/* Optimization of PHI nodes by converting them into straightline code.
- Copyright (C) 2004, 2005, 2006, 2007, 2008 Free Software Foundation,
- Inc.
+ Copyright (C) 2004-2013 Free Software Foundation, Inc.
This file is part of GCC.
#include "config.h"
#include "system.h"
#include "coretypes.h"
+#include "hash-table.h"
#include "tm.h"
-#include "ggc.h"
#include "tree.h"
-#include "rtl.h"
+#include "stor-layout.h"
#include "flags.h"
#include "tm_p.h"
#include "basic-block.h"
-#include "timevar.h"
-#include "diagnostic.h"
-#include "tree-flow.h"
+#include "pointer-set.h"
+#include "tree-ssa-alias.h"
+#include "internal-fn.h"
+#include "gimple-expr.h"
+#include "is-a.h"
+#include "gimple.h"
+#include "gimplify.h"
+#include "gimple-iterator.h"
+#include "gimplify-me.h"
+#include "gimple-ssa.h"
+#include "tree-cfg.h"
+#include "tree-phinodes.h"
+#include "ssa-iterators.h"
+#include "stringpool.h"
+#include "tree-ssanames.h"
+#include "expr.h"
+#include "tree-dfa.h"
#include "tree-pass.h"
-#include "tree-dump.h"
#include "langhooks.h"
-#include "pointer-set.h"
#include "domwalk.h"
+#include "cfgloop.h"
+#include "tree-data-ref.h"
+#include "gimple-pretty-print.h"
+#include "insn-config.h"
+#include "expr.h"
+#include "optabs.h"
+#include "tree-scalar-evolution.h"
+
+#ifndef HAVE_conditional_move
+#define HAVE_conditional_move (0)
+#endif
static unsigned int tree_ssa_phiopt (void);
-static unsigned int tree_ssa_phiopt_worker (bool);
+static unsigned int tree_ssa_phiopt_worker (bool, bool);
static bool conditional_replacement (basic_block, basic_block,
edge, edge, gimple, tree, tree);
-static bool value_replacement (basic_block, basic_block,
- edge, edge, gimple, tree, tree);
+static int value_replacement (basic_block, basic_block,
+ edge, edge, gimple, tree, tree);
static bool minmax_replacement (basic_block, basic_block,
edge, edge, gimple, tree, tree);
static bool abs_replacement (basic_block, basic_block,
edge, edge, gimple, tree, tree);
static bool cond_store_replacement (basic_block, basic_block, edge, edge,
struct pointer_set_t *);
+static bool cond_if_else_store_replacement (basic_block, basic_block, basic_block);
static struct pointer_set_t * get_non_trapping (void);
static void replace_phi_edge_with_variable (basic_block, edge, gimple, tree);
+static void hoist_adjacent_loads (basic_block, basic_block,
+ basic_block, basic_block);
+static bool gate_hoist_loads (void);
/* This pass tries to replaces an if-then-else block with an
assignment. We have four kinds of transformations. Some of these
This opportunity can sometimes occur as a result of other
optimizations.
+
+ Another case caught by value replacement looks like this:
+
+ bb0:
+ t1 = a == CONST;
+ t2 = b > c;
+ t3 = t1 & t2;
+ if (t3 != 0) goto bb1; else goto bb2;
+ bb1:
+ bb2:
+ x = PHI (CONST, a)
+
+ Gets replaced with:
+ bb0:
+ bb2:
+ t1 = a == CONST;
+ t2 = b > c;
+ t3 = t1 & t2;
+ x = a;
+
ABS Replacement
---------------
bb2:
x = PHI <x' (bb0), ...>;
- A similar transformation is done for MAX_EXPR. */
+ A similar transformation is done for MAX_EXPR.
+
+
+ This pass also performs a fifth transformation of a slightly different
+ flavor.
+
+ Adjacent Load Hoisting
+ ----------------------
+
+ This transformation replaces
+
+ bb0:
+ if (...) goto bb2; else goto bb1;
+ bb1:
+ x1 = (<expr>).field1;
+ goto bb3;
+ bb2:
+ x2 = (<expr>).field2;
+ bb3:
+ # x = PHI <x1, x2>;
+
+ with
+
+ bb0:
+ x1 = (<expr>).field1;
+ x2 = (<expr>).field2;
+ if (...) goto bb2; else goto bb1;
+ bb1:
+ goto bb3;
+ bb2:
+ bb3:
+ # x = PHI <x1, x2>;
+
+ The purpose of this transformation is to enable generation of conditional
+ move instructions such as Intel CMOVE or PowerPC ISEL. Because one of
+ the loads is speculative, the transformation is restricted to very
+ specific cases to avoid introducing a page fault. We are looking for
+ the common idiom:
+
+ if (...)
+ x = y->left;
+ else
+ x = y->right;
+
+ where left and right are typically adjacent pointers in a tree structure. */
static unsigned int
tree_ssa_phiopt (void)
{
- return tree_ssa_phiopt_worker (false);
+ return tree_ssa_phiopt_worker (false, gate_hoist_loads ());
}
/* This pass tries to transform conditional stores into unconditional
bb0:
if (cond) goto bb2; else goto bb1;
bb1:
- *p = RHS
+ *p = RHS;
bb2:
with
condtmp' = *p;
bb2:
condtmp = PHI <RHS, condtmp'>
- *p = condtmp
+ *p = condtmp;
This transformation can only be done under several constraints,
- documented below. */
+ documented below. It also replaces:
+
+ bb0:
+ if (cond) goto bb2; else goto bb1;
+ bb1:
+ *p = RHS1;
+ goto bb3;
+ bb2:
+ *p = RHS2;
+ bb3:
+
+ with
+
+ bb0:
+ if (cond) goto bb3; else goto bb1;
+ bb1:
+ bb3:
+ condtmp = PHI <RHS1, RHS2>
+ *p = condtmp; */
static unsigned int
tree_ssa_cs_elim (void)
{
- return tree_ssa_phiopt_worker (true);
+ unsigned todo;
+ /* ??? We are not interested in loop related info, but the following
+ will create it, ICEing as we didn't init loops with pre-headers.
+ An interfacing issue of find_data_references_in_bb. */
+ loop_optimizer_init (LOOPS_NORMAL);
+ scev_initialize ();
+ todo = tree_ssa_phiopt_worker (true, false);
+ scev_finalize ();
+ loop_optimizer_finalize ();
+ return todo;
}
-/* For conditional store replacement we need a temporary to
- put the old contents of the memory in. */
-static tree condstoretemp;
+/* Return the singleton PHI in the SEQ of PHIs for edges E0 and E1. */
+
+static gimple
+single_non_singleton_phi_for_edges (gimple_seq seq, edge e0, edge e1)
+{
+ gimple_stmt_iterator i;
+ gimple phi = NULL;
+ if (gimple_seq_singleton_p (seq))
+ return gsi_stmt (gsi_start (seq));
+ for (i = gsi_start (seq); !gsi_end_p (i); gsi_next (&i))
+ {
+ gimple p = gsi_stmt (i);
+ /* If the PHI arguments are equal then we can skip this PHI. */
+ if (operand_equal_for_phi_arg_p (gimple_phi_arg_def (p, e0->dest_idx),
+ gimple_phi_arg_def (p, e1->dest_idx)))
+ continue;
+
+ /* If we already have a PHI that has the two edge arguments are
+ different, then return it is not a singleton for these PHIs. */
+ if (phi)
+ return NULL;
+
+ phi = p;
+ }
+ return phi;
+}
/* The core routine of conditional store replacement and normal
phi optimizations. Both share much of the infrastructure in how
to match applicable basic block patterns. DO_STORE_ELIM is true
- when we want to do conditional store replacement, false otherwise. */
+ when we want to do conditional store replacement, false otherwise.
+ DO_HOIST_LOADS is true when we want to hoist adjacent loads out
+ of diamond control flow patterns, false otherwise. */
static unsigned int
-tree_ssa_phiopt_worker (bool do_store_elim)
+tree_ssa_phiopt_worker (bool do_store_elim, bool do_hoist_loads)
{
basic_block bb;
basic_block *bb_order;
struct pointer_set_t *nontrap = 0;
if (do_store_elim)
- {
- condstoretemp = NULL_TREE;
- /* Calculate the set of non-trapping memory accesses. */
- nontrap = get_non_trapping ();
- }
+ /* Calculate the set of non-trapping memory accesses. */
+ nontrap = get_non_trapping ();
/* Search every basic block for COND_EXPR we may be able to optimize.
This ensures that we collapse inner ifs before visiting the
outer ones, and also that we do not try to visit a removed
block. */
- bb_order = blocks_in_phiopt_order ();
- n = n_basic_blocks - NUM_FIXED_BLOCKS;
+ bb_order = single_pred_before_succ_order ();
+ n = n_basic_blocks_for_fn (cfun) - NUM_FIXED_BLOCKS;
- for (i = 0; i < n; i++)
+ for (i = 0; i < n; i++)
{
gimple cond_stmt, phi;
basic_block bb1, bb2;
e1 = e2;
e2 = e_tmp;
}
+ else if (do_store_elim
+ && EDGE_SUCC (bb1, 0)->dest == EDGE_SUCC (bb2, 0)->dest)
+ {
+ basic_block bb3 = EDGE_SUCC (bb1, 0)->dest;
+
+ if (!single_succ_p (bb1)
+ || (EDGE_SUCC (bb1, 0)->flags & EDGE_FALLTHRU) == 0
+ || !single_succ_p (bb2)
+ || (EDGE_SUCC (bb2, 0)->flags & EDGE_FALLTHRU) == 0
+ || EDGE_COUNT (bb3->preds) != 2)
+ continue;
+ if (cond_if_else_store_replacement (bb1, bb2, bb3))
+ cfgchanged = true;
+ continue;
+ }
+ else if (do_hoist_loads
+ && EDGE_SUCC (bb1, 0)->dest == EDGE_SUCC (bb2, 0)->dest)
+ {
+ basic_block bb3 = EDGE_SUCC (bb1, 0)->dest;
+
+ if (!FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (cond_stmt)))
+ && single_succ_p (bb1)
+ && single_succ_p (bb2)
+ && single_pred_p (bb1)
+ && single_pred_p (bb2)
+ && EDGE_COUNT (bb->succs) == 2
+ && EDGE_COUNT (bb3->preds) == 2
+ /* If one edge or the other is dominant, a conditional move
+ is likely to perform worse than the well-predicted branch. */
+ && !predictable_edge_p (EDGE_SUCC (bb, 0))
+ && !predictable_edge_p (EDGE_SUCC (bb, 1)))
+ hoist_adjacent_loads (bb, bb1, bb2, bb3);
+ continue;
+ }
else
- continue;
+ continue;
e1 = EDGE_SUCC (bb1, 0);
else
{
gimple_seq phis = phi_nodes (bb2);
+ gimple_stmt_iterator gsi;
+ bool candorest = true;
- /* Check to make sure that there is only one PHI node.
- TODO: we could do it with more than one iff the other PHI nodes
- have the same elements for these two edges. */
- if (! gimple_seq_singleton_p (phis))
+ /* Value replacement can work with more than one PHI
+ so try that first. */
+ for (gsi = gsi_start (phis); !gsi_end_p (gsi); gsi_next (&gsi))
+ {
+ phi = gsi_stmt (gsi);
+ arg0 = gimple_phi_arg_def (phi, e1->dest_idx);
+ arg1 = gimple_phi_arg_def (phi, e2->dest_idx);
+ if (value_replacement (bb, bb1, e1, e2, phi, arg0, arg1) == 2)
+ {
+ candorest = false;
+ cfgchanged = true;
+ break;
+ }
+ }
+
+ if (!candorest)
+ continue;
+
+ phi = single_non_singleton_phi_for_edges (phis, e1, e2);
+ if (!phi)
continue;
- phi = gsi_stmt (gsi_start (phis));
arg0 = gimple_phi_arg_def (phi, e1->dest_idx);
arg1 = gimple_phi_arg_def (phi, e2->dest_idx);
/* Do the replacement of conditional if it can be done. */
if (conditional_replacement (bb, bb1, e1, e2, phi, arg0, arg1))
cfgchanged = true;
- else if (value_replacement (bb, bb1, e1, e2, phi, arg0, arg1))
- cfgchanged = true;
else if (abs_replacement (bb, bb1, e1, e2, phi, arg0, arg1))
cfgchanged = true;
else if (minmax_replacement (bb, bb1, e1, e2, phi, arg0, arg1))
}
free (bb_order);
-
+
if (do_store_elim)
pointer_set_destroy (nontrap);
/* If the CFG has changed, we should cleanup the CFG. */
return 0;
}
-/* Returns the list of basic blocks in the function in an order that guarantees
- that if a block X has just a single predecessor Y, then Y is after X in the
- ordering. */
-
-basic_block *
-blocks_in_phiopt_order (void)
-{
- basic_block x, y;
- basic_block *order = XNEWVEC (basic_block, n_basic_blocks);
- unsigned n = n_basic_blocks - NUM_FIXED_BLOCKS;
- unsigned np, i;
- sbitmap visited = sbitmap_alloc (last_basic_block);
-
-#define MARK_VISITED(BB) (SET_BIT (visited, (BB)->index))
-#define VISITED_P(BB) (TEST_BIT (visited, (BB)->index))
-
- sbitmap_zero (visited);
-
- MARK_VISITED (ENTRY_BLOCK_PTR);
- FOR_EACH_BB (x)
- {
- if (VISITED_P (x))
- continue;
-
- /* Walk the predecessors of x as long as they have precisely one
- predecessor and add them to the list, so that they get stored
- after x. */
- for (y = x, np = 1;
- single_pred_p (y) && !VISITED_P (single_pred (y));
- y = single_pred (y))
- np++;
- for (y = x, i = n - np;
- single_pred_p (y) && !VISITED_P (single_pred (y));
- y = single_pred (y), i++)
- {
- order[i] = y;
- MARK_VISITED (y);
- }
- order[i] = y;
- MARK_VISITED (y);
-
- gcc_assert (i == n - 1);
- n -= np;
- }
-
- sbitmap_free (visited);
- gcc_assert (n == 0);
- return order;
-
-#undef MARK_VISITED
-#undef VISITED_P
-}
-
-
-/* Return TRUE if block BB has no executable statements, otherwise return
- FALSE. */
-
-bool
-empty_block_p (basic_block bb)
-{
- /* BB must have no executable statements. */
- gimple_stmt_iterator gsi = gsi_after_labels (bb);
- if (gsi_end_p (gsi))
- return true;
- if (is_gimple_debug (gsi_stmt (gsi)))
- gsi_next_nondebug (&gsi);
- return gsi_end_p (gsi);
-}
-
/* Replace PHI node element whose edge is E in block BB with variable NEW.
Remove the edge from COND_BLOCK which does not lead to BB (COND_BLOCK
is known to have two edges, one of which must reach BB). */
gimple_stmt_iterator gsi;
edge true_edge, false_edge;
tree new_var, new_var2;
+ bool neg;
/* FIXME: Gimplification of complex type is too hard for now. */
- if (TREE_CODE (TREE_TYPE (arg0)) == COMPLEX_TYPE
- || TREE_CODE (TREE_TYPE (arg1)) == COMPLEX_TYPE)
+ /* We aren't prepared to handle vectors either (and it is a question
+ if it would be worthwhile anyway). */
+ if (!(INTEGRAL_TYPE_P (TREE_TYPE (arg0))
+ || POINTER_TYPE_P (TREE_TYPE (arg0)))
+ || !(INTEGRAL_TYPE_P (TREE_TYPE (arg1))
+ || POINTER_TYPE_P (TREE_TYPE (arg1))))
return false;
- /* The PHI arguments have the constants 0 and 1, then convert
- it to the conditional. */
+ /* The PHI arguments have the constants 0 and 1, or 0 and -1, then
+ convert it to the conditional. */
if ((integer_zerop (arg0) && integer_onep (arg1))
|| (integer_zerop (arg1) && integer_onep (arg0)))
- ;
+ neg = false;
+ else if ((integer_zerop (arg0) && integer_all_onesp (arg1))
+ || (integer_zerop (arg1) && integer_all_onesp (arg0)))
+ neg = true;
else
return false;
falls through into BB.
There is a single PHI node at the join point (BB) and its arguments
- are constants (0, 1).
+ are constants (0, 1) or (0, -1).
So, given the condition COND, and the two PHI arguments, we can
rewrite this PHI into non-branching code:
/* To handle special cases like floating point comparison, it is easier and
less error-prone to build a tree and gimplify it on the fly though it is
less efficient. */
- cond = fold_build2 (gimple_cond_code (stmt), boolean_type_node,
- gimple_cond_lhs (stmt), gimple_cond_rhs (stmt));
+ cond = fold_build2_loc (gimple_location (stmt),
+ gimple_cond_code (stmt), boolean_type_node,
+ gimple_cond_lhs (stmt), gimple_cond_rhs (stmt));
/* We need to know which is the true edge and which is the false
edge so that we know when to invert the condition below. */
extract_true_false_edges_from_block (cond_bb, &true_edge, &false_edge);
if ((e0 == true_edge && integer_zerop (arg0))
- || (e0 == false_edge && integer_onep (arg0))
+ || (e0 == false_edge && !integer_zerop (arg0))
|| (e1 == true_edge && integer_zerop (arg1))
- || (e1 == false_edge && integer_onep (arg1)))
- cond = fold_build1 (TRUTH_NOT_EXPR, TREE_TYPE (cond), cond);
+ || (e1 == false_edge && !integer_zerop (arg1)))
+ cond = fold_build1_loc (gimple_location (stmt),
+ TRUTH_NOT_EXPR, TREE_TYPE (cond), cond);
+
+ if (neg)
+ {
+ cond = fold_convert_loc (gimple_location (stmt),
+ TREE_TYPE (result), cond);
+ cond = fold_build1_loc (gimple_location (stmt),
+ NEGATE_EXPR, TREE_TYPE (cond), cond);
+ }
/* Insert our new statements at the end of conditional block before the
COND_STMT. */
{
source_location locus_0, locus_1;
- new_var2 = create_tmp_var (TREE_TYPE (result), NULL);
- add_referenced_var (new_var2);
+ new_var2 = make_ssa_name (TREE_TYPE (result), NULL);
new_stmt = gimple_build_assign_with_ops (CONVERT_EXPR, new_var2,
new_var, NULL);
- new_var2 = make_ssa_name (new_var2, new_stmt);
- gimple_assign_set_lhs (new_stmt, new_var2);
gsi_insert_before (&gsi, new_stmt, GSI_SAME_STMT);
new_var = new_var2;
return true;
}
+/* Update *ARG which is defined in STMT so that it contains the
+ computed value if that seems profitable. Return true if the
+ statement is made dead by that rewriting. */
+
+static bool
+jump_function_from_stmt (tree *arg, gimple stmt)
+{
+ enum tree_code code = gimple_assign_rhs_code (stmt);
+ if (code == ADDR_EXPR)
+ {
+ /* For arg = &p->i transform it to p, if possible. */
+ tree rhs1 = gimple_assign_rhs1 (stmt);
+ HOST_WIDE_INT offset;
+ tree tem = get_addr_base_and_unit_offset (TREE_OPERAND (rhs1, 0),
+ &offset);
+ if (tem
+ && TREE_CODE (tem) == MEM_REF
+ && (mem_ref_offset (tem) + double_int::from_shwi (offset)).is_zero ())
+ {
+ *arg = TREE_OPERAND (tem, 0);
+ return true;
+ }
+ }
+ /* TODO: Much like IPA-CP jump-functions we want to handle constant
+ additions symbolically here, and we'd need to update the comparison
+ code that compares the arg + cst tuples in our caller. For now the
+ code above exactly handles the VEC_BASE pattern from vec.h. */
+ return false;
+}
+
+/* RHS is a source argument in a BIT_AND_EXPR which feeds a conditional
+ of the form SSA_NAME NE 0.
+
+ If RHS is fed by a simple EQ_EXPR comparison of two values, see if
+ the two input values of the EQ_EXPR match arg0 and arg1.
+
+ If so update *code and return TRUE. Otherwise return FALSE. */
+
+static bool
+rhs_is_fed_for_value_replacement (const_tree arg0, const_tree arg1,
+ enum tree_code *code, const_tree rhs)
+{
+ /* Obviously if RHS is not an SSA_NAME, we can't look at the defining
+ statement. */
+ if (TREE_CODE (rhs) == SSA_NAME)
+ {
+ gimple def1 = SSA_NAME_DEF_STMT (rhs);
+
+ /* Verify the defining statement has an EQ_EXPR on the RHS. */
+ if (is_gimple_assign (def1) && gimple_assign_rhs_code (def1) == EQ_EXPR)
+ {
+ /* Finally verify the source operands of the EQ_EXPR are equal
+ to arg0 and arg1. */
+ tree op0 = gimple_assign_rhs1 (def1);
+ tree op1 = gimple_assign_rhs2 (def1);
+ if ((operand_equal_for_phi_arg_p (arg0, op0)
+ && operand_equal_for_phi_arg_p (arg1, op1))
+ || (operand_equal_for_phi_arg_p (arg0, op1)
+ && operand_equal_for_phi_arg_p (arg1, op0)))
+ {
+ /* We will perform the optimization. */
+ *code = gimple_assign_rhs_code (def1);
+ return true;
+ }
+ }
+ }
+ return false;
+}
+
+/* Return TRUE if arg0/arg1 are equal to the rhs/lhs or lhs/rhs of COND.
+
+ Also return TRUE if arg0/arg1 are equal to the source arguments of a
+ an EQ comparison feeding a BIT_AND_EXPR which feeds COND.
+
+ Return FALSE otherwise. */
+
+static bool
+operand_equal_for_value_replacement (const_tree arg0, const_tree arg1,
+ enum tree_code *code, gimple cond)
+{
+ gimple def;
+ tree lhs = gimple_cond_lhs (cond);
+ tree rhs = gimple_cond_rhs (cond);
+
+ if ((operand_equal_for_phi_arg_p (arg0, lhs)
+ && operand_equal_for_phi_arg_p (arg1, rhs))
+ || (operand_equal_for_phi_arg_p (arg1, lhs)
+ && operand_equal_for_phi_arg_p (arg0, rhs)))
+ return true;
+
+ /* Now handle more complex case where we have an EQ comparison
+ which feeds a BIT_AND_EXPR which feeds COND.
+
+ First verify that COND is of the form SSA_NAME NE 0. */
+ if (*code != NE_EXPR || !integer_zerop (rhs)
+ || TREE_CODE (lhs) != SSA_NAME)
+ return false;
+
+ /* Now ensure that SSA_NAME is set by a BIT_AND_EXPR. */
+ def = SSA_NAME_DEF_STMT (lhs);
+ if (!is_gimple_assign (def) || gimple_assign_rhs_code (def) != BIT_AND_EXPR)
+ return false;
+
+ /* Now verify arg0/arg1 correspond to the source arguments of an
+ EQ comparison feeding the BIT_AND_EXPR. */
+
+ tree tmp = gimple_assign_rhs1 (def);
+ if (rhs_is_fed_for_value_replacement (arg0, arg1, code, tmp))
+ return true;
+
+ tmp = gimple_assign_rhs2 (def);
+ if (rhs_is_fed_for_value_replacement (arg0, arg1, code, tmp))
+ return true;
+
+ return false;
+}
+
/* The function value_replacement does the main work of doing the value
- replacement. Return true if the replacement is done. Otherwise return
- false.
+ replacement. Return non-zero if the replacement is done. Otherwise return
+ 0. If we remove the middle basic block, return 2.
BB is the basic block where the replacement is going to be done on. ARG0
is argument 0 from the PHI. Likewise for ARG1. */
-static bool
+static int
value_replacement (basic_block cond_bb, basic_block middle_bb,
edge e0, edge e1, gimple phi,
tree arg0, tree arg1)
{
+ gimple_stmt_iterator gsi;
gimple cond;
edge true_edge, false_edge;
enum tree_code code;
+ bool emtpy_or_with_defined_p = true;
/* If the type says honor signed zeros we cannot do this
optimization. */
if (HONOR_SIGNED_ZEROS (TYPE_MODE (TREE_TYPE (arg1))))
- return false;
+ return 0;
- if (!empty_block_p (middle_bb))
- return false;
+ /* If there is a statement in MIDDLE_BB that defines one of the PHI
+ arguments, then adjust arg0 or arg1. */
+ gsi = gsi_after_labels (middle_bb);
+ if (!gsi_end_p (gsi) && is_gimple_debug (gsi_stmt (gsi)))
+ gsi_next_nondebug (&gsi);
+ while (!gsi_end_p (gsi))
+ {
+ gimple stmt = gsi_stmt (gsi);
+ tree lhs;
+ gsi_next_nondebug (&gsi);
+ if (!is_gimple_assign (stmt))
+ {
+ emtpy_or_with_defined_p = false;
+ continue;
+ }
+ /* Now try to adjust arg0 or arg1 according to the computation
+ in the statement. */
+ lhs = gimple_assign_lhs (stmt);
+ if (!(lhs == arg0
+ && jump_function_from_stmt (&arg0, stmt))
+ || (lhs == arg1
+ && jump_function_from_stmt (&arg1, stmt)))
+ emtpy_or_with_defined_p = false;
+ }
cond = last_stmt (cond_bb);
code = gimple_cond_code (cond);
/* This transformation is only valid for equality comparisons. */
if (code != NE_EXPR && code != EQ_EXPR)
- return false;
+ return 0;
/* We need to know which is the true edge and which is the false
edge so that we know if have abs or negative abs. */
We now need to verify that the two arguments in the PHI node match
the two arguments to the equality comparison. */
- if ((operand_equal_for_phi_arg_p (arg0, gimple_cond_lhs (cond))
- && operand_equal_for_phi_arg_p (arg1, gimple_cond_rhs (cond)))
- || (operand_equal_for_phi_arg_p (arg1, gimple_cond_lhs (cond))
- && operand_equal_for_phi_arg_p (arg0, gimple_cond_rhs (cond))))
+ if (operand_equal_for_value_replacement (arg0, arg1, &code, cond))
{
edge e;
tree arg;
else
arg = arg1;
- replace_phi_edge_with_variable (cond_bb, e1, phi, arg);
+ /* If the middle basic block was empty or is defining the
+ PHI arguments and this is a single phi where the args are different
+ for the edges e0 and e1 then we can remove the middle basic block. */
+ if (emtpy_or_with_defined_p
+ && single_non_singleton_phi_for_edges (phi_nodes (gimple_bb (phi)),
+ e0, e1))
+ {
+ replace_phi_edge_with_variable (cond_bb, e1, phi, arg);
+ /* Note that we optimized this PHI. */
+ return 2;
+ }
+ else
+ {
+ /* Replace the PHI arguments with arg. */
+ SET_PHI_ARG_DEF (phi, e0->dest_idx, arg);
+ SET_PHI_ARG_DEF (phi, e1->dest_idx, arg);
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "PHI ");
+ print_generic_expr (dump_file, gimple_phi_result (phi), 0);
+ fprintf (dump_file, " reduced for COND_EXPR in block %d to ",
+ cond_bb->index);
+ print_generic_expr (dump_file, arg, 0);
+ fprintf (dump_file, ".\n");
+ }
+ return 1;
+ }
- /* Note that we optimized this PHI. */
- return true;
}
- return false;
+ return 0;
}
/* The function minmax_replacement does the main work of doing the minmax
cond = last_stmt (cond_bb);
cmp = gimple_cond_code (cond);
- result = PHI_RESULT (phi);
/* This transformation is only valid for order comparisons. Record which
operand is smaller/larger if the result of the comparison is true. */
&& operand_equal_for_phi_arg_p (arg_false, larger))
{
/* Case
-
+
if (smaller < larger)
rslt = smaller;
else
optimize. */
if (assign == NULL)
return false;
-
+
/* If we got here, then we have found the only executable statement
in OTHER_BLOCK. If it is anything other than arg = -arg1 or
arg1 = -arg0, then we can not optimize. */
return false;
rhs = gimple_assign_rhs1 (assign);
-
+
/* The assignment has to be arg0 = -arg1 or arg1 = -arg0. */
if (!(lhs == arg0 && rhs == arg1)
&& !(lhs == arg1 && rhs == arg0))
result = duplicate_ssa_name (result, NULL);
if (negate)
- {
- tree tmp = create_tmp_var (TREE_TYPE (result), NULL);
- add_referenced_var (tmp);
- lhs = make_ssa_name (tmp, NULL);
- }
+ lhs = make_ssa_name (TREE_TYPE (result), NULL);
else
lhs = result;
/* Auxiliary functions to determine the set of memory accesses which
can't trap because they are preceded by accesses to the same memory
- portion. We do that for INDIRECT_REFs, so we only need to track
+ portion. We do that for MEM_REFs, so we only need to track
the SSA_NAME of the pointer indirectly referenced. The algorithm
simply is a walk over all instructions in dominator order. When
- we see an INDIRECT_REF we determine if we've already seen a same
+ we see an MEM_REF we determine if we've already seen a same
ref anywhere up to the root of the dominator tree. If we do the
current access can't trap. If we don't see any dominating access
the current access might trap, but might also make later accesses
trap even if a store doesn't (write-only memory). This probably is
overly conservative. */
-/* A hash-table of SSA_NAMEs, and in which basic block an INDIRECT_REF
+/* A hash-table of SSA_NAMEs, and in which basic block an MEM_REF
through it was seen, which would constitute a no-trap region for
same accesses. */
struct name_to_bb
{
- tree ssa_name;
+ unsigned int ssa_name_ver;
+ unsigned int phase;
+ bool store;
+ HOST_WIDE_INT offset, size;
basic_block bb;
- unsigned store : 1;
};
-/* The hash table for remembering what we've seen. */
-static htab_t seen_ssa_names;
+/* Hashtable helpers. */
+
+struct ssa_names_hasher : typed_free_remove <name_to_bb>
+{
+ typedef name_to_bb value_type;
+ typedef name_to_bb compare_type;
+ static inline hashval_t hash (const value_type *);
+ static inline bool equal (const value_type *, const compare_type *);
+};
+
+/* Used for quick clearing of the hash-table when we see calls.
+ Hash entries with phase < nt_call_phase are invalid. */
+static unsigned int nt_call_phase;
-/* The set of INDIRECT_REFs which can't trap. */
-static struct pointer_set_t *nontrap_set;
+/* The hash function. */
-/* The hash function, based on the pointer to the pointer SSA_NAME. */
-static hashval_t
-name_to_bb_hash (const void *p)
+inline hashval_t
+ssa_names_hasher::hash (const value_type *n)
{
- const_tree n = ((const struct name_to_bb *)p)->ssa_name;
- return htab_hash_pointer (n) ^ ((const struct name_to_bb *)p)->store;
+ return n->ssa_name_ver ^ (((hashval_t) n->store) << 31)
+ ^ (n->offset << 6) ^ (n->size << 3);
}
-/* The equality function of *P1 and *P2. SSA_NAMEs are shared, so
- it's enough to simply compare them for equality. */
-static int
-name_to_bb_eq (const void *p1, const void *p2)
-{
- const struct name_to_bb *n1 = (const struct name_to_bb *)p1;
- const struct name_to_bb *n2 = (const struct name_to_bb *)p2;
+/* The equality function of *P1 and *P2. */
- return n1->ssa_name == n2->ssa_name && n1->store == n2->store;
+inline bool
+ssa_names_hasher::equal (const value_type *n1, const compare_type *n2)
+{
+ return n1->ssa_name_ver == n2->ssa_name_ver
+ && n1->store == n2->store
+ && n1->offset == n2->offset
+ && n1->size == n2->size;
}
+/* The hash table for remembering what we've seen. */
+static hash_table <ssa_names_hasher> seen_ssa_names;
+
/* We see the expression EXP in basic block BB. If it's an interesting
- expression (an INDIRECT_REF through an SSA_NAME) possibly insert the
+ expression (an MEM_REF through an SSA_NAME) possibly insert the
expression into the set NONTRAP or the hash table of seen expressions.
STORE is true if this expression is on the LHS, otherwise it's on
the RHS. */
add_or_mark_expr (basic_block bb, tree exp,
struct pointer_set_t *nontrap, bool store)
{
- if (INDIRECT_REF_P (exp)
- && TREE_CODE (TREE_OPERAND (exp, 0)) == SSA_NAME)
+ HOST_WIDE_INT size;
+
+ if (TREE_CODE (exp) == MEM_REF
+ && TREE_CODE (TREE_OPERAND (exp, 0)) == SSA_NAME
+ && tree_fits_shwi_p (TREE_OPERAND (exp, 1))
+ && (size = int_size_in_bytes (TREE_TYPE (exp))) > 0)
{
tree name = TREE_OPERAND (exp, 0);
struct name_to_bb map;
- void **slot;
+ name_to_bb **slot;
struct name_to_bb *n2bb;
basic_block found_bb = 0;
- /* Try to find the last seen INDIRECT_REF through the same
+ /* Try to find the last seen MEM_REF through the same
SSA_NAME, which can trap. */
- map.ssa_name = name;
+ map.ssa_name_ver = SSA_NAME_VERSION (name);
+ map.phase = 0;
map.bb = 0;
map.store = store;
- slot = htab_find_slot (seen_ssa_names, &map, INSERT);
- n2bb = (struct name_to_bb *) *slot;
- if (n2bb)
+ map.offset = tree_to_shwi (TREE_OPERAND (exp, 1));
+ map.size = size;
+
+ slot = seen_ssa_names.find_slot (&map, INSERT);
+ n2bb = *slot;
+ if (n2bb && n2bb->phase >= nt_call_phase)
found_bb = n2bb->bb;
- /* If we've found a trapping INDIRECT_REF, _and_ it dominates EXP
+ /* If we've found a trapping MEM_REF, _and_ it dominates EXP
(it's in a basic block on the path from us to the dominator root)
then we can't trap. */
- if (found_bb && found_bb->aux == (void *)1)
+ if (found_bb && (((size_t)found_bb->aux) & 1) == 1)
{
pointer_set_insert (nontrap, exp);
}
/* EXP might trap, so insert it into the hash table. */
if (n2bb)
{
+ n2bb->phase = nt_call_phase;
n2bb->bb = bb;
}
else
{
n2bb = XNEW (struct name_to_bb);
- n2bb->ssa_name = name;
+ n2bb->ssa_name_ver = SSA_NAME_VERSION (name);
+ n2bb->phase = nt_call_phase;
n2bb->bb = bb;
n2bb->store = store;
+ n2bb->offset = map.offset;
+ n2bb->size = size;
*slot = n2bb;
}
}
}
}
+class nontrapping_dom_walker : public dom_walker
+{
+public:
+ nontrapping_dom_walker (cdi_direction direction, pointer_set_t *ps)
+ : dom_walker (direction), m_nontrapping (ps) {}
+
+ virtual void before_dom_children (basic_block);
+ virtual void after_dom_children (basic_block);
+
+private:
+ pointer_set_t *m_nontrapping;
+};
+
/* Called by walk_dominator_tree, when entering the block BB. */
-static void
-nt_init_block (struct dom_walk_data *data ATTRIBUTE_UNUSED, basic_block bb)
+void
+nontrapping_dom_walker::before_dom_children (basic_block bb)
{
+ edge e;
+ edge_iterator ei;
gimple_stmt_iterator gsi;
- /* Mark this BB as being on the path to dominator root. */
- bb->aux = (void*)1;
+
+ /* If we haven't seen all our predecessors, clear the hash-table. */
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ if ((((size_t)e->src->aux) & 2) == 0)
+ {
+ nt_call_phase++;
+ break;
+ }
+
+ /* Mark this BB as being on the path to dominator root and as visited. */
+ bb->aux = (void*)(1 | 2);
/* And walk the statements in order. */
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
{
gimple stmt = gsi_stmt (gsi);
- if (is_gimple_assign (stmt))
+ if (is_gimple_call (stmt) && !nonfreeing_call_p (stmt))
+ nt_call_phase++;
+ else if (gimple_assign_single_p (stmt) && !gimple_has_volatile_ops (stmt))
{
- add_or_mark_expr (bb, gimple_assign_lhs (stmt), nontrap_set, true);
- add_or_mark_expr (bb, gimple_assign_rhs1 (stmt), nontrap_set, false);
- if (get_gimple_rhs_num_ops (gimple_assign_rhs_code (stmt)) > 1)
- add_or_mark_expr (bb, gimple_assign_rhs2 (stmt), nontrap_set,
- false);
+ add_or_mark_expr (bb, gimple_assign_lhs (stmt), m_nontrapping, true);
+ add_or_mark_expr (bb, gimple_assign_rhs1 (stmt), m_nontrapping, false);
}
}
}
/* Called by walk_dominator_tree, when basic block BB is exited. */
-static void
-nt_fini_block (struct dom_walk_data *data ATTRIBUTE_UNUSED, basic_block bb)
+void
+nontrapping_dom_walker::after_dom_children (basic_block bb)
{
/* This BB isn't on the path to dominator root anymore. */
- bb->aux = NULL;
+ bb->aux = (void*)2;
}
/* This is the entry point of gathering non trapping memory accesses.
It will do a dominator walk over the whole function, and it will
make use of the bb->aux pointers. It returns a set of trees
- (the INDIRECT_REFs itself) which can't trap. */
+ (the MEM_REFs itself) which can't trap. */
static struct pointer_set_t *
get_non_trapping (void)
{
- struct pointer_set_t *nontrap;
- struct dom_walk_data walk_data;
-
- nontrap = pointer_set_create ();
- seen_ssa_names = htab_create (128, name_to_bb_hash, name_to_bb_eq,
- free);
+ nt_call_phase = 0;
+ pointer_set_t *nontrap = pointer_set_create ();
+ seen_ssa_names.create (128);
/* We're going to do a dominator walk, so ensure that we have
dominance information. */
calculate_dominance_info (CDI_DOMINATORS);
- /* Setup callbacks for the generic dominator tree walker. */
- nontrap_set = nontrap;
- walk_data.dom_direction = CDI_DOMINATORS;
- walk_data.initialize_block_local_data = NULL;
- walk_data.before_dom_children = nt_init_block;
- walk_data.after_dom_children = nt_fini_block;
- walk_data.global_data = NULL;
- walk_data.block_local_data_size = 0;
+ nontrapping_dom_walker (CDI_DOMINATORS, nontrap)
+ .walk (cfun->cfg->x_entry_block_ptr);
- init_walk_dominator_tree (&walk_data);
- walk_dominator_tree (&walk_data, ENTRY_BLOCK_PTR);
- fini_walk_dominator_tree (&walk_data);
- htab_delete (seen_ssa_names);
+ seen_ssa_names.dispose ();
+ clear_aux_for_blocks ();
return nontrap;
}
edge e0, edge e1, struct pointer_set_t *nontrap)
{
gimple assign = last_and_only_stmt (middle_bb);
- tree lhs, rhs, name;
+ tree lhs, rhs, name, name2;
gimple newphi, new_stmt;
gimple_stmt_iterator gsi;
source_location locus;
- enum tree_code code;
/* Check if middle_bb contains of only one store. */
if (!assign
- || gimple_code (assign) != GIMPLE_ASSIGN)
+ || !gimple_assign_single_p (assign)
+ || gimple_has_volatile_ops (assign))
return false;
locus = gimple_location (assign);
lhs = gimple_assign_lhs (assign);
rhs = gimple_assign_rhs1 (assign);
- if (!INDIRECT_REF_P (lhs))
+ if (TREE_CODE (lhs) != MEM_REF
+ || TREE_CODE (TREE_OPERAND (lhs, 0)) != SSA_NAME
+ || !is_gimple_reg_type (TREE_TYPE (lhs)))
return false;
- /* RHS is either a single SSA_NAME or a constant. */
- code = gimple_assign_rhs_code (assign);
- if (get_gimple_rhs_class (code) != GIMPLE_SINGLE_RHS
- || (code != SSA_NAME && !is_gimple_min_invariant (rhs)))
- return false;
/* Prove that we can move the store down. We could also check
TREE_THIS_NOTRAP here, but in that case we also could move stores,
whose value is not available readily, which we want to avoid. */
/* Now we've checked the constraints, so do the transformation:
1) Remove the single store. */
- mark_symbols_for_renaming (assign);
gsi = gsi_for_stmt (assign);
+ unlink_stmt_vdef (assign);
gsi_remove (&gsi, true);
+ release_defs (assign);
- /* 2) Create a temporary where we can store the old content
- of the memory touched by the store, if we need to. */
- if (!condstoretemp || TREE_TYPE (lhs) != TREE_TYPE (condstoretemp))
- {
- condstoretemp = create_tmp_var (TREE_TYPE (lhs), "cstore");
- get_var_ann (condstoretemp);
- if (TREE_CODE (TREE_TYPE (lhs)) == COMPLEX_TYPE
- || TREE_CODE (TREE_TYPE (lhs)) == VECTOR_TYPE)
- DECL_GIMPLE_REG_P (condstoretemp) = 1;
- }
- add_referenced_var (condstoretemp);
-
- /* 3) Insert a load from the memory of the store to the temporary
+ /* 2) Insert a load from the memory of the store to the temporary
on the edge which did not contain the store. */
lhs = unshare_expr (lhs);
- new_stmt = gimple_build_assign (condstoretemp, lhs);
- name = make_ssa_name (condstoretemp, new_stmt);
- gimple_assign_set_lhs (new_stmt, name);
+ name = make_temp_ssa_name (TREE_TYPE (lhs), NULL, "cstore");
+ new_stmt = gimple_build_assign (name, lhs);
gimple_set_location (new_stmt, locus);
- mark_symbols_for_renaming (new_stmt);
gsi_insert_on_edge (e1, new_stmt);
- /* 4) Create a PHI node at the join block, with one argument
+ /* 3) Create a PHI node at the join block, with one argument
holding the old RHS, and the other holding the temporary
where we stored the old memory contents. */
- newphi = create_phi_node (condstoretemp, join_bb);
+ name2 = make_temp_ssa_name (TREE_TYPE (lhs), NULL, "cstore");
+ newphi = create_phi_node (name2, join_bb);
add_phi_arg (newphi, rhs, e0, locus);
add_phi_arg (newphi, name, e1, locus);
lhs = unshare_expr (lhs);
new_stmt = gimple_build_assign (lhs, PHI_RESULT (newphi));
- mark_symbols_for_renaming (new_stmt);
- /* 5) Insert that PHI node. */
+ /* 4) Insert that PHI node. */
gsi = gsi_after_labels (join_bb);
if (gsi_end_p (gsi))
{
return true;
}
+/* Do the main work of conditional store replacement. */
+
+static bool
+cond_if_else_store_replacement_1 (basic_block then_bb, basic_block else_bb,
+ basic_block join_bb, gimple then_assign,
+ gimple else_assign)
+{
+ tree lhs_base, lhs, then_rhs, else_rhs, name;
+ source_location then_locus, else_locus;
+ gimple_stmt_iterator gsi;
+ gimple newphi, new_stmt;
+
+ if (then_assign == NULL
+ || !gimple_assign_single_p (then_assign)
+ || gimple_clobber_p (then_assign)
+ || gimple_has_volatile_ops (then_assign)
+ || else_assign == NULL
+ || !gimple_assign_single_p (else_assign)
+ || gimple_clobber_p (else_assign)
+ || gimple_has_volatile_ops (else_assign))
+ return false;
+
+ lhs = gimple_assign_lhs (then_assign);
+ if (!is_gimple_reg_type (TREE_TYPE (lhs))
+ || !operand_equal_p (lhs, gimple_assign_lhs (else_assign), 0))
+ return false;
+
+ lhs_base = get_base_address (lhs);
+ if (lhs_base == NULL_TREE
+ || (!DECL_P (lhs_base) && TREE_CODE (lhs_base) != MEM_REF))
+ return false;
+
+ then_rhs = gimple_assign_rhs1 (then_assign);
+ else_rhs = gimple_assign_rhs1 (else_assign);
+ then_locus = gimple_location (then_assign);
+ else_locus = gimple_location (else_assign);
+
+ /* Now we've checked the constraints, so do the transformation:
+ 1) Remove the stores. */
+ gsi = gsi_for_stmt (then_assign);
+ unlink_stmt_vdef (then_assign);
+ gsi_remove (&gsi, true);
+ release_defs (then_assign);
+
+ gsi = gsi_for_stmt (else_assign);
+ unlink_stmt_vdef (else_assign);
+ gsi_remove (&gsi, true);
+ release_defs (else_assign);
+
+ /* 2) Create a PHI node at the join block, with one argument
+ holding the old RHS, and the other holding the temporary
+ where we stored the old memory contents. */
+ name = make_temp_ssa_name (TREE_TYPE (lhs), NULL, "cstore");
+ newphi = create_phi_node (name, join_bb);
+ add_phi_arg (newphi, then_rhs, EDGE_SUCC (then_bb, 0), then_locus);
+ add_phi_arg (newphi, else_rhs, EDGE_SUCC (else_bb, 0), else_locus);
+
+ new_stmt = gimple_build_assign (lhs, PHI_RESULT (newphi));
+
+ /* 3) Insert that PHI node. */
+ gsi = gsi_after_labels (join_bb);
+ if (gsi_end_p (gsi))
+ {
+ gsi = gsi_last_bb (join_bb);
+ gsi_insert_after (&gsi, new_stmt, GSI_NEW_STMT);
+ }
+ else
+ gsi_insert_before (&gsi, new_stmt, GSI_NEW_STMT);
+
+ return true;
+}
+
+/* Conditional store replacement. We already know
+ that the recognized pattern looks like so:
+
+ split:
+ if (cond) goto THEN_BB; else goto ELSE_BB (edge E1)
+ THEN_BB:
+ ...
+ X = Y;
+ ...
+ goto JOIN_BB;
+ ELSE_BB:
+ ...
+ X = Z;
+ ...
+ fallthrough (edge E0)
+ JOIN_BB:
+ some more
+
+ We check that it is safe to sink the store to JOIN_BB by verifying that
+ there are no read-after-write or write-after-write dependencies in
+ THEN_BB and ELSE_BB. */
+
+static bool
+cond_if_else_store_replacement (basic_block then_bb, basic_block else_bb,
+ basic_block join_bb)
+{
+ gimple then_assign = last_and_only_stmt (then_bb);
+ gimple else_assign = last_and_only_stmt (else_bb);
+ vec<data_reference_p> then_datarefs, else_datarefs;
+ vec<ddr_p> then_ddrs, else_ddrs;
+ gimple then_store, else_store;
+ bool found, ok = false, res;
+ struct data_dependence_relation *ddr;
+ data_reference_p then_dr, else_dr;
+ int i, j;
+ tree then_lhs, else_lhs;
+ basic_block blocks[3];
+
+ if (MAX_STORES_TO_SINK == 0)
+ return false;
+
+ /* Handle the case with single statement in THEN_BB and ELSE_BB. */
+ if (then_assign && else_assign)
+ return cond_if_else_store_replacement_1 (then_bb, else_bb, join_bb,
+ then_assign, else_assign);
+
+ /* Find data references. */
+ then_datarefs.create (1);
+ else_datarefs.create (1);
+ if ((find_data_references_in_bb (NULL, then_bb, &then_datarefs)
+ == chrec_dont_know)
+ || !then_datarefs.length ()
+ || (find_data_references_in_bb (NULL, else_bb, &else_datarefs)
+ == chrec_dont_know)
+ || !else_datarefs.length ())
+ {
+ free_data_refs (then_datarefs);
+ free_data_refs (else_datarefs);
+ return false;
+ }
+
+ /* Find pairs of stores with equal LHS. */
+ stack_vec<gimple, 1> then_stores, else_stores;
+ FOR_EACH_VEC_ELT (then_datarefs, i, then_dr)
+ {
+ if (DR_IS_READ (then_dr))
+ continue;
+
+ then_store = DR_STMT (then_dr);
+ then_lhs = gimple_get_lhs (then_store);
+ if (then_lhs == NULL_TREE)
+ continue;
+ found = false;
+
+ FOR_EACH_VEC_ELT (else_datarefs, j, else_dr)
+ {
+ if (DR_IS_READ (else_dr))
+ continue;
+
+ else_store = DR_STMT (else_dr);
+ else_lhs = gimple_get_lhs (else_store);
+ if (else_lhs == NULL_TREE)
+ continue;
+
+ if (operand_equal_p (then_lhs, else_lhs, 0))
+ {
+ found = true;
+ break;
+ }
+ }
+
+ if (!found)
+ continue;
+
+ then_stores.safe_push (then_store);
+ else_stores.safe_push (else_store);
+ }
+
+ /* No pairs of stores found. */
+ if (!then_stores.length ()
+ || then_stores.length () > (unsigned) MAX_STORES_TO_SINK)
+ {
+ free_data_refs (then_datarefs);
+ free_data_refs (else_datarefs);
+ return false;
+ }
+
+ /* Compute and check data dependencies in both basic blocks. */
+ then_ddrs.create (1);
+ else_ddrs.create (1);
+ if (!compute_all_dependences (then_datarefs, &then_ddrs,
+ vNULL, false)
+ || !compute_all_dependences (else_datarefs, &else_ddrs,
+ vNULL, false))
+ {
+ free_dependence_relations (then_ddrs);
+ free_dependence_relations (else_ddrs);
+ free_data_refs (then_datarefs);
+ free_data_refs (else_datarefs);
+ return false;
+ }
+ blocks[0] = then_bb;
+ blocks[1] = else_bb;
+ blocks[2] = join_bb;
+ renumber_gimple_stmt_uids_in_blocks (blocks, 3);
+
+ /* Check that there are no read-after-write or write-after-write dependencies
+ in THEN_BB. */
+ FOR_EACH_VEC_ELT (then_ddrs, i, ddr)
+ {
+ struct data_reference *dra = DDR_A (ddr);
+ struct data_reference *drb = DDR_B (ddr);
+
+ if (DDR_ARE_DEPENDENT (ddr) != chrec_known
+ && ((DR_IS_READ (dra) && DR_IS_WRITE (drb)
+ && gimple_uid (DR_STMT (dra)) > gimple_uid (DR_STMT (drb)))
+ || (DR_IS_READ (drb) && DR_IS_WRITE (dra)
+ && gimple_uid (DR_STMT (drb)) > gimple_uid (DR_STMT (dra)))
+ || (DR_IS_WRITE (dra) && DR_IS_WRITE (drb))))
+ {
+ free_dependence_relations (then_ddrs);
+ free_dependence_relations (else_ddrs);
+ free_data_refs (then_datarefs);
+ free_data_refs (else_datarefs);
+ return false;
+ }
+ }
+
+ /* Check that there are no read-after-write or write-after-write dependencies
+ in ELSE_BB. */
+ FOR_EACH_VEC_ELT (else_ddrs, i, ddr)
+ {
+ struct data_reference *dra = DDR_A (ddr);
+ struct data_reference *drb = DDR_B (ddr);
+
+ if (DDR_ARE_DEPENDENT (ddr) != chrec_known
+ && ((DR_IS_READ (dra) && DR_IS_WRITE (drb)
+ && gimple_uid (DR_STMT (dra)) > gimple_uid (DR_STMT (drb)))
+ || (DR_IS_READ (drb) && DR_IS_WRITE (dra)
+ && gimple_uid (DR_STMT (drb)) > gimple_uid (DR_STMT (dra)))
+ || (DR_IS_WRITE (dra) && DR_IS_WRITE (drb))))
+ {
+ free_dependence_relations (then_ddrs);
+ free_dependence_relations (else_ddrs);
+ free_data_refs (then_datarefs);
+ free_data_refs (else_datarefs);
+ return false;
+ }
+ }
+
+ /* Sink stores with same LHS. */
+ FOR_EACH_VEC_ELT (then_stores, i, then_store)
+ {
+ else_store = else_stores[i];
+ res = cond_if_else_store_replacement_1 (then_bb, else_bb, join_bb,
+ then_store, else_store);
+ ok = ok || res;
+ }
+
+ free_dependence_relations (then_ddrs);
+ free_dependence_relations (else_ddrs);
+ free_data_refs (then_datarefs);
+ free_data_refs (else_datarefs);
+
+ return ok;
+}
+
+/* Return TRUE if STMT has a VUSE whose corresponding VDEF is in BB. */
+
+static bool
+local_mem_dependence (gimple stmt, basic_block bb)
+{
+ tree vuse = gimple_vuse (stmt);
+ gimple def;
+
+ if (!vuse)
+ return false;
+
+ def = SSA_NAME_DEF_STMT (vuse);
+ return (def && gimple_bb (def) == bb);
+}
+
+/* Given a "diamond" control-flow pattern where BB0 tests a condition,
+ BB1 and BB2 are "then" and "else" blocks dependent on this test,
+ and BB3 rejoins control flow following BB1 and BB2, look for
+ opportunities to hoist loads as follows. If BB3 contains a PHI of
+ two loads, one each occurring in BB1 and BB2, and the loads are
+ provably of adjacent fields in the same structure, then move both
+ loads into BB0. Of course this can only be done if there are no
+ dependencies preventing such motion.
+
+ One of the hoisted loads will always be speculative, so the
+ transformation is currently conservative:
+
+ - The fields must be strictly adjacent.
+ - The two fields must occupy a single memory block that is
+ guaranteed to not cross a page boundary.
+
+ The last is difficult to prove, as such memory blocks should be
+ aligned on the minimum of the stack alignment boundary and the
+ alignment guaranteed by heap allocation interfaces. Thus we rely
+ on a parameter for the alignment value.
+
+ Provided a good value is used for the last case, the first
+ restriction could possibly be relaxed. */
+
+static void
+hoist_adjacent_loads (basic_block bb0, basic_block bb1,
+ basic_block bb2, basic_block bb3)
+{
+ int param_align = PARAM_VALUE (PARAM_L1_CACHE_LINE_SIZE);
+ unsigned param_align_bits = (unsigned) (param_align * BITS_PER_UNIT);
+ gimple_stmt_iterator gsi;
+
+ /* Walk the phis in bb3 looking for an opportunity. We are looking
+ for phis of two SSA names, one each of which is defined in bb1 and
+ bb2. */
+ for (gsi = gsi_start_phis (bb3); !gsi_end_p (gsi); gsi_next (&gsi))
+ {
+ gimple phi_stmt = gsi_stmt (gsi);
+ gimple def1, def2, defswap;
+ tree arg1, arg2, ref1, ref2, field1, field2, fieldswap;
+ tree tree_offset1, tree_offset2, tree_size2, next;
+ int offset1, offset2, size2;
+ unsigned align1;
+ gimple_stmt_iterator gsi2;
+ basic_block bb_for_def1, bb_for_def2;
+
+ if (gimple_phi_num_args (phi_stmt) != 2
+ || virtual_operand_p (gimple_phi_result (phi_stmt)))
+ continue;
+
+ arg1 = gimple_phi_arg_def (phi_stmt, 0);
+ arg2 = gimple_phi_arg_def (phi_stmt, 1);
+
+ if (TREE_CODE (arg1) != SSA_NAME
+ || TREE_CODE (arg2) != SSA_NAME
+ || SSA_NAME_IS_DEFAULT_DEF (arg1)
+ || SSA_NAME_IS_DEFAULT_DEF (arg2))
+ continue;
+
+ def1 = SSA_NAME_DEF_STMT (arg1);
+ def2 = SSA_NAME_DEF_STMT (arg2);
+
+ if ((gimple_bb (def1) != bb1 || gimple_bb (def2) != bb2)
+ && (gimple_bb (def2) != bb1 || gimple_bb (def1) != bb2))
+ continue;
+
+ /* Check the mode of the arguments to be sure a conditional move
+ can be generated for it. */
+ if (optab_handler (movcc_optab, TYPE_MODE (TREE_TYPE (arg1)))
+ == CODE_FOR_nothing)
+ continue;
+
+ /* Both statements must be assignments whose RHS is a COMPONENT_REF. */
+ if (!gimple_assign_single_p (def1)
+ || !gimple_assign_single_p (def2)
+ || gimple_has_volatile_ops (def1)
+ || gimple_has_volatile_ops (def2))
+ continue;
+
+ ref1 = gimple_assign_rhs1 (def1);
+ ref2 = gimple_assign_rhs1 (def2);
+
+ if (TREE_CODE (ref1) != COMPONENT_REF
+ || TREE_CODE (ref2) != COMPONENT_REF)
+ continue;
+
+ /* The zeroth operand of the two component references must be
+ identical. It is not sufficient to compare get_base_address of
+ the two references, because this could allow for different
+ elements of the same array in the two trees. It is not safe to
+ assume that the existence of one array element implies the
+ existence of a different one. */
+ if (!operand_equal_p (TREE_OPERAND (ref1, 0), TREE_OPERAND (ref2, 0), 0))
+ continue;
+
+ field1 = TREE_OPERAND (ref1, 1);
+ field2 = TREE_OPERAND (ref2, 1);
+
+ /* Check for field adjacency, and ensure field1 comes first. */
+ for (next = DECL_CHAIN (field1);
+ next && TREE_CODE (next) != FIELD_DECL;
+ next = DECL_CHAIN (next))
+ ;
+
+ if (next != field2)
+ {
+ for (next = DECL_CHAIN (field2);
+ next && TREE_CODE (next) != FIELD_DECL;
+ next = DECL_CHAIN (next))
+ ;
+
+ if (next != field1)
+ continue;
+
+ fieldswap = field1;
+ field1 = field2;
+ field2 = fieldswap;
+ defswap = def1;
+ def1 = def2;
+ def2 = defswap;
+ }
+
+ bb_for_def1 = gimple_bb (def1);
+ bb_for_def2 = gimple_bb (def2);
+
+ /* Check for proper alignment of the first field. */
+ tree_offset1 = bit_position (field1);
+ tree_offset2 = bit_position (field2);
+ tree_size2 = DECL_SIZE (field2);
+
+ if (!tree_fits_uhwi_p (tree_offset1)
+ || !tree_fits_uhwi_p (tree_offset2)
+ || !tree_fits_uhwi_p (tree_size2))
+ continue;
+
+ offset1 = tree_to_uhwi (tree_offset1);
+ offset2 = tree_to_uhwi (tree_offset2);
+ size2 = tree_to_uhwi (tree_size2);
+ align1 = DECL_ALIGN (field1) % param_align_bits;
+
+ if (offset1 % BITS_PER_UNIT != 0)
+ continue;
+
+ /* For profitability, the two field references should fit within
+ a single cache line. */
+ if (align1 + offset2 - offset1 + size2 > param_align_bits)
+ continue;
+
+ /* The two expressions cannot be dependent upon vdefs defined
+ in bb1/bb2. */
+ if (local_mem_dependence (def1, bb_for_def1)
+ || local_mem_dependence (def2, bb_for_def2))
+ continue;
+
+ /* The conditions are satisfied; hoist the loads from bb1 and bb2 into
+ bb0. We hoist the first one first so that a cache miss is handled
+ efficiently regardless of hardware cache-fill policy. */
+ gsi2 = gsi_for_stmt (def1);
+ gsi_move_to_bb_end (&gsi2, bb0);
+ gsi2 = gsi_for_stmt (def2);
+ gsi_move_to_bb_end (&gsi2, bb0);
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file,
+ "\nHoisting adjacent loads from %d and %d into %d: \n",
+ bb_for_def1->index, bb_for_def2->index, bb0->index);
+ print_gimple_stmt (dump_file, def1, 0, TDF_VOPS|TDF_MEMSYMS);
+ print_gimple_stmt (dump_file, def2, 0, TDF_VOPS|TDF_MEMSYMS);
+ }
+ }
+}
+
+/* Determine whether we should attempt to hoist adjacent loads out of
+ diamond patterns in pass_phiopt. Always hoist loads if
+ -fhoist-adjacent-loads is specified and the target machine has
+ both a conditional move instruction and a defined cache line size. */
+
+static bool
+gate_hoist_loads (void)
+{
+ return (flag_hoist_adjacent_loads == 1
+ && PARAM_VALUE (PARAM_L1_CACHE_LINE_SIZE)
+ && HAVE_conditional_move);
+}
+
/* Always do these optimizations if we have SSA
trees to work on. */
static bool
return 1;
}
-struct gimple_opt_pass pass_phiopt =
+namespace {
+
+const pass_data pass_data_phiopt =
{
- {
- GIMPLE_PASS,
- "phiopt", /* name */
- gate_phiopt, /* gate */
- tree_ssa_phiopt, /* execute */
- NULL, /* sub */
- NULL, /* next */
- 0, /* static_pass_number */
- TV_TREE_PHIOPT, /* 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_verify_ssa
- | TODO_verify_flow
- | TODO_verify_stmts /* todo_flags_finish */
- }
+ GIMPLE_PASS, /* type */
+ "phiopt", /* name */
+ OPTGROUP_NONE, /* optinfo_flags */
+ true, /* has_gate */
+ true, /* has_execute */
+ TV_TREE_PHIOPT, /* tv_id */
+ ( PROP_cfg | PROP_ssa ), /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ ( TODO_verify_ssa | TODO_verify_flow
+ | TODO_verify_stmts ), /* todo_flags_finish */
};
+class pass_phiopt : public gimple_opt_pass
+{
+public:
+ pass_phiopt (gcc::context *ctxt)
+ : gimple_opt_pass (pass_data_phiopt, ctxt)
+ {}
+
+ /* opt_pass methods: */
+ opt_pass * clone () { return new pass_phiopt (m_ctxt); }
+ bool gate () { return gate_phiopt (); }
+ unsigned int execute () { return tree_ssa_phiopt (); }
+
+}; // class pass_phiopt
+
+} // anon namespace
+
+gimple_opt_pass *
+make_pass_phiopt (gcc::context *ctxt)
+{
+ return new pass_phiopt (ctxt);
+}
+
static bool
gate_cselim (void)
{
return flag_tree_cselim;
}
-struct gimple_opt_pass pass_cselim =
+namespace {
+
+const pass_data pass_data_cselim =
{
- {
- GIMPLE_PASS,
- "cselim", /* name */
- gate_cselim, /* gate */
- tree_ssa_cs_elim, /* execute */
- NULL, /* sub */
- NULL, /* next */
- 0, /* static_pass_number */
- TV_TREE_PHIOPT, /* 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_verify_ssa
- | TODO_verify_flow
- | TODO_verify_stmts /* todo_flags_finish */
- }
+ GIMPLE_PASS, /* type */
+ "cselim", /* name */
+ OPTGROUP_NONE, /* optinfo_flags */
+ true, /* has_gate */
+ true, /* has_execute */
+ TV_TREE_PHIOPT, /* tv_id */
+ ( PROP_cfg | PROP_ssa ), /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ ( TODO_verify_ssa | TODO_verify_flow
+ | TODO_verify_stmts ), /* todo_flags_finish */
};
+
+class pass_cselim : public gimple_opt_pass
+{
+public:
+ pass_cselim (gcc::context *ctxt)
+ : gimple_opt_pass (pass_data_cselim, ctxt)
+ {}
+
+ /* opt_pass methods: */
+ bool gate () { return gate_cselim (); }
+ unsigned int execute () { return tree_ssa_cs_elim (); }
+
+}; // class pass_cselim
+
+} // anon namespace
+
+gimple_opt_pass *
+make_pass_cselim (gcc::context *ctxt)
+{
+ return new pass_cselim (ctxt);
+}
projects / gcc.git / blobdiff