/* Forward propagation of expressions for single use variables.
- Copyright (C) 2004, 2005 Free Software Foundation, Inc.
+ Copyright (C) 2004, 2005, 2007, 2008 Free Software Foundation, Inc.
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
-the Free Software Foundation; either version 2, or (at your option)
+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,
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
-along with GCC; see the file COPYING. If not, write to
-the Free Software Foundation, 51 Franklin Street, Fifth Floor,
-Boston, MA 02110-1301, USA. */
+along with GCC; see the file COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
#include "config.h"
#include "system.h"
static bool cfg_changed;
-/* Get the next statement we can propagate NAMEs value into skipping
+/* Get the next statement we can propagate NAME's value into skipping
trivial copies. Returns the statement that is suitable as a
propagation destination or NULL_TREE if there is no such one.
This only returns destinations in a single-use chain. FINAL_NAME_P
/* If name is not a simple copy destination, we found it. */
if (TREE_CODE (GIMPLE_STMT_OPERAND (def_stmt, 1)) != SSA_NAME)
{
+ tree rhs;
+
if (!single_use_only && single_use_p)
*single_use_p = single_use;
- return def_stmt;
+ /* We can look through pointer conversions in the search
+ for a useful stmt for the comparison folding. */
+ rhs = GIMPLE_STMT_OPERAND (def_stmt, 1);
+ if ((TREE_CODE (rhs) == NOP_EXPR
+ || TREE_CODE (rhs) == CONVERT_EXPR)
+ && TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME
+ && POINTER_TYPE_P (TREE_TYPE (rhs))
+ && POINTER_TYPE_P (TREE_TYPE (TREE_OPERAND (rhs, 0))))
+ name = TREE_OPERAND (rhs, 0);
+ else
+ return def_stmt;
+ }
+ else
+ {
+ /* Continue searching the def of the copy source name. */
+ name = GIMPLE_STMT_OPERAND (def_stmt, 1);
}
-
- /* Continue searching the def of the copy source name. */
- name = GIMPLE_STMT_OPERAND (def_stmt, 1);
} while (1);
}
{
tree rhs = GIMPLE_STMT_OPERAND (def_stmt, 1);
+ /* If the rhs has side-effects we cannot propagate from it. */
+ if (TREE_SIDE_EFFECTS (rhs))
+ return false;
+
+ /* If the rhs is a load we cannot propagate from it. */
+ if (REFERENCE_CLASS_P (rhs))
+ return false;
+
+ /* Constants can be always propagated. */
+ if (is_gimple_min_invariant (rhs))
+ return true;
+
/* We cannot propagate ssa names that occur in abnormal phi nodes. */
switch (TREE_CODE_LENGTH (TREE_CODE (rhs)))
{
/* Require that we got a boolean type out if we put one in. */
gcc_assert (TREE_CODE (TREE_TYPE (t)) == TREE_CODE (type));
- /* For (bool)x use x != 0. */
- if (TREE_CODE (t) == NOP_EXPR
- && TREE_TYPE (t) == boolean_type_node)
- {
- tree top0 = TREE_OPERAND (t, 0);
- t = build2 (NE_EXPR, type,
- top0, build_int_cst (TREE_TYPE (top0), 0));
- }
- /* For !x use x == 0. */
- else if (TREE_CODE (t) == TRUTH_NOT_EXPR)
- {
- tree top0 = TREE_OPERAND (t, 0);
- t = build2 (EQ_EXPR, type,
- top0, build_int_cst (TREE_TYPE (top0), 0));
- }
- /* For cmp ? 1 : 0 use cmp. */
- else if (TREE_CODE (t) == COND_EXPR
- && COMPARISON_CLASS_P (TREE_OPERAND (t, 0))
- && integer_onep (TREE_OPERAND (t, 1))
- && integer_zerop (TREE_OPERAND (t, 2)))
- {
- tree top0 = TREE_OPERAND (t, 0);
- t = build2 (TREE_CODE (top0), type,
- TREE_OPERAND (top0, 0), TREE_OPERAND (top0, 1));
- }
+ /* Canonicalize the combined condition for use in a COND_EXPR. */
+ t = canonicalize_cond_expr_cond (t);
/* Bail out if we required an invariant but didn't get one. */
- if (invariant_only
- && !is_gimple_min_invariant (t))
+ if (!t
+ || (invariant_only
+ && !is_gimple_min_invariant (t)))
return NULL_TREE;
- /* A valid conditional for a COND_EXPR is either a gimple value
- or a comparison with two gimple value operands. */
- if (is_gimple_val (t)
- || (COMPARISON_CLASS_P (t)
- && is_gimple_val (TREE_OPERAND (t, 0))
- && is_gimple_val (TREE_OPERAND (t, 1))))
- return t;
-
- return NULL_TREE;
+ return t;
}
/* Propagate from the ssa name definition statements of COND_EXPR
- in statement STMT into the conditional if that simplifies it. */
+ in statement STMT into the conditional if that simplifies it.
+ Returns zero if no statement was changed, one if there were
+ changes and two if cfg_cleanup needs to run. */
-static void
+static int
forward_propagate_into_cond (tree cond_expr, tree stmt)
{
+ int did_something = 0;
+
do {
tree tmp = NULL_TREE;
tree cond = COND_EXPR_COND (cond_expr);
- tree name, def_stmt, rhs;
- bool single_use_p;
+ tree name, def_stmt, rhs0 = NULL_TREE, rhs1 = NULL_TREE;
+ bool single_use0_p = false, single_use1_p = false;
/* We can do tree combining on SSA_NAME and comparison expressions. */
if (COMPARISON_CLASS_P (cond)
/* For comparisons use the first operand, that is likely to
simplify comparisons against constants. */
name = TREE_OPERAND (cond, 0);
- def_stmt = get_prop_source_stmt (name, false, &single_use_p);
+ def_stmt = get_prop_source_stmt (name, false, &single_use0_p);
if (def_stmt != NULL_TREE
&& can_propagate_from (def_stmt))
{
tree op1 = TREE_OPERAND (cond, 1);
- rhs = GIMPLE_STMT_OPERAND (def_stmt, 1);
+ rhs0 = GIMPLE_STMT_OPERAND (def_stmt, 1);
tmp = combine_cond_expr_cond (TREE_CODE (cond), boolean_type_node,
- fold_convert (TREE_TYPE (op1), rhs),
- op1, !single_use_p);
+ fold_convert (TREE_TYPE (op1), rhs0),
+ op1, !single_use0_p);
}
/* If that wasn't successful, try the second operand. */
if (tmp == NULL_TREE
{
tree op0 = TREE_OPERAND (cond, 0);
name = TREE_OPERAND (cond, 1);
- def_stmt = get_prop_source_stmt (name, false, &single_use_p);
+ def_stmt = get_prop_source_stmt (name, false, &single_use1_p);
if (def_stmt == NULL_TREE
|| !can_propagate_from (def_stmt))
- return;
+ return did_something;
- rhs = GIMPLE_STMT_OPERAND (def_stmt, 1);
+ rhs1 = GIMPLE_STMT_OPERAND (def_stmt, 1);
tmp = combine_cond_expr_cond (TREE_CODE (cond), boolean_type_node,
op0,
- fold_convert (TREE_TYPE (op0), rhs),
- !single_use_p);
+ fold_convert (TREE_TYPE (op0), rhs1),
+ !single_use1_p);
}
+ /* If that wasn't successful either, try both operands. */
+ if (tmp == NULL_TREE
+ && rhs0 != NULL_TREE
+ && rhs1 != NULL_TREE)
+ tmp = combine_cond_expr_cond (TREE_CODE (cond), boolean_type_node,
+ rhs0,
+ fold_convert (TREE_TYPE (rhs0), rhs1),
+ !(single_use0_p && single_use1_p));
}
else if (TREE_CODE (cond) == SSA_NAME)
{
def_stmt = get_prop_source_stmt (name, true, NULL);
if (def_stmt == NULL_TREE
|| !can_propagate_from (def_stmt))
- return;
+ return did_something;
- rhs = GIMPLE_STMT_OPERAND (def_stmt, 1);
- tmp = combine_cond_expr_cond (NE_EXPR, boolean_type_node, rhs,
- build_int_cst (TREE_TYPE (rhs), 0),
+ rhs0 = GIMPLE_STMT_OPERAND (def_stmt, 1);
+ tmp = combine_cond_expr_cond (NE_EXPR, boolean_type_node, rhs0,
+ build_int_cst (TREE_TYPE (rhs0), 0),
false);
}
/* Remove defining statements. */
remove_prop_source_from_use (name, NULL);
+ if (is_gimple_min_invariant (tmp))
+ did_something = 2;
+ else if (did_something == 0)
+ did_something = 1;
+
/* Continue combining. */
continue;
}
break;
} while (1);
+
+ return did_something;
}
/* We've just substituted an ADDR_EXPR into stmt. Update all the
mark_symbols_for_renaming (stmt);
}
-/* DEF_RHS defines LHS which is contains the address of the 0th element
- in an array. USE_STMT uses LHS to compute the address of an
+/* DEF_RHS contains the address of the 0th element in an array.
+ USE_STMT uses type of DEF_RHS to compute the address of an
arbitrary element within the array. The (variable) byte offset
of the element is contained in OFFSET.
with the new address computation. */
static bool
-forward_propagate_addr_into_variable_array_index (tree offset, tree lhs,
+forward_propagate_addr_into_variable_array_index (tree offset,
tree def_rhs, tree use_stmt)
{
tree index;
- /* The offset must be defined by a simple GIMPLE_MODIFY_STMT statement. */
- if (TREE_CODE (offset) != GIMPLE_MODIFY_STMT)
- return false;
-
- /* The RHS of the statement which defines OFFSET must be a gimple
- cast of another SSA_NAME. */
- offset = GIMPLE_STMT_OPERAND (offset, 1);
- if (!is_gimple_cast (offset))
- return false;
-
- offset = TREE_OPERAND (offset, 0);
- if (TREE_CODE (offset) != SSA_NAME)
- return false;
-
- /* Get the defining statement of the offset before type
- conversion. */
- offset = SSA_NAME_DEF_STMT (offset);
+ /* Try to find an expression for a proper index. This is either
+ a multiplication expression by the element size or just the
+ ssa name we came along in case the element size is one. */
+ if (integer_onep (TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (def_rhs)))))
+ index = offset;
+ else
+ {
+ /* Get the offset's defining statement. */
+ offset = SSA_NAME_DEF_STMT (offset);
- /* The statement which defines OFFSET before type conversion
- must be a simple GIMPLE_MODIFY_STMT. */
- if (TREE_CODE (offset) != GIMPLE_MODIFY_STMT)
- return false;
+ /* The statement which defines OFFSET before type conversion
+ must be a simple GIMPLE_MODIFY_STMT. */
+ if (TREE_CODE (offset) != GIMPLE_MODIFY_STMT)
+ return false;
- /* The RHS of the statement which defines OFFSET must be a
- multiplication of an object by the size of the array elements.
- This implicitly verifies that the size of the array elements
- is constant. */
- offset = GIMPLE_STMT_OPERAND (offset, 1);
- if (TREE_CODE (offset) != MULT_EXPR
- || TREE_CODE (TREE_OPERAND (offset, 1)) != INTEGER_CST
- || !simple_cst_equal (TREE_OPERAND (offset, 1),
- TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (lhs)))))
- return false;
+ /* The RHS of the statement which defines OFFSET must be a
+ multiplication of an object by the size of the array elements.
+ This implicitly verifies that the size of the array elements
+ is constant. */
+ offset = GIMPLE_STMT_OPERAND (offset, 1);
+ if (TREE_CODE (offset) != MULT_EXPR
+ || TREE_CODE (TREE_OPERAND (offset, 1)) != INTEGER_CST
+ || !simple_cst_equal (TREE_OPERAND (offset, 1),
+ TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (def_rhs)))))
+ return false;
- /* The first operand to the MULT_EXPR is the desired index. */
- index = TREE_OPERAND (offset, 0);
+ /* The first operand to the MULT_EXPR is the desired index. */
+ index = TREE_OPERAND (offset, 0);
+ }
/* Replace the pointer addition with array indexing. */
GIMPLE_STMT_OPERAND (use_stmt, 1) = unshare_expr (def_rhs);
be not totally successful, yet things may have been changed). */
static bool
-forward_propagate_addr_expr_1 (tree name, tree def_rhs, tree use_stmt)
+forward_propagate_addr_expr_1 (tree name, tree def_rhs, tree use_stmt,
+ bool single_use_p)
{
tree lhs, rhs, array_ref;
+ tree *rhsp, *lhsp;
- /* Strip away any outer COMPONENT_REF/ARRAY_REF nodes from the LHS.
- ADDR_EXPR will not appear on the LHS. */
- lhs = GIMPLE_STMT_OPERAND (use_stmt, 0);
- while (handled_component_p (lhs))
- lhs = TREE_OPERAND (lhs, 0);
+ gcc_assert (TREE_CODE (def_rhs) == ADDR_EXPR);
+ lhs = GIMPLE_STMT_OPERAND (use_stmt, 0);
rhs = GIMPLE_STMT_OPERAND (use_stmt, 1);
+ /* Trivial cases. The use statement could be a trivial copy or a
+ useless conversion. Recurse to the uses of the lhs as copyprop does
+ not copy through different variant pointers and FRE does not catch
+ all useless conversions. Treat the case of a single-use name and
+ a conversion to def_rhs type separate, though. */
+ if (TREE_CODE (lhs) == SSA_NAME
+ && (rhs == name
+ || TREE_CODE (rhs) == NOP_EXPR
+ || TREE_CODE (rhs) == CONVERT_EXPR)
+ && useless_type_conversion_p (TREE_TYPE (rhs), TREE_TYPE (def_rhs)))
+ {
+ /* Only recurse if we don't deal with a single use. */
+ if (!single_use_p)
+ return forward_propagate_addr_expr (lhs, def_rhs);
+
+ GIMPLE_STMT_OPERAND (use_stmt, 1) = unshare_expr (def_rhs);
+ return true;
+ }
+
+ /* Now strip away any outer COMPONENT_REF/ARRAY_REF nodes from the LHS.
+ ADDR_EXPR will not appear on the LHS. */
+ lhsp = &GIMPLE_STMT_OPERAND (use_stmt, 0);
+ while (handled_component_p (*lhsp))
+ lhsp = &TREE_OPERAND (*lhsp, 0);
+ lhs = *lhsp;
+
/* Now see if the LHS node is an INDIRECT_REF using NAME. If so,
propagate the ADDR_EXPR into the use of NAME and fold the result. */
- if (TREE_CODE (lhs) == INDIRECT_REF && TREE_OPERAND (lhs, 0) == name)
+ if (TREE_CODE (lhs) == INDIRECT_REF
+ && TREE_OPERAND (lhs, 0) == name
+ && useless_type_conversion_p (TREE_TYPE (TREE_OPERAND (lhs, 0)),
+ TREE_TYPE (def_rhs))
+ /* ??? This looks redundant, but is required for bogus types
+ that can sometimes occur. */
+ && useless_type_conversion_p (TREE_TYPE (lhs),
+ TREE_TYPE (TREE_OPERAND (def_rhs, 0))))
{
- /* This should always succeed in creating gimple, so there is
- no need to save enough state to undo this propagation. */
- TREE_OPERAND (lhs, 0) = unshare_expr (def_rhs);
+ *lhsp = unshare_expr (TREE_OPERAND (def_rhs, 0));
fold_stmt_inplace (use_stmt);
tidy_after_forward_propagate_addr (use_stmt);
- /* Continue propagating into the RHS. */
+ /* Continue propagating into the RHS if this was not the only use. */
+ if (single_use_p)
+ return true;
}
- /* Trivial case. The use statement could be a trivial copy or a
- useless conversion. Recurse to the uses of the lhs as copyprop does
- not copy through differen variant pointers and FRE does not catch
- all useless conversions. */
- else if ((TREE_CODE (lhs) == SSA_NAME
- && rhs == name)
- || ((TREE_CODE (rhs) == NOP_EXPR
- || TREE_CODE (rhs) == CONVERT_EXPR)
- && tree_ssa_useless_type_conversion_1 (TREE_TYPE (rhs),
- TREE_TYPE (def_rhs))))
- return forward_propagate_addr_expr (lhs, def_rhs);
-
/* Strip away any outer COMPONENT_REF, ARRAY_REF or ADDR_EXPR
nodes from the RHS. */
- while (handled_component_p (rhs)
- || TREE_CODE (rhs) == ADDR_EXPR)
- rhs = TREE_OPERAND (rhs, 0);
+ rhsp = &GIMPLE_STMT_OPERAND (use_stmt, 1);
+ while (handled_component_p (*rhsp)
+ || TREE_CODE (*rhsp) == ADDR_EXPR)
+ rhsp = &TREE_OPERAND (*rhsp, 0);
+ rhs = *rhsp;
/* Now see if the RHS node is an INDIRECT_REF using NAME. If so,
propagate the ADDR_EXPR into the use of NAME and fold the result. */
- if (TREE_CODE (rhs) == INDIRECT_REF && TREE_OPERAND (rhs, 0) == name)
+ if (TREE_CODE (rhs) == INDIRECT_REF
+ && TREE_OPERAND (rhs, 0) == name
+ && useless_type_conversion_p (TREE_TYPE (TREE_OPERAND (rhs, 0)),
+ TREE_TYPE (def_rhs))
+ /* ??? This looks redundant, but is required for bogus types
+ that can sometimes occur. */
+ && useless_type_conversion_p (TREE_TYPE (rhs),
+ TREE_TYPE (TREE_OPERAND (def_rhs, 0))))
{
- /* This should always succeed in creating gimple, so there is
- no need to save enough state to undo this propagation. */
- TREE_OPERAND (rhs, 0) = unshare_expr (def_rhs);
+ *rhsp = unshare_expr (TREE_OPERAND (def_rhs, 0));
fold_stmt_inplace (use_stmt);
tidy_after_forward_propagate_addr (use_stmt);
return true;
}
+ /* If the use of the ADDR_EXPR is not a POINTER_PLUS_EXPR, there
+ is nothing to do. */
+ if (TREE_CODE (rhs) != POINTER_PLUS_EXPR
+ || TREE_OPERAND (rhs, 0) != name)
+ return false;
+
/* The remaining cases are all for turning pointer arithmetic into
array indexing. They only apply when we have the address of
element zero in an array. If that is not the case then there
|| !integer_zerop (TREE_OPERAND (array_ref, 1)))
return false;
- /* If the use of the ADDR_EXPR must be a PLUS_EXPR, or else there
- is nothing to do. */
- if (TREE_CODE (rhs) != PLUS_EXPR)
- return false;
-
- /* Try to optimize &x[0] + C where C is a multiple of the size
+ /* Try to optimize &x[0] p+ C where C is a multiple of the size
of the elements in X into &x[C/element size]. */
- if (TREE_OPERAND (rhs, 0) == name
- && TREE_CODE (TREE_OPERAND (rhs, 1)) == INTEGER_CST)
+ if (TREE_CODE (TREE_OPERAND (rhs, 1)) == INTEGER_CST)
{
tree orig = unshare_expr (rhs);
TREE_OPERAND (rhs, 0) = unshare_expr (def_rhs);
}
}
- /* Try to optimize &x[0] + OFFSET where OFFSET is defined by
+ /* Try to optimize &x[0] p+ OFFSET where OFFSET is defined by
converting a multiplication of an index by the size of the
array elements, then the result is converted into the proper
type for the arithmetic. */
- if (TREE_OPERAND (rhs, 0) == name
- && TREE_CODE (TREE_OPERAND (rhs, 1)) == SSA_NAME
+ if (TREE_CODE (TREE_OPERAND (rhs, 1)) == SSA_NAME
/* Avoid problems with IVopts creating PLUS_EXPRs with a
different type than their operands. */
- && lang_hooks.types_compatible_p (TREE_TYPE (name), TREE_TYPE (rhs)))
+ && useless_type_conversion_p (TREE_TYPE (rhs), TREE_TYPE (name)))
{
bool res;
- tree offset_stmt = SSA_NAME_DEF_STMT (TREE_OPERAND (rhs, 1));
- res = forward_propagate_addr_into_variable_array_index (offset_stmt, lhs,
- def_rhs, use_stmt);
- return res;
- }
-
- /* Same as the previous case, except the operands of the PLUS_EXPR
- were reversed. */
- if (TREE_OPERAND (rhs, 1) == name
- && TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME
- /* Avoid problems with IVopts creating PLUS_EXPRs with a
- different type than their operands. */
- && lang_hooks.types_compatible_p (TREE_TYPE (name), TREE_TYPE (rhs)))
- {
- bool res;
- tree offset_stmt = SSA_NAME_DEF_STMT (TREE_OPERAND (rhs, 0));
- res = forward_propagate_addr_into_variable_array_index (offset_stmt, lhs,
+ res = forward_propagate_addr_into_variable_array_index (TREE_OPERAND (rhs, 1),
def_rhs, use_stmt);
return res;
}
imm_use_iterator iter;
tree use_stmt;
bool all = true;
+ bool single_use_p = has_single_use (name);
FOR_EACH_IMM_USE_STMT (use_stmt, iter, name)
{
bool result;
+ tree use_rhs;
/* If the use is not in a simple assignment statement, then
there is nothing we can do. */
continue;
}
- /* If the use is in a deeper loop nest, then we do not want
+ /* If the use is in a deeper loop nest, then we do not want
to propagate the ADDR_EXPR into the loop as that is likely
adding expression evaluations into the loop. */
if (bb_for_stmt (use_stmt)->loop_depth > stmt_loop_depth)
all = false;
continue;
}
-
+
push_stmt_changes (&use_stmt);
- result = forward_propagate_addr_expr_1 (name, rhs, use_stmt);
+ result = forward_propagate_addr_expr_1 (name, rhs, use_stmt,
+ single_use_p);
all &= result;
pop_stmt_changes (&use_stmt);
/* Remove intermediate now unused copy and conversion chains. */
+ use_rhs = GIMPLE_STMT_OPERAND (use_stmt, 1);
if (result
&& TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 0)) == SSA_NAME
- && (TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 1)) == SSA_NAME
- || TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 1)) == NOP_EXPR
- || TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 1)) == CONVERT_EXPR))
+ && (TREE_CODE (use_rhs) == SSA_NAME
+ || ((TREE_CODE (use_rhs) == NOP_EXPR
+ || TREE_CODE (use_rhs) == CONVERT_EXPR)
+ && TREE_CODE (TREE_OPERAND (use_rhs, 0)) == SSA_NAME)))
{
block_stmt_iterator bsi = bsi_for_stmt (use_stmt);
release_defs (use_stmt);
continue;
}
- if (TREE_CODE (rhs) == ADDR_EXPR)
+ if (TREE_CODE (rhs) == ADDR_EXPR
+ /* Handle pointer conversions on invariant addresses
+ as well, as this is valid gimple. */
+ || ((TREE_CODE (rhs) == NOP_EXPR
+ || TREE_CODE (rhs) == CONVERT_EXPR)
+ && TREE_CODE (TREE_OPERAND (rhs, 0)) == ADDR_EXPR
+ && POINTER_TYPE_P (TREE_TYPE (rhs))))
{
- if (forward_propagate_addr_expr (lhs, rhs))
+ STRIP_NOPS (rhs);
+ if (!stmt_references_abnormal_ssa_name (stmt)
+ && forward_propagate_addr_expr (lhs, rhs))
{
release_defs (stmt);
todoflags |= TODO_remove_unused_locals;
}
else if (TREE_CODE (rhs) == COND_EXPR)
{
- forward_propagate_into_cond (rhs, stmt);
+ int did_something;
+ fold_defer_overflow_warnings ();
+ did_something = forward_propagate_into_cond (rhs, stmt);
+ if (did_something == 2)
+ cfg_changed = true;
+ fold_undefer_overflow_warnings (!TREE_NO_WARNING (rhs)
+ && did_something, stmt, WARN_STRICT_OVERFLOW_CONDITIONAL);
bsi_next (&bsi);
}
else if (COMPARISON_CLASS_P (rhs))
}
else if (TREE_CODE (stmt) == COND_EXPR)
{
- forward_propagate_into_cond (stmt, stmt);
+ int did_something;
+ fold_defer_overflow_warnings ();
+ did_something = forward_propagate_into_cond (stmt, stmt);
+ if (did_something == 2)
+ cfg_changed = true;
+ fold_undefer_overflow_warnings (did_something, stmt,
+ WARN_STRICT_OVERFLOW_CONDITIONAL);
bsi_next (&bsi);
}
else
return 1;
}
-struct tree_opt_pass pass_forwprop = {
+struct gimple_opt_pass pass_forwprop =
+{
+ {
+ GIMPLE_PASS,
"forwprop", /* name */
gate_forwprop, /* gate */
tree_ssa_forward_propagate_single_use_vars, /* execute */
TODO_dump_func
| TODO_ggc_collect
| TODO_update_ssa
- | TODO_verify_ssa, /* todo_flags_finish */
- 0 /* letter */
+ | TODO_verify_ssa /* todo_flags_finish */
+ }
};
-
-/* Structure to keep track of the value of a dereferenced PHI result
- and the set of virtual operands used for that dereference. */
-
-struct phiprop_d
-{
- tree value;
- tree vop_stmt;
-};
-
-/* Verify if the value recorded for NAME in PHIVN is still valid at
- the start of basic block BB. */
-
-static bool
-phivn_valid_p (struct phiprop_d *phivn, tree name, basic_block bb)
-{
- tree vop_stmt = phivn[SSA_NAME_VERSION (name)].vop_stmt;
- ssa_op_iter ui;
- tree vuse;
-
- /* The def stmts of all virtual uses need to be post-dominated
- by bb. */
- FOR_EACH_SSA_TREE_OPERAND (vuse, vop_stmt, ui, SSA_OP_VUSE)
- {
- tree use_stmt;
- imm_use_iterator ui2;
- bool ok = true;
-
- FOR_EACH_IMM_USE_STMT (use_stmt, ui2, vuse)
- {
- /* If BB does not dominate a VDEF, the value is invalid. */
- if (((TREE_CODE (use_stmt) == GIMPLE_MODIFY_STMT
- && !ZERO_SSA_OPERANDS (use_stmt, SSA_OP_VDEF))
- || TREE_CODE (use_stmt) == PHI_NODE)
- && !dominated_by_p (CDI_DOMINATORS, bb_for_stmt (use_stmt), bb))
- {
- ok = false;
- BREAK_FROM_IMM_USE_STMT (ui2);
- }
- }
- if (!ok)
- return false;
- }
-
- return true;
-}
-
-/* Insert a new phi node for the dereference of PHI at basic_block
- BB with the virtual operands from USE_STMT. */
-
-static tree
-phiprop_insert_phi (basic_block bb, tree phi, tree use_stmt,
- struct phiprop_d *phivn, size_t n)
-{
- tree res, new_phi;
- edge_iterator ei;
- edge e;
-
- /* Build a new PHI node to replace the definition of
- the indirect reference lhs. */
- res = GIMPLE_STMT_OPERAND (use_stmt, 0);
- SSA_NAME_DEF_STMT (res) = new_phi = create_phi_node (res, bb);
-
- /* Add PHI arguments for each edge inserting loads of the
- addressable operands. */
- FOR_EACH_EDGE (e, ei, bb->preds)
- {
- tree old_arg, new_var, tmp;
-
- old_arg = PHI_ARG_DEF_FROM_EDGE (phi, e);
- while (TREE_CODE (old_arg) == SSA_NAME
- && (SSA_NAME_VERSION (old_arg) >= n
- || phivn[SSA_NAME_VERSION (old_arg)].value == NULL_TREE))
- {
- tree def_stmt = SSA_NAME_DEF_STMT (old_arg);
- old_arg = GIMPLE_STMT_OPERAND (def_stmt, 1);
- }
-
- if (TREE_CODE (old_arg) == SSA_NAME)
- /* Reuse a formely created dereference. */
- new_var = phivn[SSA_NAME_VERSION (old_arg)].value;
- else
- {
- old_arg = TREE_OPERAND (old_arg, 0);
- new_var = create_tmp_var (TREE_TYPE (old_arg), NULL);
- tmp = build2 (GIMPLE_MODIFY_STMT, void_type_node,
- NULL_TREE, unshare_expr (old_arg));
- if (TREE_CODE (TREE_TYPE (old_arg)) == COMPLEX_TYPE
- || TREE_CODE (TREE_TYPE (old_arg)) == VECTOR_TYPE)
- DECL_GIMPLE_REG_P (new_var) = 1;
- add_referenced_var (new_var);
- new_var = make_ssa_name (new_var, tmp);
- GIMPLE_STMT_OPERAND (tmp, 0) = new_var;
-
- bsi_insert_on_edge (e, tmp);
-
- update_stmt (tmp);
- mark_symbols_for_renaming (tmp);
- }
-
- add_phi_arg (new_phi, new_var, e);
- }
-
- update_stmt (new_phi);
-
- return res;
-}
-
-/* Propagate between the phi node arguments of PHI in BB and phi result
- users. For now this matches
- # p_2 = PHI <&x, &y>
- <Lx>:;
- p_3 = p_2;
- z_2 = *p_3;
- and converts it to
- # z_2 = PHI <x, y>
- <Lx>:;
- Returns true if a transformation was done and edge insertions
- need to be committed. Global data PHIVN and N is used to track
- past transformation results. We need to be especially careful here
- with aliasing issues as we are moving memory reads. */
-
-static bool
-propagate_with_phi (basic_block bb, tree phi, struct phiprop_d *phivn, size_t n)
-{
- tree ptr = PHI_RESULT (phi);
- tree use_stmt, res = NULL_TREE;
- block_stmt_iterator bsi;
- imm_use_iterator ui;
- use_operand_p arg_p, use;
- ssa_op_iter i;
- bool phi_inserted;
-
- if (MTAG_P (SSA_NAME_VAR (ptr))
- || !POINTER_TYPE_P (TREE_TYPE (ptr))
- || !is_gimple_reg_type (TREE_TYPE (TREE_TYPE (ptr))))
- return false;
-
- /* Check if we can "cheaply" dereference all phi arguments. */
- FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE)
- {
- tree arg = USE_FROM_PTR (arg_p);
- /* Walk the ssa chain until we reach a ssa name we already
- created a value for or we reach a definition of the form
- ssa_name_n = &var; */
- while (TREE_CODE (arg) == SSA_NAME
- && !SSA_NAME_IS_DEFAULT_DEF (arg)
- && (SSA_NAME_VERSION (arg) >= n
- || phivn[SSA_NAME_VERSION (arg)].value == NULL_TREE))
- {
- tree def_stmt = SSA_NAME_DEF_STMT (arg);
- if (TREE_CODE (def_stmt) != GIMPLE_MODIFY_STMT)
- return false;
- arg = GIMPLE_STMT_OPERAND (def_stmt, 1);
- }
- if ((TREE_CODE (arg) != ADDR_EXPR
- /* Avoid to have to decay *&a to a[0] later. */
- || !is_gimple_reg_type (TREE_TYPE (TREE_OPERAND (arg, 0))))
- && !(TREE_CODE (arg) == SSA_NAME
- && phivn[SSA_NAME_VERSION (arg)].value != NULL_TREE
- && phivn_valid_p (phivn, arg, bb)))
- return false;
- }
-
- /* Find a dereferencing use. First follow (single use) ssa
- copy chains for ptr. */
- while (single_imm_use (ptr, &use, &use_stmt)
- && TREE_CODE (use_stmt) == GIMPLE_MODIFY_STMT
- && GIMPLE_STMT_OPERAND (use_stmt, 1) == ptr
- && TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 0)) == SSA_NAME)
- ptr = GIMPLE_STMT_OPERAND (use_stmt, 0);
-
- /* Replace the first dereference of *ptr if there is one and if we
- can move the loads to the place of the ptr phi node. */
- phi_inserted = false;
- FOR_EACH_IMM_USE_STMT (use_stmt, ui, ptr)
- {
- ssa_op_iter ui2;
- tree vuse;
-
- /* Check whether this is a load of *ptr. */
- if (!(TREE_CODE (use_stmt) == GIMPLE_MODIFY_STMT
- && TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 0)) == SSA_NAME
- && TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 1)) == INDIRECT_REF
- && TREE_OPERAND (GIMPLE_STMT_OPERAND (use_stmt, 1), 0) == ptr
- /* We cannot replace a load that may throw or is volatile. */
- && !tree_can_throw_internal (use_stmt)))
- continue;
-
- /* Check if we can move the loads. The def stmts of all virtual uses
- need to be post-dominated by bb. */
- FOR_EACH_SSA_TREE_OPERAND (vuse, use_stmt, ui2, SSA_OP_VUSE)
- {
- tree def_stmt = SSA_NAME_DEF_STMT (vuse);
- if (!SSA_NAME_IS_DEFAULT_DEF (vuse)
- && (bb_for_stmt (def_stmt) == bb
- || !dominated_by_p (CDI_DOMINATORS,
- bb, bb_for_stmt (def_stmt))))
- goto next;
- }
-
- /* Found a proper dereference. Insert a phi node if this
- is the first load transformation. */
- if (!phi_inserted)
- {
- res = phiprop_insert_phi (bb, phi, use_stmt, phivn, n);
-
- /* Remember the value we created for *ptr. */
- phivn[SSA_NAME_VERSION (ptr)].value = res;
- phivn[SSA_NAME_VERSION (ptr)].vop_stmt = use_stmt;
-
- /* Remove old stmt. The phi is taken care of by DCE, if we
- want to delete it here we also have to delete all intermediate
- copies. */
- bsi = bsi_for_stmt (use_stmt);
- bsi_remove (&bsi, 0);
-
- phi_inserted = true;
- }
- else
- {
- /* Further replacements are easy, just make a copy out of the
- load. */
- GIMPLE_STMT_OPERAND (use_stmt, 1) = res;
- update_stmt (use_stmt);
- }
-
-next:;
- /* Continue searching for a proper dereference. */
- }
-
- return phi_inserted;
-}
-
-/* Helper walking the dominator tree starting from BB and processing
- phi nodes with global data PHIVN and N. */
-
-static bool
-tree_ssa_phiprop_1 (basic_block bb, struct phiprop_d *phivn, size_t n)
-{
- bool did_something = false;
- basic_block son;
- tree phi;
-
- for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
- did_something |= propagate_with_phi (bb, phi, phivn, n);
-
- for (son = first_dom_son (CDI_DOMINATORS, bb);
- son;
- son = next_dom_son (CDI_DOMINATORS, son))
- did_something |= tree_ssa_phiprop_1 (son, phivn, n);
-
- return did_something;
-}
-
-/* Main entry for phiprop pass. */
-
-static unsigned int
-tree_ssa_phiprop (void)
-{
- struct phiprop_d *phivn;
-
- calculate_dominance_info (CDI_DOMINATORS);
-
- phivn = XCNEWVEC (struct phiprop_d, num_ssa_names);
-
- if (tree_ssa_phiprop_1 (ENTRY_BLOCK_PTR, phivn, num_ssa_names))
- bsi_commit_edge_inserts ();
-
- free (phivn);
-
- return 0;
-}
-
-static bool
-gate_phiprop (void)
-{
- return 1;
-}
-
-struct tree_opt_pass pass_phiprop = {
- "phiprop", /* name */
- gate_phiprop, /* gate */
- tree_ssa_phiprop, /* execute */
- NULL, /* sub */
- NULL, /* next */
- 0, /* static_pass_number */
- TV_TREE_FORWPROP, /* tv_id */
- PROP_cfg | PROP_ssa, /* properties_required */
- 0, /* properties_provided */
- 0, /* properties_destroyed */
- 0, /* todo_flags_start */
- TODO_dump_func
- | TODO_ggc_collect
- | TODO_update_ssa
- | TODO_verify_ssa, /* todo_flags_finish */
- 0 /* letter */
-};
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