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re PR tree-optimization/46562 (CCP currently needs iteration for &a[i])

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2011-03-24  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/46562
	* tree.c (build_invariant_address): New function.
	* tree.h (build_invariant_address): Declare.
	* tree-dfa.c (get_addr_base_and_unit_offset): Wrap around
	a renamed function moved ...
	* tree-flow-inline.h (get_addr_base_and_unit_offset_1): ... here.
	Take valueization callback parameter.
	* tree-flow.h (gimple_fold_stmt_to_constant): Declare.
	* gimple-fold.h: New file.
	* tree-ssa-ccp.c (ccp_fold): Use gimple_fold_stmt_to_constant_1.
	(ccp_fold, fold_const_aggregate_ref,
	fold_ctor_reference, fold_nonarray_ctor_reference,
	fold_array_ctor_reference, fold_string_cst_ctor_reference,
	get_base_constructor): Move ...
	* gimple-fold.c: ... here.
	(gimple_fold_stmt_to_constant_1): New function
	split out from ccp_fold.  Take a valueization callback parameter.
	Valueize all operands.
	(gimple_fold_stmt_to_constant): New wrapper function.
	(fold_const_aggregate_ref_1): New function split out from
	fold_const_aggregate_ref.  Take a valueization callback parameter.
	(fold_const_aggregate_ref): Wrap fold_const_aggregate_ref_1.
	* tree-ssa-sccvn.c (simplify_binary_expression): Simplify
	invariant POINTER_PLUS_EXPRs to invariant form.
	(vn_valueize): New function.
	(try_to_simplify): Simplify by using gimple_fold_stmt_to_constant.
	* tree-vrp.c (vrp_valueize): New function.
	(vrp_visit_assignment_or_call): Use gimple_fold_stmt_to_constant
	to fold statements to constants.
	* tree-ssa-pre.c (eliminate): Properly guard propagation of
	function declarations.
	* Makefile.in (tree-ssa-sccvn.o, tree-vrp.o, gimple-fold.o,
	tree-ssa-ccp.o): Add gimple-fold.h dependencies.

	* c-c++-common/pr46562-2.c: New testcase.
	* c-c++-common/pr46562.c: Likewise.

From-SVN: r171386
This commit is contained in:
Richard Guenther 2011-03-24 11:23:29 +00:00 committed by Richard Biener
parent f3e8ab1973
commit cfef45c809
17 changed files with 984 additions and 732 deletions

36
gcc/ChangeLog

@ -1,3 +1,39 @@
2011-03-24 Richard Guenther <rguenther@suse.de>
PR tree-optimization/46562
* tree.c (build_invariant_address): New function.
* tree.h (build_invariant_address): Declare.
* tree-dfa.c (get_addr_base_and_unit_offset): Wrap around
a renamed function moved ...
* tree-flow-inline.h (get_addr_base_and_unit_offset_1): ... here.
Take valueization callback parameter.
* tree-flow.h (gimple_fold_stmt_to_constant): Declare.
* gimple-fold.h: New file.
* tree-ssa-ccp.c (ccp_fold): Use gimple_fold_stmt_to_constant_1.
(ccp_fold, fold_const_aggregate_ref,
fold_ctor_reference, fold_nonarray_ctor_reference,
fold_array_ctor_reference, fold_string_cst_ctor_reference,
get_base_constructor): Move ...
* gimple-fold.c: ... here.
(gimple_fold_stmt_to_constant_1): New function
split out from ccp_fold. Take a valueization callback parameter.
Valueize all operands.
(gimple_fold_stmt_to_constant): New wrapper function.
(fold_const_aggregate_ref_1): New function split out from
fold_const_aggregate_ref. Take a valueization callback parameter.
(fold_const_aggregate_ref): Wrap fold_const_aggregate_ref_1.
* tree-ssa-sccvn.c (simplify_binary_expression): Simplify
invariant POINTER_PLUS_EXPRs to invariant form.
(vn_valueize): New function.
(try_to_simplify): Simplify by using gimple_fold_stmt_to_constant.
* tree-vrp.c (vrp_valueize): New function.
(vrp_visit_assignment_or_call): Use gimple_fold_stmt_to_constant
to fold statements to constants.
* tree-ssa-pre.c (eliminate): Properly guard propagation of
function declarations.
* Makefile.in (tree-ssa-sccvn.o, tree-vrp.o, gimple-fold.o,
tree-ssa-ccp.o): Add gimple-fold.h dependencies.
2011-03-24 Richard Sandiford <richard.sandiford@linaro.org>
* config/h8300/predicates.md (jump_address_operand): Fix register

8
gcc/Makefile.in

@ -2485,12 +2485,12 @@ tree-ssa-sccvn.o : tree-ssa-sccvn.c $(TREE_FLOW_H) $(CONFIG_H) \
$(TM_H) coretypes.h $(TREE_DUMP_H) $(TREE_PASS_H) $(FLAGS_H) $(CFGLOOP_H) \
alloc-pool.h $(BASIC_BLOCK_H) $(BITMAP_H) langhooks.h $(HASHTAB_H) $(GIMPLE_H) \
$(TREE_INLINE_H) tree-iterator.h tree-ssa-propagate.h tree-ssa-sccvn.h \
$(PARAMS_H) tree-pretty-print.h gimple-pretty-print.h
$(PARAMS_H) tree-pretty-print.h gimple-pretty-print.h gimple-fold.h
tree-vrp.o : tree-vrp.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(TREE_H) \
$(TREE_FLOW_H) $(TREE_PASS_H) $(TREE_DUMP_H) $(DIAGNOSTIC_H) $(GGC_H) \
$(BASIC_BLOCK_H) tree-ssa-propagate.h $(FLAGS_H) $(TREE_DUMP_H) \
$(CFGLOOP_H) $(SCEV_H) $(TIMEVAR_H) intl.h tree-pretty-print.h \
gimple-pretty-print.h
gimple-pretty-print.h gimple-fold.h
tree-cfg.o : tree-cfg.c $(TREE_FLOW_H) $(CONFIG_H) $(SYSTEM_H) \
$(TREE_H) $(TM_P_H) $(EXPR_H) $(GGC_H) $(FLAGS_H) output.h \
$(DIAGNOSTIC_H) $(FUNCTION_H) $(TIMEVAR_H) $(TM_H) coretypes.h \
@ -2638,7 +2638,7 @@ gimple-fold.o : gimple-fold.c $(TREE_FLOW_H) $(CONFIG_H) \
$(SYSTEM_H) $(RTL_H) $(TREE_H) $(TM_P_H) $(EXPR_H) $(GGC_H) output.h \
$(DIAGNOSTIC_H) $(FUNCTION_H) $(TIMEVAR_H) $(TM_H) coretypes.h \
$(TREE_DUMP_H) $(BASIC_BLOCK_H) $(TREE_PASS_H) langhooks.h \
tree-ssa-propagate.h value-prof.h $(FLAGS_H) $(TARGET_H)
tree-ssa-propagate.h value-prof.h $(FLAGS_H) $(TARGET_H) gimple-fold.h
gimple-low.o : gimple-low.c $(CONFIG_H) $(SYSTEM_H) $(TREE_H) \
$(DIAGNOSTIC_H) $(GIMPLE_H) $(TREE_INLINE_H) langhooks.h \
$(LANGHOOKS_DEF_H) $(TREE_FLOW_H) $(TIMEVAR_H) $(TM_H) coretypes.h \
@ -3103,7 +3103,7 @@ tree-ssa-ccp.o : tree-ssa-ccp.c $(TREE_FLOW_H) $(CONFIG_H) \
$(DIAGNOSTIC_H) $(FUNCTION_H) $(TIMEVAR_H) $(TM_H) coretypes.h \
$(TREE_DUMP_H) $(BASIC_BLOCK_H) $(TREE_PASS_H) langhooks.h \
tree-ssa-propagate.h value-prof.h $(FLAGS_H) $(TARGET_H) $(DIAGNOSTIC_CORE_H) \
$(DBGCNT_H) tree-pretty-print.h gimple-pretty-print.h
$(DBGCNT_H) tree-pretty-print.h gimple-pretty-print.h gimple-fold.h
tree-sra.o : tree-sra.c $(CONFIG_H) $(SYSTEM_H) coretypes.h alloc-pool.h \
$(TM_H) $(TREE_H) $(GIMPLE_H) $(CGRAPH_H) $(TREE_FLOW_H) \
$(IPA_PROP_H) $(DIAGNOSTIC_H) statistics.h $(TREE_DUMP_H) $(TIMEVAR_H) \

637
gcc/gimple-fold.c

@ -30,6 +30,7 @@ along with GCC; see the file COPYING3. If not see
#include "tree-pass.h"
#include "tree-ssa-propagate.h"
#include "target.h"
#include "gimple-fold.h"
/* Return true when DECL can be referenced from current unit.
We can get declarations that are not possible to reference for
@ -2665,3 +2666,639 @@ maybe_fold_or_comparisons (enum tree_code code1, tree op1a, tree op1b,
else
return or_comparisons_1 (code2, op2a, op2b, code1, op1a, op1b);
}
/* Fold STMT to a constant using VALUEIZE to valueize SSA names.
Either NULL_TREE, a simplified but non-constant or a constant
is returned.
??? This should go into a gimple-fold-inline.h file to be eventually
privatized with the single valueize function used in the various TUs
to avoid the indirect function call overhead. */
tree
gimple_fold_stmt_to_constant_1 (gimple stmt, tree (*valueize) (tree))
{
location_t loc = gimple_location (stmt);
switch (gimple_code (stmt))
{
case GIMPLE_ASSIGN:
{
enum tree_code subcode = gimple_assign_rhs_code (stmt);
switch (get_gimple_rhs_class (subcode))
{
case GIMPLE_SINGLE_RHS:
{
tree rhs = gimple_assign_rhs1 (stmt);
enum tree_code_class kind = TREE_CODE_CLASS (subcode);
if (TREE_CODE (rhs) == SSA_NAME)
{
/* If the RHS is an SSA_NAME, return its known constant value,
if any. */
return (*valueize) (rhs);
}
/* Handle propagating invariant addresses into address
operations. */
else if (TREE_CODE (rhs) == ADDR_EXPR
&& !is_gimple_min_invariant (rhs))
{
HOST_WIDE_INT offset;
tree base;
base = get_addr_base_and_unit_offset_1 (TREE_OPERAND (rhs, 0),
&offset,
valueize);
if (base
&& (CONSTANT_CLASS_P (base)
|| decl_address_invariant_p (base)))
return build_invariant_address (TREE_TYPE (rhs),
base, offset);
}
else if (TREE_CODE (rhs) == CONSTRUCTOR
&& TREE_CODE (TREE_TYPE (rhs)) == VECTOR_TYPE
&& (CONSTRUCTOR_NELTS (rhs)
== TYPE_VECTOR_SUBPARTS (TREE_TYPE (rhs))))
{
unsigned i;
tree val, list;
list = NULL_TREE;
FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (rhs), i, val)
{
val = (*valueize) (val);
if (TREE_CODE (val) == INTEGER_CST
|| TREE_CODE (val) == REAL_CST
|| TREE_CODE (val) == FIXED_CST)
list = tree_cons (NULL_TREE, val, list);
else
return NULL_TREE;
}
return build_vector (TREE_TYPE (rhs), nreverse (list));
}
if (kind == tcc_reference)
{
if ((TREE_CODE (rhs) == VIEW_CONVERT_EXPR
|| TREE_CODE (rhs) == REALPART_EXPR
|| TREE_CODE (rhs) == IMAGPART_EXPR)
&& TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME)
{
tree val = (*valueize) (TREE_OPERAND (rhs, 0));
return fold_unary_loc (EXPR_LOCATION (rhs),
TREE_CODE (rhs),
TREE_TYPE (rhs), val);
}
else if (TREE_CODE (rhs) == BIT_FIELD_REF
&& TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME)
{
tree val = (*valueize) (TREE_OPERAND (rhs, 0));
return fold_ternary_loc (EXPR_LOCATION (rhs),
TREE_CODE (rhs),
TREE_TYPE (rhs), val,
TREE_OPERAND (rhs, 1),
TREE_OPERAND (rhs, 2));
}
else if (TREE_CODE (rhs) == MEM_REF
&& TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME)
{
tree val = (*valueize) (TREE_OPERAND (rhs, 0));
if (TREE_CODE (val) == ADDR_EXPR
&& is_gimple_min_invariant (val))
{
tree tem = fold_build2 (MEM_REF, TREE_TYPE (rhs),
unshare_expr (val),
TREE_OPERAND (rhs, 1));
if (tem)
rhs = tem;
}
}
return fold_const_aggregate_ref_1 (rhs, valueize);
}
else if (kind == tcc_declaration)
return get_symbol_constant_value (rhs);
return rhs;
}
case GIMPLE_UNARY_RHS:
{
/* Handle unary operators that can appear in GIMPLE form.
Note that we know the single operand must be a constant,
so this should almost always return a simplified RHS. */
tree lhs = gimple_assign_lhs (stmt);
tree op0 = (*valueize) (gimple_assign_rhs1 (stmt));
/* Conversions are useless for CCP purposes if they are
value-preserving. Thus the restrictions that
useless_type_conversion_p places for pointer type conversions
do not apply here. Substitution later will only substitute to
allowed places. */
if (CONVERT_EXPR_CODE_P (subcode)
&& POINTER_TYPE_P (TREE_TYPE (lhs))
&& POINTER_TYPE_P (TREE_TYPE (op0)))
{
tree tem;
/* Try to re-construct array references on-the-fly. */
if (!useless_type_conversion_p (TREE_TYPE (lhs),
TREE_TYPE (op0))
&& ((tem = maybe_fold_offset_to_address
(loc,
op0, integer_zero_node, TREE_TYPE (lhs)))
!= NULL_TREE))
return tem;
return op0;
}
return
fold_unary_ignore_overflow_loc (loc, subcode,
gimple_expr_type (stmt), op0);
}
case GIMPLE_BINARY_RHS:
{
/* Handle binary operators that can appear in GIMPLE form. */
tree op0 = (*valueize) (gimple_assign_rhs1 (stmt));
tree op1 = (*valueize) (gimple_assign_rhs2 (stmt));
/* Translate &x + CST into an invariant form suitable for
further propagation. */
if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR
&& TREE_CODE (op0) == ADDR_EXPR
&& TREE_CODE (op1) == INTEGER_CST)
{
tree off = fold_convert (ptr_type_node, op1);
return build_fold_addr_expr
(fold_build2 (MEM_REF,
TREE_TYPE (TREE_TYPE (op0)),
unshare_expr (op0), off));
}
return fold_binary_loc (loc, subcode,
gimple_expr_type (stmt), op0, op1);
}
case GIMPLE_TERNARY_RHS:
{
/* Handle ternary operators that can appear in GIMPLE form. */
tree op0 = (*valueize) (gimple_assign_rhs1 (stmt));
tree op1 = (*valueize) (gimple_assign_rhs2 (stmt));
tree op2 = (*valueize) (gimple_assign_rhs3 (stmt));
return fold_ternary_loc (loc, subcode,
gimple_expr_type (stmt), op0, op1, op2);
}
default:
gcc_unreachable ();
}
}
case GIMPLE_CALL:
{
tree fn = (*valueize) (gimple_call_fn (stmt));
if (TREE_CODE (fn) == ADDR_EXPR
&& TREE_CODE (TREE_OPERAND (fn, 0)) == FUNCTION_DECL
&& DECL_BUILT_IN (TREE_OPERAND (fn, 0)))
{
tree *args = XALLOCAVEC (tree, gimple_call_num_args (stmt));
tree call, retval;
unsigned i;
for (i = 0; i < gimple_call_num_args (stmt); ++i)
args[i] = (*valueize) (gimple_call_arg (stmt, i));
call = build_call_array_loc (loc,
gimple_call_return_type (stmt),
fn, gimple_call_num_args (stmt), args);
retval = fold_call_expr (EXPR_LOCATION (call), call, false);
if (retval)
/* fold_call_expr wraps the result inside a NOP_EXPR. */
STRIP_NOPS (retval);
return retval;
}
return NULL_TREE;
}
default:
return NULL_TREE;
}
}
/* Fold STMT to a constant using VALUEIZE to valueize SSA names.
Returns NULL_TREE if folding to a constant is not possible, otherwise
returns a constant according to is_gimple_min_invariant. */
tree
gimple_fold_stmt_to_constant (gimple stmt, tree (*valueize) (tree))
{
tree res = gimple_fold_stmt_to_constant_1 (stmt, valueize);
if (res && is_gimple_min_invariant (res))
return res;
return NULL_TREE;
}
/* The following set of functions are supposed to fold references using
their constant initializers. */
static tree fold_ctor_reference (tree type, tree ctor,
unsigned HOST_WIDE_INT offset,
unsigned HOST_WIDE_INT size);
/* See if we can find constructor defining value of BASE.
When we know the consructor with constant offset (such as
base is array[40] and we do know constructor of array), then
BIT_OFFSET is adjusted accordingly.
As a special case, return error_mark_node when constructor
is not explicitly available, but it is known to be zero
such as 'static const int a;'. */
static tree
get_base_constructor (tree base, HOST_WIDE_INT *bit_offset,
tree (*valueize)(tree))
{
HOST_WIDE_INT bit_offset2, size, max_size;
if (TREE_CODE (base) == MEM_REF)
{
if (!integer_zerop (TREE_OPERAND (base, 1)))
{
if (!host_integerp (TREE_OPERAND (base, 1), 0))
return NULL_TREE;
*bit_offset += (mem_ref_offset (base).low
* BITS_PER_UNIT);
}
if (valueize
&& TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
base = valueize (TREE_OPERAND (base, 0));
if (!base || TREE_CODE (base) != ADDR_EXPR)
return NULL_TREE;
base = TREE_OPERAND (base, 0);
}
/* Get a CONSTRUCTOR. If BASE is a VAR_DECL, get its
DECL_INITIAL. If BASE is a nested reference into another
ARRAY_REF or COMPONENT_REF, make a recursive call to resolve
the inner reference. */
switch (TREE_CODE (base))
{
case VAR_DECL:
if (!const_value_known_p (base))
return NULL_TREE;
/* Fallthru. */
case CONST_DECL:
if (!DECL_INITIAL (base)
&& (TREE_STATIC (base) || DECL_EXTERNAL (base)))
return error_mark_node;
return DECL_INITIAL (base);
case ARRAY_REF:
case COMPONENT_REF:
base = get_ref_base_and_extent (base, &bit_offset2, &size, &max_size);
if (max_size == -1 || size != max_size)
return NULL_TREE;
*bit_offset += bit_offset2;
return get_base_constructor (base, bit_offset, valueize);
case STRING_CST:
case CONSTRUCTOR:
return base;
default:
return NULL_TREE;
}
}
/* CTOR is STRING_CST. Fold reference of type TYPE and size SIZE
to the memory at bit OFFSET.
We do only simple job of folding byte accesses. */
static tree
fold_string_cst_ctor_reference (tree type, tree ctor,
unsigned HOST_WIDE_INT offset,
unsigned HOST_WIDE_INT size)
{
if (INTEGRAL_TYPE_P (type)
&& (TYPE_MODE (type)
== TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor))))
&& (GET_MODE_CLASS (TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor))))
== MODE_INT)
&& GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) == 1
&& size == BITS_PER_UNIT
&& !(offset % BITS_PER_UNIT))
{
offset /= BITS_PER_UNIT;
if (offset < (unsigned HOST_WIDE_INT) TREE_STRING_LENGTH (ctor))
return build_int_cst_type (type, (TREE_STRING_POINTER (ctor)
[offset]));
/* Folding
const char a[20]="hello";
return a[10];
might lead to offset greater than string length. In this case we
know value is either initialized to 0 or out of bounds. Return 0
in both cases. */
return build_zero_cst (type);
}
return NULL_TREE;
}
/* CTOR is CONSTRUCTOR of an array type. Fold reference of type TYPE and size
SIZE to the memory at bit OFFSET. */
static tree
fold_array_ctor_reference (tree type, tree ctor,
unsigned HOST_WIDE_INT offset,
unsigned HOST_WIDE_INT size)
{
unsigned HOST_WIDE_INT cnt;
tree cfield, cval;
double_int low_bound, elt_size;
double_int index, max_index;
double_int access_index;
tree domain_type = TYPE_DOMAIN (TREE_TYPE (ctor));
HOST_WIDE_INT inner_offset;
/* Compute low bound and elt size. */
if (domain_type && TYPE_MIN_VALUE (domain_type))
{
/* Static constructors for variably sized objects makes no sense. */
gcc_assert (TREE_CODE (TYPE_MIN_VALUE (domain_type)) == INTEGER_CST);
low_bound = tree_to_double_int (TYPE_MIN_VALUE (domain_type));
}
else
low_bound = double_int_zero;
/* Static constructors for variably sized objects makes no sense. */
gcc_assert (TREE_CODE(TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (ctor))))
== INTEGER_CST);
elt_size =
tree_to_double_int (TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (ctor))));
/* We can handle only constantly sized accesses that are known to not
be larger than size of array element. */
if (!TYPE_SIZE_UNIT (type)
|| TREE_CODE (TYPE_SIZE_UNIT (type)) != INTEGER_CST
|| double_int_cmp (elt_size,
tree_to_double_int (TYPE_SIZE_UNIT (type)), 0) < 0)
return NULL_TREE;
/* Compute the array index we look for. */
access_index = double_int_udiv (uhwi_to_double_int (offset / BITS_PER_UNIT),
elt_size, TRUNC_DIV_EXPR);
access_index = double_int_add (access_index, low_bound);
/* And offset within the access. */
inner_offset = offset % (double_int_to_uhwi (elt_size) * BITS_PER_UNIT);
/* See if the array field is large enough to span whole access. We do not
care to fold accesses spanning multiple array indexes. */
if (inner_offset + size > double_int_to_uhwi (elt_size) * BITS_PER_UNIT)
return NULL_TREE;
index = double_int_sub (low_bound, double_int_one);
FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), cnt, cfield, cval)
{
/* Array constructor might explicitely set index, or specify range
or leave index NULL meaning that it is next index after previous
one. */
if (cfield)
{
if (TREE_CODE (cfield) == INTEGER_CST)
max_index = index = tree_to_double_int (cfield);
else
{
gcc_assert (TREE_CODE (cfield) == RANGE_EXPR);
index = tree_to_double_int (TREE_OPERAND (cfield, 0));
max_index = tree_to_double_int (TREE_OPERAND (cfield, 1));
}
}
else
max_index = index = double_int_add (index, double_int_one);
/* Do we have match? */
if (double_int_cmp (access_index, index, 1) >= 0
&& double_int_cmp (access_index, max_index, 1) <= 0)
return fold_ctor_reference (type, cval, inner_offset, size);
}
/* When memory is not explicitely mentioned in constructor,
it is 0 (or out of range). */
return build_zero_cst (type);
}
/* CTOR is CONSTRUCTOR of an aggregate or vector.
Fold reference of type TYPE and size SIZE to the memory at bit OFFSET. */
static tree
fold_nonarray_ctor_reference (tree type, tree ctor,
unsigned HOST_WIDE_INT offset,
unsigned HOST_WIDE_INT size)
{
unsigned HOST_WIDE_INT cnt;
tree cfield, cval;
FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), cnt, cfield,
cval)
{
tree byte_offset = DECL_FIELD_OFFSET (cfield);
tree field_offset = DECL_FIELD_BIT_OFFSET (cfield);
tree field_size = DECL_SIZE (cfield);
double_int bitoffset;
double_int byte_offset_cst = tree_to_double_int (byte_offset);
double_int bits_per_unit_cst = uhwi_to_double_int (BITS_PER_UNIT);
double_int bitoffset_end;
/* Variable sized objects in static constructors makes no sense,
but field_size can be NULL for flexible array members. */
gcc_assert (TREE_CODE (field_offset) == INTEGER_CST
&& TREE_CODE (byte_offset) == INTEGER_CST
&& (field_size != NULL_TREE
? TREE_CODE (field_size) == INTEGER_CST
: TREE_CODE (TREE_TYPE (cfield)) == ARRAY_TYPE));
/* Compute bit offset of the field. */
bitoffset = double_int_add (tree_to_double_int (field_offset),
double_int_mul (byte_offset_cst,
bits_per_unit_cst));
/* Compute bit offset where the field ends. */
if (field_size != NULL_TREE)
bitoffset_end = double_int_add (bitoffset,
tree_to_double_int (field_size));
else
bitoffset_end = double_int_zero;
/* Is OFFSET in the range (BITOFFSET, BITOFFSET_END)? */
if (double_int_cmp (uhwi_to_double_int (offset), bitoffset, 0) >= 0
&& (field_size == NULL_TREE
|| double_int_cmp (uhwi_to_double_int (offset),
bitoffset_end, 0) < 0))
{
double_int access_end = double_int_add (uhwi_to_double_int (offset),
uhwi_to_double_int (size));
double_int inner_offset = double_int_sub (uhwi_to_double_int (offset),
bitoffset);
/* We do have overlap. Now see if field is large enough to
cover the access. Give up for accesses spanning multiple
fields. */
if (double_int_cmp (access_end, bitoffset_end, 0) > 0)
return NULL_TREE;
return fold_ctor_reference (type, cval,
double_int_to_uhwi (inner_offset), size);
}
}
/* When memory is not explicitely mentioned in constructor, it is 0. */
return build_zero_cst (type);
}
/* CTOR is value initializing memory, fold reference of type TYPE and size SIZE
to the memory at bit OFFSET. */
static tree
fold_ctor_reference (tree type, tree ctor, unsigned HOST_WIDE_INT offset,
unsigned HOST_WIDE_INT size)
{
tree ret;
/* We found the field with exact match. */
if (useless_type_conversion_p (type, TREE_TYPE (ctor))
&& !offset)
return canonicalize_constructor_val (ctor);
/* We are at the end of walk, see if we can view convert the
result. */
if (!AGGREGATE_TYPE_P (TREE_TYPE (ctor)) && !offset
/* VIEW_CONVERT_EXPR is defined only for matching sizes. */
&& operand_equal_p (TYPE_SIZE (type),
TYPE_SIZE (TREE_TYPE (ctor)), 0))
{
ret = canonicalize_constructor_val (ctor);
ret = fold_unary (VIEW_CONVERT_EXPR, type, ret);
if (ret)
STRIP_NOPS (ret);
return ret;
}
if (TREE_CODE (ctor) == STRING_CST)
return fold_string_cst_ctor_reference (type, ctor, offset, size);
if (TREE_CODE (ctor) == CONSTRUCTOR)
{
if (TREE_CODE (TREE_TYPE (ctor)) == ARRAY_TYPE)
return fold_array_ctor_reference (type, ctor, offset, size);
else
return fold_nonarray_ctor_reference (type, ctor, offset, size);
}
return NULL_TREE;
}
/* Return the tree representing the element referenced by T if T is an
ARRAY_REF or COMPONENT_REF into constant aggregates valuezing SSA
names using VALUEIZE. Return NULL_TREE otherwise. */
tree
fold_const_aggregate_ref_1 (tree t, tree (*valueize) (tree))
{
tree ctor, idx, base;
HOST_WIDE_INT offset, size, max_size;
tree tem;
if (TREE_CODE_CLASS (TREE_CODE (t)) == tcc_declaration)
return get_symbol_constant_value (t);
tem = fold_read_from_constant_string (t);
if (tem)
return tem;
switch (TREE_CODE (t))
{
case ARRAY_REF:
case ARRAY_RANGE_REF:
/* Constant indexes are handled well by get_base_constructor.
Only special case variable offsets.
FIXME: This code can't handle nested references with variable indexes
(they will be handled only by iteration of ccp). Perhaps we can bring
get_ref_base_and_extent here and make it use a valueize callback. */
if (TREE_CODE (TREE_OPERAND (t, 1)) == SSA_NAME
&& valueize
&& (idx = (*valueize) (TREE_OPERAND (t, 1)))
&& host_integerp (idx, 0))
{
tree low_bound, unit_size;
/* If the resulting bit-offset is constant, track it. */
if ((low_bound = array_ref_low_bound (t),
host_integerp (low_bound, 0))
&& (unit_size = array_ref_element_size (t),
host_integerp (unit_size, 1)))
{
offset = TREE_INT_CST_LOW (idx);
offset -= TREE_INT_CST_LOW (low_bound);
offset *= TREE_INT_CST_LOW (unit_size);
offset *= BITS_PER_UNIT;
base = TREE_OPERAND (t, 0);
ctor = get_base_constructor (base, &offset, valueize);
/* Empty constructor. Always fold to 0. */
if (ctor == error_mark_node)
return build_zero_cst (TREE_TYPE (t));
/* Out of bound array access. Value is undefined,
but don't fold. */
if (offset < 0)
return NULL_TREE;
/* We can not determine ctor. */
if (!ctor)
return NULL_TREE;
return fold_ctor_reference (TREE_TYPE (t), ctor, offset,
TREE_INT_CST_LOW (unit_size)
* BITS_PER_UNIT);
}
}
/* Fallthru. */
case COMPONENT_REF:
case BIT_FIELD_REF:
case TARGET_MEM_REF:
case MEM_REF:
base = get_ref_base_and_extent (t, &offset, &size, &max_size);
ctor = get_base_constructor (base, &offset, valueize);
/* Empty constructor. Always fold to 0. */
if (ctor == error_mark_node)
return build_zero_cst (TREE_TYPE (t));
/* We do not know precise address. */
if (max_size == -1 || max_size != size)
return NULL_TREE;
/* We can not determine ctor. */
if (!ctor)
return NULL_TREE;
/* Out of bound array access. Value is undefined, but don't fold. */
if (offset < 0)
return NULL_TREE;
return fold_ctor_reference (TREE_TYPE (t), ctor, offset, size);
case REALPART_EXPR:
case IMAGPART_EXPR:
{
tree c = fold_const_aggregate_ref_1 (TREE_OPERAND (t, 0), valueize);
if (c && TREE_CODE (c) == COMPLEX_CST)
return fold_build1_loc (EXPR_LOCATION (t),
TREE_CODE (t), TREE_TYPE (t), c);
break;
}
default:
break;
}
return NULL_TREE;
}
tree
fold_const_aggregate_ref (tree t)
{
return fold_const_aggregate_ref_1 (t, NULL);
}

33
gcc/gimple-fold.h Normal file

@ -0,0 +1,33 @@
/* Gimple folding definitions.
Copyright 2011 Free Software Foundation, Inc.
Contributed by Richard Guenther <rguenther@suse.de>
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/>. */
#ifndef GCC_GIMPLE_FOLD_H
#define GCC_GIMPLE_FOLD_H
#include "coretypes.h"
tree fold_const_aggregate_ref_1 (tree, tree (*) (tree));
tree fold_const_aggregate_ref (tree);
tree gimple_fold_stmt_to_constant_1 (gimple, tree (*) (tree));
tree gimple_fold_stmt_to_constant (gimple, tree (*) (tree));
#endif /* GCC_GIMPLE_FOLD_H */

29
gcc/ipa-split.c

@ -169,8 +169,9 @@ static void
dump_split_point (FILE * file, struct split_point *current)
{
fprintf (file,
"Split point at BB %i header time:%i header size: %i"
" split time: %i split size: %i\n bbs: ",
"Split point at BB %i\n"
" header time: %i header size: %i\n"
" split time: %i split size: %i\n bbs: ",
current->entry_bb->index, current->header_time,
current->header_size, current->split_time, current->split_size);
dump_bitmap (file, current->split_bbs);
@ -1036,12 +1037,13 @@ split_function (struct split_point *split_point)
/* If RETURN_BB has virtual operand PHIs, they must be removed and the
virtual operand marked for renaming as we change the CFG in a way that
tree-inline is not able to compensate for.
tree-inline is not able to compensate for.
Note this can happen whether or not we have a return value. If we have
a return value, then RETURN_BB may have PHIs for real operands too. */
if (return_bb != EXIT_BLOCK_PTR)
{
bool phi_p = false;
for (gsi = gsi_start_phis (return_bb); !gsi_end_p (gsi);)
{
gimple stmt = gsi_stmt (gsi);
@ -1052,7 +1054,28 @@ split_function (struct split_point *split_point)
}
mark_virtual_phi_result_for_renaming (stmt);
remove_phi_node (&gsi, true);
phi_p = true;
}
/* In reality we have to rename the reaching definition of the
virtual operand at return_bb as we will eventually release it
when we remove the code region we outlined.
So we have to rename all immediate virtual uses of that region
if we didn't see a PHI definition yet. */
/* ??? In real reality we want to set the reaching vdef of the
entry of the SESE region as the vuse of the call and the reaching
vdef of the exit of the SESE region as the vdef of the call. */
if (!phi_p)
for (gsi = gsi_start_bb (return_bb); !gsi_end_p (gsi); gsi_next (&gsi))
{
gimple stmt = gsi_stmt (gsi);
if (gimple_vuse (stmt))
{
gimple_set_vuse (stmt, NULL_TREE);
update_stmt (stmt);
}
if (gimple_vdef (stmt))
break;
}
}
/* Now create the actual clone. */

6
gcc/testsuite/ChangeLog

@ -1,3 +1,9 @@
2011-03-24 Richard Guenther <rguenther@suse.de>
PR tree-optimization/46562
* c-c++-common/pr46562-2.c: New testcase.
* c-c++-common/pr46562.c: Likewise.
2011-03-24 Ira Rosen <ira.rosen@linaro.org>
* gcc.dg/vect/vect-cselim-1.c: New test.

13
gcc/testsuite/c-c++-common/pr46562-2.c Normal file

@ -0,0 +1,13 @@
/* { dg-do compile } */
/* { dg-options "-O -fno-tree-ccp -fno-tree-forwprop -fdump-tree-fre" } */
static const int a[4] = {};
int foo(void)
{
int i = 1;
const int *p = &a[i];
return *p;
}
/* { dg-final { scan-tree-dump "= 0;" "fre" } } */
/* { dg-final { cleanup-tree-dump "fre" } } */

13
gcc/testsuite/c-c++-common/pr46562.c Normal file

@ -0,0 +1,13 @@
/* { dg-do compile } */
/* { dg-options "-O -fdump-tree-ccp1" } */
static const int a[4] = {};
int foo(void)
{
int i = 1;
const int *p = &a[i];
return *p;
}
/* { dg-final { scan-tree-dump "return 0;" "ccp1" } } */
/* { dg-final { cleanup-tree-dump "ccp1" } } */

105
gcc/tree-dfa.c

@ -963,110 +963,7 @@ get_ref_base_and_extent (tree exp, HOST_WIDE_INT *poffset,
tree
get_addr_base_and_unit_offset (tree exp, HOST_WIDE_INT *poffset)
{
HOST_WIDE_INT byte_offset = 0;
/* Compute cumulative byte-offset for nested component-refs and array-refs,
and find the ultimate containing object. */
while (1)
{
switch (TREE_CODE (exp))
{
case BIT_FIELD_REF:
return NULL_TREE;
case COMPONENT_REF:
{
tree field = TREE_OPERAND (exp, 1);
tree this_offset = component_ref_field_offset (exp);
HOST_WIDE_INT hthis_offset;
if (!this_offset
|| TREE_CODE (this_offset) != INTEGER_CST
|| (TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (field))
% BITS_PER_UNIT))
return NULL_TREE;
hthis_offset = TREE_INT_CST_LOW (this_offset);
hthis_offset += (TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (field))
/ BITS_PER_UNIT);
byte_offset += hthis_offset;
}
break;
case ARRAY_REF:
case ARRAY_RANGE_REF:
{
tree index = TREE_OPERAND (exp, 1);
tree low_bound, unit_size;
/* If the resulting bit-offset is constant, track it. */
if (TREE_CODE (index) == INTEGER_CST
&& (low_bound = array_ref_low_bound (exp),
TREE_CODE (low_bound) == INTEGER_CST)
&& (unit_size = array_ref_element_size (exp),
TREE_CODE (unit_size) == INTEGER_CST))
{
HOST_WIDE_INT hindex = TREE_INT_CST_LOW (index);
hindex -= TREE_INT_CST_LOW (low_bound);
hindex *= TREE_INT_CST_LOW (unit_size);
byte_offset += hindex;
}
else
return NULL_TREE;
}
break;
case REALPART_EXPR:
break;
case IMAGPART_EXPR:
byte_offset += TREE_INT_CST_LOW (TYPE_SIZE_UNIT (TREE_TYPE (exp)));
break;
case VIEW_CONVERT_EXPR:
break;
case MEM_REF:
/* Hand back the decl for MEM[&decl, off]. */
if (TREE_CODE (TREE_OPERAND (exp, 0)) == ADDR_EXPR)
{
if (!integer_zerop (TREE_OPERAND (exp, 1)))
{
double_int off = mem_ref_offset (exp);
gcc_assert (off.high == -1 || off.high == 0);
byte_offset += double_int_to_shwi (off);
}
exp = TREE_OPERAND (TREE_OPERAND (exp, 0), 0);
}
goto done;
case TARGET_MEM_REF:
/* Hand back the decl for MEM[&decl, off]. */
if (TREE_CODE (TMR_BASE (exp)) == ADDR_EXPR)
{
if (TMR_INDEX (exp) || TMR_INDEX2 (exp))
return NULL_TREE;
if (!integer_zerop (TMR_OFFSET (exp)))
{
double_int off = mem_ref_offset (exp);
gcc_assert (off.high == -1 || off.high == 0);
byte_offset += double_int_to_shwi (off);
}
exp = TREE_OPERAND (TMR_BASE (exp), 0);
}
goto done;
default:
goto done;
}
exp = TREE_OPERAND (exp, 0);
}
done:
*poffset = byte_offset;
return exp;
return get_addr_base_and_unit_offset_1 (exp, poffset, NULL);
}
/* Returns true if STMT references an SSA_NAME that has

135
gcc/tree-flow-inline.h

@ -1227,4 +1227,139 @@ make_ssa_name (tree var, gimple stmt)
return make_ssa_name_fn (cfun, var, stmt);
}
/* Returns the base object and a constant BITS_PER_UNIT offset in *POFFSET that
denotes the starting address of the memory access EXP.
Returns NULL_TREE if the offset is not constant or any component
is not BITS_PER_UNIT-aligned.
VALUEIZE if non-NULL is used to valueize SSA names. It should return
its argument or a constant if the argument is known to be constant. */
static inline tree
get_addr_base_and_unit_offset_1 (tree exp, HOST_WIDE_INT *poffset,
tree (*valueize) (tree))
{
HOST_WIDE_INT byte_offset = 0;
/* Compute cumulative byte-offset for nested component-refs and array-refs,
and find the ultimate containing object. */
while (1)
{
switch (TREE_CODE (exp))
{
case BIT_FIELD_REF:
return NULL_TREE;
case COMPONENT_REF:
{
tree field = TREE_OPERAND (exp, 1);
tree this_offset = component_ref_field_offset (exp);
HOST_WIDE_INT hthis_offset;
if (!this_offset
|| TREE_CODE (this_offset) != INTEGER_CST
|| (TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (field))
% BITS_PER_UNIT))
return NULL_TREE;
hthis_offset = TREE_INT_CST_LOW (this_offset);
hthis_offset += (TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (field))
/ BITS_PER_UNIT);
byte_offset += hthis_offset;
}
break;
case ARRAY_REF:
case ARRAY_RANGE_REF:
{
tree index = TREE_OPERAND (exp, 1);
tree low_bound, unit_size;
if (valueize
&& TREE_CODE (index) == SSA_NAME)
index = (*valueize) (index);
/* If the resulting bit-offset is constant, track it. */
if (TREE_CODE (index) == INTEGER_CST
&& (low_bound = array_ref_low_bound (exp),
TREE_CODE (low_bound) == INTEGER_CST)
&& (unit_size = array_ref_element_size (exp),
TREE_CODE (unit_size) == INTEGER_CST))
{
HOST_WIDE_INT hindex = TREE_INT_CST_LOW (index);
hindex -= TREE_INT_CST_LOW (low_bound);
hindex *= TREE_INT_CST_LOW (unit_size);
byte_offset += hindex;
}
else
return NULL_TREE;
}
break;
case REALPART_EXPR:
break;
case IMAGPART_EXPR:
byte_offset += TREE_INT_CST_LOW (TYPE_SIZE_UNIT (TREE_TYPE (exp)));
break;
case VIEW_CONVERT_EXPR:
break;
case MEM_REF:
{
tree base = TREE_OPERAND (exp, 0);
if (valueize
&& TREE_CODE (base) == SSA_NAME)
base = (*valueize) (base);
/* Hand back the decl for MEM[&decl, off]. */
if (TREE_CODE (base) == ADDR_EXPR)
{
if (!integer_zerop (TREE_OPERAND (exp, 1)))
{
double_int off = mem_ref_offset (exp);
gcc_assert (off.high == -1 || off.high == 0);
byte_offset += double_int_to_shwi (off);
}
exp = TREE_OPERAND (base, 0);
}
goto done;
}
case TARGET_MEM_REF:
{
tree base = TREE_OPERAND (exp, 0);
if (valueize
&& TREE_CODE (base) == SSA_NAME)
base = (*valueize) (base);
/* Hand back the decl for MEM[&decl, off]. */
if (TREE_CODE (base) == ADDR_EXPR)
{
if (TMR_INDEX (exp) || TMR_INDEX2 (exp))
return NULL_TREE;
if (!integer_zerop (TMR_OFFSET (exp)))
{
double_int off = mem_ref_offset (exp);
gcc_assert (off.high == -1 || off.high == 0);
byte_offset += double_int_to_shwi (off);
}
exp = TREE_OPERAND (base, 0);
}
goto done;
}
default:
goto done;
}
exp = TREE_OPERAND (exp, 0);
}
done:
*poffset = byte_offset;
return exp;
}
#endif /* _TREE_FLOW_INLINE_H */

1
gcc/tree-flow.h

@ -594,6 +594,7 @@ extern void ssanames_print_statistics (void);
/* In tree-ssa-ccp.c */
tree fold_const_aggregate_ref (tree);
tree gimple_fold_stmt_to_constant (gimple, tree (*)(tree));
/* In tree-ssa-dom.c */
extern void dump_dominator_optimization_stats (FILE *);

608
gcc/tree-ssa-ccp.c

@ -132,6 +132,7 @@ along with GCC; see the file COPYING3. If not see
#include "target.h"
#include "diagnostic-core.h"
#include "dbgcnt.h"
#include "gimple-fold.h"
/* Possible lattice values. */
@ -167,9 +168,6 @@ static prop_value_t *const_val;
static void canonicalize_float_value (prop_value_t *);
static bool ccp_fold_stmt (gimple_stmt_iterator *);
static tree fold_ctor_reference (tree type, tree ctor,
unsigned HOST_WIDE_INT offset,
unsigned HOST_WIDE_INT size);
/* Dump constant propagation value VAL to file OUTF prefixed by PREFIX. */
@ -1098,220 +1096,6 @@ ccp_fold (gimple stmt)
location_t loc = gimple_location (stmt);
switch (gimple_code (stmt))
{
case GIMPLE_ASSIGN:
{
enum tree_code subcode = gimple_assign_rhs_code (stmt);
switch (get_gimple_rhs_class (subcode))
{
case GIMPLE_SINGLE_RHS:
{
tree rhs = gimple_assign_rhs1 (stmt);
enum tree_code_class kind = TREE_CODE_CLASS (subcode);
if (TREE_CODE (rhs) == SSA_NAME)
{
/* If the RHS is an SSA_NAME, return its known constant value,
if any. */
return get_constant_value (rhs);
}
/* Handle propagating invariant addresses into address operations.
The folding we do here matches that in tree-ssa-forwprop.c. */
else if (TREE_CODE (rhs) == ADDR_EXPR)
{
tree *base;
base = &TREE_OPERAND (rhs, 0);
while (handled_component_p (*base))
base = &TREE_OPERAND (*base, 0);
if (TREE_CODE (*base) == MEM_REF
&& TREE_CODE (TREE_OPERAND (*base, 0)) == SSA_NAME)
{
tree val = get_constant_value (TREE_OPERAND (*base, 0));
if (val
&& TREE_CODE (val) == ADDR_EXPR)
{
tree ret, save = *base;
tree new_base;
new_base = fold_build2 (MEM_REF, TREE_TYPE (*base),
unshare_expr (val),
TREE_OPERAND (*base, 1));
/* We need to return a new tree, not modify the IL
or share parts of it. So play some tricks to
avoid manually building it. */
*base = new_base;
ret = unshare_expr (rhs);
recompute_tree_invariant_for_addr_expr (ret);
*base = save;
return ret;
}
}
}
else if (TREE_CODE (rhs) == CONSTRUCTOR
&& TREE_CODE (TREE_TYPE (rhs)) == VECTOR_TYPE
&& (CONSTRUCTOR_NELTS (rhs)
== TYPE_VECTOR_SUBPARTS (TREE_TYPE (rhs))))
{
unsigned i;
tree val, list;
list = NULL_TREE;
FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (rhs), i, val)
{
val = valueize_op (val);
if (TREE_CODE (val) == INTEGER_CST
|| TREE_CODE (val) == REAL_CST
|| TREE_CODE (val) == FIXED_CST)
list = tree_cons (NULL_TREE, val, list);
else
return NULL_TREE;
}
return build_vector (TREE_TYPE (rhs), nreverse (list));
}
if (kind == tcc_reference)
{
if ((TREE_CODE (rhs) == VIEW_CONVERT_EXPR
|| TREE_CODE (rhs) == REALPART_EXPR
|| TREE_CODE (rhs) == IMAGPART_EXPR)
&& TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME)
{
tree val = get_constant_value (TREE_OPERAND (rhs, 0));
if (val)
return fold_unary_loc (EXPR_LOCATION (rhs),
TREE_CODE (rhs),
TREE_TYPE (rhs), val);
}
else if (TREE_CODE (rhs) == BIT_FIELD_REF
&& TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME)
{
tree val = get_constant_value (TREE_OPERAND (rhs, 0));
if (val)
return fold_ternary_loc (EXPR_LOCATION (rhs),
TREE_CODE (rhs),
TREE_TYPE (rhs), val,
TREE_OPERAND (rhs, 1),
TREE_OPERAND (rhs, 2));
}
else if (TREE_CODE (rhs) == MEM_REF
&& TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME)
{
tree val = get_constant_value (TREE_OPERAND (rhs, 0));
if (val
&& TREE_CODE (val) == ADDR_EXPR)
{
tree tem = fold_build2 (MEM_REF, TREE_TYPE (rhs),
unshare_expr (val),
TREE_OPERAND (rhs, 1));
if (tem)
rhs = tem;
}
}
return fold_const_aggregate_ref (rhs);
}
else if (kind == tcc_declaration)
return get_symbol_constant_value (rhs);
return rhs;
}
case GIMPLE_UNARY_RHS:
{
/* Handle unary operators that can appear in GIMPLE form.
Note that we know the single operand must be a constant,
so this should almost always return a simplified RHS. */
tree lhs = gimple_assign_lhs (stmt);
tree op0 = valueize_op (gimple_assign_rhs1 (stmt));
/* Conversions are useless for CCP purposes if they are
value-preserving. Thus the restrictions that
useless_type_conversion_p places for pointer type conversions
do not apply here. Substitution later will only substitute to
allowed places. */
if (CONVERT_EXPR_CODE_P (subcode)
&& POINTER_TYPE_P (TREE_TYPE (lhs))
&& POINTER_TYPE_P (TREE_TYPE (op0)))
{
tree tem;
/* Try to re-construct array references on-the-fly. */
if (!useless_type_conversion_p (TREE_TYPE (lhs),
TREE_TYPE (op0))
&& ((tem = maybe_fold_offset_to_address
(loc,
op0, integer_zero_node, TREE_TYPE (lhs)))
!= NULL_TREE))
return tem;
return op0;
}
return
fold_unary_ignore_overflow_loc (loc, subcode,
gimple_expr_type (stmt), op0);
}
case GIMPLE_BINARY_RHS:
{
/* Handle binary operators that can appear in GIMPLE form. */
tree op0 = valueize_op (gimple_assign_rhs1 (stmt));
tree op1 = valueize_op (gimple_assign_rhs2 (stmt));
/* Translate &x + CST into an invariant form suitable for
further propagation. */
if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR
&& TREE_CODE (op0) == ADDR_EXPR
&& TREE_CODE (op1) == INTEGER_CST)
{
tree off = fold_convert (ptr_type_node, op1);
return build_fold_addr_expr
(fold_build2 (MEM_REF,
TREE_TYPE (TREE_TYPE (op0)),
unshare_expr (op0), off));
}
return fold_binary_loc (loc, subcode,
gimple_expr_type (stmt), op0, op1);
}
case GIMPLE_TERNARY_RHS:
{
/* Handle ternary operators that can appear in GIMPLE form. */
tree op0 = valueize_op (gimple_assign_rhs1 (stmt));
tree op1 = valueize_op (gimple_assign_rhs2 (stmt));
tree op2 = valueize_op (gimple_assign_rhs3 (stmt));
return fold_ternary_loc (loc, subcode,
gimple_expr_type (stmt), op0, op1, op2);
}
default:
gcc_unreachable ();
}
}
break;
case GIMPLE_CALL:
{
tree fn = valueize_op (gimple_call_fn (stmt));
if (TREE_CODE (fn) == ADDR_EXPR
&& TREE_CODE (TREE_OPERAND (fn, 0)) == FUNCTION_DECL
&& DECL_BUILT_IN (TREE_OPERAND (fn, 0)))
{
tree *args = XALLOCAVEC (tree, gimple_call_num_args (stmt));
tree call, retval;
unsigned i;
for (i = 0; i < gimple_call_num_args (stmt); ++i)
args[i] = valueize_op (gimple_call_arg (stmt, i));
call = build_call_array_loc (loc,
gimple_call_return_type (stmt),
fn, gimple_call_num_args (stmt), args);
retval = fold_call_expr (EXPR_LOCATION (call), call, false);
if (retval)
/* fold_call_expr wraps the result inside a NOP_EXPR. */
STRIP_NOPS (retval);
return retval;
}
return NULL_TREE;
}
case GIMPLE_COND:
{
/* Handle comparison operators that can appear in GIMPLE form. */
@ -1327,397 +1111,15 @@ ccp_fold (gimple stmt)
return valueize_op (gimple_switch_index (stmt));
}
case GIMPLE_ASSIGN:
case GIMPLE_CALL:
return gimple_fold_stmt_to_constant_1 (stmt, valueize_op);
default:
gcc_unreachable ();
}
}
/* See if we can find constructor defining value of BASE.
When we know the consructor with constant offset (such as
base is array[40] and we do know constructor of array), then
BIT_OFFSET is adjusted accordingly.
As a special case, return error_mark_node when constructor
is not explicitly available, but it is known to be zero
such as 'static const int a;'. */
static tree
get_base_constructor (tree base, HOST_WIDE_INT *bit_offset)
{
HOST_WIDE_INT bit_offset2, size, max_size;
if (TREE_CODE (base) == MEM_REF)
{
if (!integer_zerop (TREE_OPERAND (base, 1)))
{
if (!host_integerp (TREE_OPERAND (base, 1), 0))
return NULL_TREE;
*bit_offset += (mem_ref_offset (base).low
* BITS_PER_UNIT);
}
base = get_constant_value (TREE_OPERAND (base, 0));
if (!base || TREE_CODE (base) != ADDR_EXPR)
return NULL_TREE;
base = TREE_OPERAND (base, 0);
}
/* Get a CONSTRUCTOR. If BASE is a VAR_DECL, get its
DECL_INITIAL. If BASE is a nested reference into another
ARRAY_REF or COMPONENT_REF, make a recursive call to resolve
the inner reference. */
switch (TREE_CODE (base))
{
case VAR_DECL:
if (!const_value_known_p (base))
return NULL_TREE;
/* Fallthru. */
case CONST_DECL:
if (!DECL_INITIAL (base)
&& (TREE_STATIC (base) || DECL_EXTERNAL (base)))
return error_mark_node;
return DECL_INITIAL (base);
case ARRAY_REF:
case COMPONENT_REF:
base = get_ref_base_and_extent (base, &bit_offset2, &size, &max_size);
if (max_size == -1 || size != max_size)
return NULL_TREE;
*bit_offset += bit_offset2;
return get_base_constructor (base, bit_offset);
case STRING_CST:
case CONSTRUCTOR:
return base;
default:
return NULL_TREE;
}
}
/* CTOR is STRING_CST. Fold reference of type TYPE and size SIZE
to the memory at bit OFFSET.
We do only simple job of folding byte accesses. */
static tree
fold_string_cst_ctor_reference (tree type, tree ctor, unsigned HOST_WIDE_INT offset,
unsigned HOST_WIDE_INT size)
{
if (INTEGRAL_TYPE_P (type)
&& (TYPE_MODE (type)
== TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor))))
&& (GET_MODE_CLASS (TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor))))
== MODE_INT)
&& GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) == 1
&& size == BITS_PER_UNIT
&& !(offset % BITS_PER_UNIT))
{
offset /= BITS_PER_UNIT;
if (offset < (unsigned HOST_WIDE_INT) TREE_STRING_LENGTH (ctor))
return build_int_cst_type (type, (TREE_STRING_POINTER (ctor)
[offset]));
/* Folding
const char a[20]="hello";
return a[10];
might lead to offset greater than string length. In this case we
know value is either initialized to 0 or out of bounds. Return 0
in both cases. */
return build_zero_cst (type);
}
return NULL_TREE;
}
/* CTOR is CONSTRUCTOR of an array type. Fold reference of type TYPE and size
SIZE to the memory at bit OFFSET. */
static tree
fold_array_ctor_reference (tree type, tree ctor,
unsigned HOST_WIDE_INT offset,
unsigned HOST_WIDE_INT size)
{
unsigned HOST_WIDE_INT cnt;
tree cfield, cval;
double_int low_bound, elt_size;
double_int index, max_index;
double_int access_index;
tree domain_type = TYPE_DOMAIN (TREE_TYPE (ctor));
HOST_WIDE_INT inner_offset;
/* Compute low bound and elt size. */
if (domain_type && TYPE_MIN_VALUE (domain_type))
{
/* Static constructors for variably sized objects makes no sense. */
gcc_assert (TREE_CODE (TYPE_MIN_VALUE (domain_type)) == INTEGER_CST);
low_bound = tree_to_double_int (TYPE_MIN_VALUE (domain_type));
}
else
low_bound = double_int_zero;
/* Static constructors for variably sized objects makes no sense. */
gcc_assert (TREE_CODE(TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (ctor))))
== INTEGER_CST);
elt_size =
tree_to_double_int (TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (ctor))));
/* We can handle only constantly sized accesses that are known to not
be larger than size of array element. */
if (!TYPE_SIZE_UNIT (type)
|| TREE_CODE (TYPE_SIZE_UNIT (type)) != INTEGER_CST
|| double_int_cmp (elt_size,
tree_to_double_int (TYPE_SIZE_UNIT (type)), 0) < 0)
return NULL_TREE;
/* Compute the array index we look for. */
access_index = double_int_udiv (uhwi_to_double_int (offset / BITS_PER_UNIT),
elt_size, TRUNC_DIV_EXPR);
access_index = double_int_add (access_index, low_bound);
/* And offset within the access. */
inner_offset = offset % (double_int_to_uhwi (elt_size) * BITS_PER_UNIT);
/* See if the array field is large enough to span whole access. We do not
care to fold accesses spanning multiple array indexes. */
if (inner_offset + size > double_int_to_uhwi (elt_size) * BITS_PER_UNIT)
return NULL_TREE;
index = double_int_sub (low_bound, double_int_one);
FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), cnt, cfield, cval)
{
/* Array constructor might explicitely set index, or specify range
or leave index NULL meaning that it is next index after previous
one. */
if (cfield)
{
if (TREE_CODE (cfield) == INTEGER_CST)
max_index = index = tree_to_double_int (cfield);
else
{
gcc_assert (TREE_CODE (cfield) == RANGE_EXPR);
index = tree_to_double_int (TREE_OPERAND (cfield, 0));
max_index = tree_to_double_int (TREE_OPERAND (cfield, 1));
}
}
else
max_index = index = double_int_add (index, double_int_one);
/* Do we have match? */
if (double_int_cmp (access_index, index, 1) >= 0
&& double_int_cmp (access_index, max_index, 1) <= 0)
return fold_ctor_reference (type, cval, inner_offset, size);
}
/* When memory is not explicitely mentioned in constructor,
it is 0 (or out of range). */
return build_zero_cst (type);
}
/* CTOR is CONSTRUCTOR of an aggregate or vector.
Fold reference of type TYPE and size SIZE to the memory at bit OFFSET. */
static tree
fold_nonarray_ctor_reference (tree type, tree ctor,
unsigned HOST_WIDE_INT offset,
unsigned HOST_WIDE_INT size)
{
unsigned HOST_WIDE_INT cnt;
tree cfield, cval;
FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), cnt, cfield,
cval)
{
tree byte_offset = DECL_FIELD_OFFSET (cfield);
tree field_offset = DECL_FIELD_BIT_OFFSET (cfield);
tree field_size = DECL_SIZE (cfield);
double_int bitoffset;
double_int byte_offset_cst = tree_to_double_int (byte_offset);
double_int bits_per_unit_cst = uhwi_to_double_int (BITS_PER_UNIT);
double_int bitoffset_end;
/* Variable sized objects in static constructors makes no sense,
but field_size can be NULL for flexible array members. */
gcc_assert (TREE_CODE (field_offset) == INTEGER_CST
&& TREE_CODE (byte_offset) == INTEGER_CST
&& (field_size != NULL_TREE
? TREE_CODE (field_size) == INTEGER_CST
: TREE_CODE (TREE_TYPE (cfield)) == ARRAY_TYPE));
/* Compute bit offset of the field. */
bitoffset = double_int_add (tree_to_double_int (field_offset),
double_int_mul (byte_offset_cst,
bits_per_unit_cst));
/* Compute bit offset where the field ends. */
if (field_size != NULL_TREE)
bitoffset_end = double_int_add (bitoffset,
tree_to_double_int (field_size));
else
bitoffset_end = double_int_zero;
/* Is OFFSET in the range (BITOFFSET, BITOFFSET_END)? */
if (double_int_cmp (uhwi_to_double_int (offset), bitoffset, 0) >= 0
&& (field_size == NULL_TREE
|| double_int_cmp (uhwi_to_double_int (offset),
bitoffset_end, 0) < 0))
{
double_int access_end = double_int_add (uhwi_to_double_int (offset),
uhwi_to_double_int (size));
double_int inner_offset = double_int_sub (uhwi_to_double_int (offset),
bitoffset);
/* We do have overlap. Now see if field is large enough to
cover the access. Give up for accesses spanning multiple
fields. */
if (double_int_cmp (access_end, bitoffset_end, 0) > 0)
return NULL_TREE;
return fold_ctor_reference (type, cval,
double_int_to_uhwi (inner_offset), size);
}
}
/* When memory is not explicitely mentioned in constructor, it is 0. */
return build_zero_cst (type);
}
/* CTOR is value initializing memory, fold reference of type TYPE and size SIZE
to the memory at bit OFFSET. */
static tree
fold_ctor_reference (tree type, tree ctor, unsigned HOST_WIDE_INT offset,
unsigned HOST_WIDE_INT size)
{
tree ret;
/* We found the field with exact match. */
if (useless_type_conversion_p (type, TREE_TYPE (ctor))
&& !offset)
return canonicalize_constructor_val (ctor);
/* We are at the end of walk, see if we can view convert the
result. */
if (!AGGREGATE_TYPE_P (TREE_TYPE (ctor)) && !offset
/* VIEW_CONVERT_EXPR is defined only for matching sizes. */
&& operand_equal_p (TYPE_SIZE (type),
TYPE_SIZE (TREE_TYPE (ctor)), 0))
{
ret = canonicalize_constructor_val (ctor);
ret = fold_unary (VIEW_CONVERT_EXPR, type, ret);
if (ret)
STRIP_NOPS (ret);
return ret;
}
if (TREE_CODE (ctor) == STRING_CST)
return fold_string_cst_ctor_reference (type, ctor, offset, size);
if (TREE_CODE (ctor) == CONSTRUCTOR)
{
if (TREE_CODE (TREE_TYPE (ctor)) == ARRAY_TYPE)
return fold_array_ctor_reference (type, ctor, offset, size);
else
return fold_nonarray_ctor_reference (type, ctor, offset, size);
}
return NULL_TREE;
}
/* Return the tree representing the element referenced by T if T is an
ARRAY_REF or COMPONENT_REF into constant aggregates. Return
NULL_TREE otherwise. */
tree
fold_const_aggregate_ref (tree t)
{
tree ctor, idx, base;
HOST_WIDE_INT offset, size, max_size;
tree tem;
if (TREE_CODE_CLASS (TREE_CODE (t)) == tcc_declaration)
return get_symbol_constant_value (t);
tem = fold_read_from_constant_string (t);
if (tem)
return tem;
switch (TREE_CODE (t))
{
case ARRAY_REF:
case ARRAY_RANGE_REF:
/* Constant indexes are handled well by get_base_constructor.
Only special case variable offsets.
FIXME: This code can't handle nested references with variable indexes
(they will be handled only by iteration of ccp). Perhaps we can bring
get_ref_base_and_extent here and make it use get_constant_value. */
if (TREE_CODE (TREE_OPERAND (t, 1)) == SSA_NAME
&& (idx = get_constant_value (TREE_OPERAND (t, 1)))
&& host_integerp (idx, 0))
{
tree low_bound, unit_size;
/* If the resulting bit-offset is constant, track it. */
if ((low_bound = array_ref_low_bound (t),
host_integerp (low_bound, 0))
&& (unit_size = array_ref_element_size (t),
host_integerp (unit_size, 1)))
{
offset = TREE_INT_CST_LOW (idx);
offset -= TREE_INT_CST_LOW (low_bound);
offset *= TREE_INT_CST_LOW (unit_size);
offset *= BITS_PER_UNIT;
base = TREE_OPERAND (t, 0);
ctor = get_base_constructor (base, &offset);
/* Empty constructor. Always fold to 0. */
if (ctor == error_mark_node)
return build_zero_cst (TREE_TYPE (t));
/* Out of bound array access. Value is undefined, but don't fold. */
if (offset < 0)
return NULL_TREE;
/* We can not determine ctor. */
if (!ctor)
return NULL_TREE;
return fold_ctor_reference (TREE_TYPE (t), ctor, offset,
TREE_INT_CST_LOW (unit_size)
* BITS_PER_UNIT);
}
}
/* Fallthru. */
case COMPONENT_REF:
case BIT_FIELD_REF:
case TARGET_MEM_REF:
case MEM_REF:
base = get_ref_base_and_extent (t, &offset, &size, &max_size);
ctor = get_base_constructor (base, &offset);
/* Empty constructor. Always fold to 0. */
if (ctor == error_mark_node)
return build_zero_cst (TREE_TYPE (t));
/* We do not know precise address. */
if (max_size == -1 || max_size != size)
return NULL_TREE;
/* We can not determine ctor. */
if (!ctor)
return NULL_TREE;
/* Out of bound array access. Value is undefined, but don't fold. */
if (offset < 0)
return NULL_TREE;
return fold_ctor_reference (TREE_TYPE (t), ctor, offset, size);
case REALPART_EXPR:
case IMAGPART_EXPR:
{
tree c = fold_const_aggregate_ref (TREE_OPERAND (t, 0));
if (c && TREE_CODE (c) == COMPLEX_CST)
return fold_build1_loc (EXPR_LOCATION (t),
TREE_CODE (t), TREE_TYPE (t), c);
break;
}
default:
break;
}
return NULL_TREE;
}
/* Apply the operation CODE in type TYPE to the value, mask pair
RVAL and RMASK representing a value of type RTYPE and set
the value, mask pair *VAL and *MASK to the result. */

7
gcc/tree-ssa-pre.c

@ -4380,9 +4380,12 @@ eliminate (void)
if (is_gimple_call (stmt)
&& TREE_CODE (gimple_call_fn (stmt)) == SSA_NAME)
{
tree fn = VN_INFO (gimple_call_fn (stmt))->valnum;
tree orig_fn = gimple_call_fn (stmt);
tree fn = VN_INFO (orig_fn)->valnum;
if (TREE_CODE (fn) == ADDR_EXPR
&& TREE_CODE (TREE_OPERAND (fn, 0)) == FUNCTION_DECL)
&& TREE_CODE (TREE_OPERAND (fn, 0)) == FUNCTION_DECL
&& useless_type_conversion_p (TREE_TYPE (orig_fn),
TREE_TYPE (fn)))
{
bool can_make_abnormal_goto
= stmt_can_make_abnormal_goto (stmt);

46
gcc/tree-ssa-sccvn.c

@ -44,6 +44,7 @@ along with GCC; see the file COPYING3. If not see
#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"
@ -2770,6 +2771,16 @@ simplify_binary_expression (gimple stmt)
op1 = SSA_VAL (op1);
}
/* Pointer plus constant can be represented as invariant address.
Do so to allow further propatation, see also tree forwprop. */
if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR
&& host_integerp (op1, 1)
&& TREE_CODE (op0) == ADDR_EXPR
&& is_gimple_min_invariant (op0))
return build_invariant_address (TREE_TYPE (op0),
TREE_OPERAND (op0, 0),
TREE_INT_CST_LOW (op1));
/* Avoid folding if nothing changed. */
if (op0 == gimple_assign_rhs1 (stmt)
&& op1 == gimple_assign_rhs2 (stmt))
@ -2849,6 +2860,19 @@ simplify_unary_expression (gimple stmt)
return NULL_TREE;
}
/* Valueize NAME if it is an SSA name, otherwise just return it. */
static inline tree
vn_valueize (tree name)
{
if (TREE_CODE (name) == SSA_NAME)
{
tree tem = SSA_VAL (name);
return tem == VN_TOP ? name : tem;
}
return name;
}
/* Try to simplify RHS using equivalences and constant folding. */
static tree
@ -2862,21 +2886,15 @@ try_to_simplify (gimple stmt)
&& TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME)
return NULL_TREE;
/* First try constant folding based on our current lattice. */
tem = gimple_fold_stmt_to_constant (stmt, vn_valueize);
if (tem)
return tem;
/* If that didn't work try combining multiple statements. */
switch (TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)))
{
case tcc_declaration:
tem = get_symbol_constant_value (gimple_assign_rhs1 (stmt));
if (tem)
return tem;
break;
case tcc_reference:
/* Do not do full-blown reference lookup here, but simplify
reads from constant aggregates. */
tem = fold_const_aggregate_ref (gimple_assign_rhs1 (stmt));
if (tem)
return tem;
/* Fallthrough for some codes that can operate on registers. */
if (!(TREE_CODE (gimple_assign_rhs1 (stmt)) == REALPART_EXPR
|| TREE_CODE (gimple_assign_rhs1 (stmt)) == IMAGPART_EXPR
@ -2886,11 +2904,11 @@ try_to_simplify (gimple stmt)
into binary ops, but it's debatable whether it is worth it. */
case tcc_unary:
return simplify_unary_expression (stmt);
break;
case tcc_comparison:
case tcc_binary:
return simplify_binary_expression (stmt);
break;
default:
break;
}

24
gcc/tree-vrp.c

@ -39,6 +39,7 @@ along with GCC; see the file COPYING3. If not see
#include "tree-scalar-evolution.h"
#include "tree-ssa-propagate.h"
#include "tree-chrec.h"
#include "gimple-fold.h"
/* Type of value ranges. See value_range_d for a description of these
@ -5614,6 +5615,21 @@ vrp_initialize (void)
}
}
/* Return the singleton value-range for NAME or NAME. */
static inline tree
vrp_valueize (tree name)
{
if (TREE_CODE (name) == SSA_NAME)
{
value_range_t *vr = get_value_range (name);
if (vr->type == VR_RANGE
&& (vr->min == vr->max
|| operand_equal_p (vr->min, vr->max, 0)))
return vr->min;
}
return name;
}
/* Visit assignment STMT. If it produces an interesting range, record
the SSA name in *OUTPUT_P. */
@ -5637,7 +5653,12 @@ vrp_visit_assignment_or_call (gimple stmt, tree *output_p)
{
value_range_t new_vr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
if (code == GIMPLE_CALL)
/* Try folding the statement to a constant first. */
tree tem = gimple_fold_stmt_to_constant (stmt, vrp_valueize);
if (tem && !is_overflow_infinity (tem))
set_value_range (&new_vr, VR_RANGE, tem, tem, NULL);
/* Then dispatch to value-range extracting functions. */
else if (code == GIMPLE_CALL)
extract_range_basic (&new_vr, stmt);
else
extract_range_from_assignment (&new_vr, stmt);
@ -6366,7 +6387,6 @@ vrp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p)
/* In general, assignments with virtual operands are not useful
for deriving ranges, with the obvious exception of calls to
builtin functions. */
if ((is_gimple_call (stmt)
&& gimple_call_fndecl (stmt) != NULL_TREE
&& DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))

14
gcc/tree.c

@ -4013,6 +4013,20 @@ reference_alias_ptr_type (const_tree t)
return build_pointer_type (TYPE_MAIN_VARIANT (TREE_TYPE (base)));
}
/* Return an invariant ADDR_EXPR of type TYPE taking the address of BASE
offsetted by OFFSET units. */
tree
build_invariant_address (tree type, tree base, HOST_WIDE_INT offset)
{
tree ref = fold_build2 (MEM_REF, TREE_TYPE (type),
build_fold_addr_expr (base),
build_int_cst (ptr_type_node, offset));
tree addr = build1 (ADDR_EXPR, type, ref);
recompute_tree_invariant_for_addr_expr (addr);
return addr;
}
/* Similar except don't specify the TREE_TYPE
and leave the TREE_SIDE_EFFECTS as 0.
It is permissible for arguments to be null,

1
gcc/tree.h

@ -5096,6 +5096,7 @@ extern tree build_simple_mem_ref_loc (location_t, tree);
build_simple_mem_ref_loc (UNKNOWN_LOCATION, T)
extern double_int mem_ref_offset (const_tree);
extern tree reference_alias_ptr_type (const_tree);
extern tree build_invariant_address (tree, tree, HOST_WIDE_INT);
extern tree constant_boolean_node (int, tree);
extern tree div_if_zero_remainder (enum tree_code, const_tree, const_tree);