#include "tm_p.h"
#include "ggc.h"
#include "basic-block.h"
+#include "cfgloop.h"
#include "output.h"
#include "errors.h"
#include "expr.h"
of the form SSA_NAME COND CONST we create a new vrp_element to record
how the condition affects the possible values SSA_NAME may have.
- Each record contains the condition tested (COND), and the the range of
+ Each record contains the condition tested (COND), and the range of
values the variable may legitimately have if COND is true. Note the
range of values may be a smaller range than COND specifies if we have
recorded other ranges for this variable. Each record also contains the
{
struct dom_walk_data walk_data;
unsigned int i;
+ struct loops loops_info;
memset (&opt_stats, 0, sizeof (opt_stats));
calculate_dominance_info (CDI_DOMINATORS);
+ /* We need to know which edges exit loops so that we can
+ aggressively thread through loop headers to an exit
+ edge. */
+ flow_loops_find (&loops_info);
+ mark_loop_exit_edges (&loops_info);
+ flow_loops_free (&loops_info);
+
+ /* Clean up the CFG so that any forwarder blocks created by loop
+ canonicalization are removed. */
+ cleanup_tree_cfg ();
+
/* If we prove certain blocks are unreachable, then we want to
repeat the dominator optimization process as PHI nodes may
have turned into copies which allows better propagation of
/* Optimize the dominator tree. */
cfg_altered = false;
+ /* We need accurate information regarding back edges in the CFG
+ for jump threading. */
+ mark_dfs_back_edges ();
+
/* Recursively walk the dominator tree optimizing statements. */
walk_dominator_tree (&walk_data, ENTRY_BLOCK_PTR);
free_all_edge_infos ();
+ {
+ block_stmt_iterator bsi;
+ basic_block bb;
+ FOR_EACH_BB (bb)
+ {
+ for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
+ {
+ update_stmt_if_modified (bsi_stmt (bsi));
+ }
+ }
+ }
/* Thread jumps, creating duplicate blocks as needed. */
- cfg_altered = thread_through_all_blocks ();
+ cfg_altered |= thread_through_all_blocks ();
/* Removal of statements may make some EH edges dead. Purge
such edges from the CFG as needed. */
bitmap_zero (need_eh_cleanup);
}
- free_dominance_info (CDI_DOMINATORS);
- cfg_altered = cleanup_tree_cfg ();
+ if (cfg_altered)
+ free_dominance_info (CDI_DOMINATORS);
+
+ cfg_altered |= cleanup_tree_cfg ();
+
+ if (rediscover_loops_after_threading)
+ {
+ /* Rerun basic loop analysis to discover any newly
+ created loops and update the set of exit edges. */
+ rediscover_loops_after_threading = false;
+ flow_loops_find (&loops_info);
+ mark_loop_exit_edges (&loops_info);
+ flow_loops_free (&loops_info);
+
+ /* Remove any forwarder blocks inserted by loop
+ header canonicalization. */
+ cleanup_tree_cfg ();
+ }
+
calculate_dominance_info (CDI_DOMINATORS);
rewrite_ssa_into_ssa ();
arm will be taken. */
if (stmt
&& (TREE_CODE (stmt) == COND_EXPR
- || TREE_CODE (stmt) == SWITCH_EXPR))
+ || TREE_CODE (stmt) == SWITCH_EXPR
+ || TREE_CODE (stmt) == GOTO_EXPR))
{
tree cond, cached_lhs;
expression in the hash tables. */
if (TREE_CODE (stmt) == COND_EXPR)
cond = COND_EXPR_COND (stmt);
+ else if (TREE_CODE (stmt) == GOTO_EXPR)
+ cond = GOTO_DESTINATION (stmt);
else
cond = SWITCH_COND (stmt);
the edge from BB through its successor.
Do this before we remove entries from our equivalence tables. */
- if (EDGE_COUNT (bb->succs) == 1
- && (EDGE_SUCC (bb, 0)->flags & EDGE_ABNORMAL) == 0
- && (get_immediate_dominator (CDI_DOMINATORS, EDGE_SUCC (bb, 0)->dest) != bb
- || phi_nodes (EDGE_SUCC (bb, 0)->dest)))
+ if (single_succ_p (bb)
+ && (single_succ_edge (bb)->flags & EDGE_ABNORMAL) == 0
+ && (get_immediate_dominator (CDI_DOMINATORS, single_succ (bb)) != bb
+ || phi_nodes (single_succ (bb))))
{
- thread_across_edge (walk_data, EDGE_SUCC (bb, 0));
+ thread_across_edge (walk_data, single_succ_edge (bb));
+ }
+ else if ((last = last_stmt (bb))
+ && TREE_CODE (last) == GOTO_EXPR
+ && TREE_CODE (TREE_OPERAND (last, 0)) == SSA_NAME)
+ {
+ edge_iterator ei;
+ edge e;
+
+ FOR_EACH_EDGE (e, ei, bb->succs)
+ {
+ thread_across_edge (walk_data, e);
+ }
}
else if ((last = last_stmt (bb))
&& TREE_CODE (last) == COND_EXPR
/* Build a new conditional using NEW_CODE, OP0 and OP1 and store
the new conditional into *p, then store a boolean_true_node
- into the the *(p + 1). */
+ into *(p + 1). */
static void
build_and_record_new_cond (enum tree_code new_code, tree op0, tree op1, tree *p)
&& FLOAT_TYPE_P (TREE_TYPE (exp)));
}
+/* Returns true when STMT is a simple iv increment. It detects the
+ following situation:
+
+ i_1 = phi (..., i_2)
+ i_2 = i_1 +/- ... */
+
+static bool
+simple_iv_increment_p (tree stmt)
+{
+ tree lhs, rhs, preinc, phi;
+ unsigned i;
+
+ if (TREE_CODE (stmt) != MODIFY_EXPR)
+ return false;
+
+ lhs = TREE_OPERAND (stmt, 0);
+ if (TREE_CODE (lhs) != SSA_NAME)
+ return false;
+
+ rhs = TREE_OPERAND (stmt, 1);
+
+ if (TREE_CODE (rhs) != PLUS_EXPR
+ && TREE_CODE (rhs) != MINUS_EXPR)
+ return false;
+
+ preinc = TREE_OPERAND (rhs, 0);
+ if (TREE_CODE (preinc) != SSA_NAME)
+ return false;
+
+ phi = SSA_NAME_DEF_STMT (preinc);
+ if (TREE_CODE (phi) != PHI_NODE)
+ return false;
+
+ for (i = 0; i < (unsigned) PHI_NUM_ARGS (phi); i++)
+ if (PHI_ARG_DEF (phi, i) == lhs)
+ return true;
+
+ return false;
+}
+
/* STMT is a MODIFY_EXPR for which we were unable to find RHS in the
hash tables. Try to simplify the RHS using whatever equivalences
we may have recorded.
{
tree rhs_def_stmt = SSA_NAME_DEF_STMT (TREE_OPERAND (rhs, 0));
+ /* If the statement defines an induction variable, do not propagate
+ its value, so that we do not create overlapping life ranges. */
+ if (simple_iv_increment_p (rhs_def_stmt))
+ goto dont_fold_assoc;
+
/* See if the RHS_DEF_STMT has the same form as our statement. */
if (TREE_CODE (rhs_def_stmt) == MODIFY_EXPR)
{
/* If this is not a real stmt, ann will be NULL and we
avoid processing the operands. */
if (ann)
- modify_stmt (stmt);
+ mark_stmt_modified (stmt);
/* Lookup the condition and return its known value if it
exists. */
if (!fail)
{
SWITCH_COND (stmt) = def;
- modify_stmt (stmt);
+ mark_stmt_modified (stmt);
return lookup_avail_expr (stmt, insert);
}
edge e;
edge_iterator ei;
- /* This can get rather expensive if the implementation is naive in
- how it finds the phi alternative associated with a particular edge. */
FOR_EACH_EDGE (e, ei, bb->succs)
{
tree phi;
|| ! def
|| TREE_CODE (def) != SSA_NAME
|| SSA_NAME_OCCURS_IN_ABNORMAL_PHI (def)
- || NUM_V_MAY_DEFS (v_may_defs) != 0)
+ || NUM_V_MAY_DEFS (v_may_defs) != 0
+ /* Do not record equivalences for increments of ivs. This would create
+ overlapping live ranges for a very questionable gain. */
+ || simple_iv_increment_p (stmt))
insert = false;
/* Check if the expression has been computed before. */
retval = true;
propagate_tree_value (expr_p, cached_lhs);
- modify_stmt (stmt);
+ mark_stmt_modified (stmt);
}
return retval;
}
/* And note that we modified this statement. This is now
safe, even if we changed virtual operands since we will
rescan the statement and rewrite its operands again. */
- modify_stmt (stmt);
+ mark_stmt_modified (stmt);
}
return may_have_exposed_new_symbols;
}
stmt = bsi_stmt (si);
- get_stmt_operands (stmt);
+ update_stmt_if_modified (stmt);
ann = stmt_ann (stmt);
opt_stats.num_stmts++;
may_have_exposed_new_symbols = false;
/* And make sure we record the fact that we modified this
statement. */
- modify_stmt (stmt);
+ mark_stmt_modified (stmt);
return cached_lhs;
}
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