#include "tree-pass.h"
#include "tree-dump.h"
#include "langhooks.h"
+#include "flags.h"
/* This pass propagates the RHS of assignment statements into use
sites of the LHS of the assignment. It's basically a specialized
This will (of course) be extended as other needs arise. */
+static bool forward_propagate_addr_expr (tree name, tree rhs);
/* Set to true if we delete EH edges during the optimization. */
static bool cfg_changed;
-/* Given an SSA_NAME VAR, return true if and only if VAR is defined by
- a comparison. */
+/* Get the next statement we can propagate NAME's value into skipping
+ trivial copies. Returns the statement that is suitable as a
+ propagation destination or NULL_TREE if there is no such one.
+ This only returns destinations in a single-use chain. FINAL_NAME_P
+ if non-NULL is written to the ssa name that represents the use. */
-static bool
-ssa_name_defined_by_comparison_p (tree var)
+static tree
+get_prop_dest_stmt (tree name, tree *final_name_p)
{
- tree def = SSA_NAME_DEF_STMT (var);
+ use_operand_p use;
+ tree use_stmt;
- if (TREE_CODE (def) == MODIFY_EXPR)
- {
- tree rhs = TREE_OPERAND (def, 1);
- return COMPARISON_CLASS_P (rhs);
- }
+ do {
+ /* If name has multiple uses, bail out. */
+ if (!single_imm_use (name, &use, &use_stmt))
+ return NULL_TREE;
- return 0;
+ /* If this is not a trivial copy, we found it. */
+ if (TREE_CODE (use_stmt) != GIMPLE_MODIFY_STMT
+ || TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 0)) != SSA_NAME
+ || GIMPLE_STMT_OPERAND (use_stmt, 1) != name)
+ break;
+
+ /* Continue searching uses of the copy destination. */
+ name = GIMPLE_STMT_OPERAND (use_stmt, 0);
+ } while (1);
+
+ if (final_name_p)
+ *final_name_p = name;
+
+ return use_stmt;
}
-/* Forward propagate a single-use variable into COND once. Return a
- new condition if successful. Return NULL_TREE otherwise. */
+/* Get the statement we can propagate from into NAME skipping
+ trivial copies. Returns the statement which defines the
+ propagation source or NULL_TREE if there is no such one.
+ If SINGLE_USE_ONLY is set considers only sources which have
+ a single use chain up to NAME. If SINGLE_USE_P is non-null,
+ it is set to whether the chain to NAME is a single use chain
+ or not. SINGLE_USE_P is not written to if SINGLE_USE_ONLY is set. */
static tree
-forward_propagate_into_cond_1 (tree cond, tree *test_var_p)
+get_prop_source_stmt (tree name, bool single_use_only, bool *single_use_p)
{
- tree new_cond = NULL_TREE;
- enum tree_code cond_code = TREE_CODE (cond);
- tree test_var = NULL_TREE;
- tree def;
- tree def_rhs;
-
- /* If the condition is not a lone variable or an equality test of an
- SSA_NAME against an integral constant, then we do not have an
- optimizable case.
-
- Note these conditions also ensure the COND_EXPR has no
- virtual operands or other side effects. */
- if (cond_code != SSA_NAME
- && !((cond_code == EQ_EXPR || cond_code == NE_EXPR)
- && TREE_CODE (TREE_OPERAND (cond, 0)) == SSA_NAME
- && CONSTANT_CLASS_P (TREE_OPERAND (cond, 1))
- && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (cond, 1)))))
- return NULL_TREE;
+ bool single_use = true;
+
+ do {
+ tree def_stmt = SSA_NAME_DEF_STMT (name);
+
+ if (!has_single_use (name))
+ {
+ single_use = false;
+ if (single_use_only)
+ return NULL_TREE;
+ }
+
+ /* If name is defined by a PHI node or is the default def, bail out. */
+ if (TREE_CODE (def_stmt) != GIMPLE_MODIFY_STMT)
+ return NULL_TREE;
+
+ /* If name is not a simple copy destination, we found it. */
+ if (TREE_CODE (GIMPLE_STMT_OPERAND (def_stmt, 1)) != SSA_NAME)
+ {
+ if (!single_use_only && single_use_p)
+ *single_use_p = single_use;
+
+ return def_stmt;
+ }
+
+ /* Continue searching the def of the copy source name. */
+ name = GIMPLE_STMT_OPERAND (def_stmt, 1);
+ } while (1);
+}
- /* Extract the single variable used in the test into TEST_VAR. */
- if (cond_code == SSA_NAME)
- test_var = cond;
- else
- test_var = TREE_OPERAND (cond, 0);
+/* Checks if the destination ssa name in DEF_STMT can be used as
+ propagation source. Returns true if so, otherwise false. */
- /* Now get the defining statement for TEST_VAR. Skip this case if
- it's not defined by some MODIFY_EXPR. */
- def = SSA_NAME_DEF_STMT (test_var);
- if (TREE_CODE (def) != MODIFY_EXPR)
- return NULL_TREE;
-
- def_rhs = TREE_OPERAND (def, 1);
+static bool
+can_propagate_from (tree def_stmt)
+{
+ tree rhs = GIMPLE_STMT_OPERAND (def_stmt, 1);
- /* If TEST_VAR is set by adding or subtracting a constant
- from an SSA_NAME, then it is interesting to us as we
- can adjust the constant in the conditional and thus
- eliminate the arithmetic operation. */
- if (TREE_CODE (def_rhs) == PLUS_EXPR
- || TREE_CODE (def_rhs) == MINUS_EXPR)
+ /* We cannot propagate ssa names that occur in abnormal phi nodes. */
+ switch (TREE_CODE_LENGTH (TREE_CODE (rhs)))
{
- tree op0 = TREE_OPERAND (def_rhs, 0);
- tree op1 = TREE_OPERAND (def_rhs, 1);
-
- /* The first operand must be an SSA_NAME and the second
- operand must be a constant. */
- if (TREE_CODE (op0) != SSA_NAME
- || !CONSTANT_CLASS_P (op1)
- || !INTEGRAL_TYPE_P (TREE_TYPE (op1)))
- return NULL_TREE;
-
- /* Don't propagate if the first operand occurs in
- an abnormal PHI. */
- if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op0))
- return NULL_TREE;
-
- if (has_single_use (test_var))
- {
- enum tree_code new_code;
- tree t;
-
- /* If the variable was defined via X + C, then we must
- subtract C from the constant in the conditional.
- Otherwise we add C to the constant in the
- conditional. The result must fold into a valid
- gimple operand to be optimizable. */
- new_code = (TREE_CODE (def_rhs) == PLUS_EXPR
- ? MINUS_EXPR : PLUS_EXPR);
- t = int_const_binop (new_code, TREE_OPERAND (cond, 1), op1, 0);
- if (!is_gimple_val (t))
- return NULL_TREE;
-
- new_cond = build2 (cond_code, boolean_type_node, op0, t);
- }
+ case 3:
+ if (TREE_OPERAND (rhs, 2) != NULL_TREE
+ && TREE_CODE (TREE_OPERAND (rhs, 2)) == SSA_NAME
+ && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (TREE_OPERAND (rhs, 2)))
+ return false;
+ case 2:
+ if (TREE_OPERAND (rhs, 1) != NULL_TREE
+ && TREE_CODE (TREE_OPERAND (rhs, 1)) == SSA_NAME
+ && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (TREE_OPERAND (rhs, 1)))
+ return false;
+ case 1:
+ if (TREE_OPERAND (rhs, 0) != NULL_TREE
+ && TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME
+ && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (TREE_OPERAND (rhs, 0)))
+ return false;
+ break;
+
+ default:
+ return false;
}
- /* These cases require comparisons of a naked SSA_NAME or
- comparison of an SSA_NAME against zero or one. */
- else if (TREE_CODE (cond) == SSA_NAME
- || integer_zerop (TREE_OPERAND (cond, 1))
- || integer_onep (TREE_OPERAND (cond, 1)))
- {
- /* If TEST_VAR is set from a relational operation
- between two SSA_NAMEs or a combination of an SSA_NAME
- and a constant, then it is interesting. */
- if (COMPARISON_CLASS_P (def_rhs))
- {
- tree op0 = TREE_OPERAND (def_rhs, 0);
- tree op1 = TREE_OPERAND (def_rhs, 1);
-
- /* Both operands of DEF_RHS must be SSA_NAMEs or
- constants. */
- if ((TREE_CODE (op0) != SSA_NAME
- && !is_gimple_min_invariant (op0))
- || (TREE_CODE (op1) != SSA_NAME
- && !is_gimple_min_invariant (op1)))
- return NULL_TREE;
-
- /* Don't propagate if the first operand occurs in
- an abnormal PHI. */
- if (TREE_CODE (op0) == SSA_NAME
- && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op0))
- return NULL_TREE;
-
- /* Don't propagate if the second operand occurs in
- an abnormal PHI. */
- if (TREE_CODE (op1) == SSA_NAME
- && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op1))
- return NULL_TREE;
-
- if (has_single_use (test_var))
- {
- /* TEST_VAR was set from a relational operator. */
- new_cond = build2 (TREE_CODE (def_rhs),
- boolean_type_node, op0, op1);
-
- /* Invert the conditional if necessary. */
- if ((cond_code == EQ_EXPR
- && integer_zerop (TREE_OPERAND (cond, 1)))
- || (cond_code == NE_EXPR
- && integer_onep (TREE_OPERAND (cond, 1))))
- {
- new_cond = invert_truthvalue (new_cond);
-
- /* If we did not get a simple relational
- expression or bare SSA_NAME, then we can
- not optimize this case. */
- if (!COMPARISON_CLASS_P (new_cond)
- && TREE_CODE (new_cond) != SSA_NAME)
- new_cond = NULL_TREE;
- }
- }
- }
-
- /* If TEST_VAR is set from a TRUTH_NOT_EXPR, then it
- is interesting. */
- else if (TREE_CODE (def_rhs) == TRUTH_NOT_EXPR)
- {
- enum tree_code new_code;
-
- def_rhs = TREE_OPERAND (def_rhs, 0);
-
- /* DEF_RHS must be an SSA_NAME or constant. */
- if (TREE_CODE (def_rhs) != SSA_NAME
- && !is_gimple_min_invariant (def_rhs))
- return NULL_TREE;
-
- /* Don't propagate if the operand occurs in
- an abnormal PHI. */
- if (TREE_CODE (def_rhs) == SSA_NAME
- && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (def_rhs))
- return NULL_TREE;
-
- if (cond_code == SSA_NAME
- || (cond_code == NE_EXPR
- && integer_zerop (TREE_OPERAND (cond, 1)))
- || (cond_code == EQ_EXPR
- && integer_onep (TREE_OPERAND (cond, 1))))
- new_code = EQ_EXPR;
- else
- new_code = NE_EXPR;
-
- new_cond = build2 (new_code, boolean_type_node, def_rhs,
- fold_convert (TREE_TYPE (def_rhs),
- integer_zero_node));
- }
-
- /* If TEST_VAR was set from a cast of an integer type
- to a boolean type or a cast of a boolean to an
- integral, then it is interesting. */
- else if (TREE_CODE (def_rhs) == NOP_EXPR
- || TREE_CODE (def_rhs) == CONVERT_EXPR)
- {
- tree outer_type;
- tree inner_type;
-
- outer_type = TREE_TYPE (def_rhs);
- inner_type = TREE_TYPE (TREE_OPERAND (def_rhs, 0));
-
- if ((TREE_CODE (outer_type) == BOOLEAN_TYPE
- && INTEGRAL_TYPE_P (inner_type))
- || (TREE_CODE (inner_type) == BOOLEAN_TYPE
- && INTEGRAL_TYPE_P (outer_type)))
- ;
- else if (INTEGRAL_TYPE_P (outer_type)
- && INTEGRAL_TYPE_P (inner_type)
- && TREE_CODE (TREE_OPERAND (def_rhs, 0)) == SSA_NAME
- && ssa_name_defined_by_comparison_p (TREE_OPERAND (def_rhs,
- 0)))
- ;
- else
- return NULL_TREE;
-
- /* Don't propagate if the operand occurs in
- an abnormal PHI. */
- if (TREE_CODE (TREE_OPERAND (def_rhs, 0)) == SSA_NAME
- && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (TREE_OPERAND
- (def_rhs, 0)))
- return NULL_TREE;
-
- if (has_single_use (test_var))
- {
- enum tree_code new_code;
- tree new_arg;
-
- if (cond_code == SSA_NAME
- || (cond_code == NE_EXPR
- && integer_zerop (TREE_OPERAND (cond, 1)))
- || (cond_code == EQ_EXPR
- && integer_onep (TREE_OPERAND (cond, 1))))
- new_code = NE_EXPR;
- else
- new_code = EQ_EXPR;
-
- new_arg = TREE_OPERAND (def_rhs, 0);
- new_cond = build2 (new_code, boolean_type_node, new_arg,
- fold_convert (TREE_TYPE (new_arg),
- integer_zero_node));
- }
- }
- }
+ /* If the definition is a conversion of a pointer to a function type,
+ then we can not apply optimizations as some targets require function
+ pointers to be canonicalized and in this case this optimization could
+ eliminate a necessary canonicalization. */
+ if ((TREE_CODE (rhs) == NOP_EXPR
+ || TREE_CODE (rhs) == CONVERT_EXPR)
+ && POINTER_TYPE_P (TREE_TYPE (TREE_OPERAND (rhs, 0)))
+ && TREE_CODE (TREE_TYPE (TREE_TYPE
+ (TREE_OPERAND (rhs, 0)))) == FUNCTION_TYPE)
+ return false;
- *test_var_p = test_var;
- return new_cond;
+ return true;
}
-/* COND is a condition of the form:
+/* Remove a copy chain ending in NAME along the defs but not
+ further or including UP_TO_STMT. If NAME was replaced in
+ its only use then this function can be used to clean up
+ dead stmts. Returns true if UP_TO_STMT can be removed
+ as well, otherwise false. */
- x == const or x != const
-
- Look back to x's defining statement and see if x is defined as
+static bool
+remove_prop_source_from_use (tree name, tree up_to_stmt)
+{
+ block_stmt_iterator bsi;
+ tree stmt;
- x = (type) y;
+ do {
+ if (!has_zero_uses (name))
+ return false;
- If const is unchanged if we convert it to type, then we can build
- the equivalent expression:
+ stmt = SSA_NAME_DEF_STMT (name);
+ if (stmt == up_to_stmt)
+ return true;
+ bsi = bsi_for_stmt (stmt);
+ release_defs (stmt);
+ bsi_remove (&bsi, true);
- y == const or y != const
+ name = GIMPLE_STMT_OPERAND (stmt, 1);
+ } while (TREE_CODE (name) == SSA_NAME);
- Which may allow further optimizations.
+ return false;
+}
- Return the equivalent comparison or NULL if no such equivalent comparison
- was found. */
+/* Combine OP0 CODE OP1 in the context of a COND_EXPR. Returns
+ the folded result in a form suitable for COND_EXPR_COND or
+ NULL_TREE, if there is no suitable simplified form. If
+ INVARIANT_ONLY is true only gimple_min_invariant results are
+ considered simplified. */
static tree
-find_equivalent_equality_comparison (tree cond)
+combine_cond_expr_cond (enum tree_code code, tree type,
+ tree op0, tree op1, bool invariant_only)
{
- tree op0 = TREE_OPERAND (cond, 0);
- tree op1 = TREE_OPERAND (cond, 1);
- tree def_stmt = SSA_NAME_DEF_STMT (op0);
-
- while (def_stmt
- && TREE_CODE (def_stmt) == MODIFY_EXPR
- && TREE_CODE (TREE_OPERAND (def_stmt, 1)) == SSA_NAME)
- def_stmt = SSA_NAME_DEF_STMT (TREE_OPERAND (def_stmt, 1));
-
- /* OP0 might have been a parameter, so first make sure it
- was defined by a MODIFY_EXPR. */
- if (def_stmt && TREE_CODE (def_stmt) == MODIFY_EXPR)
- {
- tree def_rhs = TREE_OPERAND (def_stmt, 1);
-
- /* If either operand to the comparison is a pointer to
- a function, then we can not apply this optimization
- as some targets require function pointers to be
- canonicalized and in this case this optimization would
- eliminate a necessary canonicalization. */
- if ((POINTER_TYPE_P (TREE_TYPE (op0))
- && TREE_CODE (TREE_TYPE (TREE_TYPE (op0))) == FUNCTION_TYPE)
- || (POINTER_TYPE_P (TREE_TYPE (op1))
- && TREE_CODE (TREE_TYPE (TREE_TYPE (op1))) == FUNCTION_TYPE))
- return NULL;
-
- /* Now make sure the RHS of the MODIFY_EXPR is a typecast. */
- if ((TREE_CODE (def_rhs) == NOP_EXPR
- || TREE_CODE (def_rhs) == CONVERT_EXPR)
- && TREE_CODE (TREE_OPERAND (def_rhs, 0)) == SSA_NAME)
- {
- tree def_rhs_inner = TREE_OPERAND (def_rhs, 0);
- tree def_rhs_inner_type = TREE_TYPE (def_rhs_inner);
- tree new;
-
- if (TYPE_PRECISION (def_rhs_inner_type)
- > TYPE_PRECISION (TREE_TYPE (def_rhs)))
- return NULL;
-
- /* If the inner type of the conversion is a pointer to
- a function, then we can not apply this optimization
- as some targets require function pointers to be
- canonicalized. This optimization would result in
- canonicalization of the pointer when it was not originally
- needed/intended. */
- if (POINTER_TYPE_P (def_rhs_inner_type)
- && TREE_CODE (TREE_TYPE (def_rhs_inner_type)) == FUNCTION_TYPE)
- return NULL;
-
- /* What we want to prove is that if we convert OP1 to
- the type of the object inside the NOP_EXPR that the
- result is still equivalent to SRC.
-
- If that is true, the build and return new equivalent
- condition which uses the source of the typecast and the
- new constant (which has only changed its type). */
- new = fold_build1 (TREE_CODE (def_rhs), def_rhs_inner_type, op1);
- STRIP_USELESS_TYPE_CONVERSION (new);
- if (is_gimple_val (new) && tree_int_cst_equal (new, op1))
- return build2 (TREE_CODE (cond), TREE_TYPE (cond),
- def_rhs_inner, new);
- }
- }
- return NULL;
-}
+ tree t;
-/* STMT is a COND_EXPR
+ gcc_assert (TREE_CODE_CLASS (code) == tcc_comparison);
- This routine attempts to find equivalent forms of the condition
- which we may be able to optimize better. */
+ t = fold_binary (code, type, op0, op1);
+ if (!t)
+ return NULL_TREE;
-static void
-simplify_cond (tree stmt)
-{
- tree cond = COND_EXPR_COND (stmt);
+ /* Require that we got a boolean type out if we put one in. */
+ gcc_assert (TREE_CODE (TREE_TYPE (t)) == TREE_CODE (type));
- if (COMPARISON_CLASS_P (cond))
+ /* For (bool)x use x != 0. */
+ if (TREE_CODE (t) == NOP_EXPR
+ && TREE_TYPE (t) == boolean_type_node)
{
- tree op0 = TREE_OPERAND (cond, 0);
- tree op1 = TREE_OPERAND (cond, 1);
-
- if (TREE_CODE (op0) == SSA_NAME && is_gimple_min_invariant (op1))
- {
- /* First see if we have test of an SSA_NAME against a constant
- where the SSA_NAME is defined by an earlier typecast which
- is irrelevant when performing tests against the given
- constant. */
- if (TREE_CODE (cond) == EQ_EXPR || TREE_CODE (cond) == NE_EXPR)
- {
- tree new_cond = find_equivalent_equality_comparison (cond);
-
- if (new_cond)
- {
- COND_EXPR_COND (stmt) = new_cond;
- update_stmt (stmt);
- }
- }
- }
+ tree top0 = TREE_OPERAND (t, 0);
+ t = build2 (NE_EXPR, type,
+ top0, build_int_cst (TREE_TYPE (top0), 0));
}
-}
-
-/* Forward propagate a single-use variable into COND_EXPR as many
- times as possible. */
-
-static void
-forward_propagate_into_cond (tree cond_expr)
-{
- gcc_assert (TREE_CODE (cond_expr) == COND_EXPR);
-
- while (1)
+ /* For !x use x == 0. */
+ else if (TREE_CODE (t) == TRUTH_NOT_EXPR)
{
- tree test_var = NULL_TREE;
- tree cond = COND_EXPR_COND (cond_expr);
- tree new_cond = forward_propagate_into_cond_1 (cond, &test_var);
+ 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));
+ }
- /* Return if unsuccessful. */
- if (new_cond == NULL_TREE)
- break;
+ /* Bail out if we required an invariant but didn't get one. */
+ if (invariant_only
+ && !is_gimple_min_invariant (t))
+ return NULL_TREE;
- /* Dump details. */
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, " Replaced '");
- print_generic_expr (dump_file, cond, dump_flags);
- fprintf (dump_file, "' with '");
- print_generic_expr (dump_file, new_cond, dump_flags);
- fprintf (dump_file, "'\n");
- }
+ /* 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;
- COND_EXPR_COND (cond_expr) = new_cond;
- update_stmt (cond_expr);
+ return NULL_TREE;
+}
- if (has_zero_uses (test_var))
- {
- tree def = SSA_NAME_DEF_STMT (test_var);
- block_stmt_iterator bsi = bsi_for_stmt (def);
- bsi_remove (&bsi, true);
- }
- }
+/* Propagate from the ssa name definition statements of COND_EXPR
+ in statement STMT into the conditional if that simplifies it. */
- /* There are further simplifications that can be performed
- on COND_EXPRs. Specifically, when comparing an SSA_NAME
- against a constant where the SSA_NAME is the result of a
- conversion. Perhaps this should be folded into the rest
- of the COND_EXPR simplification code. */
- simplify_cond (cond_expr);
+static bool
+forward_propagate_into_cond (tree cond_expr, tree stmt)
+{
+ bool did_something = false;
+
+ do {
+ tree tmp = NULL_TREE;
+ tree cond = COND_EXPR_COND (cond_expr);
+ tree name, def_stmt, rhs;
+ bool single_use_p;
+
+ /* We can do tree combining on SSA_NAME and comparison expressions. */
+ if (COMPARISON_CLASS_P (cond)
+ && TREE_CODE (TREE_OPERAND (cond, 0)) == SSA_NAME)
+ {
+ /* For comparisons use the first operand, that is likely to
+ simplify comparisons against constants. */
+ name = TREE_OPERAND (cond, 0);
+ def_stmt = get_prop_source_stmt (name, false, &single_use_p);
+ if (def_stmt != NULL_TREE
+ && can_propagate_from (def_stmt))
+ {
+ tree op1 = TREE_OPERAND (cond, 1);
+ rhs = GIMPLE_STMT_OPERAND (def_stmt, 1);
+ tmp = combine_cond_expr_cond (TREE_CODE (cond), boolean_type_node,
+ fold_convert (TREE_TYPE (op1), rhs),
+ op1, !single_use_p);
+ }
+ /* If that wasn't successful, try the second operand. */
+ if (tmp == NULL_TREE
+ && TREE_CODE (TREE_OPERAND (cond, 1)) == SSA_NAME)
+ {
+ tree op0 = TREE_OPERAND (cond, 0);
+ name = TREE_OPERAND (cond, 1);
+ def_stmt = get_prop_source_stmt (name, false, &single_use_p);
+ if (def_stmt == NULL_TREE
+ || !can_propagate_from (def_stmt))
+ return did_something;
+
+ rhs = GIMPLE_STMT_OPERAND (def_stmt, 1);
+ tmp = combine_cond_expr_cond (TREE_CODE (cond), boolean_type_node,
+ op0,
+ fold_convert (TREE_TYPE (op0), rhs),
+ !single_use_p);
+ }
+ }
+ else if (TREE_CODE (cond) == SSA_NAME)
+ {
+ name = cond;
+ def_stmt = get_prop_source_stmt (name, true, NULL);
+ if (def_stmt == NULL_TREE
+ || !can_propagate_from (def_stmt))
+ return did_something;
+
+ rhs = GIMPLE_STMT_OPERAND (def_stmt, 1);
+ tmp = combine_cond_expr_cond (NE_EXPR, boolean_type_node, rhs,
+ build_int_cst (TREE_TYPE (rhs), 0),
+ false);
+ }
+
+ if (tmp)
+ {
+ if (dump_file && tmp)
+ {
+ fprintf (dump_file, " Replaced '");
+ print_generic_expr (dump_file, cond, 0);
+ fprintf (dump_file, "' with '");
+ print_generic_expr (dump_file, tmp, 0);
+ fprintf (dump_file, "'\n");
+ }
+
+ COND_EXPR_COND (cond_expr) = unshare_expr (tmp);
+ update_stmt (stmt);
+
+ /* Remove defining statements. */
+ remove_prop_source_from_use (name, NULL);
+
+ did_something = true;
+
+ /* Continue combining. */
+ continue;
+ }
+
+ break;
+ } while (1);
+
+ return did_something;
}
/* We've just substituted an ADDR_EXPR into stmt. Update all the
&& tree_purge_dead_eh_edges (bb_for_stmt (stmt)))
cfg_changed = true;
- if (TREE_CODE (TREE_OPERAND (stmt, 1)) == ADDR_EXPR)
- recompute_tree_invariant_for_addr_expr (TREE_OPERAND (stmt, 1));
+ if (TREE_CODE (GIMPLE_STMT_OPERAND (stmt, 1)) == ADDR_EXPR)
+ recompute_tree_invariant_for_addr_expr (GIMPLE_STMT_OPERAND (stmt, 1));
- mark_new_vars_to_rename (stmt);
+ mark_symbols_for_renaming (stmt);
}
-/* STMT defines LHS which is contains the address of the 0th element
+/* 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
arbitrary element within the array. The (variable) byte offset
of the element is contained in OFFSET.
static bool
forward_propagate_addr_into_variable_array_index (tree offset, tree lhs,
- tree stmt, tree use_stmt)
+ tree def_rhs, tree use_stmt)
{
tree index;
- /* The offset must be defined by a simple MODIFY_EXPR statement. */
- if (TREE_CODE (offset) != MODIFY_EXPR)
+ /* 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 = TREE_OPERAND (offset, 1);
+ offset = GIMPLE_STMT_OPERAND (offset, 1);
if (!is_gimple_cast (offset))
return false;
offset = SSA_NAME_DEF_STMT (offset);
/* The statement which defines OFFSET before type conversion
- must be a simple MODIFY_EXPR. */
- if (TREE_CODE (offset) != MODIFY_EXPR)
+ 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 = TREE_OPERAND (offset, 1);
+ 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),
index = TREE_OPERAND (offset, 0);
/* Replace the pointer addition with array indexing. */
- TREE_OPERAND (use_stmt, 1) = unshare_expr (TREE_OPERAND (stmt, 1));
- TREE_OPERAND (TREE_OPERAND (TREE_OPERAND (use_stmt, 1), 0), 1) = index;
+ GIMPLE_STMT_OPERAND (use_stmt, 1) = unshare_expr (def_rhs);
+ TREE_OPERAND (TREE_OPERAND (GIMPLE_STMT_OPERAND (use_stmt, 1), 0), 1)
+ = index;
/* That should have created gimple, so there is no need to
record information to undo the propagation. */
return true;
}
-/* STMT is a statement of the form SSA_NAME = ADDR_EXPR <whatever>.
+/* NAME is a SSA_NAME representing DEF_RHS which is of the form
+ ADDR_EXPR <whatever>.
Try to forward propagate the ADDR_EXPR into the use USE_STMT.
Often this will allow for removal of an ADDR_EXPR and INDIRECT_REF
node or for recovery of array indexing from pointer arithmetic.
- CHANGED is an optional pointer to a boolean variable set to true if
- either the LHS or RHS was changed in the USE_STMT.
-
Return true if the propagation was successful (the propagation can
be not totally successful, yet things may have been changed). */
static bool
-forward_propagate_addr_expr_1 (tree stmt, tree use_stmt, bool *changed)
+forward_propagate_addr_expr_1 (tree name, tree def_rhs, tree use_stmt)
{
- tree name = TREE_OPERAND (stmt, 0);
tree lhs, rhs, array_ref;
/* Strip away any outer COMPONENT_REF/ARRAY_REF nodes from the LHS.
ADDR_EXPR will not appear on the LHS. */
- lhs = TREE_OPERAND (use_stmt, 0);
- while (TREE_CODE (lhs) == COMPONENT_REF || TREE_CODE (lhs) == ARRAY_REF)
+ lhs = GIMPLE_STMT_OPERAND (use_stmt, 0);
+ while (handled_component_p (lhs))
lhs = TREE_OPERAND (lhs, 0);
+ rhs = GIMPLE_STMT_OPERAND (use_stmt, 1);
+
/* Now see if the LHS node is an INDIRECT_REF using NAME. If so,
propagate the ADDR_EXPR into the use of NAME and fold the result. */
if (TREE_CODE (lhs) == INDIRECT_REF && TREE_OPERAND (lhs, 0) == name)
{
/* This should always succeed in creating gimple, so there is
no need to save enough state to undo this propagation. */
- TREE_OPERAND (lhs, 0) = unshare_expr (TREE_OPERAND (stmt, 1));
+ TREE_OPERAND (lhs, 0) = unshare_expr (def_rhs);
fold_stmt_inplace (use_stmt);
tidy_after_forward_propagate_addr (use_stmt);
- if (changed)
- *changed = true;
- }
- /* Trivial case. The use statement could be a trivial copy. We
- go ahead and handle that case here since it's trivial and
- removes the need to run copy-prop before this pass to get
- the best results. Also note that by handling this case here
- we can catch some cascading effects, ie the single use is
- in a copy, and the copy is used later by a single INDIRECT_REF
- for example. */
- else if (TREE_CODE (lhs) == SSA_NAME && TREE_OPERAND (use_stmt, 1) == name)
- {
- TREE_OPERAND (use_stmt, 1) = unshare_expr (TREE_OPERAND (stmt, 1));
- tidy_after_forward_propagate_addr (use_stmt);
- if (changed)
- *changed = true;
- return true;
+ /* Continue propagating into the RHS. */
}
+ /* 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. */
- rhs = TREE_OPERAND (use_stmt, 1);
- while (TREE_CODE (rhs) == COMPONENT_REF
- || TREE_CODE (rhs) == ARRAY_REF
+ while (handled_component_p (rhs)
|| TREE_CODE (rhs) == ADDR_EXPR)
rhs = TREE_OPERAND (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 (TREE_OPERAND (stmt, 1));
+ TREE_OPERAND (rhs, 0) = unshare_expr (def_rhs);
fold_stmt_inplace (use_stmt);
tidy_after_forward_propagate_addr (use_stmt);
- if (changed)
- *changed = true;
return true;
}
array indexing. They only apply when we have the address of
element zero in an array. If that is not the case then there
is nothing to do. */
- array_ref = TREE_OPERAND (TREE_OPERAND (stmt, 1), 0);
+ array_ref = TREE_OPERAND (def_rhs, 0);
if (TREE_CODE (array_ref) != ARRAY_REF
|| TREE_CODE (TREE_TYPE (TREE_OPERAND (array_ref, 0))) != ARRAY_TYPE
|| !integer_zerop (TREE_OPERAND (array_ref, 1)))
&& TREE_CODE (TREE_OPERAND (rhs, 1)) == INTEGER_CST)
{
tree orig = unshare_expr (rhs);
- TREE_OPERAND (rhs, 0) = unshare_expr (TREE_OPERAND (stmt, 1));
+ TREE_OPERAND (rhs, 0) = unshare_expr (def_rhs);
/* If folding succeeds, then we have just exposed new variables
in USE_STMT which will need to be renamed. If folding fails,
if (fold_stmt_inplace (use_stmt))
{
tidy_after_forward_propagate_addr (use_stmt);
- if (changed)
- *changed = true;
return true;
}
else
{
- TREE_OPERAND (use_stmt, 1) = orig;
+ GIMPLE_STMT_OPERAND (use_stmt, 1) = orig;
update_stmt (use_stmt);
return false;
}
tree offset_stmt = SSA_NAME_DEF_STMT (TREE_OPERAND (rhs, 1));
res = forward_propagate_addr_into_variable_array_index (offset_stmt, lhs,
- stmt, use_stmt);
- if (res && changed)
- *changed = true;
+ def_rhs, use_stmt);
return res;
}
bool res;
tree offset_stmt = SSA_NAME_DEF_STMT (TREE_OPERAND (rhs, 0));
res = forward_propagate_addr_into_variable_array_index (offset_stmt, lhs,
- stmt, use_stmt);
- if (res && changed)
- *changed = true;
+ def_rhs, use_stmt);
return res;
}
return false;
}
/* STMT is a statement of the form SSA_NAME = ADDR_EXPR <whatever>.
- SOME is a pointer to a boolean value indicating whether we
- propagated the address expression anywhere.
Try to forward propagate the ADDR_EXPR into all uses of the SSA_NAME.
Often this will allow for removal of an ADDR_EXPR and INDIRECT_REF
Returns true, if all uses have been propagated into. */
static bool
-forward_propagate_addr_expr (tree stmt, bool *some)
+forward_propagate_addr_expr (tree name, tree rhs)
{
- int stmt_loop_depth = bb_for_stmt (stmt)->loop_depth;
- tree name = TREE_OPERAND (stmt, 0);
+ int stmt_loop_depth = bb_for_stmt (SSA_NAME_DEF_STMT (name))->loop_depth;
imm_use_iterator iter;
tree use_stmt;
bool all = true;
/* If the use is not in a simple assignment statement, then
there is nothing we can do. */
- if (TREE_CODE (use_stmt) != MODIFY_EXPR)
+ if (TREE_CODE (use_stmt) != GIMPLE_MODIFY_STMT)
{
all = false;
continue;
continue;
}
- result = forward_propagate_addr_expr_1 (stmt, use_stmt, some);
- *some |= result;
+ push_stmt_changes (&use_stmt);
+
+ result = forward_propagate_addr_expr_1 (name, rhs, use_stmt);
all &= result;
+
+ pop_stmt_changes (&use_stmt);
+
+ /* Remove intermediate now unused copy and conversion chains. */
+ if (result
+ && TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 0)) == SSA_NAME
+ && (TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 1)) == SSA_NAME
+ || TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 1)) == NOP_EXPR
+ || TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 1)) == CONVERT_EXPR))
+ {
+ block_stmt_iterator bsi = bsi_for_stmt (use_stmt);
+ release_defs (use_stmt);
+ bsi_remove (&bsi, true);
+ }
}
return all;
}
+/* Forward propagate the comparison COND defined in STMT like
+ cond_1 = x CMP y to uses of the form
+ a_1 = (T')cond_1
+ a_1 = !cond_1
+ a_1 = cond_1 != 0
+ Returns true if stmt is now unused. */
+
+static bool
+forward_propagate_comparison (tree cond, tree stmt)
+{
+ tree name = GIMPLE_STMT_OPERAND (stmt, 0);
+ tree use_stmt, tmp = NULL_TREE;
+
+ /* Don't propagate ssa names that occur in abnormal phis. */
+ if ((TREE_CODE (TREE_OPERAND (cond, 0)) == SSA_NAME
+ && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (TREE_OPERAND (cond, 0)))
+ || (TREE_CODE (TREE_OPERAND (cond, 1)) == SSA_NAME
+ && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (TREE_OPERAND (cond, 1))))
+ return false;
+
+ /* Do not un-cse comparisons. But propagate through copies. */
+ use_stmt = get_prop_dest_stmt (name, &name);
+ if (use_stmt == NULL_TREE)
+ return false;
+
+ /* Conversion of the condition result to another integral type. */
+ if (TREE_CODE (use_stmt) == GIMPLE_MODIFY_STMT
+ && (TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 1)) == CONVERT_EXPR
+ || TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 1)) == NOP_EXPR
+ || COMPARISON_CLASS_P (GIMPLE_STMT_OPERAND (use_stmt, 1))
+ || TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 1)) == TRUTH_NOT_EXPR)
+ && INTEGRAL_TYPE_P (TREE_TYPE (GIMPLE_STMT_OPERAND (use_stmt, 0))))
+ {
+ tree lhs = GIMPLE_STMT_OPERAND (use_stmt, 0);
+ tree rhs = GIMPLE_STMT_OPERAND (use_stmt, 1);
+
+ /* We can propagate the condition into a conversion. */
+ if (TREE_CODE (rhs) == CONVERT_EXPR
+ || TREE_CODE (rhs) == NOP_EXPR)
+ {
+ /* Avoid using fold here as that may create a COND_EXPR with
+ non-boolean condition as canonical form. */
+ tmp = build2 (TREE_CODE (cond), TREE_TYPE (lhs),
+ TREE_OPERAND (cond, 0), TREE_OPERAND (cond, 1));
+ }
+ /* We can propagate the condition into X op CST where op
+ is EQ_EXRP or NE_EXPR and CST is either one or zero. */
+ else if (COMPARISON_CLASS_P (rhs)
+ && TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME
+ && TREE_CODE (TREE_OPERAND (rhs, 1)) == INTEGER_CST)
+ {
+ enum tree_code code = TREE_CODE (rhs);
+ tree cst = TREE_OPERAND (rhs, 1);
+
+ tmp = combine_cond_expr_cond (code, TREE_TYPE (lhs),
+ fold_convert (TREE_TYPE (cst), cond),
+ cst, false);
+ if (tmp == NULL_TREE)
+ return false;
+ }
+ /* We can propagate the condition into a statement that
+ computes the logical negation of the comparison result. */
+ else if (TREE_CODE (rhs) == TRUTH_NOT_EXPR)
+ {
+ tree type = TREE_TYPE (TREE_OPERAND (cond, 0));
+ bool nans = HONOR_NANS (TYPE_MODE (type));
+ enum tree_code code;
+ code = invert_tree_comparison (TREE_CODE (cond), nans);
+ if (code == ERROR_MARK)
+ return false;
+
+ tmp = build2 (code, TREE_TYPE (lhs), TREE_OPERAND (cond, 0),
+ TREE_OPERAND (cond, 1));
+ }
+ else
+ return false;
+
+ GIMPLE_STMT_OPERAND (use_stmt, 1) = unshare_expr (tmp);
+ update_stmt (use_stmt);
+
+ /* Remove defining statements. */
+ remove_prop_source_from_use (name, stmt);
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, " Replaced '");
+ print_generic_expr (dump_file, rhs, dump_flags);
+ fprintf (dump_file, "' with '");
+ print_generic_expr (dump_file, tmp, dump_flags);
+ fprintf (dump_file, "'\n");
+ }
+
+ return true;
+ }
+
+ return false;
+}
+
/* If we have lhs = ~x (STMT), look and see if earlier we had x = ~y.
If so, we can change STMT into lhs = y which can later be copy
propagated. Similarly for negation.
static void
simplify_not_neg_expr (tree stmt)
{
- tree rhs = TREE_OPERAND (stmt, 1);
+ tree rhs = GIMPLE_STMT_OPERAND (stmt, 1);
tree rhs_def_stmt = SSA_NAME_DEF_STMT (TREE_OPERAND (rhs, 0));
/* See if the RHS_DEF_STMT has the same form as our statement. */
- if (TREE_CODE (rhs_def_stmt) == MODIFY_EXPR
- && TREE_CODE (TREE_OPERAND (rhs_def_stmt, 1)) == TREE_CODE (rhs))
+ if (TREE_CODE (rhs_def_stmt) == GIMPLE_MODIFY_STMT
+ && TREE_CODE (GIMPLE_STMT_OPERAND (rhs_def_stmt, 1)) == TREE_CODE (rhs))
{
- tree rhs_def_operand = TREE_OPERAND (TREE_OPERAND (rhs_def_stmt, 1), 0);
+ tree rhs_def_operand =
+ TREE_OPERAND (GIMPLE_STMT_OPERAND (rhs_def_stmt, 1), 0);
/* Verify that RHS_DEF_OPERAND is a suitable SSA_NAME. */
if (TREE_CODE (rhs_def_operand) == SSA_NAME
&& ! SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs_def_operand))
{
- TREE_OPERAND (stmt, 1) = rhs_def_operand;
+ GIMPLE_STMT_OPERAND (stmt, 1) = rhs_def_operand;
update_stmt (stmt);
}
}
if (TREE_CODE (cond) == SSA_NAME)
{
def = SSA_NAME_DEF_STMT (cond);
- if (TREE_CODE (def) == MODIFY_EXPR)
+ if (TREE_CODE (def) == GIMPLE_MODIFY_STMT)
{
- def = TREE_OPERAND (def, 1);
+ def = GIMPLE_STMT_OPERAND (def, 1);
if (TREE_CODE (def) == NOP_EXPR)
{
int need_precision;
need_precision = TYPE_PRECISION (ti);
fail = false;
- if (TYPE_UNSIGNED (to) && !TYPE_UNSIGNED (ti))
+ if (! INTEGRAL_TYPE_P (ti))
+ fail = true;
+ else if (TYPE_UNSIGNED (to) && !TYPE_UNSIGNED (ti))
fail = true;
else if (!TYPE_UNSIGNED (to) && TYPE_UNSIGNED (ti))
need_precision += 1;
/* If this statement sets an SSA_NAME to an address,
try to propagate the address into the uses of the SSA_NAME. */
- if (TREE_CODE (stmt) == MODIFY_EXPR)
+ if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT)
{
- tree lhs = TREE_OPERAND (stmt, 0);
- tree rhs = TREE_OPERAND (stmt, 1);
+ tree lhs = GIMPLE_STMT_OPERAND (stmt, 0);
+ tree rhs = GIMPLE_STMT_OPERAND (stmt, 1);
if (TREE_CODE (lhs) != SSA_NAME)
if (TREE_CODE (rhs) == ADDR_EXPR)
{
- bool some = false;
- if (forward_propagate_addr_expr (stmt, &some))
- bsi_remove (&bsi, true);
+ if (forward_propagate_addr_expr (lhs, rhs))
+ {
+ release_defs (stmt);
+ todoflags |= TODO_remove_unused_locals;
+ bsi_remove (&bsi, true);
+ }
else
bsi_next (&bsi);
- if (some)
- todoflags |= TODO_update_smt_usage;
}
else if ((TREE_CODE (rhs) == BIT_NOT_EXPR
|| TREE_CODE (rhs) == NEGATE_EXPR)
simplify_not_neg_expr (stmt);
bsi_next (&bsi);
}
+ else if (TREE_CODE (rhs) == COND_EXPR)
+ {
+ bool did_something;
+ fold_defer_overflow_warnings ();
+ did_something = forward_propagate_into_cond (rhs, stmt);
+ fold_undefer_overflow_warnings (!TREE_NO_WARNING (rhs)
+ && did_something, stmt, WARN_STRICT_OVERFLOW_CONDITIONAL);
+ bsi_next (&bsi);
+ }
+ else if (COMPARISON_CLASS_P (rhs))
+ {
+ if (forward_propagate_comparison (rhs, stmt))
+ {
+ release_defs (stmt);
+ todoflags |= TODO_remove_unused_locals;
+ bsi_remove (&bsi, true);
+ }
+ else
+ bsi_next (&bsi);
+ }
else
bsi_next (&bsi);
}
}
else if (TREE_CODE (stmt) == COND_EXPR)
{
- forward_propagate_into_cond (stmt);
+ bool did_something;
+ fold_defer_overflow_warnings ();
+ did_something = forward_propagate_into_cond (stmt, stmt);
+ fold_undefer_overflow_warnings (!TREE_NO_WARNING (stmt)
+ && did_something, stmt,
+ WARN_STRICT_OVERFLOW_CONDITIONAL);
bsi_next (&bsi);
}
else
}
if (cfg_changed)
- cleanup_tree_cfg ();
+ todoflags |= TODO_cleanup_cfg;
return todoflags;
}
NULL, /* next */
0, /* static_pass_number */
TV_TREE_FORWPROP, /* tv_id */
- PROP_cfg | PROP_ssa
- | PROP_alias, /* properties_required */
+ PROP_cfg | PROP_ssa, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ TODO_dump_func
+ | TODO_ggc_collect
+ | TODO_update_ssa
+ | TODO_verify_ssa, /* todo_flags_finish */
+ 0 /* letter */
+};
+
+
+/* Structure to keep track of the value of a dereferenced PHI result
+ and the set of virtual operands used for that dereference. */
+
+struct phiprop_d
+{
+ tree value;
+ tree vop_stmt;
+};
+
+/* Verify if the value recorded for NAME in PHIVN is still valid at
+ the start of basic block BB. */
+
+static bool
+phivn_valid_p (struct phiprop_d *phivn, tree name, basic_block bb)
+{
+ tree vop_stmt = phivn[SSA_NAME_VERSION (name)].vop_stmt;
+ ssa_op_iter ui;
+ tree vuse;
+
+ /* The def stmts of all virtual uses need to be post-dominated
+ by bb. */
+ FOR_EACH_SSA_TREE_OPERAND (vuse, vop_stmt, ui, SSA_OP_VUSE)
+ {
+ tree use_stmt;
+ imm_use_iterator ui2;
+ bool ok = true;
+
+ FOR_EACH_IMM_USE_STMT (use_stmt, ui2, vuse)
+ {
+ /* If BB does not dominate a VDEF, the value is invalid. */
+ if (((TREE_CODE (use_stmt) == GIMPLE_MODIFY_STMT
+ && !ZERO_SSA_OPERANDS (use_stmt, SSA_OP_VDEF))
+ || TREE_CODE (use_stmt) == PHI_NODE)
+ && !dominated_by_p (CDI_DOMINATORS, bb_for_stmt (use_stmt), bb))
+ {
+ ok = false;
+ BREAK_FROM_IMM_USE_STMT (ui2);
+ }
+ }
+ if (!ok)
+ return false;
+ }
+
+ return true;
+}
+
+/* Insert a new phi node for the dereference of PHI at basic_block
+ BB with the virtual operands from USE_STMT. */
+
+static tree
+phiprop_insert_phi (basic_block bb, tree phi, tree use_stmt,
+ struct phiprop_d *phivn, size_t n)
+{
+ tree res, new_phi;
+ edge_iterator ei;
+ edge e;
+
+ /* Build a new PHI node to replace the definition of
+ the indirect reference lhs. */
+ res = GIMPLE_STMT_OPERAND (use_stmt, 0);
+ SSA_NAME_DEF_STMT (res) = new_phi = create_phi_node (res, bb);
+
+ /* Add PHI arguments for each edge inserting loads of the
+ addressable operands. */
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ {
+ tree old_arg, new_var, tmp;
+
+ old_arg = PHI_ARG_DEF_FROM_EDGE (phi, e);
+ while (TREE_CODE (old_arg) == SSA_NAME
+ && (SSA_NAME_VERSION (old_arg) >= n
+ || phivn[SSA_NAME_VERSION (old_arg)].value == NULL_TREE))
+ {
+ tree def_stmt = SSA_NAME_DEF_STMT (old_arg);
+ old_arg = GIMPLE_STMT_OPERAND (def_stmt, 1);
+ }
+
+ if (TREE_CODE (old_arg) == SSA_NAME)
+ /* Reuse a 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 */
- PROP_smt_usage, /* properties_destroyed */
+ 0, /* properties_destroyed */
0, /* todo_flags_start */
- TODO_dump_func /* todo_flags_finish */
+ TODO_dump_func
| TODO_ggc_collect
- | TODO_update_ssa | TODO_verify_ssa,
- 0 /* letter */
+ | TODO_update_ssa
+ | TODO_verify_ssa, /* todo_flags_finish */
+ 0 /* letter */
};