uses of the copy destination. */
name = GIMPLE_STMT_OPERAND (use_stmt, 0);
} while (1);
if (final_name_p)
*final_name_p = name;
return use_stmt;
}
/* Get the statement we can propagate from into NAME skipping
trivial copies. Returns the statement which defines the
propagation source or NULL_TREE if there is no such one.
If SINGLE_USE_ONLY is set considers only sources which have
a single use chain up to NAME. If SINGLE_USE_P is non-null,
it is set to whether the chain to NAME is a single use chain
or not. SINGLE_USE_P is not written to if SINGLE_USE_ONLY is set. */
static tree
get_prop_source_stmt (tree name, bool single_use_only, bool *single_use_p)
{
bool single_use = true;
do {
tree def_stmt = SSA_NAME_DEF_STMT (name);
if (!has_single_use (name))
{
single_use = false;
if (single_use_only)
return NULL_TREE;
}
/* If name is defined by a PHI node or is the default def, bail out. */
if (TREE_CODE (def_stmt) != GIMPLE_MODIFY_STMT)
return NULL_TREE;
/* If name is not a simple copy destination, we found it. */
if (TREE_CODE (GIMPLE_STMT_OPERAND (def_stmt, 1)) != SSA_NAME)
{
if (!single_use_only && single_use_p)
*single_use_p = single_use;
return def_stmt;
}
/* Continue searching the def of the copy source name. */
name = GIMPLE_STMT_OPERAND (def_stmt, 1);
} while (1);
}
/* Checks if the destination ssa name in DEF_STMT can be used as
propagation source. Returns true if so, otherwise false. */
static bool
can_propagate_from (tree def_stmt)
{
tree rhs = GIMPLE_STMT_OPERAND (def_stmt, 1);
/* We cannot propagate ssa names that occur in abnormal phi nodes. */
switch (TREE_CODE_LENGTH (TREE_CODE (rhs)))
{
case 3:
if (TREE_OPERAND (rhs, 2) != NULL_TREE
&& TREE_CODE (TREE_OPERAND (rhs, 2)) == SSA_NAME
&& SSA_NAME_OCCURS_IN_ABNORMAL_PHI (TREE_OPERAND (rhs, 2)))
return false;
case 2:
if (TREE_OPERAND (rhs, 1) != NULL_TREE
&& TREE_CODE (TREE_OPERAND (rhs, 1)) == SSA_NAME
&& SSA_NAME_OCCURS_IN_ABNORMAL_PHI (TREE_OPERAND (rhs, 1)))
return false;
case 1:
if (TREE_OPERAND (rhs, 0) != NULL_TREE
&& TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME
&& SSA_NAME_OCCURS_IN_ABNORMAL_PHI (TREE_OPERAND (rhs, 0)))
return false;
break;
default:
return false;
}
/* If the definition is a conversion of a pointer to a function type,
then we can not apply optimizations as some targets require function
pointers to be canonicalized and in this case this optimization could
eliminate a necessary canonicalization. */
if ((TREE_CODE (rhs) == NOP_EXPR
|| TREE_CODE (rhs) == CONVERT_EXPR)
&& POINTER_TYPE_P (TREE_TYPE (TREE_OPERAND (rhs, 0)))
&& TREE_CODE (TREE_TYPE (TREE_TYPE
(TREE_OPERAND (rhs, 0)))) == FUNCTION_TYPE)
return false;
return true;
}
/* Remove a copy chain ending in NAME along the defs but not
further or including UP_TO_STMT. If NAME was replaced in
its only use then this function can be used to clean up
dead stmts. Returns true if UP_TO_STMT can be removed
as well, otherwise false. */
static bool
remove_prop_source_from_use (tree name, tree up_to_stmt)
{
block_stmt_iterator bsi;
tree stmt;
do {
if (!has_zero_uses (name))
return false;
stmt = SSA_NAME_DEF_STMT (name);
if (stmt == up_to_stmt)
return true;
bsi = bsi_for_stmt (stmt);
release_defs (stmt);
bsi_remove (&bsi, true);
name = GIMPLE_STMT_OPERAND (stmt, 1);
} while (TREE_CODE (name) == SSA_NAME);
return false;
}
/* Combine OP0 CODE OP1 in the context of a COND_EXPR. Returns
the folded result in a form suitable for COND_EXPR_COND or
NULL_TREE, if there is no suitable simplified form. If
INVARIANT_ONLY is true only gimple_min_invariant results are
considered simplified. */
static tree
combine_cond_expr_cond (enum tree_code code, tree type,
tree op0, tree op1, bool invariant_only)
{
tree t;
gcc_assert (TREE_CODE_CLASS (code) == tcc_comparison);
t = fold_binary (code, type, op0, op1);
if (!t)
return NULL_TREE;
/* Require that we got a boolean type out if we put one in. */
gcc_assert (TREE_CODE (TREE_TYPE (t)) == TREE_CODE (type));
/* For (bool)x use x != 0. */
if (TREE_CODE (t) == NOP_EXPR
&& TREE_TYPE (t) == boolean_type_node)
{
tree top0 = TREE_OPERAND (t, 0);
t = build2 (NE_EXPR, type,
top0, build_int_cst (TREE_TYPE (top0), 0));
}
/* For !x use x == 0. */
else if (TREE_CODE (t) == TRUTH_NOT_EXPR)
{
tree top0 = TREE_OPERAND (t, 0);
t = build2 (EQ_EXPR, type,
top0, build_int_cst (TREE_TYPE (top0), 0));
}
/* For cmp ? 1 : 0 use cmp. */
else if (TREE_CODE (t) == COND_EXPR
&& COMPARISON_CLASS_P (TREE_OPERAND (t, 0))
&& integer_onep (TREE_OPERAND (t, 1))
&& integer_zerop (TREE_OPERAND (t, 2)))
{
tree top0 = TREE_OPERAND (t, 0);
t = build2 (TREE_CODE (top0), type,
TREE_OPERAND (top0, 0), TREE_OPERAND (top0, 1));
}
/* Bail out if we required an invariant but didn't get one. */
if (invariant_only
&& !is_gimple_min_invariant (t))
return NULL_TREE;
/* A valid conditional for a COND_EXPR is either a gimple value
or a comparison with two gimple value operands. */
if (is_gimple_val (t)
|| (COMPARISON_CLASS_P (t)
&& is_gimple_val (TREE_OPERAND (t, 0))
&& is_gimple_val (TREE_OPERAND (t, 1))))
return t;
return NULL_TREE;
}
/* Propagate from the ssa name definition statements of COND_EXPR
in statement STMT into the conditional if that simplifies it.
Returns zero if no statement was changed, one if there were
changes and two if cfg_cleanup needs to run. */
static int
forward_propagate_into_cond (tree cond_expr, tree stmt)
{
int did_something = 0;
do {
tree tmp = NULL_TREE;
tree cond = COND_EXPR_COND (cond_expr);
tree name, def_stmt, rhs;
bool single_use_p;
/* We can do tree combining on SSA_NAME and comparison expressions. */
if (COMPARISON_CLASS_P (cond)
&& TREE_CODE (TREE_OPERAND (cond, 0)) == SSA_NAME)
{
/* For comparisons use the first operand, that is likely to
simplify comparisons against constants. */
name = TREE_OPERAND (cond, 0);
def_stmt = get_prop_source_stmt (name, false, &single_use_p);
if (def_stmt != NULL_TREE
&& can_propagate_from (def_stmt))
{
tree op1 = TREE_OPERAND (cond, 1);
rhs = GIMPLE_STMT_OPERAND (def_stmt, 1);
tmp = combine_cond_expr_cond (TREE_CODE (cond), boolean_type_node,
fold_convert (TREE_TYPE (op1), rhs),
op1, !single_use_p);
}
/* If that wasn't successful, try the second operand. */
if (tmp == NULL_TREE
&& TREE_CODE (TREE_OPERAND (cond, 1)) == SSA_NAME)
{
tree op0 = TREE_OPERAND (cond, 0);
name = TREE_OPERAND (cond, 1);
def_stmt = get_prop_source_stmt (name, false, &single_use_p);
if (def_stmt == NULL_TREE
|| !can_propagate_from (def_stmt))
return did_something;
rhs = GIMPLE_STMT_OPERAND (def_stmt, 1);
tmp = combine_cond_expr_cond (TREE_CODE (cond), boolean_type_node,
op0,
fold_convert (TREE_TYPE (op0), rhs),
!single_use_p);
}
}
else if (TREE_CODE (cond) == SSA_NAME)
{
name = cond;
def_stmt = get_prop_source_stmt (name, true, NULL);
if (def_stmt == NULL_TREE
|| !can_propagate_from (def_stmt))
return did_something;
rhs = GIMPLE_STMT_OPERAND (def_stmt, 1);
tmp = combine_cond_expr_cond (NE_EXPR, boolean_type_node, rhs,
build_int_cst (TREE_TYPE (rhs), 0),
false);
}
if (tmp)
{
if (dump_file && tmp)
{
fprintf (dump_file, " Replaced '");
print_generic_expr (dump_file, cond, 0);
fprintf (dump_file, "' with '");
print_generic_expr (dump_file, tmp, 0);
fprintf (dump_file, "'\n");
}
COND_EXPR_COND (cond_expr) = unshare_expr (tmp);
update_stmt (stmt);
/* Remove defining statements. */
remove_prop_source_from_use (name, NULL);
if (is_gimple_min_invariant (tmp))
did_something = 2;
else if (did_something == 0)
did_something = 1;
/* Continue combining. */
continue;
}
break;
} while (1);
return did_something;
}
/* We've just substituted an ADDR_EXPR into stmt. Update all the
relevant data structures to match. */
static void
tidy_after_forward_propagate_addr (tree stmt)
{
/* We may have turned a trapping insn into a non-trapping insn. */
if (maybe_clean_or_replace_eh_stmt (stmt, stmt)
&& tree_purge_dead_eh_edges (bb_for_stmt (stmt)))
cfg_changed = true;
if (TREE_CODE (GIMPLE_STMT_OPERAND (stmt, 1)) == ADDR_EXPR)
recompute_tree_invariant_for_addr_expr (GIMPLE_STMT_OPERAND (stmt, 1));
mark_symbols_for_renaming (stmt);
}
/* DEF_RHS contains the address of the 0th element in an array.
USE_STMT uses type of DEF_RHS to compute the address of an
arbitrary element within the array. The (variable) byte offset
of the element is contained in OFFSET.
We walk back through the use-def chains of OFFSET to verify that
it is indeed computing the offset of an element within the array
and extract the index corresponding to the given byte offset.
We then try to fold the entire address expression into a form
&array[index].
If we are successful, we replace the right hand side of USE_STMT
with the new address computation. */
static bool
forward_propagate_addr_into_variable_array_index (tree offset,
tree def_rhs, tree use_stmt)
{
tree index;
/* Try to find an expression for a proper index. This is either
a multiplication expression by the element size or just the
ssa name we came along in case the element size is one. */
if (integer_onep (TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (def_rhs)))))
index = offset;
else
{
/* Get the offset's defining statement. */
offset = SSA_NAME_DEF_STMT (offset);
/* The statement which defines OFFSET before type conversion
must be a simple GIMPLE_MODIFY_STMT. */
if (TREE_CODE (offset) != GIMPLE_MODIFY_STMT)
return false;
/* The RHS of the statement which defines OFFSET must be a
multiplication of an object by the size of the array elements.
This implicitly verifies that the size of the array elements
is constant. */
offset = GIMPLE_STMT_OPERAND (offset, 1);
if (TREE_CODE (offset) != MULT_EXPR
|| TREE_CODE (TREE_OPERAND (offset, 1)) != INTEGER_CST
|| !simple_cst_equal (TREE_OPERAND (offset, 1),
TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (def_rhs)))))
return false;
/* The first operand to the MULT_EXPR is the desired index. */
index = TREE_OPERAND (offset, 0);
}
/* Replace the pointer addition with array indexing. */
GIMPLE_STMT_OPERAND (use_stmt, 1) = unshare_expr (def_rhs);
TREE_OPERAND (TREE_OPERAND (GIMPLE_STMT_OPERAND (use_stmt, 1), 0), 1)
= index;
/* That should have created gimple, so there is no need to
record information to undo the propagation. */
fold_stmt_inplace (use_stmt);
tidy_after_forward_propagate_addr (use_stmt);
return true;
}
/* NAME is a SSA_NAME representing DEF_RHS which is of the form
ADDR_EXPR <whatever>.
Try to forward propagate the ADDR_EXPR into the use USE_STMT.
Often this will allow for removal of an ADDR_EXPR and INDIRECT_REF
node or for recovery of array indexing from pointer arithmetic.
Return true if the propagation was successful (the propagation can
be not totally successful, yet things may have been changed). */
static bool
forward_propagate_addr_expr_1 (tree name, tree def_rhs, tree use_stmt,
bool single_use_p)
{
tree lhs, rhs, array_ref;
/* Strip away any outer COMPONENT_REF/ARRAY_REF nodes from the LHS.
ADDR_EXPR will not appear on the LHS. */
lhs = GIMPLE_STMT_OPERAND (use_stmt, 0);
while (handled_component_p (lhs))
lhs = TREE_OPERAND (lhs, 0);
rhs = GIMPLE_STMT_OPERAND (use_stmt, 1);
/* Now see if the LHS node is an INDIRECT_REF using NAME. If so,
propagate the ADDR_EXPR into the use of NAME and fold the result. */
if (TREE_CODE (lhs) == INDIRECT_REF && TREE_OPERAND (lhs, 0) == name)
{
/* This should always succeed in creating gimple, so there is
no need to save enough state to undo this propagation. */
TREE_OPERAND (lhs, 0) = unshare_expr (def_rhs);
fold_stmt_inplace (use_stmt);
tidy_after_forward_propagate_addr (use_stmt);
/* Continue propagating into the RHS. */
}
/* Trivial cases. The use statement could be a trivial copy or a
useless conversion. Recurse to the uses of the lhs as copyprop does
not copy through differen variant pointers and FRE does not catch
all useless conversions. Treat the case of a single-use name and
a conversion to def_rhs type separate, though. */
else if (TREE_CODE (lhs) == SSA_NAME
&& (TREE_CODE (rhs) == NOP_EXPR
|| TREE_CODE (rhs) == CONVERT_EXPR)
&& TREE_TYPE (rhs) == TREE_TYPE (def_rhs)
&& single_use_p)
{
GIMPLE_STMT_OPERAND (use_stmt, 1) = unshare_expr (def_rhs);
return true;
}
else if ((TREE_CODE (lhs) == SSA_NAME
&& rhs == name)
|| ((TREE_CODE (rhs) == NOP_EXPR
|| TREE_CODE (rhs) == CONVERT_EXPR)
&& tree_ssa_useless_type_conversion_1 (TREE_TYPE (rhs),
TREE_TYPE (def_rhs))))
return forward_propagate_addr_expr (lhs, def_rhs);
/* Strip away any outer COMPONENT_REF, ARRAY_REF or ADDR_EXPR
nodes from the RHS. */
while (handled_component_p (rhs)
|| TREE_CODE (rhs) == ADDR_EXPR)
rhs = TREE_OPERAND (rhs, 0);
/* Now see if the RHS node is an INDIRECT_REF using NAME. If so,
propagate the ADDR_EXPR into the use of NAME and fold the result. */
if (TREE_CODE (rhs) == INDIRECT_REF && TREE_OPERAND (rhs, 0) == name)
{
/* This should always succeed in creating gimple, so there is
no need to save enough state to undo this propagation. */
TREE_OPERAND (rhs, 0) = unshare_expr (def_rhs);
fold_stmt_inplace (use_stmt);
tidy_after_forward_propagate_addr (use_stmt);
return true;
}
/* The remaining cases are all for turning pointer arithmetic into
array indexing. They only apply when we have the address of
element zero in an array. If that is not the case then there
is nothing to do. */
array_ref = TREE_OPERAND (def_rhs, 0);
if (TREE_CODE (array_ref) != ARRAY_REF
|| TREE_CODE (TREE_TYPE (TREE_OPERAND (array_ref, 0))) != ARRAY_TYPE
|| !integer_zerop (TREE_OPERAND (array_ref, 1)))
return false;
/* If the use of the ADDR_EXPR is not a POINTER_PLUS_EXPR, there
is nothing to do. */
if (TREE_CODE (rhs) != POINTER_PLUS_EXPR)
return false;
/* Try to optimize &x[0] p+ C where C is a multiple of the size
of the elements in X into &x[C/element size]. */
if (TREE_OPERAND (rhs, 0) == name
&& TREE_CODE (TREE_OPERAND (rhs, 1)) == INTEGER_CST)
{
tree orig = unshare_expr (rhs);
TREE_OPERAND (rhs, 0) = unshare_expr (def_rhs);
/* If folding succeeds, then we have just exposed new variables
in USE_STMT which will need to be renamed. If folding fails,
then we need to put everything back the way it was. */
if (fold_stmt_inplace (use_stmt))
{
tidy_after_forward_propagate_addr (use_stmt);
return true;
}
else
{
GIMPLE_STMT_OPERAND (use_stmt, 1) = orig;
update_stmt (use_stmt);
return false;
}
}
/* Try to optimize &x[0] p+ OFFSET where OFFSET is defined by
converting a multiplication of an index by the size of the
array elements, then the result is converted into the proper
type for the arithmetic. */
if (TREE_OPERAND (rhs, 0) == name
&& TREE_CODE (TREE_OPERAND (rhs, 1)) == SSA_NAME
/* Avoid problems with IVopts creating PLUS_EXPRs with a
different type than their operands. */
&& lang_hooks.types_compatible_p (TREE_TYPE (name), TREE_TYPE (rhs)))
{
bool res;
res = forward_propagate_addr_into_variable_array_index (TREE_OPERAND (rhs, 1),
def_rhs, use_stmt);
return res;
}
return false;
}
/* STMT is a statement of the form SSA_NAME = ADDR_EXPR <whatever>.
Try to forward propagate the ADDR_EXPR into all uses of the SSA_NAME.
Often this will allow for removal of an ADDR_EXPR and INDIRECT_REF
node or for recovery of array indexing from pointer arithmetic.
Returns true, if all uses have been propagated into. */
static bool
forward_propagate_addr_expr (tree name, tree rhs)
{
int stmt_loop_depth = bb_for_stmt (SSA_NAME_DEF_STMT (name))->loop_depth;
imm_use_iterator iter;
tree use_stmt;
bool all = true;
bool single_use_p = has_single_use (name);
FOR_EACH_IMM_USE_STMT (use_stmt, iter, name)
{
bool result;
/* If the use is not in a simple assignment statement, then
there is nothing we can do. */
if (TREE_CODE (use_stmt) != GIMPLE_MODIFY_STMT)
{
all = false;
continue;
}
/* If the use is in a deeper loop nest, then we do not want
to propagate the ADDR_EXPR into the loop as that is likely
adding expression evaluations into the loop. */
if (bb_for_stmt (use_stmt)->loop_depth > stmt_loop_depth)
{
all = false;
continue;
}
/* If the use_stmt has side-effects, don't propagate into it. */
if (stmt_ann (use_stmt)->has_volatile_ops)
{
all = false;
continue;
}
push_stmt_changes (&use_stmt);
result = forward_propagate_addr_expr_1 (name, rhs, use_stmt,
single_use_p);
all &= result;
pop_stmt_changes (&use_stmt);
/* Remove intermediate now unused copy and conversion chains. */
if (result
&& TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 0)) == SSA_NAME
&& (TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 1)) == SSA_NAME
|| TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 1)) == NOP_EXPR
|| TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 1)) == CONVERT_EXPR))
{
block_stmt_iterator bsi = bsi_for_stmt (use_stmt);
release_defs (use_stmt);
bsi_remove (&bsi, true);
}
}
return all;
}
/* Forward propagate the comparison COND defined in STMT like
cond_1 = x CMP y to uses of the form
a_1 = (T')cond_1
a_1 = !cond_1
a_1 = cond_1 != 0
Returns true if stmt is now unused. */
static bool
forward_propagate_comparison (tree cond, tree stmt)
{
tree name = GIMPLE_STMT_OPERAND (stmt, 0);
tree use_stmt, tmp = NULL_TREE;
/* Don't propagate ssa names that occur in abnormal phis. */
if ((TREE_CODE (TREE_OPERAND (cond, 0)) == SSA_NAME
&& SSA_NAME_OCCURS_IN_ABNORMAL_PHI (TREE_OPERAND (cond, 0)))
|| (TREE_CODE (TREE_OPERAND (cond, 1)) == SSA_NAME
&& SSA_NAME_OCCURS_IN_ABNORMAL_PHI (TREE_OPERAND (cond, 1))))
return false;
/* Do not un-cse comparisons. But propagate through copies. */
use_stmt = get_prop_dest_stmt (name, &name);
if (use_stmt == NULL_TREE)
return false;
/* Conversion of the condition result to another integral type. */
if (TREE_CODE (use_stmt) == GIMPLE_MODIFY_STMT
&& (TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 1)) == CONVERT_EXPR
|| TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 1)) == NOP_EXPR
|| COMPARISON_CLASS_P (GIMPLE_STMT_OPERAND (use_stmt, 1))
|| TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 1)) == TRUTH_NOT_EXPR)
&& INTEGRAL_TYPE_P (TREE_TYPE (GIMPLE_STMT_OPERAND (use_stmt, 0))))
{
tree lhs = GIMPLE_STMT_OPERAND (use_stmt, 0);
tree rhs = GIMPLE_STMT_OPERAND (use_stmt, 1);
/* We can propagate the condition into a conversion. */
if (TREE_CODE (rhs) == CONVERT_EXPR
|| TREE_CODE (rhs) == NOP_EXPR)
{
/* Avoid using fold here as that may create a COND_EXPR with
non-boolean condition as canonical form. */
tmp = build2 (TREE_CODE (cond), TREE_TYPE (lhs),
TREE_OPERAND (cond, 0), TREE_OPERAND (cond, 1));
}
/* We can propagate the condition into X op CST where op
is EQ_EXRP or NE_EXPR and CST is either one or zero. */
else if (COMPARISON_CLASS_P (rhs)
&& TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME
&& TREE_CODE (TREE_OPERAND (rhs, 1)) == INTEGER_CST)
{
enum tree_code code = TREE_CODE (rhs);
tree cst = TREE_OPERAND (rhs, 1);
tmp = combine_cond_expr_cond (code, TREE_TYPE (lhs),
fold_convert (TREE_TYPE (cst), cond),
cst, false);
if (tmp == NULL_TREE)
return false;
}
/* We can propagate the condition into a statement that
computes the logical negation of the comparison result. */
else if (TREE_CODE (rhs) == TRUTH_NOT_EXPR)
{
tree type = TREE_TYPE (TREE_OPERAND (cond, 0));
bool nans = HONOR_NANS (TYPE_MODE (type));
enum tree_code code;
code = invert_tree_comparison (TREE_CODE (cond), nans);
if (code == ERROR_MARK)
return false;
tmp = build2 (code, TREE_TYPE (lhs), TREE_OPERAND (cond, 0),
TREE_OPERAND (cond, 1));
}
else
return false;
GIMPLE_STMT_OPERAND (use_stmt, 1) = unshare_expr (tmp);
update_stmt (use_stmt);
/* Remove defining statements. */
remove_prop_source_from_use (name, stmt);
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, " Replaced '");
print_generic_expr (dump_file, rhs, dump_flags);
fprintf (dump_file, "' with '");
print_generic_expr (dump_file, tmp, dump_flags);
fprintf (dump_file, "'\n");
}
return true;
}
return false;
}
/* If we have lhs = ~x (STMT), look and see if earlier we had x = ~y.
If so, we can change STMT into lhs = y which can later be copy
propagated. Similarly for negation.
This could trivially be formulated as a forward propagation
to immediate uses. However, we already had an implementation
from DOM which used backward propagation via the use-def links.
It turns out that backward propagation is actually faster as
there's less work to do for each NOT/NEG expression we find.
Backwards propagation needs to look at the statement in a single
backlink. Forward propagation needs to look at potentially more
than one forward link. */
static void
simplify_not_neg_expr (tree stmt)
{
tree rhs = GIMPLE_STMT_OPERAND (stmt, 1);
tree rhs_def_stmt = SSA_NAME_DEF_STMT (TREE_OPERAND (rhs, 0));
/* See if the RHS_DEF_STMT has the same form as our statement. */
if (TREE_CODE (rhs_def_stmt) == GIMPLE_MODIFY_STMT
&& TREE_CODE (GIMPLE_STMT_OPERAND (rhs_def_stmt, 1)) == TREE_CODE (rhs))
{
tree rhs_def_operand =
TREE_OPERAND (GIMPLE_STMT_OPERAND (rhs_def_stmt, 1), 0);
/* Verify that RHS_DEF_OPERAND is a suitable SSA_NAME. */
if (TREE_CODE (rhs_def_operand) == SSA_NAME
&& ! SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs_def_operand))
{
GIMPLE_STMT_OPERAND (stmt, 1) = rhs_def_operand;
update_stmt (stmt);
}
}
}
/* STMT is a SWITCH_EXPR for which we attempt to find equivalent forms of
the condition which we may be able to optimize better. */
static void
simplify_switch_expr (tree stmt)
{
tree cond = SWITCH_COND (stmt);
tree def, to, ti;
/* The optimization that we really care about is removing unnecessary
casts. That will let us do much better in propagating the inferred
constant at the switch target. */
if (TREE_CODE (cond) == SSA_NAME)
{
def = SSA_NAME_DEF_STMT (cond);
if (TREE_CODE (def) == GIMPLE_MODIFY_STMT)
{
def = GIMPLE_STMT_OPERAND (def, 1);
if (TREE_CODE (def) == NOP_EXPR)
{
int need_precision;
bool fail;
def = TREE_OPERAND (def, 0);
#ifdef ENABLE_CHECKING
/* ??? Why was Jeff testing this? We are gimple... */
gcc_assert (is_gimple_val (def));
#endif
to = TREE_TYPE (cond);
ti = TREE_TYPE (def);
/* If we have an extension that preserves value, then we
can copy the source value into the switch. */
need_precision = TYPE_PRECISION (ti);
fail = false;
if (! INTEGRAL_TYPE_P (ti))
fail = true;
else if (TYPE_UNSIGNED (to) && !TYPE_UNSIGNED (ti))
fail = true;
else if (!TYPE_UNSIGNED (to) && TYPE_UNSIGNED (ti))
need_precision += 1;
if (TYPE_PRECISION (to) < need_precision)
fail = true;
if (!fail)
{
SWITCH_COND (stmt) = def;
update_stmt (stmt);
}
}
}
}
}
/* Main entry point for the forward propagation optimizer. */
static unsigned int
tree_ssa_forward_propagate_single_use_vars (void)
{
basic_block bb;
unsigned int todoflags = 0;
cfg_changed = false;
FOR_EACH_BB (bb)
{
block_stmt_iterator bsi;
/* Note we update BSI within the loop as necessary. */
for (bsi = bsi_start (bb); !bsi_end_p (bsi); )
{
tree stmt = bsi_stmt (bsi);
/* If this statement sets an SSA_NAME to an address,
try to propagate the address into the uses of the SSA_NAME. */
if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT)
{
tree lhs = GIMPLE_STMT_OPERAND (stmt, 0);
tree rhs = GIMPLE_STMT_OPERAND (stmt, 1);
if (TREE_CODE (lhs) != SSA_NAME)
{
bsi_next (&bsi);
continue;
}
if (TREE_CODE (rhs) == ADDR_EXPR)
{
if (forward_propagate_addr_expr (lhs, rhs))
{
release_defs (stmt);
todoflags |= TODO_remove_unused_locals;
bsi_remove (&bsi, true);
}
else
bsi_next (&bsi);
}
else if ((TREE_CODE (rhs) == BIT_NOT_EXPR
|| TREE_CODE (rhs) == NEGATE_EXPR)
&& TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME)
{
simplify_not_neg_expr (stmt);
bsi_next (&bsi);
}
else if (TREE_CODE (rhs) == COND_EXPR)
{
int did_something;
fold_defer_overflow_warnings ();
did_something = forward_propagate_into_cond (rhs, stmt);
if (did_something == 2)
cfg_changed = true;
fold_undefer_overflow_warnings (!TREE_NO_WARNING (rhs)
&& did_something, stmt, WARN_STRICT_OVERFLOW_CONDITIONAL);
bsi_next (&bsi);
}
else if (COMPARISON_CLASS_P (rhs))
{
if (forward_propagate_comparison (rhs, stmt))
{
release_defs (stmt);
todoflags |= TODO_remove_unused_locals;
bsi_remove (&bsi, true);
}
else
bsi_next (&bsi);
}
else
bsi_next (&bsi);
}
else if (TREE_CODE (stmt) == SWITCH_EXPR)
{
simplify_switch_expr (stmt);
bsi_next (&bsi);
}
else if (TREE_CODE (stmt) == COND_EXPR)
{
int did_something;
fold_defer_overflow_warnings ();
did_something = forward_propagate_into_cond (stmt, stmt);
if (did_something == 2)
cfg_changed = true;
fold_undefer_overflow_warnings (!TREE_NO_WARNING (stmt)
&& did_something, stmt,
WARN_STRICT_OVERFLOW_CONDITIONAL);
bsi_next (&bsi);
}
else
bsi_next (&bsi);
}
}
if (cfg_changed)
todoflags |= TODO_cleanup_cfg;
return todoflags;
}
static bool
gate_forwprop (void)
{
return 1;
}
struct tree_opt_pass pass_forwprop = {
"forwprop", /* name */
gate_forwprop, /* gate */
tree_ssa_forward_propagate_single_use_vars, /* execute */
NULL, /* sub */
NULL, /* next */
0, /* static_pass_number */
TV_TREE_FORWPROP, /* tv_id */
PROP_cfg | PROP_ssa, /* properties_required */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
TODO_dump_func
| TODO_ggc_collect
| TODO_update_ssa
| TODO_verify_ssa, /* todo_flags_finish */
0 /* letter */
};
/* Structure to keep track of the value of a dereferenced PHI result
and the set of virtual operands used for that dereference. */
struct phiprop_d
{
tree value;
tree vop_stmt;
};
/* Verify if the value recorded for NAME in PHIVN is still valid at
the start of basic block BB. */
static bool
phivn_valid_p (struct phiprop_d *phivn, tree name, basic_block bb)
{
tree vop_stmt = phivn[SSA_NAME_VERSION (name)].vop_stmt;
ssa_op_iter ui;
tree vuse;
/* The def stmts of all virtual uses need to be post-dominated
by bb. */
FOR_EACH_SSA_TREE_OPERAND (vuse, vop_stmt, ui, SSA_OP_VUSE)
{
tree use_stmt;
imm_use_iterator ui2;
bool ok = true;
FOR_EACH_IMM_USE_STMT (use_stmt, ui2, vuse)
{
/* If BB does not dominate a VDEF, the value is invalid. */
if (((TREE_CODE (use_stmt) == GIMPLE_MODIFY_STMT
&& !ZERO_SSA_OPERANDS (use_stmt, SSA_OP_VDEF))
|| TREE_CODE (use_stmt) == PHI_NODE)
&& !dominated_by_p (CDI_DOMINATORS, bb_for_stmt (use_stmt), bb))
{
ok = false;
BREAK_FROM_IMM_USE_STMT (ui2);
}
}
if (!ok)
return false;
}
return true;
}
/* Insert a new phi node for the dereference of PHI at basic_block
BB with the virtual operands from USE_STMT. */
static tree
phiprop_insert_phi (basic_block bb, tree phi, tree use_stmt,
struct phiprop_d *phivn, size_t n)
{
tree res, new_phi;
edge_iterator ei;
edge e;
/* Build a new PHI node to replace the definition of
the indirect reference lhs. */
res = GIMPLE_STMT_OPERAND (use_stmt, 0);
SSA_NAME_DEF_STMT (res) = new_phi = create_phi_node (res, bb);
/* Add PHI arguments for each edge inserting loads of the
addressable operands. */
FOR_EACH_EDGE (e, ei, bb->preds)
{
tree old_arg, new_var, tmp;
old_arg = PHI_ARG_DEF_FROM_EDGE (phi, e);
while (TREE_CODE (old_arg) == SSA_NAME
&& (SSA_NAME_VERSION (old_arg) >= n
|| phivn[SSA_NAME_VERSION (old_arg)].value == NULL_TREE))
{
tree def_stmt = SSA_NAME_DEF_STMT (old_arg);
old_arg = GIMPLE_STMT_OPERAND (def_stmt, 1);
}
if (TREE_CODE (old_arg) == SSA_NAME)
/* Reuse a formerly created dereference. */
new_var = phivn[SSA_NAME_VERSION (old_arg)].value;
else
{
old_arg = TREE_OPERAND (old_arg, 0);
new_var = create_tmp_var (TREE_TYPE (old_arg), NULL);
tmp = build2 (GIMPLE_MODIFY_STMT, void_type_node,
NULL_TREE, unshare_expr (old_arg));
if (TREE_CODE (TREE_TYPE (old_arg)) == COMPLEX_TYPE
|| TREE_CODE (TREE_TYPE (old_arg)) == VECTOR_TYPE)
DECL_GIMPLE_REG_P (new_var) = 1;
add_referenced_var (new_var);
new_var = make_ssa_name (new_var, tmp);
GIMPLE_STMT_OPERAND (tmp, 0) = new_var;
bsi_insert_on_edge (e, tmp);
update_stmt (tmp);
mark_symbols_for_renaming (tmp);
}
add_phi_arg (new_phi, new_var, e);
}
update_stmt (new_phi);
return res;
}
/* Propagate between the phi node arguments of PHI in BB and phi result
users. For now this matches
# p_2 = PHI <&x, &y>
<Lx>:;
p_3 = p_2;
z_2 = *p_3;
and converts it to
# z_2 = PHI <x, y>
<Lx>:;
Returns true if a transformation was done and edge insertions
need to be committed. Global data PHIVN and N is used to track
past transformation results. We need to be especially careful here
with aliasing issues as we are moving memory reads. */
static bool
propagate_with_phi (basic_block bb, tree phi, struct phiprop_d *phivn, size_t n)
{
tree ptr = PHI_RESULT (phi);
tree use_stmt, res = NULL_TREE;
block_stmt_iterator bsi;
imm_use_iterator ui;
use_operand_p arg_p, use;
ssa_op_iter i;
bool phi_inserted;
if (MTAG_P (SSA_NAME_VAR (ptr))
|| !POINTER_TYPE_P (TREE_TYPE (ptr))
|| !is_gimple_reg_type (TREE_TYPE (TREE_TYPE (ptr))))
return false;
/* Check if we can "cheaply" dereference all phi arguments. */
FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE)
{
tree arg = USE_FROM_PTR (arg_p);
/* Walk the ssa chain until we reach a ssa name we already
created a value for or we reach a definition of the form
ssa_name_n = &var; */
while (TREE_CODE (arg) == SSA_NAME
&& !SSA_NAME_IS_DEFAULT_DEF (arg)
&& (SSA_NAME_VERSION (arg) >= n
|| phivn[SSA_NAME_VERSION (arg)].value == NULL_TREE))
{
tree def_stmt = SSA_NAME_DEF_STMT (arg);
if (TREE_CODE (def_stmt) != GIMPLE_MODIFY_STMT)
return false;
arg = GIMPLE_STMT_OPERAND (def_stmt, 1);
}
if ((TREE_CODE (arg) != ADDR_EXPR
/* Avoid to have to decay *&a to a[0] later. */
|| !is_gimple_reg_type (TREE_TYPE (TREE_OPERAND (arg, 0))))
&& !(TREE_CODE (arg) == SSA_NAME
&& phivn[SSA_NAME_VERSION (arg)].value != NULL_TREE
&& phivn_valid_p (phivn, arg, bb)))
return false;
}
/* Find a dereferencing use. First follow (single use) ssa
copy chains for ptr. */
while (single_imm_use (ptr, &use, &use_stmt)
&& TREE_CODE (use_stmt) == GIMPLE_MODIFY_STMT
&& GIMPLE_STMT_OPERAND (use_stmt, 1) == ptr
&& TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 0)) == SSA_NAME)
ptr = GIMPLE_STMT_OPERAND (use_stmt, 0);
/* Replace the first dereference of *ptr if there is one and if we
can move the loads to the place of the ptr phi node. */
phi_inserted = false;
FOR_EACH_IMM_USE_STMT (use_stmt, ui, ptr)
{
ssa_op_iter ui2;
tree vuse;
/* Check whether this is a load of *ptr. */
if (!(TREE_CODE (use_stmt) == GIMPLE_MODIFY_STMT
&& TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 0)) == SSA_NAME
&& TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 1)) == INDIRECT_REF
&& TREE_OPERAND (GIMPLE_STMT_OPERAND (use_stmt, 1), 0) == ptr
/* We cannot replace a load that may throw or is volatile. */
&& !tree_can_throw_internal (use_stmt)))
continue;
/* Check if we can move the loads. The def stmts of all virtual uses
need to be post-dominated by bb. */
FOR_EACH_SSA_TREE_OPERAND (vuse, use_stmt, ui2, SSA_OP_VUSE)
{
tree def_stmt = SSA_NAME_DEF_STMT (vuse);
if (!SSA_NAME_IS_DEFAULT_DEF (vuse)
&& (bb_for_stmt (def_stmt) == bb
|| !dominated_by_p (CDI_DOMINATORS,
bb, bb_for_stmt (def_stmt))))
goto next;
}
/* Found a proper dereference. Insert a phi node if this
is the first load transformation. */
if (!phi_inserted)
{
res = phiprop_insert_phi (bb, phi, use_stmt, phivn, n);
/* Remember the value we created for *ptr. */
phivn[SSA_NAME_VERSION (ptr)].value = res;
phivn[SSA_NAME_VERSION (ptr)].vop_stmt = use_stmt;
/* Remove old stmt. The phi is taken care of by DCE, if we
want to delete it here we also have to delete all intermediate
copies. */
bsi = bsi_for_stmt (use_stmt);
bsi_remove (&bsi, 0);
phi_inserted = true;
}
else
{
/* Further replacements are easy, just make a copy out of the
load. */
GIMPLE_STMT_OPERAND (use_stmt, 1) = res;
update_stmt (use_stmt);
}
next:;
/* Continue searching for a proper dereference. */
}
return phi_inserted;
}
/* Helper walking the dominator tree starting from BB and processing
phi nodes with global data PHIVN and N. */
static bool
tree_ssa_phiprop_1 (basic_block bb, struct phiprop_d *phivn, size_t n)
{
bool did_something = false;
basic_block son;
tree phi;
for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
did_something |= propagate_with_phi (bb, phi, phivn, n);
for (son = first_dom_son (CDI_DOMINATORS, bb);
son;
son = next_dom_son (CDI_DOMINATORS, son))
did_something |= tree_ssa_phiprop_1 (son, phivn, n);
return did_something;
}
/* Main entry for phiprop pass. */
static unsigned int
tree_ssa_phiprop (void)
{
struct phiprop_d *phivn;
calculate_dominance_info (CDI_DOMINATORS);
phivn = XCNEWVEC (struct phiprop_d, num_ssa_names);
if (tree_ssa_phiprop_1 (ENTRY_BLOCK_PTR, phivn, num_ssa_names))
bsi_commit_edge_inserts ();
free (phivn);
return 0;
}
static bool
gate_phiprop (void)
{
return 1;
}
struct tree_opt_pass pass_phiprop = {
"phiprop", /* name */
gate_phiprop, /* gate */
tree_ssa_phiprop, /* execute */
NULL, /* sub */
NULL, /* next */
0, /* static_pass_number */
TV_TREE_FORWPROP, /* tv_id */
PROP_cfg | PROP_ssa, /* properties_required */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
TODO_dump_func
| TODO_ggc_collect
| TODO_update_ssa
| TODO_verify_ssa, /* todo_flags_finish */
0 /* letter */
};
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