X-Git-Url: http://git.sourceforge.jp/view?a=blobdiff_plain;f=gcc%2Ftree-ssa-phiopt.c;h=72ba04a09b87ce7350923fd8f9af3f2c075f6a10;hb=8d40ea4504ee85e1a6b73103edb1776141d5d22e;hp=3c241e43fc54de713d0f7560e547ceaa3c5d2b31;hpb=cbcbd868bd5105a82cf3a9a679b073f785c170bb;p=pf3gnuchains%2Fgcc-fork.git
diff --git a/gcc/tree-ssa-phiopt.c b/gcc/tree-ssa-phiopt.c
index 3c241e43fc5..72ba04a09b8 100644
--- a/gcc/tree-ssa-phiopt.c
+++ b/gcc/tree-ssa-phiopt.c
@@ -1,28 +1,27 @@
/* Optimization of PHI nodes by converting them into straightline code.
- Copyright (C) 2004 Free Software Foundation, Inc.
+ Copyright (C) 2004, 2005, 2006, 2007, 2008 Free Software Foundation,
+ Inc.
This file is part of GCC.
-
+
GCC is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
-Free Software Foundation; either version 2, or (at your option) any
+Free Software Foundation; either version 3, or (at your option) any
later version.
-
+
GCC is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
-
+
You should have received a copy of the GNU General Public License
-along with GCC; see the file COPYING. If not, write to the Free
-Software Foundation, 59 Temple Place - Suite 330, Boston, MA
-02111-1307, USA. */
+along with GCC; see the file COPYING3. If not see
+. */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
-#include "errors.h"
#include "ggc.h"
#include "tree.h"
#include "rtl.h"
@@ -35,218 +34,381 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA
#include "tree-pass.h"
#include "tree-dump.h"
#include "langhooks.h"
-
-static void tree_ssa_phiopt (void);
-static bool conditional_replacement (basic_block, tree, tree, tree);
-static bool value_replacement (basic_block, tree, tree, tree);
-static bool abs_replacement (basic_block, tree, tree, tree);
-static void replace_phi_with_stmt (block_stmt_iterator, basic_block,
- basic_block, tree, tree);
-static bool candidate_bb_for_phi_optimization (basic_block,
- basic_block *,
- basic_block *);
-
-/* This pass eliminates PHI nodes which can be trivially implemented as
- an assignment from a conditional expression. i.e. if we have something
- like:
+#include "pointer-set.h"
+#include "domwalk.h"
+
+static unsigned int tree_ssa_phiopt (void);
+static unsigned int tree_ssa_phiopt_worker (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 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 struct pointer_set_t * get_non_trapping (void);
+static void replace_phi_edge_with_variable (basic_block, edge, gimple, tree);
+
+/* This pass tries to replaces an if-then-else block with an
+ assignment. We have four kinds of transformations. Some of these
+ transformations are also performed by the ifcvt RTL optimizer.
+
+ Conditional Replacement
+ -----------------------
+
+ This transformation, implemented in conditional_replacement,
+ replaces
bb0:
if (cond) goto bb2; else goto bb1;
bb1:
bb2:
- x = PHI (0 (bb1), 1 (bb0)
+ x = PHI <0 (bb1), 1 (bb0), ...>;
+
+ with
+
+ bb0:
+ x' = cond;
+ goto bb2;
+ bb2:
+ x = PHI ;
+
+ We remove bb1 as it becomes unreachable. This occurs often due to
+ gimplification of conditionals.
+
+ Value Replacement
+ -----------------
+
+ This transformation, implemented in value_replacement, replaces
- We can rewrite that as:
-
bb0:
+ if (a != b) goto bb2; else goto bb1;
bb1:
bb2:
- x = cond;
+ x = PHI ;
- bb1 will become unreachable and bb0 and bb2 will almost always
- be merged into a single block. This occurs often due to gimplification
- of conditionals.
-
- Also done is the following optimization:
+ with
bb0:
- if (a != b) goto bb2; else goto bb1;
+ bb2:
+ x = PHI ;
+
+ This opportunity can sometimes occur as a result of other
+ optimizations.
+
+ ABS Replacement
+ ---------------
+
+ This transformation, implemented in abs_replacement, replaces
+
+ bb0:
+ if (a >= 0) goto bb2; else goto bb1;
bb1:
+ x = -a;
bb2:
- x = PHI (a (bb1), b (bb0))
+ x = PHI ;
+
+ with
+
+ bb0:
+ x' = ABS_EXPR< a >;
+ bb2:
+ x = PHI ;
+
+ MIN/MAX Replacement
+ -------------------
- We can rewrite that as:
+ This transformation, minmax_replacement replaces
bb0:
+ if (a <= b) goto bb2; else goto bb1;
bb1:
bb2:
- x = b;
+ x = PHI ;
- This can sometimes occur as a result of other optimizations. A
- similar transformation is done by the ifcvt RTL optimizer.
+ with
- This pass also eliminates PHI nodes which are really absolute
- values. i.e. if we have something like:
+ bb0:
+ x' = MIN_EXPR (a, b)
+ bb2:
+ x = PHI ;
+
+ A similar transformation is done for MAX_EXPR. */
+
+static unsigned int
+tree_ssa_phiopt (void)
+{
+ return tree_ssa_phiopt_worker (false);
+}
+
+/* This pass tries to transform conditional stores into unconditional
+ ones, enabling further simplifications with the simpler then and else
+ blocks. In particular it replaces this:
bb0:
- if (a >= 0) goto bb2; else goto bb1;
+ if (cond) goto bb2; else goto bb1;
bb1:
- x = -a;
+ *p = RHS
bb2:
- x = PHI (x (bb1), a (bb0));
- We can rewrite that as:
+ with
bb0:
+ if (cond) goto bb1; else goto bb2;
bb1:
+ condtmp' = *p;
bb2:
- x = ABS_EXPR< a >;
+ condtmp = PHI
+ *p = condtmp
- bb1 will become unreachable and bb0 and bb2 will almost always be merged
- into a single block. Similar transformations are done by the ifcvt
- RTL optimizer. */
+ This transformation can only be done under several constraints,
+ documented below. */
-static void
-tree_ssa_phiopt (void)
+static unsigned int
+tree_ssa_cs_elim (void)
+{
+ return tree_ssa_phiopt_worker (true);
+}
+
+/* For conditional store replacement we need a temporary to
+ put the old contents of the memory in. */
+static tree condstoretemp;
+
+/* 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. */
+static unsigned int
+tree_ssa_phiopt_worker (bool do_store_elim)
{
basic_block bb;
- bool removed_phis = false;
+ basic_block *bb_order;
+ unsigned n, i;
+ bool cfgchanged = false;
+ struct pointer_set_t *nontrap = 0;
- /* Search every basic block for PHI nodes we may be able to optimize. */
- FOR_EACH_BB (bb)
+ if (do_store_elim)
{
- tree arg0, arg1, phi;
+ condstoretemp = NULL_TREE;
+ /* 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.
+
+ We walk the blocks in order that guarantees that a block with
+ a single predecessor is processed before the predecessor.
+ 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;
+
+ for (i = 0; i < n; i++)
+ {
+ gimple cond_stmt, phi;
+ basic_block bb1, bb2;
+ edge e1, e2;
+ tree arg0, arg1;
+
+ bb = bb_order[i];
+
+ cond_stmt = last_stmt (bb);
+ /* Check to see if the last statement is a GIMPLE_COND. */
+ if (!cond_stmt
+ || gimple_code (cond_stmt) != GIMPLE_COND)
+ continue;
+
+ e1 = EDGE_SUCC (bb, 0);
+ bb1 = e1->dest;
+ e2 = EDGE_SUCC (bb, 1);
+ bb2 = e2->dest;
+
+ /* We cannot do the optimization on abnormal edges. */
+ if ((e1->flags & EDGE_ABNORMAL) != 0
+ || (e2->flags & EDGE_ABNORMAL) != 0)
+ continue;
+
+ /* If either bb1's succ or bb2 or bb2's succ is non NULL. */
+ if (EDGE_COUNT (bb1->succs) == 0
+ || bb2 == NULL
+ || EDGE_COUNT (bb2->succs) == 0)
+ continue;
+
+ /* Find the bb which is the fall through to the other. */
+ if (EDGE_SUCC (bb1, 0)->dest == bb2)
+ ;
+ else if (EDGE_SUCC (bb2, 0)->dest == bb1)
+ {
+ basic_block bb_tmp = bb1;
+ edge e_tmp = e1;
+ bb1 = bb2;
+ bb2 = bb_tmp;
+ e1 = e2;
+ e2 = e_tmp;
+ }
+ else
+ continue;
- /* We're searching for blocks with one PHI node which has two
- arguments. */
- phi = phi_nodes (bb);
- if (phi && PHI_CHAIN (phi) == NULL
- && PHI_NUM_ARGS (phi) == 2)
+ e1 = EDGE_SUCC (bb1, 0);
+
+ /* Make sure that bb1 is just a fall through. */
+ if (!single_succ_p (bb1)
+ || (e1->flags & EDGE_FALLTHRU) == 0)
+ continue;
+
+ /* Also make sure that bb1 only have one predecessor and that it
+ is bb. */
+ if (!single_pred_p (bb1)
+ || single_pred (bb1) != bb)
+ continue;
+
+ if (do_store_elim)
+ {
+ /* bb1 is the middle block, bb2 the join block, bb the split block,
+ e1 the fallthrough edge from bb1 to bb2. We can't do the
+ optimization if the join block has more than two predecessors. */
+ if (EDGE_COUNT (bb2->preds) > 2)
+ continue;
+ if (cond_store_replacement (bb1, bb2, e1, e2, nontrap))
+ cfgchanged = true;
+ }
+ else
{
- arg0 = PHI_ARG_DEF (phi, 0);
- arg1 = PHI_ARG_DEF (phi, 1);
-
+ gimple_seq phis = phi_nodes (bb2);
+
+ /* 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))
+ 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);
+
+ /* Something is wrong if we cannot find the arguments in the PHI
+ node. */
+ gcc_assert (arg0 != NULL && arg1 != NULL);
+
/* Do the replacement of conditional if it can be done. */
- if (conditional_replacement (bb, phi, arg0, arg1)
- || value_replacement (bb, phi, arg0, arg1)
- || abs_replacement (bb, phi, arg0, arg1))
- {
- /* We have done the replacement so we need to rebuild the
- cfg when this pass is complete. */
- removed_phis = true;
- }
+ 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))
+ cfgchanged = true;
}
}
+
+ free (bb_order);
+
+ if (do_store_elim)
+ pointer_set_destroy (nontrap);
+ /* If the CFG has changed, we should cleanup the CFG. */
+ if (cfgchanged && do_store_elim)
+ {
+ /* In cond-store replacement we have added some loads on edges
+ and new VOPS (as we moved the store, and created a load). */
+ gsi_commit_edge_inserts ();
+ return TODO_cleanup_cfg | TODO_update_ssa_only_virtuals;
+ }
+ else if (cfgchanged)
+ return TODO_cleanup_cfg;
+ return 0;
}
-/* Return TRUE if block BB has no executable statements, otherwise return
- FALSE. */
-bool
-empty_block_p (basic_block bb)
+/* 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)
{
- block_stmt_iterator bsi;
+ 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);
- /* BB must have no executable statements. */
- bsi = bsi_start (bb);
- while (!bsi_end_p (bsi)
- && (TREE_CODE (bsi_stmt (bsi)) == LABEL_EXPR
- || IS_EMPTY_STMT (bsi_stmt (bsi))))
- bsi_next (&bsi);
-
- if (!bsi_end_p (bsi))
- return false;
+#define MARK_VISITED(BB) (SET_BIT (visited, (BB)->index))
+#define VISITED_P(BB) (TEST_BIT (visited, (BB)->index))
- return true;
-}
+ sbitmap_zero (visited);
-/* BB is a basic block which has only one PHI node with precisely two
- arguments.
+ 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);
- Examine both of BB's predecessors to see if one ends with a
- COND_EXPR and the other is a successor of the COND_EXPR. If so, then
- we may be able to optimize PHI nodes at the start of BB.
+ gcc_assert (i == n - 1);
+ n -= np;
+ }
- If so, mark store the block with the COND_EXPR into COND_BLOCK_P
- and the other block into OTHER_BLOCK_P and return true, otherwise
- return false. */
+ sbitmap_free (visited);
+ gcc_assert (n == 0);
+ return order;
-static bool
-candidate_bb_for_phi_optimization (basic_block bb,
- basic_block *cond_block_p,
- basic_block *other_block_p)
+#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)
{
- tree last0, last1;
- basic_block cond_block, other_block;
-
- /* One of the alternatives must come from a block ending with
- a COND_EXPR. */
- last0 = last_stmt (EDGE_PRED (bb, 0)->src);
- last1 = last_stmt (EDGE_PRED (bb, 1)->src);
- if (last0 && TREE_CODE (last0) == COND_EXPR)
- {
- cond_block = EDGE_PRED (bb, 0)->src;
- other_block = EDGE_PRED (bb, 1)->src;
- }
- else if (last1 && TREE_CODE (last1) == COND_EXPR)
- {
- other_block = EDGE_PRED (bb, 0)->src;
- cond_block = EDGE_PRED (bb, 1)->src;
- }
- else
- return false;
-
- /* COND_BLOCK must have precisely two successors. We indirectly
- verify that those successors are BB and OTHER_BLOCK. */
- if (EDGE_COUNT (cond_block->succs) != 2
- || (EDGE_SUCC (cond_block, 0)->flags & EDGE_ABNORMAL) != 0
- || (EDGE_SUCC (cond_block, 1)->flags & EDGE_ABNORMAL) != 0)
- return false;
-
- /* OTHER_BLOCK must have a single predecessor which is COND_BLOCK,
- OTHER_BLOCK must have a single successor which is BB and
- OTHER_BLOCK must have no PHI nodes. */
- if (EDGE_COUNT (other_block->preds) != 1
- || EDGE_PRED (other_block, 0)->src != cond_block
- || EDGE_COUNT (other_block->succs) != 1
- || EDGE_SUCC (other_block, 0)->dest != bb
- || phi_nodes (other_block))
- return false;
-
- *cond_block_p = cond_block;
- *other_block_p = other_block;
- /* Everything looks OK. */
- return true;
+ /* BB must have no executable statements. */
+ return gsi_end_p (gsi_after_labels (bb));
}
-/* Replace PHI in block BB with statement NEW. NEW is inserted after
- BSI. Remove the edge from COND_BLOCK which does not lead to BB (COND_BLOCK
+/* 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). */
static void
-replace_phi_with_stmt (block_stmt_iterator bsi, basic_block bb,
- basic_block cond_block, tree phi, tree new)
+replace_phi_edge_with_variable (basic_block cond_block,
+ edge e, gimple phi, tree new_tree)
{
+ basic_block bb = gimple_bb (phi);
basic_block block_to_remove;
+ gimple_stmt_iterator gsi;
+
+ /* Change the PHI argument to new. */
+ SET_USE (PHI_ARG_DEF_PTR (phi, e->dest_idx), new_tree);
- /* Insert our new statement at the head of our block. */
- bsi_insert_after (&bsi, new, BSI_NEW_STMT);
-
- /* Register our new statement as the defining statement for
- the result. */
- SSA_NAME_DEF_STMT (PHI_RESULT (phi)) = new;
-
- /* Remove the now useless PHI node.
-
- We do not want to use remove_phi_node since that releases the
- SSA_NAME as well and the SSA_NAME is still being used. */
- release_phi_node (phi);
- bb_ann (bb)->phi_nodes = NULL;
-
/* Remove the empty basic block. */
if (EDGE_SUCC (cond_block, 0)->dest == bb)
{
EDGE_SUCC (cond_block, 0)->flags |= EDGE_FALLTHRU;
EDGE_SUCC (cond_block, 0)->flags &= ~(EDGE_TRUE_VALUE | EDGE_FALSE_VALUE);
+ EDGE_SUCC (cond_block, 0)->probability = REG_BR_PROB_BASE;
+ EDGE_SUCC (cond_block, 0)->count += EDGE_SUCC (cond_block, 1)->count;
block_to_remove = EDGE_SUCC (cond_block, 1)->dest;
}
@@ -255,15 +417,17 @@ replace_phi_with_stmt (block_stmt_iterator bsi, basic_block bb,
EDGE_SUCC (cond_block, 1)->flags |= EDGE_FALLTHRU;
EDGE_SUCC (cond_block, 1)->flags
&= ~(EDGE_TRUE_VALUE | EDGE_FALSE_VALUE);
+ EDGE_SUCC (cond_block, 1)->probability = REG_BR_PROB_BASE;
+ EDGE_SUCC (cond_block, 1)->count += EDGE_SUCC (cond_block, 0)->count;
block_to_remove = EDGE_SUCC (cond_block, 0)->dest;
}
delete_basic_block (block_to_remove);
-
+
/* Eliminate the COND_EXPR at the end of COND_BLOCK. */
- bsi = bsi_last (cond_block);
- bsi_remove (&bsi);
-
+ gsi = gsi_last_bb (cond_block);
+ gsi_remove (&gsi, true);
+
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file,
"COND_EXPR in block %d and PHI in block %d converted to straightline code.\n",
@@ -278,16 +442,21 @@ replace_phi_with_stmt (block_stmt_iterator bsi, basic_block bb,
is argument 0 from PHI. Likewise for ARG1. */
static bool
-conditional_replacement (basic_block bb, tree phi, tree arg0, tree arg1)
+conditional_replacement (basic_block cond_bb, basic_block middle_bb,
+ edge e0, edge e1, gimple phi,
+ tree arg0, tree arg1)
{
tree result;
- tree old_result = NULL;
- basic_block other_block = NULL;
- basic_block cond_block = NULL;
- tree new, cond;
- block_stmt_iterator bsi;
+ gimple stmt, new_stmt;
+ tree cond;
+ gimple_stmt_iterator gsi;
edge true_edge, false_edge;
- tree new_var = NULL;
+ tree new_var, new_var2;
+
+ /* 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)
+ return false;
/* The PHI arguments have the constants 0 and 1, then convert
it to the conditional. */
@@ -296,109 +465,65 @@ conditional_replacement (basic_block bb, tree phi, tree arg0, tree arg1)
;
else
return false;
-
- if (!candidate_bb_for_phi_optimization (bb, &cond_block, &other_block)
- || !empty_block_p (other_block))
+
+ if (!empty_block_p (middle_bb))
return false;
-
- /* If the condition is not a naked SSA_NAME and its type does not
- match the type of the result, then we have to create a new
- variable to optimize this case as it would likely create
- non-gimple code when the condition was converted to the
- result's type. */
- cond = COND_EXPR_COND (last_stmt (cond_block));
- result = PHI_RESULT (phi);
- if (TREE_CODE (cond) != SSA_NAME
- && !lang_hooks.types_compatible_p (TREE_TYPE (cond), TREE_TYPE (result)))
- {
- new_var = make_rename_temp (TREE_TYPE (cond), NULL);
- old_result = cond;
- cond = new_var;
- }
-
- /* If the condition was a naked SSA_NAME and the type is not the
- same as the type of the result, then convert the type of the
- condition. */
- if (!lang_hooks.types_compatible_p (TREE_TYPE (cond), TREE_TYPE (result)))
- cond = fold_convert (TREE_TYPE (result), cond);
-
- /* 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_block, &true_edge, &false_edge);
-
- /* Insert our new statement at the head of our block. */
- bsi = bsi_after_labels (bb);
-
- if (old_result)
- {
- tree new1;
- if (!COMPARISON_CLASS_P (old_result))
- return false;
-
- new1 = build (TREE_CODE (old_result), TREE_TYPE (old_result),
- TREE_OPERAND (old_result, 0),
- TREE_OPERAND (old_result, 1));
-
- new1 = build (MODIFY_EXPR, TREE_TYPE (old_result), new_var, new1);
- bsi_insert_after (&bsi, new1, BSI_NEW_STMT);
- }
-
- /* At this point we know we have a COND_EXPR with two successors.
+
+ /* At this point we know we have a GIMPLE_COND with two successors.
One successor is BB, the other successor is an empty block which
falls through into BB.
-
+
There is a single PHI node at the join point (BB) and its arguments
are constants (0, 1).
-
+
So, given the condition COND, and the two PHI arguments, we can
- rewrite this PHI into non-branching code:
-
+ rewrite this PHI into non-branching code:
+
dest = (COND) or dest = COND'
-
+
We use the condition as-is if the argument associated with the
true edge has the value one or the argument associated with the
false edge as the value zero. Note that those conditions are not
- the same since only one of the outgoing edges from the COND_EXPR
+ the same since only one of the outgoing edges from the GIMPLE_COND
will directly reach BB and thus be associated with an argument. */
- if ((PHI_ARG_EDGE (phi, 0) == true_edge && integer_onep (arg0))
- || (PHI_ARG_EDGE (phi, 0) == false_edge && integer_zerop (arg0))
- || (PHI_ARG_EDGE (phi, 1) == true_edge && integer_onep (arg1))
- || (PHI_ARG_EDGE (phi, 1) == false_edge && integer_zerop (arg1)))
+
+ stmt = last_stmt (cond_bb);
+ result = PHI_RESULT (phi);
+
+ /* 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));
+
+ /* 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))
+ || (e1 == true_edge && integer_zerop (arg1))
+ || (e1 == false_edge && integer_onep (arg1)))
+ cond = fold_build1 (TRUTH_NOT_EXPR, TREE_TYPE (cond), cond);
+
+ /* Insert our new statements at the end of conditional block before the
+ COND_STMT. */
+ gsi = gsi_for_stmt (stmt);
+ new_var = force_gimple_operand_gsi (&gsi, cond, true, NULL, true,
+ GSI_SAME_STMT);
+
+ if (!useless_type_conversion_p (TREE_TYPE (result), TREE_TYPE (new_var)))
{
- new = build (MODIFY_EXPR, TREE_TYPE (PHI_RESULT (phi)),
- PHI_RESULT (phi), cond);
+ new_var2 = create_tmp_var (TREE_TYPE (result), NULL);
+ add_referenced_var (new_var2);
+ 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;
}
- else
- {
- tree cond1 = invert_truthvalue (cond);
-
- cond = cond1;
- /* If what we get back is a conditional expression, there is no
- way that it can be gimple. */
- if (TREE_CODE (cond) == COND_EXPR)
- return false;
-
- /* If what we get back is not gimple try to create it as gimple by
- using a temporary variable. */
- if (is_gimple_cast (cond)
- && !is_gimple_val (TREE_OPERAND (cond, 0)))
- {
- tree temp = TREE_OPERAND (cond, 0);
- tree new_var_1 = make_rename_temp (TREE_TYPE (temp), NULL);
- new = build (MODIFY_EXPR, TREE_TYPE (new_var_1), new_var_1, temp);
- bsi_insert_after (&bsi, new, BSI_NEW_STMT);
- cond = fold_convert (TREE_TYPE (result), new_var_1);
- }
-
- if (TREE_CODE (cond) == TRUTH_NOT_EXPR
- && !is_gimple_val (TREE_OPERAND (cond, 0)))
- return false;
- new = build (MODIFY_EXPR, TREE_TYPE (PHI_RESULT (phi)),
- PHI_RESULT (phi), cond);
- }
-
- replace_phi_with_stmt (bsi, bb, cond_block, phi, new);
+ replace_phi_edge_with_variable (cond_bb, e1, phi, new_var);
/* Note that we optimized this PHI. */
return true;
@@ -411,33 +536,32 @@ conditional_replacement (basic_block bb, tree phi, tree arg0, tree arg1)
is argument 0 from the PHI. Likewise for ARG1. */
static bool
-value_replacement (basic_block bb, tree phi, tree arg0, tree arg1)
+value_replacement (basic_block cond_bb, basic_block middle_bb,
+ edge e0, edge e1, gimple phi,
+ tree arg0, tree arg1)
{
- tree result;
- basic_block other_block = NULL;
- basic_block cond_block = NULL;
- tree new, cond;
+ gimple cond;
edge true_edge, false_edge;
+ enum tree_code code;
/* If the type says honor signed zeros we cannot do this
optimization. */
if (HONOR_SIGNED_ZEROS (TYPE_MODE (TREE_TYPE (arg1))))
return false;
- if (!candidate_bb_for_phi_optimization (bb, &cond_block, &other_block)
- || !empty_block_p (other_block))
+ if (!empty_block_p (middle_bb))
return false;
- cond = COND_EXPR_COND (last_stmt (cond_block));
- result = PHI_RESULT (phi);
+ cond = last_stmt (cond_bb);
+ code = gimple_cond_code (cond);
/* This transformation is only valid for equality comparisons. */
- if (TREE_CODE (cond) != NE_EXPR && TREE_CODE (cond) != EQ_EXPR)
+ if (code != NE_EXPR && code != EQ_EXPR)
return false;
/* 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. */
- extract_true_false_edges_from_block (cond_block, &true_edge, &false_edge);
+ extract_true_false_edges_from_block (cond_bb, &true_edge, &false_edge);
/* At this point we know we have a COND_EXPR with two successors.
One successor is BB, the other successor is an empty block which
@@ -449,11 +573,11 @@ value_replacement (basic_block bb, tree phi, tree arg0, tree arg1)
We now need to verify that the two arguments in the PHI node match
the two arguments to the equality comparison. */
-
- if ((operand_equal_p (arg0, TREE_OPERAND (cond, 0), 0)
- && operand_equal_p (arg1, TREE_OPERAND (cond, 1), 0))
- || (operand_equal_p (arg1, TREE_OPERAND (cond, 0), 0)
- && operand_equal_p (arg0, TREE_OPERAND (cond, 1), 0)))
+
+ 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))))
{
edge e;
tree arg;
@@ -461,26 +585,23 @@ value_replacement (basic_block bb, tree phi, tree arg0, tree arg1)
/* For NE_EXPR, we want to build an assignment result = arg where
arg is the PHI argument associated with the true edge. For
EQ_EXPR we want the PHI argument associated with the false edge. */
- e = (TREE_CODE (cond) == NE_EXPR ? true_edge : false_edge);
+ e = (code == NE_EXPR ? true_edge : false_edge);
/* Unfortunately, E may not reach BB (it may instead have gone to
OTHER_BLOCK). If that is the case, then we want the single outgoing
edge from OTHER_BLOCK which reaches BB and represents the desired
path from COND_BLOCK. */
- if (e->dest == other_block)
- e = EDGE_SUCC (e->dest, 0);
+ if (e->dest == middle_bb)
+ e = single_succ_edge (e->dest);
/* Now we know the incoming edge to BB that has the argument for the
RHS of our new assignment statement. */
- if (PHI_ARG_EDGE (phi, 0) == e)
+ if (e0 == e)
arg = arg0;
else
arg = arg1;
- /* Build the new assignment. */
- new = build (MODIFY_EXPR, TREE_TYPE (result), result, arg);
-
- replace_phi_with_stmt (bsi_after_labels (bb), bb, cond_block, phi, new);
+ replace_phi_edge_with_variable (cond_bb, e1, phi, arg);
/* Note that we optimized this PHI. */
return true;
@@ -488,111 +609,330 @@ value_replacement (basic_block bb, tree phi, tree arg0, tree arg1)
return false;
}
-/* The function absolute_replacement does the main work of doing the absolute
+/* The function minmax_replacement does the main work of doing the minmax
replacement. Return true if the replacement is done. Otherwise return
false.
- bb is the basic block where the replacement is going to be done on. arg0
- is argument 0 from the phi. Likewise for arg1. */
+ 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
-abs_replacement (basic_block bb, tree phi, tree arg0, tree arg1)
+minmax_replacement (basic_block cond_bb, basic_block middle_bb,
+ edge e0, edge e1, gimple phi,
+ tree arg0, tree arg1)
{
- tree result;
- basic_block other_block = NULL;
- basic_block cond_block = NULL;
- tree new, cond;
- block_stmt_iterator bsi;
+ tree result, type;
+ gimple cond, new_stmt;
edge true_edge, false_edge;
- tree assign = NULL;
- edge e;
- tree rhs = NULL, lhs = NULL;
- bool negate;
- enum tree_code cond_code;
+ enum tree_code cmp, minmax, ass_code;
+ tree smaller, larger, arg_true, arg_false;
+ gimple_stmt_iterator gsi, gsi_from;
- /* If the type says honor signed zeros we cannot do this
- optimization. */
- if (HONOR_SIGNED_ZEROS (TYPE_MODE (TREE_TYPE (arg1))))
+ type = TREE_TYPE (PHI_RESULT (phi));
+
+ /* The optimization may be unsafe due to NaNs. */
+ if (HONOR_NANS (TYPE_MODE (type)))
return false;
- if (!candidate_bb_for_phi_optimization (bb, &cond_block, &other_block))
+ 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. */
+ if (cmp == LT_EXPR || cmp == LE_EXPR)
+ {
+ smaller = gimple_cond_lhs (cond);
+ larger = gimple_cond_rhs (cond);
+ }
+ else if (cmp == GT_EXPR || cmp == GE_EXPR)
+ {
+ smaller = gimple_cond_rhs (cond);
+ larger = gimple_cond_lhs (cond);
+ }
+ else
return false;
- /* OTHER_BLOCK must have only one executable statement which must have the
- form arg0 = -arg1 or arg1 = -arg0. */
- bsi = bsi_start (other_block);
- while (!bsi_end_p (bsi))
+ /* 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. */
+ extract_true_false_edges_from_block (cond_bb, &true_edge, &false_edge);
+
+ /* Forward the edges over the middle basic block. */
+ if (true_edge->dest == middle_bb)
+ true_edge = EDGE_SUCC (true_edge->dest, 0);
+ if (false_edge->dest == middle_bb)
+ false_edge = EDGE_SUCC (false_edge->dest, 0);
+
+ if (true_edge == e0)
+ {
+ gcc_assert (false_edge == e1);
+ arg_true = arg0;
+ arg_false = arg1;
+ }
+ else
{
- tree stmt = bsi_stmt (bsi);
+ gcc_assert (false_edge == e0);
+ gcc_assert (true_edge == e1);
+ arg_true = arg1;
+ arg_false = arg0;
+ }
- /* Empty statements and labels are uninteresting. */
- if (TREE_CODE (stmt) == LABEL_EXPR
- || IS_EMPTY_STMT (stmt))
- {
- bsi_next (&bsi);
- continue;
- }
+ if (empty_block_p (middle_bb))
+ {
+ if (operand_equal_for_phi_arg_p (arg_true, smaller)
+ && operand_equal_for_phi_arg_p (arg_false, larger))
+ {
+ /* Case
+
+ if (smaller < larger)
+ rslt = smaller;
+ else
+ rslt = larger; */
+ minmax = MIN_EXPR;
+ }
+ else if (operand_equal_for_phi_arg_p (arg_false, smaller)
+ && operand_equal_for_phi_arg_p (arg_true, larger))
+ minmax = MAX_EXPR;
+ else
+ return false;
+ }
+ else
+ {
+ /* Recognize the following case, assuming d <= u:
+
+ if (a <= u)
+ b = MAX (a, d);
+ x = PHI
+
+ This is equivalent to
+
+ b = MAX (a, d);
+ x = MIN (b, u); */
+
+ gimple assign = last_and_only_stmt (middle_bb);
+ tree lhs, op0, op1, bound;
- /* If we found the assignment, but it was not the only executable
- statement in OTHER_BLOCK, then we can not optimize. */
- if (assign)
+ if (!assign
+ || gimple_code (assign) != GIMPLE_ASSIGN)
return false;
- /* If we got here, then we have found the first executable statement
- in OTHER_BLOCK. If it is anything other than arg = -arg1 or
- arg1 = -arg0, then we can not optimize. */
- if (TREE_CODE (stmt) == MODIFY_EXPR)
- {
- lhs = TREE_OPERAND (stmt, 0);
- rhs = TREE_OPERAND (stmt, 1);
-
- if (TREE_CODE (rhs) == NEGATE_EXPR)
- {
- rhs = TREE_OPERAND (rhs, 0);
-
- /* The assignment has to be arg0 = -arg1 or arg1 = -arg0. */
- if ((lhs == arg0 && rhs == arg1)
- || (lhs == arg1 && rhs == arg0))
- {
- assign = stmt;
- bsi_next (&bsi);
- }
+ lhs = gimple_assign_lhs (assign);
+ ass_code = gimple_assign_rhs_code (assign);
+ if (ass_code != MAX_EXPR && ass_code != MIN_EXPR)
+ return false;
+ op0 = gimple_assign_rhs1 (assign);
+ op1 = gimple_assign_rhs2 (assign);
+
+ if (true_edge->src == middle_bb)
+ {
+ /* We got here if the condition is true, i.e., SMALLER < LARGER. */
+ if (!operand_equal_for_phi_arg_p (lhs, arg_true))
+ return false;
+
+ if (operand_equal_for_phi_arg_p (arg_false, larger))
+ {
+ /* Case
+
+ if (smaller < larger)
+ {
+ r' = MAX_EXPR (smaller, bound)
+ }
+ r = PHI --> to be turned to MIN_EXPR. */
+ if (ass_code != MAX_EXPR)
+ return false;
+
+ minmax = MIN_EXPR;
+ if (operand_equal_for_phi_arg_p (op0, smaller))
+ bound = op1;
+ else if (operand_equal_for_phi_arg_p (op1, smaller))
+ bound = op0;
else
return false;
- }
+
+ /* We need BOUND <= LARGER. */
+ if (!integer_nonzerop (fold_build2 (LE_EXPR, boolean_type_node,
+ bound, larger)))
+ return false;
+ }
+ else if (operand_equal_for_phi_arg_p (arg_false, smaller))
+ {
+ /* Case
+
+ if (smaller < larger)
+ {
+ r' = MIN_EXPR (larger, bound)
+ }
+ r = PHI --> to be turned to MAX_EXPR. */
+ if (ass_code != MIN_EXPR)
+ return false;
+
+ minmax = MAX_EXPR;
+ if (operand_equal_for_phi_arg_p (op0, larger))
+ bound = op1;
+ else if (operand_equal_for_phi_arg_p (op1, larger))
+ bound = op0;
+ else
+ return false;
+
+ /* We need BOUND >= SMALLER. */
+ if (!integer_nonzerop (fold_build2 (GE_EXPR, boolean_type_node,
+ bound, smaller)))
+ return false;
+ }
else
return false;
- }
+ }
else
- return false;
+ {
+ /* We got here if the condition is false, i.e., SMALLER > LARGER. */
+ if (!operand_equal_for_phi_arg_p (lhs, arg_false))
+ return false;
+
+ if (operand_equal_for_phi_arg_p (arg_true, larger))
+ {
+ /* Case
+
+ if (smaller > larger)
+ {
+ r' = MIN_EXPR (smaller, bound)
+ }
+ r = PHI --> to be turned to MAX_EXPR. */
+ if (ass_code != MIN_EXPR)
+ return false;
+
+ minmax = MAX_EXPR;
+ if (operand_equal_for_phi_arg_p (op0, smaller))
+ bound = op1;
+ else if (operand_equal_for_phi_arg_p (op1, smaller))
+ bound = op0;
+ else
+ return false;
+
+ /* We need BOUND >= LARGER. */
+ if (!integer_nonzerop (fold_build2 (GE_EXPR, boolean_type_node,
+ bound, larger)))
+ return false;
+ }
+ else if (operand_equal_for_phi_arg_p (arg_true, smaller))
+ {
+ /* Case
+
+ if (smaller > larger)
+ {
+ r' = MAX_EXPR (larger, bound)
+ }
+ r = PHI --> to be turned to MIN_EXPR. */
+ if (ass_code != MAX_EXPR)
+ return false;
+
+ minmax = MIN_EXPR;
+ if (operand_equal_for_phi_arg_p (op0, larger))
+ bound = op1;
+ else if (operand_equal_for_phi_arg_p (op1, larger))
+ bound = op0;
+ else
+ return false;
+
+ /* We need BOUND <= SMALLER. */
+ if (!integer_nonzerop (fold_build2 (LE_EXPR, boolean_type_node,
+ bound, smaller)))
+ return false;
+ }
+ else
+ return false;
+ }
+
+ /* Move the statement from the middle block. */
+ gsi = gsi_last_bb (cond_bb);
+ gsi_from = gsi_last_bb (middle_bb);
+ gsi_move_before (&gsi_from, &gsi);
}
+ /* Emit the statement to compute min/max. */
+ result = duplicate_ssa_name (PHI_RESULT (phi), NULL);
+ new_stmt = gimple_build_assign_with_ops (minmax, result, arg0, arg1);
+ gsi = gsi_last_bb (cond_bb);
+ gsi_insert_before (&gsi, new_stmt, GSI_NEW_STMT);
+
+ replace_phi_edge_with_variable (cond_bb, e1, phi, result);
+ return true;
+}
+
+/* The function absolute_replacement does the main work of doing the absolute
+ replacement. Return true if the replacement is done. Otherwise return
+ false.
+ 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
+abs_replacement (basic_block cond_bb, basic_block middle_bb,
+ edge e0 ATTRIBUTE_UNUSED, edge e1,
+ gimple phi, tree arg0, tree arg1)
+{
+ tree result;
+ gimple new_stmt, cond;
+ gimple_stmt_iterator gsi;
+ edge true_edge, false_edge;
+ gimple assign;
+ edge e;
+ tree rhs, lhs;
+ bool negate;
+ enum tree_code cond_code;
+
+ /* If the type says honor signed zeros we cannot do this
+ optimization. */
+ if (HONOR_SIGNED_ZEROS (TYPE_MODE (TREE_TYPE (arg1))))
+ return false;
+
+ /* OTHER_BLOCK must have only one executable statement which must have the
+ form arg0 = -arg1 or arg1 = -arg0. */
+
+ assign = last_and_only_stmt (middle_bb);
/* If we did not find the proper negation assignment, then we can not
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. */
+ if (gimple_code (assign) != GIMPLE_ASSIGN)
+ return false;
+
+ lhs = gimple_assign_lhs (assign);
+
+ if (gimple_assign_rhs_code (assign) != NEGATE_EXPR)
+ 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))
+ return false;
- cond = COND_EXPR_COND (last_stmt (cond_block));
+ cond = last_stmt (cond_bb);
result = PHI_RESULT (phi);
/* Only relationals comparing arg[01] against zero are interesting. */
- cond_code = TREE_CODE (cond);
+ cond_code = gimple_cond_code (cond);
if (cond_code != GT_EXPR && cond_code != GE_EXPR
&& cond_code != LT_EXPR && cond_code != LE_EXPR)
return false;
/* Make sure the conditional is arg[01] OP y. */
- if (TREE_OPERAND (cond, 0) != rhs)
+ if (gimple_cond_lhs (cond) != rhs)
return false;
- if (FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (cond, 1)))
- ? real_zerop (TREE_OPERAND (cond, 1))
- : integer_zerop (TREE_OPERAND (cond, 1)))
+ if (FLOAT_TYPE_P (TREE_TYPE (gimple_cond_rhs (cond)))
+ ? real_zerop (gimple_cond_rhs (cond))
+ : integer_zerop (gimple_cond_rhs (cond)))
;
else
return false;
/* 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. */
- extract_true_false_edges_from_block (cond_block, &true_edge, &false_edge);
+ extract_true_false_edges_from_block (cond_bb, &true_edge, &false_edge);
/* For GT_EXPR/GE_EXPR, if the true edge goes to OTHER_BLOCK, then we
will need to negate the result. Similarly for LT_EXPR/LE_EXPR if
@@ -601,57 +941,334 @@ abs_replacement (basic_block bb, tree phi, tree arg0, tree arg1)
e = true_edge;
else
e = false_edge;
-
- if (e->dest == other_block)
+
+ if (e->dest == middle_bb)
negate = true;
else
negate = false;
-
+
+ result = duplicate_ssa_name (result, NULL);
+
if (negate)
- lhs = make_rename_temp (TREE_TYPE (result), NULL);
+ {
+ tree tmp = create_tmp_var (TREE_TYPE (result), NULL);
+ add_referenced_var (tmp);
+ lhs = make_ssa_name (tmp, NULL);
+ }
else
lhs = result;
/* Build the modify expression with abs expression. */
- new = build (MODIFY_EXPR, TREE_TYPE (lhs),
- lhs, build1 (ABS_EXPR, TREE_TYPE (lhs), rhs));
+ new_stmt = gimple_build_assign_with_ops (ABS_EXPR, lhs, rhs, NULL);
- replace_phi_with_stmt (bsi_after_labels (bb), bb, cond_block, phi, new);
+ gsi = gsi_last_bb (cond_bb);
+ gsi_insert_before (&gsi, new_stmt, GSI_NEW_STMT);
if (negate)
{
-
- /* Get the right BSI. We want to insert after the recently
+ /* Get the right GSI. We want to insert after the recently
added ABS_EXPR statement (which we know is the first statement
in the block. */
- bsi = bsi_start (bb);
- bsi_next (&bsi);
- new = build (MODIFY_EXPR, TREE_TYPE (result),
- result, build1 (NEGATE_EXPR, TREE_TYPE (lhs), lhs));
+ new_stmt = gimple_build_assign_with_ops (NEGATE_EXPR, result, lhs, NULL);
- bsi_insert_after (&bsi, new, BSI_NEW_STMT);
-
- /* Register the new statement as defining the temporary -- this is
- normally done by replace_phi_with_stmt, but the link will be wrong
- if we had to negate the resulting value. */
- SSA_NAME_DEF_STMT (result) = new;
+ gsi_insert_after (&gsi, new_stmt, GSI_NEW_STMT);
}
+ replace_phi_edge_with_variable (cond_bb, e1, phi, result);
+
/* Note that we optimized this PHI. */
return true;
}
+/* 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
+ 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
+ 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
+ non-trapping, so we remember it. We need to be careful with loads
+ or stores, for instance a load might not trap, while a store would,
+ so if we see a dominating read access this doesn't mean that a later
+ write access would not trap. Hence we also need to differentiate the
+ type of access(es) seen.
+
+ ??? We currently are very conservative and assume that a load might
+ 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
+ through it was seen, which would constitute a no-trap region for
+ same accesses. */
+struct name_to_bb
+{
+ tree ssa_name;
+ basic_block bb;
+ unsigned store : 1;
+};
+
+/* The hash table for remembering what we've seen. */
+static htab_t seen_ssa_names;
+
+/* The set of INDIRECT_REFs which can't trap. */
+static struct pointer_set_t *nontrap_set;
+
+/* The hash function, based on the pointer to the pointer SSA_NAME. */
+static hashval_t
+name_to_bb_hash (const void *p)
+{
+ const_tree n = ((const struct name_to_bb *)p)->ssa_name;
+ return htab_hash_pointer (n) ^ ((const struct name_to_bb *)p)->store;
+}
+
+/* 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;
+
+ return n1->ssa_name == n2->ssa_name && n1->store == n2->store;
+}
+
+/* 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 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. */
+static void
+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)
+ {
+ tree name = TREE_OPERAND (exp, 0);
+ struct name_to_bb map;
+ void **slot;
+ struct name_to_bb *n2bb;
+ basic_block found_bb = 0;
+
+ /* Try to find the last seen INDIRECT_REF through the same
+ SSA_NAME, which can trap. */
+ map.ssa_name = name;
+ map.bb = 0;
+ map.store = store;
+ slot = htab_find_slot (seen_ssa_names, &map, INSERT);
+ n2bb = (struct name_to_bb *) *slot;
+ if (n2bb)
+ found_bb = n2bb->bb;
+
+ /* If we've found a trapping INDIRECT_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)
+ {
+ pointer_set_insert (nontrap, exp);
+ }
+ else
+ {
+ /* EXP might trap, so insert it into the hash table. */
+ if (n2bb)
+ {
+ n2bb->bb = bb;
+ }
+ else
+ {
+ n2bb = XNEW (struct name_to_bb);
+ n2bb->ssa_name = name;
+ n2bb->bb = bb;
+ n2bb->store = store;
+ *slot = n2bb;
+ }
+ }
+ }
+}
+
+/* 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)
+{
+ gimple_stmt_iterator gsi;
+ /* Mark this BB as being on the path to dominator root. */
+ bb->aux = (void*)1;
+
+ /* 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))
+ {
+ 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);
+ }
+ }
+}
+
+/* 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)
+{
+ /* This BB isn't on the path to dominator root anymore. */
+ bb->aux = NULL;
+}
+
+/* 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. */
+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);
+ /* 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.walk_stmts_backward = false;
+ walk_data.dom_direction = CDI_DOMINATORS;
+ walk_data.initialize_block_local_data = NULL;
+ walk_data.before_dom_children_before_stmts = nt_init_block;
+ walk_data.before_dom_children_walk_stmts = NULL;
+ walk_data.before_dom_children_after_stmts = NULL;
+ walk_data.after_dom_children_before_stmts = NULL;
+ walk_data.after_dom_children_walk_stmts = NULL;
+ walk_data.after_dom_children_after_stmts = nt_fini_block;
+ walk_data.global_data = NULL;
+ walk_data.block_local_data_size = 0;
+ walk_data.interesting_blocks = NULL;
+
+ 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);
+
+ return nontrap;
+}
+
+/* Do the main work of conditional store replacement. We already know
+ that the recognized pattern looks like so:
+
+ split:
+ if (cond) goto MIDDLE_BB; else goto JOIN_BB (edge E1)
+ MIDDLE_BB:
+ something
+ fallthrough (edge E0)
+ JOIN_BB:
+ some more
+
+ We check that MIDDLE_BB contains only one store, that that store
+ doesn't trap (not via NOTRAP, but via checking if an access to the same
+ memory location dominates us) and that the store has a "simple" RHS. */
+
+static bool
+cond_store_replacement (basic_block middle_bb, basic_block join_bb,
+ edge e0, edge e1, struct pointer_set_t *nontrap)
+{
+ gimple assign = last_and_only_stmt (middle_bb);
+ tree lhs, rhs, name;
+ gimple newphi, new_stmt;
+ gimple_stmt_iterator gsi;
+ enum tree_code code;
+
+ /* Check if middle_bb contains of only one store. */
+ if (!assign
+ || gimple_code (assign) != GIMPLE_ASSIGN)
+ return false;
+
+ lhs = gimple_assign_lhs (assign);
+ rhs = gimple_assign_rhs1 (assign);
+ if (!INDIRECT_REF_P (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. */
+ if (!pointer_set_contains (nontrap, lhs))
+ return false;
+
+ /* 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);
+ gsi_remove (&gsi, true);
+
+ /* 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
+ 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);
+ 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
+ holding the old RHS, and the other holding the temporary
+ where we stored the old memory contents. */
+ newphi = create_phi_node (condstoretemp, join_bb);
+ add_phi_arg (newphi, rhs, e0);
+ add_phi_arg (newphi, name, e1);
+
+ lhs = unshare_expr (lhs);
+ new_stmt = gimple_build_assign (lhs, PHI_RESULT (newphi));
+ mark_symbols_for_renaming (new_stmt);
+
+ /* 5) 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;
+}
/* Always do these optimizations if we have SSA
- trees to work on. */
+ trees to work on. */
static bool
gate_phiopt (void)
{
return 1;
}
-
-struct tree_opt_pass pass_phiopt =
+
+struct gimple_opt_pass pass_phiopt =
{
+ {
+ GIMPLE_PASS,
"phiopt", /* name */
gate_phiopt, /* gate */
tree_ssa_phiopt, /* execute */
@@ -663,10 +1280,39 @@ struct tree_opt_pass pass_phiopt =
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
- TODO_cleanup_cfg | TODO_dump_func | TODO_ggc_collect /* todo_flags_finish */
- | TODO_verify_ssa | TODO_rename_vars
- | TODO_verify_flow,
- 0 /* letter */
+ TODO_dump_func
+ | TODO_ggc_collect
+ | TODO_verify_ssa
+ | TODO_verify_flow
+ | TODO_verify_stmts /* todo_flags_finish */
+ }
};
-
+static bool
+gate_cselim (void)
+{
+ return flag_tree_cselim;
+}
+
+struct gimple_opt_pass pass_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 | PROP_alias, /* 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 */
+ }
+};