[PATCH] Introduce gimple-fold.c, make tree-ssa-ccp.c CCP again
Richard Guenther
rguenther@suse.de
Thu Apr 15 12:06:00 GMT 2010
This moves all the folding stuff we have accumulated in tree-ssa-ccp.c
to gimple-fold.c. With that patch tree-ssa-ccp.c again looks like
CCP.
Well, that was it for obvious code movement that was on my TODO list
for too long.
Bootstrapped and tested on x86_64-unknown-linux-gnu.
Richard.
2010-04-15 Richard Guenther <rguenther@suse.de>
* Makefile.in (OBJS-common): Add gimple-fold.o.
(gimple-fold.o): New rule.
* tree.h (maybe_fold_offset_to_reference,
maybe_fold_offset_to_address, maybe_fold_stmt_addition): Move
prototypes ...
* gimple.h: ... here.
* tree-flow.h (fold_stmt, fold_stmt_inplace, get_symbol_constant_value,
may_propagate_address_into_dereference): Move prototypes ...
* gimple.h: ... here.
* tree-ssa-ccp.c (get_symbol_constant_value,
may_propagate_address_into_dereference, maybe_fold_offset_to_array_ref,
maybe_fold_offset_to_component_ref, maybe_fold_offset_to_reference,
maybe_fold_offset_to_address, maybe_fold_stmt_indirect,
maybe_fold_stmt_addition, maybe_fold_reference, get_maxval_strlen,
ccp_fold_builtin, fold_gimple_assign, fold_gimple_cond,
fold_gimple_call, fold_stmt_1, fold_stmt, fold_stmt_inplace,
gimplify_and_update_call_from_tree): Move ...
* gimple-fold.c: ... here. New file.
(ccp_fold_builtin): Rename to ...
(gimple_fold_builtin): ... this.
* tree-ssa-ccp.c (execute_fold_all_builtins): Adjust.
Index: gcc/Makefile.in
===================================================================
*** gcc/Makefile.in (revision 158367)
--- gcc/Makefile.in (working copy)
*************** OBJS-common = \
*** 1207,1212 ****
--- 1207,1213 ----
ggc-common.o \
gimple.o \
gimple-iterator.o \
+ gimple-fold.o \
gimple-low.o \
gimple-pretty-print.o \
gimplify.o \
*************** gimplify.o : gimplify.c $(CONFIG_H) $(SY
*** 2534,2539 ****
--- 2535,2545 ----
$(REAL_H) $(SPLAY_TREE_H) vec.h tree-iterator.h tree-pass.h
gimple-iterator.o : gimple-iterator.c $(CONFIG_H) $(SYSTEM_H) coretypes.h \
$(TREE_H) $(GIMPLE_H) $(TREE_FLOW_H) value-prof.h
+ 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)
gimple-low.o : gimple-low.c $(CONFIG_H) $(SYSTEM_H) $(TREE_H) \
$(DIAGNOSTIC_H) $(GIMPLE_H) $(TREE_INLINE_H) $(VARRAY_H) langhooks.h \
$(LANGHOOKS_DEF_H) $(TREE_FLOW_H) $(TIMEVAR_H) $(TM_H) coretypes.h \
Index: gcc/tree.h
===================================================================
*** gcc/tree.h (revision 158367)
--- gcc/tree.h (working copy)
*************** struct GTY(()) tree_priority_map {
*** 5320,5330 ****
tree target_for_debug_bind (tree);
- /* In tree-ssa-ccp.c */
- extern tree maybe_fold_offset_to_reference (location_t, tree, tree, tree);
- extern tree maybe_fold_offset_to_address (location_t, tree, tree, tree);
- extern tree maybe_fold_stmt_addition (location_t, tree, tree, tree);
-
/* In tree-ssa-address.c. */
extern tree tree_mem_ref_addr (tree, tree);
extern void copy_mem_ref_info (tree, tree);
--- 5320,5325 ----
Index: gcc/gimple.h
===================================================================
*** gcc/gimple.h (revision 158367)
--- gcc/gimple.h (working copy)
*************** gimple_alloc_kind (enum gimple_code code
*** 4787,4790 ****
--- 4787,4802 ----
extern void dump_gimple_statistics (void);
+ /* In gimple-fold.c. */
+ void gimplify_and_update_call_from_tree (gimple_stmt_iterator *, tree);
+ tree gimple_fold_builtin (gimple);
+ bool fold_stmt (gimple_stmt_iterator *);
+ bool fold_stmt_inplace (gimple);
+ tree maybe_fold_offset_to_reference (location_t, tree, tree, tree);
+ tree maybe_fold_offset_to_address (location_t, tree, tree, tree);
+ tree maybe_fold_stmt_addition (location_t, tree, tree, tree);
+ tree get_symbol_constant_value (tree);
+ bool may_propagate_address_into_dereference (tree, tree);
+
+
#endif /* GCC_GIMPLE_H */
Index: gcc/tree-flow.h
===================================================================
*** gcc/tree-flow.h (revision 158367)
--- gcc/tree-flow.h (working copy)
*************** extern void ssanames_print_statistics (v
*** 614,625 ****
#endif
/* In tree-ssa-ccp.c */
- bool fold_stmt (gimple_stmt_iterator *);
- bool fold_stmt_inplace (gimple);
- tree get_symbol_constant_value (tree);
tree fold_const_aggregate_ref (tree);
- bool may_propagate_address_into_dereference (tree, tree);
-
/* In tree-ssa-dom.c */
extern void dump_dominator_optimization_stats (FILE *);
--- 614,620 ----
Index: gcc/tree-ssa-ccp.c
===================================================================
*** gcc/tree-ssa-ccp.c (revision 158367)
--- gcc/tree-ssa-ccp.c (working copy)
*************** debug_lattice_value (prop_value_t val)
*** 269,318 ****
}
-
- /* If SYM is a constant variable with known value, return the value.
- NULL_TREE is returned otherwise. */
-
- tree
- get_symbol_constant_value (tree sym)
- {
- if (TREE_STATIC (sym)
- && (TREE_READONLY (sym)
- || TREE_CODE (sym) == CONST_DECL))
- {
- tree val = DECL_INITIAL (sym);
- if (val)
- {
- STRIP_NOPS (val);
- if (is_gimple_min_invariant (val))
- {
- if (TREE_CODE (val) == ADDR_EXPR)
- {
- tree base = get_base_address (TREE_OPERAND (val, 0));
- if (base && TREE_CODE (base) == VAR_DECL)
- {
- TREE_ADDRESSABLE (base) = 1;
- if (gimple_referenced_vars (cfun))
- add_referenced_var (base);
- }
- }
- return val;
- }
- }
- /* Variables declared 'const' without an initializer
- have zero as the initializer if they may not be
- overridden at link or run time. */
- if (!val
- && !DECL_EXTERNAL (sym)
- && targetm.binds_local_p (sym)
- && (INTEGRAL_TYPE_P (TREE_TYPE (sym))
- || SCALAR_FLOAT_TYPE_P (TREE_TYPE (sym))))
- return fold_convert (TREE_TYPE (sym), integer_zero_node);
- }
-
- return NULL_TREE;
- }
-
/* Compute a default value for variable VAR and store it in the
CONST_VAL array. The following rules are used to get default
values:
--- 269,274 ----
*************** ccp_visit_phi_node (gimple phi)
*** 885,920 ****
return SSA_PROP_NOT_INTERESTING;
}
- /* Return true if we may propagate the address expression ADDR into the
- dereference DEREF and cancel them. */
-
- bool
- may_propagate_address_into_dereference (tree addr, tree deref)
- {
- gcc_assert (INDIRECT_REF_P (deref)
- && TREE_CODE (addr) == ADDR_EXPR);
-
- /* Don't propagate if ADDR's operand has incomplete type. */
- if (!COMPLETE_TYPE_P (TREE_TYPE (TREE_OPERAND (addr, 0))))
- return false;
-
- /* If the address is invariant then we do not need to preserve restrict
- qualifications. But we do need to preserve volatile qualifiers until
- we can annotate the folded dereference itself properly. */
- if (is_gimple_min_invariant (addr)
- && (!TREE_THIS_VOLATILE (deref)
- || TYPE_VOLATILE (TREE_TYPE (addr))))
- return useless_type_conversion_p (TREE_TYPE (deref),
- TREE_TYPE (TREE_OPERAND (addr, 0)));
-
- /* Else both the address substitution and the folding must result in
- a valid useless type conversion sequence. */
- return (useless_type_conversion_p (TREE_TYPE (TREE_OPERAND (deref, 0)),
- TREE_TYPE (addr))
- && useless_type_conversion_p (TREE_TYPE (deref),
- TREE_TYPE (TREE_OPERAND (addr, 0))));
- }
-
/* CCP specific front-end to the non-destructive constant folding
routines.
--- 841,846 ----
*************** struct gimple_opt_pass pass_ccp =
*** 1771,3180 ****
};
- /* A subroutine of fold_stmt. Attempts to fold *(A+O) to A[X].
- BASE is an array type. OFFSET is a byte displacement. ORIG_TYPE
- is the desired result type.
-
- LOC is the location of the original expression. */
-
- static tree
- maybe_fold_offset_to_array_ref (location_t loc, tree base, tree offset,
- tree orig_type,
- bool allow_negative_idx)
- {
- tree min_idx, idx, idx_type, elt_offset = integer_zero_node;
- tree array_type, elt_type, elt_size;
- tree domain_type;
-
- /* If BASE is an ARRAY_REF, we can pick up another offset (this time
- measured in units of the size of elements type) from that ARRAY_REF).
- We can't do anything if either is variable.
-
- The case we handle here is *(&A[N]+O). */
- if (TREE_CODE (base) == ARRAY_REF)
- {
- tree low_bound = array_ref_low_bound (base);
-
- elt_offset = TREE_OPERAND (base, 1);
- if (TREE_CODE (low_bound) != INTEGER_CST
- || TREE_CODE (elt_offset) != INTEGER_CST)
- return NULL_TREE;
-
- elt_offset = int_const_binop (MINUS_EXPR, elt_offset, low_bound, 0);
- base = TREE_OPERAND (base, 0);
- }
-
- /* Ignore stupid user tricks of indexing non-array variables. */
- array_type = TREE_TYPE (base);
- if (TREE_CODE (array_type) != ARRAY_TYPE)
- return NULL_TREE;
- elt_type = TREE_TYPE (array_type);
- if (!useless_type_conversion_p (orig_type, elt_type))
- return NULL_TREE;
-
- /* Use signed size type for intermediate computation on the index. */
- idx_type = signed_type_for (size_type_node);
-
- /* If OFFSET and ELT_OFFSET are zero, we don't care about the size of the
- element type (so we can use the alignment if it's not constant).
- Otherwise, compute the offset as an index by using a division. If the
- division isn't exact, then don't do anything. */
- elt_size = TYPE_SIZE_UNIT (elt_type);
- if (!elt_size)
- return NULL;
- if (integer_zerop (offset))
- {
- if (TREE_CODE (elt_size) != INTEGER_CST)
- elt_size = size_int (TYPE_ALIGN (elt_type));
-
- idx = build_int_cst (idx_type, 0);
- }
- else
- {
- unsigned HOST_WIDE_INT lquo, lrem;
- HOST_WIDE_INT hquo, hrem;
- double_int soffset;
-
- /* The final array offset should be signed, so we need
- to sign-extend the (possibly pointer) offset here
- and use signed division. */
- soffset = double_int_sext (tree_to_double_int (offset),
- TYPE_PRECISION (TREE_TYPE (offset)));
- if (TREE_CODE (elt_size) != INTEGER_CST
- || div_and_round_double (TRUNC_DIV_EXPR, 0,
- soffset.low, soffset.high,
- TREE_INT_CST_LOW (elt_size),
- TREE_INT_CST_HIGH (elt_size),
- &lquo, &hquo, &lrem, &hrem)
- || lrem || hrem)
- return NULL_TREE;
-
- idx = build_int_cst_wide (idx_type, lquo, hquo);
- }
-
- /* Assume the low bound is zero. If there is a domain type, get the
- low bound, if any, convert the index into that type, and add the
- low bound. */
- min_idx = build_int_cst (idx_type, 0);
- domain_type = TYPE_DOMAIN (array_type);
- if (domain_type)
- {
- idx_type = domain_type;
- if (TYPE_MIN_VALUE (idx_type))
- min_idx = TYPE_MIN_VALUE (idx_type);
- else
- min_idx = fold_convert (idx_type, min_idx);
-
- if (TREE_CODE (min_idx) != INTEGER_CST)
- return NULL_TREE;
-
- elt_offset = fold_convert (idx_type, elt_offset);
- }
-
- if (!integer_zerop (min_idx))
- idx = int_const_binop (PLUS_EXPR, idx, min_idx, 0);
- if (!integer_zerop (elt_offset))
- idx = int_const_binop (PLUS_EXPR, idx, elt_offset, 0);
-
- /* Make sure to possibly truncate late after offsetting. */
- idx = fold_convert (idx_type, idx);
-
- /* We don't want to construct access past array bounds. For example
- char *(c[4]);
- c[3][2];
- should not be simplified into (*c)[14] or tree-vrp will
- give false warnings. The same is true for
- struct A { long x; char d[0]; } *a;
- (char *)a - 4;
- which should be not folded to &a->d[-8]. */
- if (domain_type
- && TYPE_MAX_VALUE (domain_type)
- && TREE_CODE (TYPE_MAX_VALUE (domain_type)) == INTEGER_CST)
- {
- tree up_bound = TYPE_MAX_VALUE (domain_type);
-
- if (tree_int_cst_lt (up_bound, idx)
- /* Accesses after the end of arrays of size 0 (gcc
- extension) and 1 are likely intentional ("struct
- hack"). */
- && compare_tree_int (up_bound, 1) > 0)
- return NULL_TREE;
- }
- if (domain_type
- && TYPE_MIN_VALUE (domain_type))
- {
- if (!allow_negative_idx
- && TREE_CODE (TYPE_MIN_VALUE (domain_type)) == INTEGER_CST
- && tree_int_cst_lt (idx, TYPE_MIN_VALUE (domain_type)))
- return NULL_TREE;
- }
- else if (!allow_negative_idx
- && compare_tree_int (idx, 0) < 0)
- return NULL_TREE;
-
- {
- tree t = build4 (ARRAY_REF, elt_type, base, idx, NULL_TREE, NULL_TREE);
- SET_EXPR_LOCATION (t, loc);
- return t;
- }
- }
-
-
- /* Attempt to fold *(S+O) to S.X.
- BASE is a record type. OFFSET is a byte displacement. ORIG_TYPE
- is the desired result type.
-
- LOC is the location of the original expression. */
-
- static tree
- maybe_fold_offset_to_component_ref (location_t loc, tree record_type,
- tree base, tree offset, tree orig_type)
- {
- tree f, t, field_type, tail_array_field, field_offset;
- tree ret;
- tree new_base;
-
- if (TREE_CODE (record_type) != RECORD_TYPE
- && TREE_CODE (record_type) != UNION_TYPE
- && TREE_CODE (record_type) != QUAL_UNION_TYPE)
- return NULL_TREE;
-
- /* Short-circuit silly cases. */
- if (useless_type_conversion_p (record_type, orig_type))
- return NULL_TREE;
-
- tail_array_field = NULL_TREE;
- for (f = TYPE_FIELDS (record_type); f ; f = TREE_CHAIN (f))
- {
- int cmp;
-
- if (TREE_CODE (f) != FIELD_DECL)
- continue;
- if (DECL_BIT_FIELD (f))
- continue;
-
- if (!DECL_FIELD_OFFSET (f))
- continue;
- field_offset = byte_position (f);
- if (TREE_CODE (field_offset) != INTEGER_CST)
- continue;
-
- /* ??? Java creates "interesting" fields for representing base classes.
- They have no name, and have no context. With no context, we get into
- trouble with nonoverlapping_component_refs_p. Skip them. */
- if (!DECL_FIELD_CONTEXT (f))
- continue;
-
- /* The previous array field isn't at the end. */
- tail_array_field = NULL_TREE;
-
- /* Check to see if this offset overlaps with the field. */
- cmp = tree_int_cst_compare (field_offset, offset);
- if (cmp > 0)
- continue;
-
- field_type = TREE_TYPE (f);
-
- /* Here we exactly match the offset being checked. If the types match,
- then we can return that field. */
- if (cmp == 0
- && useless_type_conversion_p (orig_type, field_type))
- {
- t = fold_build3 (COMPONENT_REF, field_type, base, f, NULL_TREE);
- return t;
- }
-
- /* Don't care about offsets into the middle of scalars. */
- if (!AGGREGATE_TYPE_P (field_type))
- continue;
-
- /* Check for array at the end of the struct. This is often
- used as for flexible array members. We should be able to
- turn this into an array access anyway. */
- if (TREE_CODE (field_type) == ARRAY_TYPE)
- tail_array_field = f;
-
- /* Check the end of the field against the offset. */
- if (!DECL_SIZE_UNIT (f)
- || TREE_CODE (DECL_SIZE_UNIT (f)) != INTEGER_CST)
- continue;
- t = int_const_binop (MINUS_EXPR, offset, field_offset, 1);
- if (!tree_int_cst_lt (t, DECL_SIZE_UNIT (f)))
- continue;
-
- /* If we matched, then set offset to the displacement into
- this field. */
- new_base = fold_build3 (COMPONENT_REF, field_type, base, f, NULL_TREE);
- SET_EXPR_LOCATION (new_base, loc);
-
- /* Recurse to possibly find the match. */
- ret = maybe_fold_offset_to_array_ref (loc, new_base, t, orig_type,
- f == TYPE_FIELDS (record_type));
- if (ret)
- return ret;
- ret = maybe_fold_offset_to_component_ref (loc, field_type, new_base, t,
- orig_type);
- if (ret)
- return ret;
- }
-
- if (!tail_array_field)
- return NULL_TREE;
-
- f = tail_array_field;
- field_type = TREE_TYPE (f);
- offset = int_const_binop (MINUS_EXPR, offset, byte_position (f), 1);
-
- /* If we get here, we've got an aggregate field, and a possibly
- nonzero offset into them. Recurse and hope for a valid match. */
- base = fold_build3 (COMPONENT_REF, field_type, base, f, NULL_TREE);
- SET_EXPR_LOCATION (base, loc);
-
- t = maybe_fold_offset_to_array_ref (loc, base, offset, orig_type,
- f == TYPE_FIELDS (record_type));
- if (t)
- return t;
- return maybe_fold_offset_to_component_ref (loc, field_type, base, offset,
- orig_type);
- }
-
- /* Attempt to express (ORIG_TYPE)BASE+OFFSET as BASE->field_of_orig_type
- or BASE[index] or by combination of those.
-
- LOC is the location of original expression.
-
- Before attempting the conversion strip off existing ADDR_EXPRs and
- handled component refs. */
-
- tree
- maybe_fold_offset_to_reference (location_t loc, tree base, tree offset,
- tree orig_type)
- {
- tree ret;
- tree type;
-
- STRIP_NOPS (base);
- if (TREE_CODE (base) != ADDR_EXPR)
- return NULL_TREE;
-
- base = TREE_OPERAND (base, 0);
-
- /* Handle case where existing COMPONENT_REF pick e.g. wrong field of union,
- so it needs to be removed and new COMPONENT_REF constructed.
- The wrong COMPONENT_REF are often constructed by folding the
- (type *)&object within the expression (type *)&object+offset */
- if (handled_component_p (base))
- {
- HOST_WIDE_INT sub_offset, size, maxsize;
- tree newbase;
- newbase = get_ref_base_and_extent (base, &sub_offset,
- &size, &maxsize);
- gcc_assert (newbase);
- if (size == maxsize
- && size != -1
- && !(sub_offset & (BITS_PER_UNIT - 1)))
- {
- base = newbase;
- if (sub_offset)
- offset = int_const_binop (PLUS_EXPR, offset,
- build_int_cst (TREE_TYPE (offset),
- sub_offset / BITS_PER_UNIT), 1);
- }
- }
- if (useless_type_conversion_p (orig_type, TREE_TYPE (base))
- && integer_zerop (offset))
- return base;
- type = TREE_TYPE (base);
-
- ret = maybe_fold_offset_to_component_ref (loc, type, base, offset, orig_type);
- if (!ret)
- ret = maybe_fold_offset_to_array_ref (loc, base, offset, orig_type, true);
-
- return ret;
- }
-
- /* Attempt to express (ORIG_TYPE)&BASE+OFFSET as &BASE->field_of_orig_type
- or &BASE[index] or by combination of those.
-
- LOC is the location of the original expression.
-
- Before attempting the conversion strip off existing component refs. */
-
- tree
- maybe_fold_offset_to_address (location_t loc, tree addr, tree offset,
- tree orig_type)
- {
- tree t;
-
- gcc_assert (POINTER_TYPE_P (TREE_TYPE (addr))
- && POINTER_TYPE_P (orig_type));
-
- t = maybe_fold_offset_to_reference (loc, addr, offset,
- TREE_TYPE (orig_type));
- if (t != NULL_TREE)
- {
- tree orig = addr;
- tree ptr_type;
-
- /* For __builtin_object_size to function correctly we need to
- make sure not to fold address arithmetic so that we change
- reference from one array to another. This would happen for
- example for
-
- struct X { char s1[10]; char s2[10] } s;
- char *foo (void) { return &s.s2[-4]; }
-
- where we need to avoid generating &s.s1[6]. As the C and
- C++ frontends create different initial trees
- (char *) &s.s1 + -4 vs. &s.s1[-4] we have to do some
- sophisticated comparisons here. Note that checking for the
- condition after the fact is easier than trying to avoid doing
- the folding. */
- STRIP_NOPS (orig);
- if (TREE_CODE (orig) == ADDR_EXPR)
- orig = TREE_OPERAND (orig, 0);
- if ((TREE_CODE (orig) == ARRAY_REF
- || (TREE_CODE (orig) == COMPONENT_REF
- && TREE_CODE (TREE_TYPE (TREE_OPERAND (orig, 1))) == ARRAY_TYPE))
- && (TREE_CODE (t) == ARRAY_REF
- || TREE_CODE (t) == COMPONENT_REF)
- && !operand_equal_p (TREE_CODE (orig) == ARRAY_REF
- ? TREE_OPERAND (orig, 0) : orig,
- TREE_CODE (t) == ARRAY_REF
- ? TREE_OPERAND (t, 0) : t, 0))
- return NULL_TREE;
-
- ptr_type = build_pointer_type (TREE_TYPE (t));
- if (!useless_type_conversion_p (orig_type, ptr_type))
- return NULL_TREE;
- return build_fold_addr_expr_with_type_loc (loc, t, ptr_type);
- }
-
- return NULL_TREE;
- }
-
- /* A subroutine of fold_stmt. Attempt to simplify *(BASE+OFFSET).
- Return the simplified expression, or NULL if nothing could be done. */
-
- static tree
- maybe_fold_stmt_indirect (tree expr, tree base, tree offset)
- {
- tree t;
- bool volatile_p = TREE_THIS_VOLATILE (expr);
- location_t loc = EXPR_LOCATION (expr);
-
- /* We may well have constructed a double-nested PLUS_EXPR via multiple
- substitutions. Fold that down to one. Remove NON_LVALUE_EXPRs that
- are sometimes added. */
- base = fold (base);
- STRIP_TYPE_NOPS (base);
- TREE_OPERAND (expr, 0) = base;
-
- /* One possibility is that the address reduces to a string constant. */
- t = fold_read_from_constant_string (expr);
- if (t)
- return t;
-
- /* Add in any offset from a POINTER_PLUS_EXPR. */
- if (TREE_CODE (base) == POINTER_PLUS_EXPR)
- {
- tree offset2;
-
- offset2 = TREE_OPERAND (base, 1);
- if (TREE_CODE (offset2) != INTEGER_CST)
- return NULL_TREE;
- base = TREE_OPERAND (base, 0);
-
- offset = fold_convert (sizetype,
- int_const_binop (PLUS_EXPR, offset, offset2, 1));
- }
-
- if (TREE_CODE (base) == ADDR_EXPR)
- {
- tree base_addr = base;
-
- /* Strip the ADDR_EXPR. */
- base = TREE_OPERAND (base, 0);
-
- /* Fold away CONST_DECL to its value, if the type is scalar. */
- if (TREE_CODE (base) == CONST_DECL
- && is_gimple_min_invariant (DECL_INITIAL (base)))
- return DECL_INITIAL (base);
-
- /* If there is no offset involved simply return the folded base. */
- if (integer_zerop (offset))
- return base;
-
- /* Try folding *(&B+O) to B.X. */
- t = maybe_fold_offset_to_reference (loc, base_addr, offset,
- TREE_TYPE (expr));
- if (t)
- {
- /* Preserve volatileness of the original expression.
- We can end up with a plain decl here which is shared
- and we shouldn't mess with its flags. */
- if (!SSA_VAR_P (t))
- TREE_THIS_VOLATILE (t) = volatile_p;
- return t;
- }
- }
- else
- {
- /* We can get here for out-of-range string constant accesses,
- such as "_"[3]. Bail out of the entire substitution search
- and arrange for the entire statement to be replaced by a
- call to __builtin_trap. In all likelihood this will all be
- constant-folded away, but in the meantime we can't leave with
- something that get_expr_operands can't understand. */
-
- t = base;
- STRIP_NOPS (t);
- if (TREE_CODE (t) == ADDR_EXPR
- && TREE_CODE (TREE_OPERAND (t, 0)) == STRING_CST)
- {
- /* FIXME: Except that this causes problems elsewhere with dead
- code not being deleted, and we die in the rtl expanders
- because we failed to remove some ssa_name. In the meantime,
- just return zero. */
- /* FIXME2: This condition should be signaled by
- fold_read_from_constant_string directly, rather than
- re-checking for it here. */
- return integer_zero_node;
- }
-
- /* Try folding *(B+O) to B->X. Still an improvement. */
- if (POINTER_TYPE_P (TREE_TYPE (base)))
- {
- t = maybe_fold_offset_to_reference (loc, base, offset,
- TREE_TYPE (expr));
- if (t)
- return t;
- }
- }
-
- /* Otherwise we had an offset that we could not simplify. */
- return NULL_TREE;
- }
-
-
- /* A quaint feature extant in our address arithmetic is that there
- can be hidden type changes here. The type of the result need
- not be the same as the type of the input pointer.
-
- What we're after here is an expression of the form
- (T *)(&array + const)
- where array is OP0, const is OP1, RES_TYPE is T and
- the cast doesn't actually exist, but is implicit in the
- type of the POINTER_PLUS_EXPR. We'd like to turn this into
- &array[x]
- which may be able to propagate further. */
-
- tree
- maybe_fold_stmt_addition (location_t loc, tree res_type, tree op0, tree op1)
- {
- tree ptd_type;
- tree t;
-
- /* The first operand should be an ADDR_EXPR. */
- if (TREE_CODE (op0) != ADDR_EXPR)
- return NULL_TREE;
- op0 = TREE_OPERAND (op0, 0);
-
- /* It had better be a constant. */
- if (TREE_CODE (op1) != INTEGER_CST)
- {
- /* Or op0 should now be A[0] and the non-constant offset defined
- via a multiplication by the array element size. */
- if (TREE_CODE (op0) == ARRAY_REF
- && integer_zerop (TREE_OPERAND (op0, 1))
- && TREE_CODE (op1) == SSA_NAME
- && host_integerp (TYPE_SIZE_UNIT (TREE_TYPE (op0)), 1))
- {
- gimple offset_def = SSA_NAME_DEF_STMT (op1);
- if (!is_gimple_assign (offset_def))
- return NULL_TREE;
-
- if (gimple_assign_rhs_code (offset_def) == MULT_EXPR
- && TREE_CODE (gimple_assign_rhs2 (offset_def)) == INTEGER_CST
- && tree_int_cst_equal (gimple_assign_rhs2 (offset_def),
- TYPE_SIZE_UNIT (TREE_TYPE (op0))))
- return build_fold_addr_expr
- (build4 (ARRAY_REF, TREE_TYPE (op0),
- TREE_OPERAND (op0, 0),
- gimple_assign_rhs1 (offset_def),
- TREE_OPERAND (op0, 2),
- TREE_OPERAND (op0, 3)));
- else if (integer_onep (TYPE_SIZE_UNIT (TREE_TYPE (op0)))
- && gimple_assign_rhs_code (offset_def) != MULT_EXPR)
- return build_fold_addr_expr
- (build4 (ARRAY_REF, TREE_TYPE (op0),
- TREE_OPERAND (op0, 0),
- op1,
- TREE_OPERAND (op0, 2),
- TREE_OPERAND (op0, 3)));
- }
- return NULL_TREE;
- }
-
- /* If the first operand is an ARRAY_REF, expand it so that we can fold
- the offset into it. */
- while (TREE_CODE (op0) == ARRAY_REF)
- {
- tree array_obj = TREE_OPERAND (op0, 0);
- tree array_idx = TREE_OPERAND (op0, 1);
- tree elt_type = TREE_TYPE (op0);
- tree elt_size = TYPE_SIZE_UNIT (elt_type);
- tree min_idx;
-
- if (TREE_CODE (array_idx) != INTEGER_CST)
- break;
- if (TREE_CODE (elt_size) != INTEGER_CST)
- break;
-
- /* Un-bias the index by the min index of the array type. */
- min_idx = TYPE_DOMAIN (TREE_TYPE (array_obj));
- if (min_idx)
- {
- min_idx = TYPE_MIN_VALUE (min_idx);
- if (min_idx)
- {
- if (TREE_CODE (min_idx) != INTEGER_CST)
- break;
-
- array_idx = fold_convert (TREE_TYPE (min_idx), array_idx);
- if (!integer_zerop (min_idx))
- array_idx = int_const_binop (MINUS_EXPR, array_idx,
- min_idx, 0);
- }
- }
-
- /* Convert the index to a byte offset. */
- array_idx = fold_convert (sizetype, array_idx);
- array_idx = int_const_binop (MULT_EXPR, array_idx, elt_size, 0);
-
- /* Update the operands for the next round, or for folding. */
- op1 = int_const_binop (PLUS_EXPR,
- array_idx, op1, 0);
- op0 = array_obj;
- }
-
- ptd_type = TREE_TYPE (res_type);
- /* If we want a pointer to void, reconstruct the reference from the
- array element type. A pointer to that can be trivially converted
- to void *. This happens as we fold (void *)(ptr p+ off). */
- if (VOID_TYPE_P (ptd_type)
- && TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE)
- ptd_type = TREE_TYPE (TREE_TYPE (op0));
-
- /* At which point we can try some of the same things as for indirects. */
- t = maybe_fold_offset_to_array_ref (loc, op0, op1, ptd_type, true);
- if (!t)
- t = maybe_fold_offset_to_component_ref (loc, TREE_TYPE (op0), op0, op1,
- ptd_type);
- if (t)
- {
- t = build1 (ADDR_EXPR, res_type, t);
- SET_EXPR_LOCATION (t, loc);
- }
-
- return t;
- }
-
- /* Subroutine of fold_stmt. We perform several simplifications of the
- memory reference tree EXPR and make sure to re-gimplify them properly
- after propagation of constant addresses. IS_LHS is true if the
- reference is supposed to be an lvalue. */
-
- static tree
- maybe_fold_reference (tree expr, bool is_lhs)
- {
- tree *t = &expr;
-
- if (TREE_CODE (expr) == ARRAY_REF
- && !is_lhs)
- {
- tree tem = fold_read_from_constant_string (expr);
- if (tem)
- return tem;
- }
-
- /* ??? We might want to open-code the relevant remaining cases
- to avoid using the generic fold. */
- if (handled_component_p (*t)
- && CONSTANT_CLASS_P (TREE_OPERAND (*t, 0)))
- {
- tree tem = fold (*t);
- if (tem != *t)
- return tem;
- }
-
- while (handled_component_p (*t))
- t = &TREE_OPERAND (*t, 0);
-
- if (TREE_CODE (*t) == INDIRECT_REF)
- {
- tree tem = maybe_fold_stmt_indirect (*t, TREE_OPERAND (*t, 0),
- integer_zero_node);
- /* Avoid folding *"abc" = 5 into 'a' = 5. */
- if (is_lhs && tem && CONSTANT_CLASS_P (tem))
- tem = NULL_TREE;
- if (!tem
- && TREE_CODE (TREE_OPERAND (*t, 0)) == ADDR_EXPR)
- /* If we had a good reason for propagating the address here,
- make sure we end up with valid gimple. See PR34989. */
- tem = TREE_OPERAND (TREE_OPERAND (*t, 0), 0);
-
- if (tem)
- {
- *t = tem;
- tem = maybe_fold_reference (expr, is_lhs);
- if (tem)
- return tem;
- return expr;
- }
- }
- else if (!is_lhs
- && DECL_P (*t))
- {
- tree tem = get_symbol_constant_value (*t);
- if (tem
- && useless_type_conversion_p (TREE_TYPE (*t), TREE_TYPE (tem)))
- {
- *t = unshare_expr (tem);
- tem = maybe_fold_reference (expr, is_lhs);
- if (tem)
- return tem;
- return expr;
- }
- }
-
- return NULL_TREE;
- }
-
-
- /* Return the string length, maximum string length or maximum value of
- ARG in LENGTH.
- If ARG is an SSA name variable, follow its use-def chains. If LENGTH
- is not NULL and, for TYPE == 0, its value is not equal to the length
- we determine or if we are unable to determine the length or value,
- return false. VISITED is a bitmap of visited variables.
- TYPE is 0 if string length should be returned, 1 for maximum string
- length and 2 for maximum value ARG can have. */
-
- static bool
- get_maxval_strlen (tree arg, tree *length, bitmap visited, int type)
- {
- tree var, val;
- gimple def_stmt;
-
- if (TREE_CODE (arg) != SSA_NAME)
- {
- if (TREE_CODE (arg) == COND_EXPR)
- return get_maxval_strlen (COND_EXPR_THEN (arg), length, visited, type)
- && get_maxval_strlen (COND_EXPR_ELSE (arg), length, visited, type);
- /* We can end up with &(*iftmp_1)[0] here as well, so handle it. */
- else if (TREE_CODE (arg) == ADDR_EXPR
- && TREE_CODE (TREE_OPERAND (arg, 0)) == ARRAY_REF
- && integer_zerop (TREE_OPERAND (TREE_OPERAND (arg, 0), 1)))
- {
- tree aop0 = TREE_OPERAND (TREE_OPERAND (arg, 0), 0);
- if (TREE_CODE (aop0) == INDIRECT_REF
- && TREE_CODE (TREE_OPERAND (aop0, 0)) == SSA_NAME)
- return get_maxval_strlen (TREE_OPERAND (aop0, 0),
- length, visited, type);
- }
-
- if (type == 2)
- {
- val = arg;
- if (TREE_CODE (val) != INTEGER_CST
- || tree_int_cst_sgn (val) < 0)
- return false;
- }
- else
- val = c_strlen (arg, 1);
- if (!val)
- return false;
-
- if (*length)
- {
- if (type > 0)
- {
- if (TREE_CODE (*length) != INTEGER_CST
- || TREE_CODE (val) != INTEGER_CST)
- return false;
-
- if (tree_int_cst_lt (*length, val))
- *length = val;
- return true;
- }
- else if (simple_cst_equal (val, *length) != 1)
- return false;
- }
-
- *length = val;
- return true;
- }
-
- /* If we were already here, break the infinite cycle. */
- if (bitmap_bit_p (visited, SSA_NAME_VERSION (arg)))
- return true;
- bitmap_set_bit (visited, SSA_NAME_VERSION (arg));
-
- var = arg;
- def_stmt = SSA_NAME_DEF_STMT (var);
-
- switch (gimple_code (def_stmt))
- {
- case GIMPLE_ASSIGN:
- /* The RHS of the statement defining VAR must either have a
- constant length or come from another SSA_NAME with a constant
- length. */
- if (gimple_assign_single_p (def_stmt)
- || gimple_assign_unary_nop_p (def_stmt))
- {
- tree rhs = gimple_assign_rhs1 (def_stmt);
- return get_maxval_strlen (rhs, length, visited, type);
- }
- return false;
-
- case GIMPLE_PHI:
- {
- /* All the arguments of the PHI node must have the same constant
- length. */
- unsigned i;
-
- for (i = 0; i < gimple_phi_num_args (def_stmt); i++)
- {
- tree arg = gimple_phi_arg (def_stmt, i)->def;
-
- /* If this PHI has itself as an argument, we cannot
- determine the string length of this argument. However,
- if we can find a constant string length for the other
- PHI args then we can still be sure that this is a
- constant string length. So be optimistic and just
- continue with the next argument. */
- if (arg == gimple_phi_result (def_stmt))
- continue;
-
- if (!get_maxval_strlen (arg, length, visited, type))
- return false;
- }
- }
- return true;
-
- default:
- return false;
- }
- }
-
-
- /* Fold builtin call in statement STMT. Returns a simplified tree.
- We may return a non-constant expression, including another call
- to a different function and with different arguments, e.g.,
- substituting memcpy for strcpy when the string length is known.
- Note that some builtins expand into inline code that may not
- be valid in GIMPLE. Callers must take care. */
-
- static tree
- ccp_fold_builtin (gimple stmt)
- {
- tree result, val[3];
- tree callee, a;
- int arg_idx, type;
- bitmap visited;
- bool ignore;
- int nargs;
- location_t loc = gimple_location (stmt);
-
- gcc_assert (is_gimple_call (stmt));
-
- ignore = (gimple_call_lhs (stmt) == NULL);
-
- /* First try the generic builtin folder. If that succeeds, return the
- result directly. */
- result = fold_call_stmt (stmt, ignore);
- if (result)
- {
- if (ignore)
- STRIP_NOPS (result);
- return result;
- }
-
- /* Ignore MD builtins. */
- callee = gimple_call_fndecl (stmt);
- if (DECL_BUILT_IN_CLASS (callee) == BUILT_IN_MD)
- return NULL_TREE;
-
- /* If the builtin could not be folded, and it has no argument list,
- we're done. */
- nargs = gimple_call_num_args (stmt);
- if (nargs == 0)
- return NULL_TREE;
-
- /* Limit the work only for builtins we know how to simplify. */
- switch (DECL_FUNCTION_CODE (callee))
- {
- case BUILT_IN_STRLEN:
- case BUILT_IN_FPUTS:
- case BUILT_IN_FPUTS_UNLOCKED:
- arg_idx = 0;
- type = 0;
- break;
- case BUILT_IN_STRCPY:
- case BUILT_IN_STRNCPY:
- arg_idx = 1;
- type = 0;
- break;
- case BUILT_IN_MEMCPY_CHK:
- case BUILT_IN_MEMPCPY_CHK:
- case BUILT_IN_MEMMOVE_CHK:
- case BUILT_IN_MEMSET_CHK:
- case BUILT_IN_STRNCPY_CHK:
- arg_idx = 2;
- type = 2;
- break;
- case BUILT_IN_STRCPY_CHK:
- case BUILT_IN_STPCPY_CHK:
- arg_idx = 1;
- type = 1;
- break;
- case BUILT_IN_SNPRINTF_CHK:
- case BUILT_IN_VSNPRINTF_CHK:
- arg_idx = 1;
- type = 2;
- break;
- default:
- return NULL_TREE;
- }
-
- if (arg_idx >= nargs)
- return NULL_TREE;
-
- /* Try to use the dataflow information gathered by the CCP process. */
- visited = BITMAP_ALLOC (NULL);
- bitmap_clear (visited);
-
- memset (val, 0, sizeof (val));
- a = gimple_call_arg (stmt, arg_idx);
- if (!get_maxval_strlen (a, &val[arg_idx], visited, type))
- val[arg_idx] = NULL_TREE;
-
- BITMAP_FREE (visited);
-
- result = NULL_TREE;
- switch (DECL_FUNCTION_CODE (callee))
- {
- case BUILT_IN_STRLEN:
- if (val[0] && nargs == 1)
- {
- tree new_val =
- fold_convert (TREE_TYPE (gimple_call_lhs (stmt)), val[0]);
-
- /* If the result is not a valid gimple value, or not a cast
- of a valid gimple value, then we can not use the result. */
- if (is_gimple_val (new_val)
- || (is_gimple_cast (new_val)
- && is_gimple_val (TREE_OPERAND (new_val, 0))))
- return new_val;
- }
- break;
-
- case BUILT_IN_STRCPY:
- if (val[1] && is_gimple_val (val[1]) && nargs == 2)
- result = fold_builtin_strcpy (loc, callee,
- gimple_call_arg (stmt, 0),
- gimple_call_arg (stmt, 1),
- val[1]);
- break;
-
- case BUILT_IN_STRNCPY:
- if (val[1] && is_gimple_val (val[1]) && nargs == 3)
- result = fold_builtin_strncpy (loc, callee,
- gimple_call_arg (stmt, 0),
- gimple_call_arg (stmt, 1),
- gimple_call_arg (stmt, 2),
- val[1]);
- break;
-
- case BUILT_IN_FPUTS:
- if (nargs == 2)
- result = fold_builtin_fputs (loc, gimple_call_arg (stmt, 0),
- gimple_call_arg (stmt, 1),
- ignore, false, val[0]);
- break;
-
- case BUILT_IN_FPUTS_UNLOCKED:
- if (nargs == 2)
- result = fold_builtin_fputs (loc, gimple_call_arg (stmt, 0),
- gimple_call_arg (stmt, 1),
- ignore, true, val[0]);
- break;
-
- case BUILT_IN_MEMCPY_CHK:
- case BUILT_IN_MEMPCPY_CHK:
- case BUILT_IN_MEMMOVE_CHK:
- case BUILT_IN_MEMSET_CHK:
- if (val[2] && is_gimple_val (val[2]) && nargs == 4)
- result = fold_builtin_memory_chk (loc, callee,
- gimple_call_arg (stmt, 0),
- gimple_call_arg (stmt, 1),
- gimple_call_arg (stmt, 2),
- gimple_call_arg (stmt, 3),
- val[2], ignore,
- DECL_FUNCTION_CODE (callee));
- break;
-
- case BUILT_IN_STRCPY_CHK:
- case BUILT_IN_STPCPY_CHK:
- if (val[1] && is_gimple_val (val[1]) && nargs == 3)
- result = fold_builtin_stxcpy_chk (loc, callee,
- gimple_call_arg (stmt, 0),
- gimple_call_arg (stmt, 1),
- gimple_call_arg (stmt, 2),
- val[1], ignore,
- DECL_FUNCTION_CODE (callee));
- break;
-
- case BUILT_IN_STRNCPY_CHK:
- if (val[2] && is_gimple_val (val[2]) && nargs == 4)
- result = fold_builtin_strncpy_chk (loc, gimple_call_arg (stmt, 0),
- gimple_call_arg (stmt, 1),
- gimple_call_arg (stmt, 2),
- gimple_call_arg (stmt, 3),
- val[2]);
- break;
-
- case BUILT_IN_SNPRINTF_CHK:
- case BUILT_IN_VSNPRINTF_CHK:
- if (val[1] && is_gimple_val (val[1]))
- result = gimple_fold_builtin_snprintf_chk (stmt, val[1],
- DECL_FUNCTION_CODE (callee));
- break;
-
- default:
- gcc_unreachable ();
- }
-
- if (result && ignore)
- result = fold_ignored_result (result);
- return result;
- }
-
- /* Attempt to fold an assignment statement pointed-to by SI. Returns a
- replacement rhs for the statement or NULL_TREE if no simplification
- could be made. It is assumed that the operands have been previously
- folded. */
-
- static tree
- fold_gimple_assign (gimple_stmt_iterator *si)
- {
- gimple stmt = gsi_stmt (*si);
- enum tree_code subcode = gimple_assign_rhs_code (stmt);
- location_t loc = gimple_location (stmt);
-
- tree result = NULL_TREE;
-
- switch (get_gimple_rhs_class (subcode))
- {
- case GIMPLE_SINGLE_RHS:
- {
- tree rhs = gimple_assign_rhs1 (stmt);
-
- /* Try to fold a conditional expression. */
- if (TREE_CODE (rhs) == COND_EXPR)
- {
- tree op0 = COND_EXPR_COND (rhs);
- tree tem;
- bool set = false;
- location_t cond_loc = EXPR_LOCATION (rhs);
-
- if (COMPARISON_CLASS_P (op0))
- {
- fold_defer_overflow_warnings ();
- tem = fold_binary_loc (cond_loc,
- TREE_CODE (op0), TREE_TYPE (op0),
- TREE_OPERAND (op0, 0),
- TREE_OPERAND (op0, 1));
- /* This is actually a conditional expression, not a GIMPLE
- conditional statement, however, the valid_gimple_rhs_p
- test still applies. */
- set = (tem && is_gimple_condexpr (tem)
- && valid_gimple_rhs_p (tem));
- fold_undefer_overflow_warnings (set, stmt, 0);
- }
- else if (is_gimple_min_invariant (op0))
- {
- tem = op0;
- set = true;
- }
- else
- return NULL_TREE;
-
- if (set)
- result = fold_build3_loc (cond_loc, COND_EXPR, TREE_TYPE (rhs), tem,
- COND_EXPR_THEN (rhs), COND_EXPR_ELSE (rhs));
- }
-
- else if (TREE_CODE (rhs) == TARGET_MEM_REF)
- return maybe_fold_tmr (rhs);
-
- else if (REFERENCE_CLASS_P (rhs))
- return maybe_fold_reference (rhs, false);
-
- else if (TREE_CODE (rhs) == ADDR_EXPR)
- {
- tree tem = maybe_fold_reference (TREE_OPERAND (rhs, 0), true);
- if (tem)
- result = fold_convert (TREE_TYPE (rhs),
- build_fold_addr_expr_loc (loc, tem));
- }
-
- else if (TREE_CODE (rhs) == CONSTRUCTOR
- && TREE_CODE (TREE_TYPE (rhs)) == VECTOR_TYPE
- && (CONSTRUCTOR_NELTS (rhs)
- == TYPE_VECTOR_SUBPARTS (TREE_TYPE (rhs))))
- {
- /* Fold a constant vector CONSTRUCTOR to VECTOR_CST. */
- unsigned i;
- tree val;
-
- FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (rhs), i, val)
- if (TREE_CODE (val) != INTEGER_CST
- && TREE_CODE (val) != REAL_CST
- && TREE_CODE (val) != FIXED_CST)
- return NULL_TREE;
-
- return build_vector_from_ctor (TREE_TYPE (rhs),
- CONSTRUCTOR_ELTS (rhs));
- }
-
- else if (DECL_P (rhs))
- return unshare_expr (get_symbol_constant_value (rhs));
-
- /* If we couldn't fold the RHS, hand over to the generic
- fold routines. */
- if (result == NULL_TREE)
- result = fold (rhs);
-
- /* Strip away useless type conversions. Both the NON_LVALUE_EXPR
- that may have been added by fold, and "useless" type
- conversions that might now be apparent due to propagation. */
- STRIP_USELESS_TYPE_CONVERSION (result);
-
- if (result != rhs && valid_gimple_rhs_p (result))
- return result;
-
- return NULL_TREE;
- }
- break;
-
- case GIMPLE_UNARY_RHS:
- {
- tree rhs = gimple_assign_rhs1 (stmt);
-
- result = fold_unary_loc (loc, subcode, gimple_expr_type (stmt), rhs);
- if (result)
- {
- /* If the operation was a conversion do _not_ mark a
- resulting constant with TREE_OVERFLOW if the original
- constant was not. These conversions have implementation
- defined behavior and retaining the TREE_OVERFLOW flag
- here would confuse later passes such as VRP. */
- if (CONVERT_EXPR_CODE_P (subcode)
- && TREE_CODE (result) == INTEGER_CST
- && TREE_CODE (rhs) == INTEGER_CST)
- TREE_OVERFLOW (result) = TREE_OVERFLOW (rhs);
-
- STRIP_USELESS_TYPE_CONVERSION (result);
- if (valid_gimple_rhs_p (result))
- return result;
- }
- else if (CONVERT_EXPR_CODE_P (subcode)
- && POINTER_TYPE_P (gimple_expr_type (stmt))
- && POINTER_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))
- {
- tree type = gimple_expr_type (stmt);
- tree t = maybe_fold_offset_to_address (loc,
- gimple_assign_rhs1 (stmt),
- integer_zero_node, type);
- if (t)
- return t;
- }
- }
- break;
-
- case GIMPLE_BINARY_RHS:
- /* Try to fold pointer addition. */
- if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR)
- {
- tree type = TREE_TYPE (gimple_assign_rhs1 (stmt));
- if (TREE_CODE (TREE_TYPE (type)) == ARRAY_TYPE)
- {
- type = build_pointer_type (TREE_TYPE (TREE_TYPE (type)));
- if (!useless_type_conversion_p
- (TREE_TYPE (gimple_assign_lhs (stmt)), type))
- type = TREE_TYPE (gimple_assign_rhs1 (stmt));
- }
- result = maybe_fold_stmt_addition (gimple_location (stmt),
- type,
- gimple_assign_rhs1 (stmt),
- gimple_assign_rhs2 (stmt));
- }
-
- if (!result)
- result = fold_binary_loc (loc, subcode,
- TREE_TYPE (gimple_assign_lhs (stmt)),
- gimple_assign_rhs1 (stmt),
- gimple_assign_rhs2 (stmt));
-
- if (result)
- {
- STRIP_USELESS_TYPE_CONVERSION (result);
- if (valid_gimple_rhs_p (result))
- return result;
-
- /* Fold might have produced non-GIMPLE, so if we trust it blindly
- we lose canonicalization opportunities. Do not go again
- through fold here though, or the same non-GIMPLE will be
- produced. */
- if (commutative_tree_code (subcode)
- && tree_swap_operands_p (gimple_assign_rhs1 (stmt),
- gimple_assign_rhs2 (stmt), false))
- return build2 (subcode, TREE_TYPE (gimple_assign_lhs (stmt)),
- gimple_assign_rhs2 (stmt),
- gimple_assign_rhs1 (stmt));
- }
- break;
-
- case GIMPLE_INVALID_RHS:
- gcc_unreachable ();
- }
-
- return NULL_TREE;
- }
-
- /* Attempt to fold a conditional statement. Return true if any changes were
- made. We only attempt to fold the condition expression, and do not perform
- any transformation that would require alteration of the cfg. It is
- assumed that the operands have been previously folded. */
-
- static bool
- fold_gimple_cond (gimple stmt)
- {
- tree result = fold_binary_loc (gimple_location (stmt),
- gimple_cond_code (stmt),
- boolean_type_node,
- gimple_cond_lhs (stmt),
- gimple_cond_rhs (stmt));
-
- if (result)
- {
- STRIP_USELESS_TYPE_CONVERSION (result);
- if (is_gimple_condexpr (result) && valid_gimple_rhs_p (result))
- {
- gimple_cond_set_condition_from_tree (stmt, result);
- return true;
- }
- }
-
- return false;
- }
-
- static void gimplify_and_update_call_from_tree (gimple_stmt_iterator *, tree);
-
- /* Attempt to fold a call statement referenced by the statement iterator GSI.
- The statement may be replaced by another statement, e.g., if the call
- simplifies to a constant value. Return true if any changes were made.
- It is assumed that the operands have been previously folded. */
-
- static bool
- fold_gimple_call (gimple_stmt_iterator *gsi)
- {
- gimple stmt = gsi_stmt (*gsi);
-
- tree callee = gimple_call_fndecl (stmt);
-
- /* Check for builtins that CCP can handle using information not
- available in the generic fold routines. */
- if (callee && DECL_BUILT_IN (callee))
- {
- tree result = ccp_fold_builtin (stmt);
-
- if (result)
- {
- if (!update_call_from_tree (gsi, result))
- gimplify_and_update_call_from_tree (gsi, result);
- return true;
- }
- }
- else
- {
- /* Check for resolvable OBJ_TYPE_REF. The only sorts we can resolve
- here are when we've propagated the address of a decl into the
- object slot. */
- /* ??? Should perhaps do this in fold proper. However, doing it
- there requires that we create a new CALL_EXPR, and that requires
- copying EH region info to the new node. Easier to just do it
- here where we can just smash the call operand. */
- /* ??? Is there a good reason not to do this in fold_stmt_inplace? */
- callee = gimple_call_fn (stmt);
- if (TREE_CODE (callee) == OBJ_TYPE_REF
- && lang_hooks.fold_obj_type_ref
- && TREE_CODE (OBJ_TYPE_REF_OBJECT (callee)) == ADDR_EXPR
- && DECL_P (TREE_OPERAND
- (OBJ_TYPE_REF_OBJECT (callee), 0)))
- {
- tree t;
-
- /* ??? Caution: Broken ADDR_EXPR semantics means that
- looking at the type of the operand of the addr_expr
- can yield an array type. See silly exception in
- check_pointer_types_r. */
- t = TREE_TYPE (TREE_TYPE (OBJ_TYPE_REF_OBJECT (callee)));
- t = lang_hooks.fold_obj_type_ref (callee, t);
- if (t)
- {
- gimple_call_set_fn (stmt, t);
- return true;
- }
- }
- }
-
- return false;
- }
-
- /* Worker for both fold_stmt and fold_stmt_inplace. The INPLACE argument
- distinguishes both cases. */
-
- static bool
- fold_stmt_1 (gimple_stmt_iterator *gsi, bool inplace)
- {
- bool changed = false;
- gimple stmt = gsi_stmt (*gsi);
- unsigned i;
-
- /* Fold the main computation performed by the statement. */
- switch (gimple_code (stmt))
- {
- case GIMPLE_ASSIGN:
- {
- unsigned old_num_ops = gimple_num_ops (stmt);
- tree new_rhs = fold_gimple_assign (gsi);
- tree lhs = gimple_assign_lhs (stmt);
- if (new_rhs
- && !useless_type_conversion_p (TREE_TYPE (lhs),
- TREE_TYPE (new_rhs)))
- new_rhs = fold_convert (TREE_TYPE (lhs), new_rhs);
- if (new_rhs
- && (!inplace
- || get_gimple_rhs_num_ops (TREE_CODE (new_rhs)) < old_num_ops))
- {
- gimple_assign_set_rhs_from_tree (gsi, new_rhs);
- changed = true;
- }
- break;
- }
-
- case GIMPLE_COND:
- changed |= fold_gimple_cond (stmt);
- break;
-
- case GIMPLE_CALL:
- /* Fold *& in call arguments. */
- for (i = 0; i < gimple_call_num_args (stmt); ++i)
- if (REFERENCE_CLASS_P (gimple_call_arg (stmt, i)))
- {
- tree tmp = maybe_fold_reference (gimple_call_arg (stmt, i), false);
- if (tmp)
- {
- gimple_call_set_arg (stmt, i, tmp);
- changed = true;
- }
- }
- /* The entire statement may be replaced in this case. */
- if (!inplace)
- changed |= fold_gimple_call (gsi);
- break;
-
- case GIMPLE_ASM:
- /* Fold *& in asm operands. */
- for (i = 0; i < gimple_asm_noutputs (stmt); ++i)
- {
- tree link = gimple_asm_output_op (stmt, i);
- tree op = TREE_VALUE (link);
- if (REFERENCE_CLASS_P (op)
- && (op = maybe_fold_reference (op, true)) != NULL_TREE)
- {
- TREE_VALUE (link) = op;
- changed = true;
- }
- }
- for (i = 0; i < gimple_asm_ninputs (stmt); ++i)
- {
- tree link = gimple_asm_input_op (stmt, i);
- tree op = TREE_VALUE (link);
- if (REFERENCE_CLASS_P (op)
- && (op = maybe_fold_reference (op, false)) != NULL_TREE)
- {
- TREE_VALUE (link) = op;
- changed = true;
- }
- }
- break;
-
- default:;
- }
-
- stmt = gsi_stmt (*gsi);
-
- /* Fold *& on the lhs. */
- if (gimple_has_lhs (stmt))
- {
- tree lhs = gimple_get_lhs (stmt);
- if (lhs && REFERENCE_CLASS_P (lhs))
- {
- tree new_lhs = maybe_fold_reference (lhs, true);
- if (new_lhs)
- {
- gimple_set_lhs (stmt, new_lhs);
- changed = true;
- }
- }
- }
-
- return changed;
- }
-
- /* Fold the statement pointed to by GSI. In some cases, this function may
- replace the whole statement with a new one. Returns true iff folding
- makes any changes.
- The statement pointed to by GSI should be in valid gimple form but may
- be in unfolded state as resulting from for example constant propagation
- which can produce *&x = 0. */
-
- bool
- fold_stmt (gimple_stmt_iterator *gsi)
- {
- return fold_stmt_1 (gsi, false);
- }
-
- /* Perform the minimal folding on statement STMT. Only operations like
- *&x created by constant propagation are handled. The statement cannot
- be replaced with a new one. Return true if the statement was
- changed, false otherwise.
- The statement STMT should be in valid gimple form but may
- be in unfolded state as resulting from for example constant propagation
- which can produce *&x = 0. */
-
- bool
- fold_stmt_inplace (gimple stmt)
- {
- gimple_stmt_iterator gsi = gsi_for_stmt (stmt);
- bool changed = fold_stmt_1 (&gsi, true);
- gcc_assert (gsi_stmt (gsi) == stmt);
- return changed;
- }
/* Try to optimize out __builtin_stack_restore. Optimize it out
if there is another __builtin_stack_restore in the same basic
--- 1697,1702 ----
*************** optimize_stdarg_builtin (gimple call)
*** 3337,3416 ****
}
}
- /* Convert EXPR into a GIMPLE value suitable for substitution on the
- RHS of an assignment. Insert the necessary statements before
- iterator *SI_P. The statement at *SI_P, which must be a GIMPLE_CALL
- is replaced. If the call is expected to produces a result, then it
- is replaced by an assignment of the new RHS to the result variable.
- If the result is to be ignored, then the call is replaced by a
- GIMPLE_NOP. */
-
- static void
- gimplify_and_update_call_from_tree (gimple_stmt_iterator *si_p, tree expr)
- {
- tree lhs;
- tree tmp = NULL_TREE; /* Silence warning. */
- gimple stmt, new_stmt;
- gimple_stmt_iterator i;
- gimple_seq stmts = gimple_seq_alloc();
- struct gimplify_ctx gctx;
- gimple last = NULL;
-
- stmt = gsi_stmt (*si_p);
-
- gcc_assert (is_gimple_call (stmt));
-
- lhs = gimple_call_lhs (stmt);
-
- push_gimplify_context (&gctx);
-
- if (lhs == NULL_TREE)
- gimplify_and_add (expr, &stmts);
- else
- tmp = get_initialized_tmp_var (expr, &stmts, NULL);
-
- pop_gimplify_context (NULL);
-
- if (gimple_has_location (stmt))
- annotate_all_with_location (stmts, gimple_location (stmt));
-
- /* The replacement can expose previously unreferenced variables. */
- for (i = gsi_start (stmts); !gsi_end_p (i); gsi_next (&i))
- {
- if (last)
- {
- gsi_insert_before (si_p, last, GSI_NEW_STMT);
- gsi_next (si_p);
- }
- new_stmt = gsi_stmt (i);
- find_new_referenced_vars (new_stmt);
- mark_symbols_for_renaming (new_stmt);
- last = new_stmt;
- }
-
- if (lhs == NULL_TREE)
- {
- unlink_stmt_vdef (stmt);
- release_defs (stmt);
- new_stmt = last;
- }
- else
- {
- if (last)
- {
- gsi_insert_before (si_p, last, GSI_NEW_STMT);
- gsi_next (si_p);
- }
- new_stmt = gimple_build_assign (lhs, tmp);
- gimple_set_vuse (new_stmt, gimple_vuse (stmt));
- gimple_set_vdef (new_stmt, gimple_vdef (stmt));
- move_ssa_defining_stmt_for_defs (new_stmt, stmt);
- }
-
- gimple_set_location (new_stmt, gimple_location (stmt));
- gsi_replace (si_p, new_stmt, false);
- }
-
/* A simple pass that attempts to fold all builtin functions. This pass
is run after we've propagated as many constants as we can. */
--- 1859,1864 ----
*************** execute_fold_all_builtins (void)
*** 3445,3451 ****
}
fcode = DECL_FUNCTION_CODE (callee);
! result = ccp_fold_builtin (stmt);
if (result)
gimple_remove_stmt_histograms (cfun, stmt);
--- 1893,1899 ----
}
fcode = DECL_FUNCTION_CODE (callee);
! result = gimple_fold_builtin (stmt);
if (result)
gimple_remove_stmt_histograms (cfun, stmt);
Index: gcc/gimple-fold.c
===================================================================
*** gcc/gimple-fold.c (revision 0)
--- gcc/gimple-fold.c (revision 0)
***************
*** 0 ****
--- 1,1596 ----
+ /* Statement simplification on GIMPLE.
+ Copyright (C) 2010 Free Software Foundation, Inc.
+ Split out from tree-ssa-ccp.c.
+
+ This file is part of GCC.
+
+ GCC is free software; you can redistribute it and/or modify it
+ under the terms of the GNU General Public License as published by the
+ Free Software Foundation; either version 3, or (at your option) any
+ later version.
+
+ GCC is distributed in the hope that it will be useful, but WITHOUT
+ ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with GCC; see the file COPYING3. If not see
+ <http://www.gnu.org/licenses/>. */
+
+ #include "config.h"
+ #include "system.h"
+ #include "coretypes.h"
+ #include "tm.h"
+ #include "tree.h"
+ #include "flags.h"
+ #include "rtl.h"
+ #include "tm_p.h"
+ #include "ggc.h"
+ #include "basic-block.h"
+ #include "output.h"
+ #include "expr.h"
+ #include "function.h"
+ #include "diagnostic.h"
+ #include "timevar.h"
+ #include "tree-dump.h"
+ #include "tree-flow.h"
+ #include "tree-pass.h"
+ #include "tree-ssa-propagate.h"
+ #include "value-prof.h"
+ #include "langhooks.h"
+ #include "target.h"
+
+
+ /* If SYM is a constant variable with known value, return the value.
+ NULL_TREE is returned otherwise. */
+
+ tree
+ get_symbol_constant_value (tree sym)
+ {
+ if (TREE_STATIC (sym)
+ && (TREE_READONLY (sym)
+ || TREE_CODE (sym) == CONST_DECL))
+ {
+ tree val = DECL_INITIAL (sym);
+ if (val)
+ {
+ STRIP_NOPS (val);
+ if (is_gimple_min_invariant (val))
+ {
+ if (TREE_CODE (val) == ADDR_EXPR)
+ {
+ tree base = get_base_address (TREE_OPERAND (val, 0));
+ if (base && TREE_CODE (base) == VAR_DECL)
+ {
+ TREE_ADDRESSABLE (base) = 1;
+ if (gimple_referenced_vars (cfun))
+ add_referenced_var (base);
+ }
+ }
+ return val;
+ }
+ }
+ /* Variables declared 'const' without an initializer
+ have zero as the initializer if they may not be
+ overridden at link or run time. */
+ if (!val
+ && !DECL_EXTERNAL (sym)
+ && targetm.binds_local_p (sym)
+ && (INTEGRAL_TYPE_P (TREE_TYPE (sym))
+ || SCALAR_FLOAT_TYPE_P (TREE_TYPE (sym))))
+ return fold_convert (TREE_TYPE (sym), integer_zero_node);
+ }
+
+ return NULL_TREE;
+ }
+
+
+ /* Return true if we may propagate the address expression ADDR into the
+ dereference DEREF and cancel them. */
+
+ bool
+ may_propagate_address_into_dereference (tree addr, tree deref)
+ {
+ gcc_assert (INDIRECT_REF_P (deref)
+ && TREE_CODE (addr) == ADDR_EXPR);
+
+ /* Don't propagate if ADDR's operand has incomplete type. */
+ if (!COMPLETE_TYPE_P (TREE_TYPE (TREE_OPERAND (addr, 0))))
+ return false;
+
+ /* If the address is invariant then we do not need to preserve restrict
+ qualifications. But we do need to preserve volatile qualifiers until
+ we can annotate the folded dereference itself properly. */
+ if (is_gimple_min_invariant (addr)
+ && (!TREE_THIS_VOLATILE (deref)
+ || TYPE_VOLATILE (TREE_TYPE (addr))))
+ return useless_type_conversion_p (TREE_TYPE (deref),
+ TREE_TYPE (TREE_OPERAND (addr, 0)));
+
+ /* Else both the address substitution and the folding must result in
+ a valid useless type conversion sequence. */
+ return (useless_type_conversion_p (TREE_TYPE (TREE_OPERAND (deref, 0)),
+ TREE_TYPE (addr))
+ && useless_type_conversion_p (TREE_TYPE (deref),
+ TREE_TYPE (TREE_OPERAND (addr, 0))));
+ }
+
+
+ /* A subroutine of fold_stmt. Attempts to fold *(A+O) to A[X].
+ BASE is an array type. OFFSET is a byte displacement. ORIG_TYPE
+ is the desired result type.
+
+ LOC is the location of the original expression. */
+
+ static tree
+ maybe_fold_offset_to_array_ref (location_t loc, tree base, tree offset,
+ tree orig_type,
+ bool allow_negative_idx)
+ {
+ tree min_idx, idx, idx_type, elt_offset = integer_zero_node;
+ tree array_type, elt_type, elt_size;
+ tree domain_type;
+
+ /* If BASE is an ARRAY_REF, we can pick up another offset (this time
+ measured in units of the size of elements type) from that ARRAY_REF).
+ We can't do anything if either is variable.
+
+ The case we handle here is *(&A[N]+O). */
+ if (TREE_CODE (base) == ARRAY_REF)
+ {
+ tree low_bound = array_ref_low_bound (base);
+
+ elt_offset = TREE_OPERAND (base, 1);
+ if (TREE_CODE (low_bound) != INTEGER_CST
+ || TREE_CODE (elt_offset) != INTEGER_CST)
+ return NULL_TREE;
+
+ elt_offset = int_const_binop (MINUS_EXPR, elt_offset, low_bound, 0);
+ base = TREE_OPERAND (base, 0);
+ }
+
+ /* Ignore stupid user tricks of indexing non-array variables. */
+ array_type = TREE_TYPE (base);
+ if (TREE_CODE (array_type) != ARRAY_TYPE)
+ return NULL_TREE;
+ elt_type = TREE_TYPE (array_type);
+ if (!useless_type_conversion_p (orig_type, elt_type))
+ return NULL_TREE;
+
+ /* Use signed size type for intermediate computation on the index. */
+ idx_type = signed_type_for (size_type_node);
+
+ /* If OFFSET and ELT_OFFSET are zero, we don't care about the size of the
+ element type (so we can use the alignment if it's not constant).
+ Otherwise, compute the offset as an index by using a division. If the
+ division isn't exact, then don't do anything. */
+ elt_size = TYPE_SIZE_UNIT (elt_type);
+ if (!elt_size)
+ return NULL;
+ if (integer_zerop (offset))
+ {
+ if (TREE_CODE (elt_size) != INTEGER_CST)
+ elt_size = size_int (TYPE_ALIGN (elt_type));
+
+ idx = build_int_cst (idx_type, 0);
+ }
+ else
+ {
+ unsigned HOST_WIDE_INT lquo, lrem;
+ HOST_WIDE_INT hquo, hrem;
+ double_int soffset;
+
+ /* The final array offset should be signed, so we need
+ to sign-extend the (possibly pointer) offset here
+ and use signed division. */
+ soffset = double_int_sext (tree_to_double_int (offset),
+ TYPE_PRECISION (TREE_TYPE (offset)));
+ if (TREE_CODE (elt_size) != INTEGER_CST
+ || div_and_round_double (TRUNC_DIV_EXPR, 0,
+ soffset.low, soffset.high,
+ TREE_INT_CST_LOW (elt_size),
+ TREE_INT_CST_HIGH (elt_size),
+ &lquo, &hquo, &lrem, &hrem)
+ || lrem || hrem)
+ return NULL_TREE;
+
+ idx = build_int_cst_wide (idx_type, lquo, hquo);
+ }
+
+ /* Assume the low bound is zero. If there is a domain type, get the
+ low bound, if any, convert the index into that type, and add the
+ low bound. */
+ min_idx = build_int_cst (idx_type, 0);
+ domain_type = TYPE_DOMAIN (array_type);
+ if (domain_type)
+ {
+ idx_type = domain_type;
+ if (TYPE_MIN_VALUE (idx_type))
+ min_idx = TYPE_MIN_VALUE (idx_type);
+ else
+ min_idx = fold_convert (idx_type, min_idx);
+
+ if (TREE_CODE (min_idx) != INTEGER_CST)
+ return NULL_TREE;
+
+ elt_offset = fold_convert (idx_type, elt_offset);
+ }
+
+ if (!integer_zerop (min_idx))
+ idx = int_const_binop (PLUS_EXPR, idx, min_idx, 0);
+ if (!integer_zerop (elt_offset))
+ idx = int_const_binop (PLUS_EXPR, idx, elt_offset, 0);
+
+ /* Make sure to possibly truncate late after offsetting. */
+ idx = fold_convert (idx_type, idx);
+
+ /* We don't want to construct access past array bounds. For example
+ char *(c[4]);
+ c[3][2];
+ should not be simplified into (*c)[14] or tree-vrp will
+ give false warnings. The same is true for
+ struct A { long x; char d[0]; } *a;
+ (char *)a - 4;
+ which should be not folded to &a->d[-8]. */
+ if (domain_type
+ && TYPE_MAX_VALUE (domain_type)
+ && TREE_CODE (TYPE_MAX_VALUE (domain_type)) == INTEGER_CST)
+ {
+ tree up_bound = TYPE_MAX_VALUE (domain_type);
+
+ if (tree_int_cst_lt (up_bound, idx)
+ /* Accesses after the end of arrays of size 0 (gcc
+ extension) and 1 are likely intentional ("struct
+ hack"). */
+ && compare_tree_int (up_bound, 1) > 0)
+ return NULL_TREE;
+ }
+ if (domain_type
+ && TYPE_MIN_VALUE (domain_type))
+ {
+ if (!allow_negative_idx
+ && TREE_CODE (TYPE_MIN_VALUE (domain_type)) == INTEGER_CST
+ && tree_int_cst_lt (idx, TYPE_MIN_VALUE (domain_type)))
+ return NULL_TREE;
+ }
+ else if (!allow_negative_idx
+ && compare_tree_int (idx, 0) < 0)
+ return NULL_TREE;
+
+ {
+ tree t = build4 (ARRAY_REF, elt_type, base, idx, NULL_TREE, NULL_TREE);
+ SET_EXPR_LOCATION (t, loc);
+ return t;
+ }
+ }
+
+
+ /* Attempt to fold *(S+O) to S.X.
+ BASE is a record type. OFFSET is a byte displacement. ORIG_TYPE
+ is the desired result type.
+
+ LOC is the location of the original expression. */
+
+ static tree
+ maybe_fold_offset_to_component_ref (location_t loc, tree record_type,
+ tree base, tree offset, tree orig_type)
+ {
+ tree f, t, field_type, tail_array_field, field_offset;
+ tree ret;
+ tree new_base;
+
+ if (TREE_CODE (record_type) != RECORD_TYPE
+ && TREE_CODE (record_type) != UNION_TYPE
+ && TREE_CODE (record_type) != QUAL_UNION_TYPE)
+ return NULL_TREE;
+
+ /* Short-circuit silly cases. */
+ if (useless_type_conversion_p (record_type, orig_type))
+ return NULL_TREE;
+
+ tail_array_field = NULL_TREE;
+ for (f = TYPE_FIELDS (record_type); f ; f = TREE_CHAIN (f))
+ {
+ int cmp;
+
+ if (TREE_CODE (f) != FIELD_DECL)
+ continue;
+ if (DECL_BIT_FIELD (f))
+ continue;
+
+ if (!DECL_FIELD_OFFSET (f))
+ continue;
+ field_offset = byte_position (f);
+ if (TREE_CODE (field_offset) != INTEGER_CST)
+ continue;
+
+ /* ??? Java creates "interesting" fields for representing base classes.
+ They have no name, and have no context. With no context, we get into
+ trouble with nonoverlapping_component_refs_p. Skip them. */
+ if (!DECL_FIELD_CONTEXT (f))
+ continue;
+
+ /* The previous array field isn't at the end. */
+ tail_array_field = NULL_TREE;
+
+ /* Check to see if this offset overlaps with the field. */
+ cmp = tree_int_cst_compare (field_offset, offset);
+ if (cmp > 0)
+ continue;
+
+ field_type = TREE_TYPE (f);
+
+ /* Here we exactly match the offset being checked. If the types match,
+ then we can return that field. */
+ if (cmp == 0
+ && useless_type_conversion_p (orig_type, field_type))
+ {
+ t = fold_build3 (COMPONENT_REF, field_type, base, f, NULL_TREE);
+ return t;
+ }
+
+ /* Don't care about offsets into the middle of scalars. */
+ if (!AGGREGATE_TYPE_P (field_type))
+ continue;
+
+ /* Check for array at the end of the struct. This is often
+ used as for flexible array members. We should be able to
+ turn this into an array access anyway. */
+ if (TREE_CODE (field_type) == ARRAY_TYPE)
+ tail_array_field = f;
+
+ /* Check the end of the field against the offset. */
+ if (!DECL_SIZE_UNIT (f)
+ || TREE_CODE (DECL_SIZE_UNIT (f)) != INTEGER_CST)
+ continue;
+ t = int_const_binop (MINUS_EXPR, offset, field_offset, 1);
+ if (!tree_int_cst_lt (t, DECL_SIZE_UNIT (f)))
+ continue;
+
+ /* If we matched, then set offset to the displacement into
+ this field. */
+ new_base = fold_build3 (COMPONENT_REF, field_type, base, f, NULL_TREE);
+ SET_EXPR_LOCATION (new_base, loc);
+
+ /* Recurse to possibly find the match. */
+ ret = maybe_fold_offset_to_array_ref (loc, new_base, t, orig_type,
+ f == TYPE_FIELDS (record_type));
+ if (ret)
+ return ret;
+ ret = maybe_fold_offset_to_component_ref (loc, field_type, new_base, t,
+ orig_type);
+ if (ret)
+ return ret;
+ }
+
+ if (!tail_array_field)
+ return NULL_TREE;
+
+ f = tail_array_field;
+ field_type = TREE_TYPE (f);
+ offset = int_const_binop (MINUS_EXPR, offset, byte_position (f), 1);
+
+ /* If we get here, we've got an aggregate field, and a possibly
+ nonzero offset into them. Recurse and hope for a valid match. */
+ base = fold_build3 (COMPONENT_REF, field_type, base, f, NULL_TREE);
+ SET_EXPR_LOCATION (base, loc);
+
+ t = maybe_fold_offset_to_array_ref (loc, base, offset, orig_type,
+ f == TYPE_FIELDS (record_type));
+ if (t)
+ return t;
+ return maybe_fold_offset_to_component_ref (loc, field_type, base, offset,
+ orig_type);
+ }
+
+ /* Attempt to express (ORIG_TYPE)BASE+OFFSET as BASE->field_of_orig_type
+ or BASE[index] or by combination of those.
+
+ LOC is the location of original expression.
+
+ Before attempting the conversion strip off existing ADDR_EXPRs and
+ handled component refs. */
+
+ tree
+ maybe_fold_offset_to_reference (location_t loc, tree base, tree offset,
+ tree orig_type)
+ {
+ tree ret;
+ tree type;
+
+ STRIP_NOPS (base);
+ if (TREE_CODE (base) != ADDR_EXPR)
+ return NULL_TREE;
+
+ base = TREE_OPERAND (base, 0);
+
+ /* Handle case where existing COMPONENT_REF pick e.g. wrong field of union,
+ so it needs to be removed and new COMPONENT_REF constructed.
+ The wrong COMPONENT_REF are often constructed by folding the
+ (type *)&object within the expression (type *)&object+offset */
+ if (handled_component_p (base))
+ {
+ HOST_WIDE_INT sub_offset, size, maxsize;
+ tree newbase;
+ newbase = get_ref_base_and_extent (base, &sub_offset,
+ &size, &maxsize);
+ gcc_assert (newbase);
+ if (size == maxsize
+ && size != -1
+ && !(sub_offset & (BITS_PER_UNIT - 1)))
+ {
+ base = newbase;
+ if (sub_offset)
+ offset = int_const_binop (PLUS_EXPR, offset,
+ build_int_cst (TREE_TYPE (offset),
+ sub_offset / BITS_PER_UNIT), 1);
+ }
+ }
+ if (useless_type_conversion_p (orig_type, TREE_TYPE (base))
+ && integer_zerop (offset))
+ return base;
+ type = TREE_TYPE (base);
+
+ ret = maybe_fold_offset_to_component_ref (loc, type, base, offset, orig_type);
+ if (!ret)
+ ret = maybe_fold_offset_to_array_ref (loc, base, offset, orig_type, true);
+
+ return ret;
+ }
+
+ /* Attempt to express (ORIG_TYPE)&BASE+OFFSET as &BASE->field_of_orig_type
+ or &BASE[index] or by combination of those.
+
+ LOC is the location of the original expression.
+
+ Before attempting the conversion strip off existing component refs. */
+
+ tree
+ maybe_fold_offset_to_address (location_t loc, tree addr, tree offset,
+ tree orig_type)
+ {
+ tree t;
+
+ gcc_assert (POINTER_TYPE_P (TREE_TYPE (addr))
+ && POINTER_TYPE_P (orig_type));
+
+ t = maybe_fold_offset_to_reference (loc, addr, offset,
+ TREE_TYPE (orig_type));
+ if (t != NULL_TREE)
+ {
+ tree orig = addr;
+ tree ptr_type;
+
+ /* For __builtin_object_size to function correctly we need to
+ make sure not to fold address arithmetic so that we change
+ reference from one array to another. This would happen for
+ example for
+
+ struct X { char s1[10]; char s2[10] } s;
+ char *foo (void) { return &s.s2[-4]; }
+
+ where we need to avoid generating &s.s1[6]. As the C and
+ C++ frontends create different initial trees
+ (char *) &s.s1 + -4 vs. &s.s1[-4] we have to do some
+ sophisticated comparisons here. Note that checking for the
+ condition after the fact is easier than trying to avoid doing
+ the folding. */
+ STRIP_NOPS (orig);
+ if (TREE_CODE (orig) == ADDR_EXPR)
+ orig = TREE_OPERAND (orig, 0);
+ if ((TREE_CODE (orig) == ARRAY_REF
+ || (TREE_CODE (orig) == COMPONENT_REF
+ && TREE_CODE (TREE_TYPE (TREE_OPERAND (orig, 1))) == ARRAY_TYPE))
+ && (TREE_CODE (t) == ARRAY_REF
+ || TREE_CODE (t) == COMPONENT_REF)
+ && !operand_equal_p (TREE_CODE (orig) == ARRAY_REF
+ ? TREE_OPERAND (orig, 0) : orig,
+ TREE_CODE (t) == ARRAY_REF
+ ? TREE_OPERAND (t, 0) : t, 0))
+ return NULL_TREE;
+
+ ptr_type = build_pointer_type (TREE_TYPE (t));
+ if (!useless_type_conversion_p (orig_type, ptr_type))
+ return NULL_TREE;
+ return build_fold_addr_expr_with_type_loc (loc, t, ptr_type);
+ }
+
+ return NULL_TREE;
+ }
+
+ /* A subroutine of fold_stmt. Attempt to simplify *(BASE+OFFSET).
+ Return the simplified expression, or NULL if nothing could be done. */
+
+ static tree
+ maybe_fold_stmt_indirect (tree expr, tree base, tree offset)
+ {
+ tree t;
+ bool volatile_p = TREE_THIS_VOLATILE (expr);
+ location_t loc = EXPR_LOCATION (expr);
+
+ /* We may well have constructed a double-nested PLUS_EXPR via multiple
+ substitutions. Fold that down to one. Remove NON_LVALUE_EXPRs that
+ are sometimes added. */
+ base = fold (base);
+ STRIP_TYPE_NOPS (base);
+ TREE_OPERAND (expr, 0) = base;
+
+ /* One possibility is that the address reduces to a string constant. */
+ t = fold_read_from_constant_string (expr);
+ if (t)
+ return t;
+
+ /* Add in any offset from a POINTER_PLUS_EXPR. */
+ if (TREE_CODE (base) == POINTER_PLUS_EXPR)
+ {
+ tree offset2;
+
+ offset2 = TREE_OPERAND (base, 1);
+ if (TREE_CODE (offset2) != INTEGER_CST)
+ return NULL_TREE;
+ base = TREE_OPERAND (base, 0);
+
+ offset = fold_convert (sizetype,
+ int_const_binop (PLUS_EXPR, offset, offset2, 1));
+ }
+
+ if (TREE_CODE (base) == ADDR_EXPR)
+ {
+ tree base_addr = base;
+
+ /* Strip the ADDR_EXPR. */
+ base = TREE_OPERAND (base, 0);
+
+ /* Fold away CONST_DECL to its value, if the type is scalar. */
+ if (TREE_CODE (base) == CONST_DECL
+ && is_gimple_min_invariant (DECL_INITIAL (base)))
+ return DECL_INITIAL (base);
+
+ /* If there is no offset involved simply return the folded base. */
+ if (integer_zerop (offset))
+ return base;
+
+ /* Try folding *(&B+O) to B.X. */
+ t = maybe_fold_offset_to_reference (loc, base_addr, offset,
+ TREE_TYPE (expr));
+ if (t)
+ {
+ /* Preserve volatileness of the original expression.
+ We can end up with a plain decl here which is shared
+ and we shouldn't mess with its flags. */
+ if (!SSA_VAR_P (t))
+ TREE_THIS_VOLATILE (t) = volatile_p;
+ return t;
+ }
+ }
+ else
+ {
+ /* We can get here for out-of-range string constant accesses,
+ such as "_"[3]. Bail out of the entire substitution search
+ and arrange for the entire statement to be replaced by a
+ call to __builtin_trap. In all likelihood this will all be
+ constant-folded away, but in the meantime we can't leave with
+ something that get_expr_operands can't understand. */
+
+ t = base;
+ STRIP_NOPS (t);
+ if (TREE_CODE (t) == ADDR_EXPR
+ && TREE_CODE (TREE_OPERAND (t, 0)) == STRING_CST)
+ {
+ /* FIXME: Except that this causes problems elsewhere with dead
+ code not being deleted, and we die in the rtl expanders
+ because we failed to remove some ssa_name. In the meantime,
+ just return zero. */
+ /* FIXME2: This condition should be signaled by
+ fold_read_from_constant_string directly, rather than
+ re-checking for it here. */
+ return integer_zero_node;
+ }
+
+ /* Try folding *(B+O) to B->X. Still an improvement. */
+ if (POINTER_TYPE_P (TREE_TYPE (base)))
+ {
+ t = maybe_fold_offset_to_reference (loc, base, offset,
+ TREE_TYPE (expr));
+ if (t)
+ return t;
+ }
+ }
+
+ /* Otherwise we had an offset that we could not simplify. */
+ return NULL_TREE;
+ }
+
+
+ /* A quaint feature extant in our address arithmetic is that there
+ can be hidden type changes here. The type of the result need
+ not be the same as the type of the input pointer.
+
+ What we're after here is an expression of the form
+ (T *)(&array + const)
+ where array is OP0, const is OP1, RES_TYPE is T and
+ the cast doesn't actually exist, but is implicit in the
+ type of the POINTER_PLUS_EXPR. We'd like to turn this into
+ &array[x]
+ which may be able to propagate further. */
+
+ tree
+ maybe_fold_stmt_addition (location_t loc, tree res_type, tree op0, tree op1)
+ {
+ tree ptd_type;
+ tree t;
+
+ /* The first operand should be an ADDR_EXPR. */
+ if (TREE_CODE (op0) != ADDR_EXPR)
+ return NULL_TREE;
+ op0 = TREE_OPERAND (op0, 0);
+
+ /* It had better be a constant. */
+ if (TREE_CODE (op1) != INTEGER_CST)
+ {
+ /* Or op0 should now be A[0] and the non-constant offset defined
+ via a multiplication by the array element size. */
+ if (TREE_CODE (op0) == ARRAY_REF
+ && integer_zerop (TREE_OPERAND (op0, 1))
+ && TREE_CODE (op1) == SSA_NAME
+ && host_integerp (TYPE_SIZE_UNIT (TREE_TYPE (op0)), 1))
+ {
+ gimple offset_def = SSA_NAME_DEF_STMT (op1);
+ if (!is_gimple_assign (offset_def))
+ return NULL_TREE;
+
+ if (gimple_assign_rhs_code (offset_def) == MULT_EXPR
+ && TREE_CODE (gimple_assign_rhs2 (offset_def)) == INTEGER_CST
+ && tree_int_cst_equal (gimple_assign_rhs2 (offset_def),
+ TYPE_SIZE_UNIT (TREE_TYPE (op0))))
+ return build_fold_addr_expr
+ (build4 (ARRAY_REF, TREE_TYPE (op0),
+ TREE_OPERAND (op0, 0),
+ gimple_assign_rhs1 (offset_def),
+ TREE_OPERAND (op0, 2),
+ TREE_OPERAND (op0, 3)));
+ else if (integer_onep (TYPE_SIZE_UNIT (TREE_TYPE (op0)))
+ && gimple_assign_rhs_code (offset_def) != MULT_EXPR)
+ return build_fold_addr_expr
+ (build4 (ARRAY_REF, TREE_TYPE (op0),
+ TREE_OPERAND (op0, 0),
+ op1,
+ TREE_OPERAND (op0, 2),
+ TREE_OPERAND (op0, 3)));
+ }
+ return NULL_TREE;
+ }
+
+ /* If the first operand is an ARRAY_REF, expand it so that we can fold
+ the offset into it. */
+ while (TREE_CODE (op0) == ARRAY_REF)
+ {
+ tree array_obj = TREE_OPERAND (op0, 0);
+ tree array_idx = TREE_OPERAND (op0, 1);
+ tree elt_type = TREE_TYPE (op0);
+ tree elt_size = TYPE_SIZE_UNIT (elt_type);
+ tree min_idx;
+
+ if (TREE_CODE (array_idx) != INTEGER_CST)
+ break;
+ if (TREE_CODE (elt_size) != INTEGER_CST)
+ break;
+
+ /* Un-bias the index by the min index of the array type. */
+ min_idx = TYPE_DOMAIN (TREE_TYPE (array_obj));
+ if (min_idx)
+ {
+ min_idx = TYPE_MIN_VALUE (min_idx);
+ if (min_idx)
+ {
+ if (TREE_CODE (min_idx) != INTEGER_CST)
+ break;
+
+ array_idx = fold_convert (TREE_TYPE (min_idx), array_idx);
+ if (!integer_zerop (min_idx))
+ array_idx = int_const_binop (MINUS_EXPR, array_idx,
+ min_idx, 0);
+ }
+ }
+
+ /* Convert the index to a byte offset. */
+ array_idx = fold_convert (sizetype, array_idx);
+ array_idx = int_const_binop (MULT_EXPR, array_idx, elt_size, 0);
+
+ /* Update the operands for the next round, or for folding. */
+ op1 = int_const_binop (PLUS_EXPR,
+ array_idx, op1, 0);
+ op0 = array_obj;
+ }
+
+ ptd_type = TREE_TYPE (res_type);
+ /* If we want a pointer to void, reconstruct the reference from the
+ array element type. A pointer to that can be trivially converted
+ to void *. This happens as we fold (void *)(ptr p+ off). */
+ if (VOID_TYPE_P (ptd_type)
+ && TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE)
+ ptd_type = TREE_TYPE (TREE_TYPE (op0));
+
+ /* At which point we can try some of the same things as for indirects. */
+ t = maybe_fold_offset_to_array_ref (loc, op0, op1, ptd_type, true);
+ if (!t)
+ t = maybe_fold_offset_to_component_ref (loc, TREE_TYPE (op0), op0, op1,
+ ptd_type);
+ if (t)
+ {
+ t = build1 (ADDR_EXPR, res_type, t);
+ SET_EXPR_LOCATION (t, loc);
+ }
+
+ return t;
+ }
+
+ /* Subroutine of fold_stmt. We perform several simplifications of the
+ memory reference tree EXPR and make sure to re-gimplify them properly
+ after propagation of constant addresses. IS_LHS is true if the
+ reference is supposed to be an lvalue. */
+
+ static tree
+ maybe_fold_reference (tree expr, bool is_lhs)
+ {
+ tree *t = &expr;
+
+ if (TREE_CODE (expr) == ARRAY_REF
+ && !is_lhs)
+ {
+ tree tem = fold_read_from_constant_string (expr);
+ if (tem)
+ return tem;
+ }
+
+ /* ??? We might want to open-code the relevant remaining cases
+ to avoid using the generic fold. */
+ if (handled_component_p (*t)
+ && CONSTANT_CLASS_P (TREE_OPERAND (*t, 0)))
+ {
+ tree tem = fold (*t);
+ if (tem != *t)
+ return tem;
+ }
+
+ while (handled_component_p (*t))
+ t = &TREE_OPERAND (*t, 0);
+
+ if (TREE_CODE (*t) == INDIRECT_REF)
+ {
+ tree tem = maybe_fold_stmt_indirect (*t, TREE_OPERAND (*t, 0),
+ integer_zero_node);
+ /* Avoid folding *"abc" = 5 into 'a' = 5. */
+ if (is_lhs && tem && CONSTANT_CLASS_P (tem))
+ tem = NULL_TREE;
+ if (!tem
+ && TREE_CODE (TREE_OPERAND (*t, 0)) == ADDR_EXPR)
+ /* If we had a good reason for propagating the address here,
+ make sure we end up with valid gimple. See PR34989. */
+ tem = TREE_OPERAND (TREE_OPERAND (*t, 0), 0);
+
+ if (tem)
+ {
+ *t = tem;
+ tem = maybe_fold_reference (expr, is_lhs);
+ if (tem)
+ return tem;
+ return expr;
+ }
+ }
+ else if (!is_lhs
+ && DECL_P (*t))
+ {
+ tree tem = get_symbol_constant_value (*t);
+ if (tem
+ && useless_type_conversion_p (TREE_TYPE (*t), TREE_TYPE (tem)))
+ {
+ *t = unshare_expr (tem);
+ tem = maybe_fold_reference (expr, is_lhs);
+ if (tem)
+ return tem;
+ return expr;
+ }
+ }
+
+ return NULL_TREE;
+ }
+
+
+ /* Attempt to fold an assignment statement pointed-to by SI. Returns a
+ replacement rhs for the statement or NULL_TREE if no simplification
+ could be made. It is assumed that the operands have been previously
+ folded. */
+
+ static tree
+ fold_gimple_assign (gimple_stmt_iterator *si)
+ {
+ gimple stmt = gsi_stmt (*si);
+ enum tree_code subcode = gimple_assign_rhs_code (stmt);
+ location_t loc = gimple_location (stmt);
+
+ tree result = NULL_TREE;
+
+ switch (get_gimple_rhs_class (subcode))
+ {
+ case GIMPLE_SINGLE_RHS:
+ {
+ tree rhs = gimple_assign_rhs1 (stmt);
+
+ /* Try to fold a conditional expression. */
+ if (TREE_CODE (rhs) == COND_EXPR)
+ {
+ tree op0 = COND_EXPR_COND (rhs);
+ tree tem;
+ bool set = false;
+ location_t cond_loc = EXPR_LOCATION (rhs);
+
+ if (COMPARISON_CLASS_P (op0))
+ {
+ fold_defer_overflow_warnings ();
+ tem = fold_binary_loc (cond_loc,
+ TREE_CODE (op0), TREE_TYPE (op0),
+ TREE_OPERAND (op0, 0),
+ TREE_OPERAND (op0, 1));
+ /* This is actually a conditional expression, not a GIMPLE
+ conditional statement, however, the valid_gimple_rhs_p
+ test still applies. */
+ set = (tem && is_gimple_condexpr (tem)
+ && valid_gimple_rhs_p (tem));
+ fold_undefer_overflow_warnings (set, stmt, 0);
+ }
+ else if (is_gimple_min_invariant (op0))
+ {
+ tem = op0;
+ set = true;
+ }
+ else
+ return NULL_TREE;
+
+ if (set)
+ result = fold_build3_loc (cond_loc, COND_EXPR, TREE_TYPE (rhs), tem,
+ COND_EXPR_THEN (rhs), COND_EXPR_ELSE (rhs));
+ }
+
+ else if (TREE_CODE (rhs) == TARGET_MEM_REF)
+ return maybe_fold_tmr (rhs);
+
+ else if (REFERENCE_CLASS_P (rhs))
+ return maybe_fold_reference (rhs, false);
+
+ else if (TREE_CODE (rhs) == ADDR_EXPR)
+ {
+ tree tem = maybe_fold_reference (TREE_OPERAND (rhs, 0), true);
+ if (tem)
+ result = fold_convert (TREE_TYPE (rhs),
+ build_fold_addr_expr_loc (loc, tem));
+ }
+
+ else if (TREE_CODE (rhs) == CONSTRUCTOR
+ && TREE_CODE (TREE_TYPE (rhs)) == VECTOR_TYPE
+ && (CONSTRUCTOR_NELTS (rhs)
+ == TYPE_VECTOR_SUBPARTS (TREE_TYPE (rhs))))
+ {
+ /* Fold a constant vector CONSTRUCTOR to VECTOR_CST. */
+ unsigned i;
+ tree val;
+
+ FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (rhs), i, val)
+ if (TREE_CODE (val) != INTEGER_CST
+ && TREE_CODE (val) != REAL_CST
+ && TREE_CODE (val) != FIXED_CST)
+ return NULL_TREE;
+
+ return build_vector_from_ctor (TREE_TYPE (rhs),
+ CONSTRUCTOR_ELTS (rhs));
+ }
+
+ else if (DECL_P (rhs))
+ return unshare_expr (get_symbol_constant_value (rhs));
+
+ /* If we couldn't fold the RHS, hand over to the generic
+ fold routines. */
+ if (result == NULL_TREE)
+ result = fold (rhs);
+
+ /* Strip away useless type conversions. Both the NON_LVALUE_EXPR
+ that may have been added by fold, and "useless" type
+ conversions that might now be apparent due to propagation. */
+ STRIP_USELESS_TYPE_CONVERSION (result);
+
+ if (result != rhs && valid_gimple_rhs_p (result))
+ return result;
+
+ return NULL_TREE;
+ }
+ break;
+
+ case GIMPLE_UNARY_RHS:
+ {
+ tree rhs = gimple_assign_rhs1 (stmt);
+
+ result = fold_unary_loc (loc, subcode, gimple_expr_type (stmt), rhs);
+ if (result)
+ {
+ /* If the operation was a conversion do _not_ mark a
+ resulting constant with TREE_OVERFLOW if the original
+ constant was not. These conversions have implementation
+ defined behavior and retaining the TREE_OVERFLOW flag
+ here would confuse later passes such as VRP. */
+ if (CONVERT_EXPR_CODE_P (subcode)
+ && TREE_CODE (result) == INTEGER_CST
+ && TREE_CODE (rhs) == INTEGER_CST)
+ TREE_OVERFLOW (result) = TREE_OVERFLOW (rhs);
+
+ STRIP_USELESS_TYPE_CONVERSION (result);
+ if (valid_gimple_rhs_p (result))
+ return result;
+ }
+ else if (CONVERT_EXPR_CODE_P (subcode)
+ && POINTER_TYPE_P (gimple_expr_type (stmt))
+ && POINTER_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))
+ {
+ tree type = gimple_expr_type (stmt);
+ tree t = maybe_fold_offset_to_address (loc,
+ gimple_assign_rhs1 (stmt),
+ integer_zero_node, type);
+ if (t)
+ return t;
+ }
+ }
+ break;
+
+ case GIMPLE_BINARY_RHS:
+ /* Try to fold pointer addition. */
+ if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR)
+ {
+ tree type = TREE_TYPE (gimple_assign_rhs1 (stmt));
+ if (TREE_CODE (TREE_TYPE (type)) == ARRAY_TYPE)
+ {
+ type = build_pointer_type (TREE_TYPE (TREE_TYPE (type)));
+ if (!useless_type_conversion_p
+ (TREE_TYPE (gimple_assign_lhs (stmt)), type))
+ type = TREE_TYPE (gimple_assign_rhs1 (stmt));
+ }
+ result = maybe_fold_stmt_addition (gimple_location (stmt),
+ type,
+ gimple_assign_rhs1 (stmt),
+ gimple_assign_rhs2 (stmt));
+ }
+
+ if (!result)
+ result = fold_binary_loc (loc, subcode,
+ TREE_TYPE (gimple_assign_lhs (stmt)),
+ gimple_assign_rhs1 (stmt),
+ gimple_assign_rhs2 (stmt));
+
+ if (result)
+ {
+ STRIP_USELESS_TYPE_CONVERSION (result);
+ if (valid_gimple_rhs_p (result))
+ return result;
+
+ /* Fold might have produced non-GIMPLE, so if we trust it blindly
+ we lose canonicalization opportunities. Do not go again
+ through fold here though, or the same non-GIMPLE will be
+ produced. */
+ if (commutative_tree_code (subcode)
+ && tree_swap_operands_p (gimple_assign_rhs1 (stmt),
+ gimple_assign_rhs2 (stmt), false))
+ return build2 (subcode, TREE_TYPE (gimple_assign_lhs (stmt)),
+ gimple_assign_rhs2 (stmt),
+ gimple_assign_rhs1 (stmt));
+ }
+ break;
+
+ case GIMPLE_INVALID_RHS:
+ gcc_unreachable ();
+ }
+
+ return NULL_TREE;
+ }
+
+ /* Attempt to fold a conditional statement. Return true if any changes were
+ made. We only attempt to fold the condition expression, and do not perform
+ any transformation that would require alteration of the cfg. It is
+ assumed that the operands have been previously folded. */
+
+ static bool
+ fold_gimple_cond (gimple stmt)
+ {
+ tree result = fold_binary_loc (gimple_location (stmt),
+ gimple_cond_code (stmt),
+ boolean_type_node,
+ gimple_cond_lhs (stmt),
+ gimple_cond_rhs (stmt));
+
+ if (result)
+ {
+ STRIP_USELESS_TYPE_CONVERSION (result);
+ if (is_gimple_condexpr (result) && valid_gimple_rhs_p (result))
+ {
+ gimple_cond_set_condition_from_tree (stmt, result);
+ return true;
+ }
+ }
+
+ return false;
+ }
+
+ /* Convert EXPR into a GIMPLE value suitable for substitution on the
+ RHS of an assignment. Insert the necessary statements before
+ iterator *SI_P. The statement at *SI_P, which must be a GIMPLE_CALL
+ is replaced. If the call is expected to produces a result, then it
+ is replaced by an assignment of the new RHS to the result variable.
+ If the result is to be ignored, then the call is replaced by a
+ GIMPLE_NOP. */
+
+ void
+ gimplify_and_update_call_from_tree (gimple_stmt_iterator *si_p, tree expr)
+ {
+ tree lhs;
+ tree tmp = NULL_TREE; /* Silence warning. */
+ gimple stmt, new_stmt;
+ gimple_stmt_iterator i;
+ gimple_seq stmts = gimple_seq_alloc();
+ struct gimplify_ctx gctx;
+ gimple last = NULL;
+
+ stmt = gsi_stmt (*si_p);
+
+ gcc_assert (is_gimple_call (stmt));
+
+ lhs = gimple_call_lhs (stmt);
+
+ push_gimplify_context (&gctx);
+
+ if (lhs == NULL_TREE)
+ gimplify_and_add (expr, &stmts);
+ else
+ tmp = get_initialized_tmp_var (expr, &stmts, NULL);
+
+ pop_gimplify_context (NULL);
+
+ if (gimple_has_location (stmt))
+ annotate_all_with_location (stmts, gimple_location (stmt));
+
+ /* The replacement can expose previously unreferenced variables. */
+ for (i = gsi_start (stmts); !gsi_end_p (i); gsi_next (&i))
+ {
+ if (last)
+ {
+ gsi_insert_before (si_p, last, GSI_NEW_STMT);
+ gsi_next (si_p);
+ }
+ new_stmt = gsi_stmt (i);
+ find_new_referenced_vars (new_stmt);
+ mark_symbols_for_renaming (new_stmt);
+ last = new_stmt;
+ }
+
+ if (lhs == NULL_TREE)
+ {
+ unlink_stmt_vdef (stmt);
+ release_defs (stmt);
+ new_stmt = last;
+ }
+ else
+ {
+ if (last)
+ {
+ gsi_insert_before (si_p, last, GSI_NEW_STMT);
+ gsi_next (si_p);
+ }
+ new_stmt = gimple_build_assign (lhs, tmp);
+ gimple_set_vuse (new_stmt, gimple_vuse (stmt));
+ gimple_set_vdef (new_stmt, gimple_vdef (stmt));
+ move_ssa_defining_stmt_for_defs (new_stmt, stmt);
+ }
+
+ gimple_set_location (new_stmt, gimple_location (stmt));
+ gsi_replace (si_p, new_stmt, false);
+ }
+
+ /* Return the string length, maximum string length or maximum value of
+ ARG in LENGTH.
+ If ARG is an SSA name variable, follow its use-def chains. If LENGTH
+ is not NULL and, for TYPE == 0, its value is not equal to the length
+ we determine or if we are unable to determine the length or value,
+ return false. VISITED is a bitmap of visited variables.
+ TYPE is 0 if string length should be returned, 1 for maximum string
+ length and 2 for maximum value ARG can have. */
+
+ static bool
+ get_maxval_strlen (tree arg, tree *length, bitmap visited, int type)
+ {
+ tree var, val;
+ gimple def_stmt;
+
+ if (TREE_CODE (arg) != SSA_NAME)
+ {
+ if (TREE_CODE (arg) == COND_EXPR)
+ return get_maxval_strlen (COND_EXPR_THEN (arg), length, visited, type)
+ && get_maxval_strlen (COND_EXPR_ELSE (arg), length, visited, type);
+ /* We can end up with &(*iftmp_1)[0] here as well, so handle it. */
+ else if (TREE_CODE (arg) == ADDR_EXPR
+ && TREE_CODE (TREE_OPERAND (arg, 0)) == ARRAY_REF
+ && integer_zerop (TREE_OPERAND (TREE_OPERAND (arg, 0), 1)))
+ {
+ tree aop0 = TREE_OPERAND (TREE_OPERAND (arg, 0), 0);
+ if (TREE_CODE (aop0) == INDIRECT_REF
+ && TREE_CODE (TREE_OPERAND (aop0, 0)) == SSA_NAME)
+ return get_maxval_strlen (TREE_OPERAND (aop0, 0),
+ length, visited, type);
+ }
+
+ if (type == 2)
+ {
+ val = arg;
+ if (TREE_CODE (val) != INTEGER_CST
+ || tree_int_cst_sgn (val) < 0)
+ return false;
+ }
+ else
+ val = c_strlen (arg, 1);
+ if (!val)
+ return false;
+
+ if (*length)
+ {
+ if (type > 0)
+ {
+ if (TREE_CODE (*length) != INTEGER_CST
+ || TREE_CODE (val) != INTEGER_CST)
+ return false;
+
+ if (tree_int_cst_lt (*length, val))
+ *length = val;
+ return true;
+ }
+ else if (simple_cst_equal (val, *length) != 1)
+ return false;
+ }
+
+ *length = val;
+ return true;
+ }
+
+ /* If we were already here, break the infinite cycle. */
+ if (bitmap_bit_p (visited, SSA_NAME_VERSION (arg)))
+ return true;
+ bitmap_set_bit (visited, SSA_NAME_VERSION (arg));
+
+ var = arg;
+ def_stmt = SSA_NAME_DEF_STMT (var);
+
+ switch (gimple_code (def_stmt))
+ {
+ case GIMPLE_ASSIGN:
+ /* The RHS of the statement defining VAR must either have a
+ constant length or come from another SSA_NAME with a constant
+ length. */
+ if (gimple_assign_single_p (def_stmt)
+ || gimple_assign_unary_nop_p (def_stmt))
+ {
+ tree rhs = gimple_assign_rhs1 (def_stmt);
+ return get_maxval_strlen (rhs, length, visited, type);
+ }
+ return false;
+
+ case GIMPLE_PHI:
+ {
+ /* All the arguments of the PHI node must have the same constant
+ length. */
+ unsigned i;
+
+ for (i = 0; i < gimple_phi_num_args (def_stmt); i++)
+ {
+ tree arg = gimple_phi_arg (def_stmt, i)->def;
+
+ /* If this PHI has itself as an argument, we cannot
+ determine the string length of this argument. However,
+ if we can find a constant string length for the other
+ PHI args then we can still be sure that this is a
+ constant string length. So be optimistic and just
+ continue with the next argument. */
+ if (arg == gimple_phi_result (def_stmt))
+ continue;
+
+ if (!get_maxval_strlen (arg, length, visited, type))
+ return false;
+ }
+ }
+ return true;
+
+ default:
+ return false;
+ }
+ }
+
+
+ /* Fold builtin call in statement STMT. Returns a simplified tree.
+ We may return a non-constant expression, including another call
+ to a different function and with different arguments, e.g.,
+ substituting memcpy for strcpy when the string length is known.
+ Note that some builtins expand into inline code that may not
+ be valid in GIMPLE. Callers must take care. */
+
+ tree
+ gimple_fold_builtin (gimple stmt)
+ {
+ tree result, val[3];
+ tree callee, a;
+ int arg_idx, type;
+ bitmap visited;
+ bool ignore;
+ int nargs;
+ location_t loc = gimple_location (stmt);
+
+ gcc_assert (is_gimple_call (stmt));
+
+ ignore = (gimple_call_lhs (stmt) == NULL);
+
+ /* First try the generic builtin folder. If that succeeds, return the
+ result directly. */
+ result = fold_call_stmt (stmt, ignore);
+ if (result)
+ {
+ if (ignore)
+ STRIP_NOPS (result);
+ return result;
+ }
+
+ /* Ignore MD builtins. */
+ callee = gimple_call_fndecl (stmt);
+ if (DECL_BUILT_IN_CLASS (callee) == BUILT_IN_MD)
+ return NULL_TREE;
+
+ /* If the builtin could not be folded, and it has no argument list,
+ we're done. */
+ nargs = gimple_call_num_args (stmt);
+ if (nargs == 0)
+ return NULL_TREE;
+
+ /* Limit the work only for builtins we know how to simplify. */
+ switch (DECL_FUNCTION_CODE (callee))
+ {
+ case BUILT_IN_STRLEN:
+ case BUILT_IN_FPUTS:
+ case BUILT_IN_FPUTS_UNLOCKED:
+ arg_idx = 0;
+ type = 0;
+ break;
+ case BUILT_IN_STRCPY:
+ case BUILT_IN_STRNCPY:
+ arg_idx = 1;
+ type = 0;
+ break;
+ case BUILT_IN_MEMCPY_CHK:
+ case BUILT_IN_MEMPCPY_CHK:
+ case BUILT_IN_MEMMOVE_CHK:
+ case BUILT_IN_MEMSET_CHK:
+ case BUILT_IN_STRNCPY_CHK:
+ arg_idx = 2;
+ type = 2;
+ break;
+ case BUILT_IN_STRCPY_CHK:
+ case BUILT_IN_STPCPY_CHK:
+ arg_idx = 1;
+ type = 1;
+ break;
+ case BUILT_IN_SNPRINTF_CHK:
+ case BUILT_IN_VSNPRINTF_CHK:
+ arg_idx = 1;
+ type = 2;
+ break;
+ default:
+ return NULL_TREE;
+ }
+
+ if (arg_idx >= nargs)
+ return NULL_TREE;
+
+ /* Try to use the dataflow information gathered by the CCP process. */
+ visited = BITMAP_ALLOC (NULL);
+ bitmap_clear (visited);
+
+ memset (val, 0, sizeof (val));
+ a = gimple_call_arg (stmt, arg_idx);
+ if (!get_maxval_strlen (a, &val[arg_idx], visited, type))
+ val[arg_idx] = NULL_TREE;
+
+ BITMAP_FREE (visited);
+
+ result = NULL_TREE;
+ switch (DECL_FUNCTION_CODE (callee))
+ {
+ case BUILT_IN_STRLEN:
+ if (val[0] && nargs == 1)
+ {
+ tree new_val =
+ fold_convert (TREE_TYPE (gimple_call_lhs (stmt)), val[0]);
+
+ /* If the result is not a valid gimple value, or not a cast
+ of a valid gimple value, then we can not use the result. */
+ if (is_gimple_val (new_val)
+ || (is_gimple_cast (new_val)
+ && is_gimple_val (TREE_OPERAND (new_val, 0))))
+ return new_val;
+ }
+ break;
+
+ case BUILT_IN_STRCPY:
+ if (val[1] && is_gimple_val (val[1]) && nargs == 2)
+ result = fold_builtin_strcpy (loc, callee,
+ gimple_call_arg (stmt, 0),
+ gimple_call_arg (stmt, 1),
+ val[1]);
+ break;
+
+ case BUILT_IN_STRNCPY:
+ if (val[1] && is_gimple_val (val[1]) && nargs == 3)
+ result = fold_builtin_strncpy (loc, callee,
+ gimple_call_arg (stmt, 0),
+ gimple_call_arg (stmt, 1),
+ gimple_call_arg (stmt, 2),
+ val[1]);
+ break;
+
+ case BUILT_IN_FPUTS:
+ if (nargs == 2)
+ result = fold_builtin_fputs (loc, gimple_call_arg (stmt, 0),
+ gimple_call_arg (stmt, 1),
+ ignore, false, val[0]);
+ break;
+
+ case BUILT_IN_FPUTS_UNLOCKED:
+ if (nargs == 2)
+ result = fold_builtin_fputs (loc, gimple_call_arg (stmt, 0),
+ gimple_call_arg (stmt, 1),
+ ignore, true, val[0]);
+ break;
+
+ case BUILT_IN_MEMCPY_CHK:
+ case BUILT_IN_MEMPCPY_CHK:
+ case BUILT_IN_MEMMOVE_CHK:
+ case BUILT_IN_MEMSET_CHK:
+ if (val[2] && is_gimple_val (val[2]) && nargs == 4)
+ result = fold_builtin_memory_chk (loc, callee,
+ gimple_call_arg (stmt, 0),
+ gimple_call_arg (stmt, 1),
+ gimple_call_arg (stmt, 2),
+ gimple_call_arg (stmt, 3),
+ val[2], ignore,
+ DECL_FUNCTION_CODE (callee));
+ break;
+
+ case BUILT_IN_STRCPY_CHK:
+ case BUILT_IN_STPCPY_CHK:
+ if (val[1] && is_gimple_val (val[1]) && nargs == 3)
+ result = fold_builtin_stxcpy_chk (loc, callee,
+ gimple_call_arg (stmt, 0),
+ gimple_call_arg (stmt, 1),
+ gimple_call_arg (stmt, 2),
+ val[1], ignore,
+ DECL_FUNCTION_CODE (callee));
+ break;
+
+ case BUILT_IN_STRNCPY_CHK:
+ if (val[2] && is_gimple_val (val[2]) && nargs == 4)
+ result = fold_builtin_strncpy_chk (loc, gimple_call_arg (stmt, 0),
+ gimple_call_arg (stmt, 1),
+ gimple_call_arg (stmt, 2),
+ gimple_call_arg (stmt, 3),
+ val[2]);
+ break;
+
+ case BUILT_IN_SNPRINTF_CHK:
+ case BUILT_IN_VSNPRINTF_CHK:
+ if (val[1] && is_gimple_val (val[1]))
+ result = gimple_fold_builtin_snprintf_chk (stmt, val[1],
+ DECL_FUNCTION_CODE (callee));
+ break;
+
+ default:
+ gcc_unreachable ();
+ }
+
+ if (result && ignore)
+ result = fold_ignored_result (result);
+ return result;
+ }
+
+ /* Attempt to fold a call statement referenced by the statement iterator GSI.
+ The statement may be replaced by another statement, e.g., if the call
+ simplifies to a constant value. Return true if any changes were made.
+ It is assumed that the operands have been previously folded. */
+
+ static bool
+ fold_gimple_call (gimple_stmt_iterator *gsi)
+ {
+ gimple stmt = gsi_stmt (*gsi);
+
+ tree callee = gimple_call_fndecl (stmt);
+
+ /* Check for builtins that CCP can handle using information not
+ available in the generic fold routines. */
+ if (callee && DECL_BUILT_IN (callee))
+ {
+ tree result = gimple_fold_builtin (stmt);
+
+ if (result)
+ {
+ if (!update_call_from_tree (gsi, result))
+ gimplify_and_update_call_from_tree (gsi, result);
+ return true;
+ }
+ }
+ else
+ {
+ /* Check for resolvable OBJ_TYPE_REF. The only sorts we can resolve
+ here are when we've propagated the address of a decl into the
+ object slot. */
+ /* ??? Should perhaps do this in fold proper. However, doing it
+ there requires that we create a new CALL_EXPR, and that requires
+ copying EH region info to the new node. Easier to just do it
+ here where we can just smash the call operand. */
+ /* ??? Is there a good reason not to do this in fold_stmt_inplace? */
+ callee = gimple_call_fn (stmt);
+ if (TREE_CODE (callee) == OBJ_TYPE_REF
+ && lang_hooks.fold_obj_type_ref
+ && TREE_CODE (OBJ_TYPE_REF_OBJECT (callee)) == ADDR_EXPR
+ && DECL_P (TREE_OPERAND
+ (OBJ_TYPE_REF_OBJECT (callee), 0)))
+ {
+ tree t;
+
+ /* ??? Caution: Broken ADDR_EXPR semantics means that
+ looking at the type of the operand of the addr_expr
+ can yield an array type. See silly exception in
+ check_pointer_types_r. */
+ t = TREE_TYPE (TREE_TYPE (OBJ_TYPE_REF_OBJECT (callee)));
+ t = lang_hooks.fold_obj_type_ref (callee, t);
+ if (t)
+ {
+ gimple_call_set_fn (stmt, t);
+ return true;
+ }
+ }
+ }
+
+ return false;
+ }
+
+ /* Worker for both fold_stmt and fold_stmt_inplace. The INPLACE argument
+ distinguishes both cases. */
+
+ static bool
+ fold_stmt_1 (gimple_stmt_iterator *gsi, bool inplace)
+ {
+ bool changed = false;
+ gimple stmt = gsi_stmt (*gsi);
+ unsigned i;
+
+ /* Fold the main computation performed by the statement. */
+ switch (gimple_code (stmt))
+ {
+ case GIMPLE_ASSIGN:
+ {
+ unsigned old_num_ops = gimple_num_ops (stmt);
+ tree new_rhs = fold_gimple_assign (gsi);
+ tree lhs = gimple_assign_lhs (stmt);
+ if (new_rhs
+ && !useless_type_conversion_p (TREE_TYPE (lhs),
+ TREE_TYPE (new_rhs)))
+ new_rhs = fold_convert (TREE_TYPE (lhs), new_rhs);
+ if (new_rhs
+ && (!inplace
+ || get_gimple_rhs_num_ops (TREE_CODE (new_rhs)) < old_num_ops))
+ {
+ gimple_assign_set_rhs_from_tree (gsi, new_rhs);
+ changed = true;
+ }
+ break;
+ }
+
+ case GIMPLE_COND:
+ changed |= fold_gimple_cond (stmt);
+ break;
+
+ case GIMPLE_CALL:
+ /* Fold *& in call arguments. */
+ for (i = 0; i < gimple_call_num_args (stmt); ++i)
+ if (REFERENCE_CLASS_P (gimple_call_arg (stmt, i)))
+ {
+ tree tmp = maybe_fold_reference (gimple_call_arg (stmt, i), false);
+ if (tmp)
+ {
+ gimple_call_set_arg (stmt, i, tmp);
+ changed = true;
+ }
+ }
+ /* The entire statement may be replaced in this case. */
+ if (!inplace)
+ changed |= fold_gimple_call (gsi);
+ break;
+
+ case GIMPLE_ASM:
+ /* Fold *& in asm operands. */
+ for (i = 0; i < gimple_asm_noutputs (stmt); ++i)
+ {
+ tree link = gimple_asm_output_op (stmt, i);
+ tree op = TREE_VALUE (link);
+ if (REFERENCE_CLASS_P (op)
+ && (op = maybe_fold_reference (op, true)) != NULL_TREE)
+ {
+ TREE_VALUE (link) = op;
+ changed = true;
+ }
+ }
+ for (i = 0; i < gimple_asm_ninputs (stmt); ++i)
+ {
+ tree link = gimple_asm_input_op (stmt, i);
+ tree op = TREE_VALUE (link);
+ if (REFERENCE_CLASS_P (op)
+ && (op = maybe_fold_reference (op, false)) != NULL_TREE)
+ {
+ TREE_VALUE (link) = op;
+ changed = true;
+ }
+ }
+ break;
+
+ default:;
+ }
+
+ stmt = gsi_stmt (*gsi);
+
+ /* Fold *& on the lhs. */
+ if (gimple_has_lhs (stmt))
+ {
+ tree lhs = gimple_get_lhs (stmt);
+ if (lhs && REFERENCE_CLASS_P (lhs))
+ {
+ tree new_lhs = maybe_fold_reference (lhs, true);
+ if (new_lhs)
+ {
+ gimple_set_lhs (stmt, new_lhs);
+ changed = true;
+ }
+ }
+ }
+
+ return changed;
+ }
+
+ /* Fold the statement pointed to by GSI. In some cases, this function may
+ replace the whole statement with a new one. Returns true iff folding
+ makes any changes.
+ The statement pointed to by GSI should be in valid gimple form but may
+ be in unfolded state as resulting from for example constant propagation
+ which can produce *&x = 0. */
+
+ bool
+ fold_stmt (gimple_stmt_iterator *gsi)
+ {
+ return fold_stmt_1 (gsi, false);
+ }
+
+ /* Perform the minimal folding on statement STMT. Only operations like
+ *&x created by constant propagation are handled. The statement cannot
+ be replaced with a new one. Return true if the statement was
+ changed, false otherwise.
+ The statement STMT should be in valid gimple form but may
+ be in unfolded state as resulting from for example constant propagation
+ which can produce *&x = 0. */
+
+ bool
+ fold_stmt_inplace (gimple stmt)
+ {
+ gimple_stmt_iterator gsi = gsi_for_stmt (stmt);
+ bool changed = fold_stmt_1 (&gsi, true);
+ gcc_assert (gsi_stmt (gsi) == stmt);
+ return changed;
+ }
+
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