Changes for DOM to use the new capability in the dom walker.
Jeff
commit 88806f8996419d50d00f33f5d9924a1638316e3b
Author: Jeff Law <l...@redhat.com>
Date: Mon Dec 7 22:43:06 2015 -0700
PR tree-optimization/68619
* tree-ssa-dom.c (dom_opt_dom_walker::before_dom_children): Propgate
return value from optimize_stmt.
(dom_opt_dom_walker): Add new argument to dom_walker constructor.
(pass_dominator:execute): If a block has an unreachable edge,
remove all jump threads through any successor of the affected block.
(record_equivalences_from_phis): Ignore alternative if the edge
does not have EDGE_EXECUTABLE set.
(single_incoming_edge_ignoring_loop_edges): Similarly.
(optimize_stmt): If a gimple_code has a compile-time constant
condition, return the edge taken for that constant value. Also
change the condition to true/false as necessary.
diff --git a/gcc/tree-ssa-dom.c b/gcc/tree-ssa-dom.c
index aeb726c..88fc517 100644
--- a/gcc/tree-ssa-dom.c
+++ b/gcc/tree-ssa-dom.c
@@ -99,7 +99,7 @@ struct opt_stats_d
static struct opt_stats_d opt_stats;
/* Local functions. */
-static void optimize_stmt (basic_block, gimple_stmt_iterator,
+static edge optimize_stmt (basic_block, gimple_stmt_iterator,
class const_and_copies *,
class avail_exprs_stack *);
static tree lookup_avail_expr (gimple *, bool, class avail_exprs_stack *);
@@ -493,12 +493,12 @@ public:
dom_opt_dom_walker (cdi_direction direction,
class const_and_copies *const_and_copies,
class avail_exprs_stack *avail_exprs_stack)
- : dom_walker (direction),
+ : dom_walker (direction, true),
m_const_and_copies (const_and_copies),
m_avail_exprs_stack (avail_exprs_stack),
m_dummy_cond (NULL) {}
- virtual void before_dom_children (basic_block);
+ virtual edge before_dom_children (basic_block);
virtual void after_dom_children (basic_block);
private:
@@ -611,6 +611,36 @@ pass_dominator::execute (function *fun)
avail_exprs_stack);
walker.walk (fun->cfg->x_entry_block_ptr);
+ /* Look for blocks where we cleared EDGE_EXECUTABLE on an outgoing
+ edge. When found, remove jump threads which contain any outgoing
+ edge from the affected block. */
+ if (cfg_altered)
+ {
+ FOR_EACH_BB_FN (bb, fun)
+ {
+ edge_iterator ei;
+ edge e;
+
+ /* First see if there are any edges without EDGE_EXECUTABLE
+ set. */
+ bool found = false;
+ FOR_EACH_EDGE (e, ei, bb->succs)
+ {
+ if ((e->flags & EDGE_EXECUTABLE) == 0)
+ {
+ found = true;
+ break;
+ }
+ }
+
+ /* If there were any such edges found, then remove jump threads
+ containing any edge leaving BB. */
+ if (found)
+ FOR_EACH_EDGE (e, ei, bb->succs)
+ remove_jump_threads_including (e);
+ }
+ }
+
{
gimple_stmt_iterator gsi;
basic_block bb;
@@ -951,6 +981,11 @@ record_equivalences_from_phis (basic_block bb)
if (lhs == t)
continue;
+ /* If the associated edge is not marked as executable, then it
+ can be ignored. */
+ if ((gimple_phi_arg_edge (phi, i)->flags & EDGE_EXECUTABLE) == 0)
+ continue;
+
t = dom_valueize (t);
/* If we have not processed an alternative yet, then set
@@ -997,6 +1032,10 @@ single_incoming_edge_ignoring_loop_edges (basic_block bb)
if (dominated_by_p (CDI_DOMINATORS, e->src, e->dest))
continue;
+ /* We can safely ignore edges that are not executable. */
+ if ((e->flags & EDGE_EXECUTABLE) == 0)
+ continue;
+
/* If we have already seen a non-loop edge, then we must have
multiple incoming non-loop edges and thus we return NULL. */
if (retval)
@@ -1294,7 +1333,7 @@ cprop_into_successor_phis (basic_block bb,
}
}
-void
+edge
dom_opt_dom_walker::before_dom_children (basic_block bb)
{
gimple_stmt_iterator gsi;
@@ -1322,12 +1361,15 @@ dom_opt_dom_walker::before_dom_children (basic_block bb)
m_avail_exprs_stack);
m_avail_exprs_stack->pop_to_marker ();
+ edge taken_edge = NULL;
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
- optimize_stmt (bb, gsi, m_const_and_copies, m_avail_exprs_stack);
+ taken_edge
+ = optimize_stmt (bb, gsi, m_const_and_copies, m_avail_exprs_stack);
/* Now prepare to process dominated blocks. */
record_edge_info (bb);
cprop_into_successor_phis (bb, m_const_and_copies);
+ return taken_edge;
}
/* We have finished processing the dominator children of BB, perform
@@ -1694,7 +1736,7 @@ cprop_into_stmt (gimple *stmt)
assignment is found, we map the value on the RHS of the assignment to
the variable in the LHS in the CONST_AND_COPIES table. */
-static void
+static edge
optimize_stmt (basic_block bb, gimple_stmt_iterator si,
class const_and_copies *const_and_copies,
class avail_exprs_stack *avail_exprs_stack)
@@ -1703,6 +1745,7 @@ optimize_stmt (basic_block bb, gimple_stmt_iterator si,
bool may_optimize_p;
bool modified_p = false;
bool was_noreturn;
+ edge retval = NULL;
old_stmt = stmt = gsi_stmt (si);
was_noreturn = is_gimple_call (stmt) && gimple_call_noreturn_p (stmt);
@@ -1823,7 +1866,7 @@ optimize_stmt (basic_block bb, gimple_stmt_iterator si,
fprintf (dump_file, " Flagged to clear EH edges.\n");
}
release_defs (stmt);
- return;
+ return retval;
}
}
}
@@ -1849,25 +1892,19 @@ optimize_stmt (basic_block bb, gimple_stmt_iterator si,
if (val && TREE_CODE (val) == INTEGER_CST)
{
- edge taken_edge = find_taken_edge (bb, val);
- if (taken_edge)
+ retval = find_taken_edge (bb, val);
+ if (retval)
{
-
- /* We need to remove any queued jump threads that
- reference outgoing edges from this block. */
- edge_iterator ei;
- edge e;
- FOR_EACH_EDGE (e, ei, bb->succs)
- remove_jump_threads_including (e);
-
- /* Now clean up the control statement at the end of
- BB and remove unexecutable edges. */
- remove_ctrl_stmt_and_useless_edges (bb, taken_edge->dest);
-
- /* Fixup the flags on the single remaining edge. */
- taken_edge->flags
- &= ~(EDGE_TRUE_VALUE | EDGE_FALSE_VALUE | EDGE_ABNORMAL);
- taken_edge->flags |= EDGE_FALLTHRU;
+ /* Fix the condition to be either true or false. */
+ if (gimple_code (stmt) == GIMPLE_COND)
+ {
+ if (integer_zerop (val))
+ gimple_cond_make_false (as_a <gcond *> (stmt));
+ else if (integer_onep (val))
+ gimple_cond_make_true (as_a <gcond *> (stmt));
+ else
+ gcc_unreachable ();
+ }
/* Further simplifications may be possible. */
cfg_altered = true;
@@ -1887,6 +1924,7 @@ optimize_stmt (basic_block bb, gimple_stmt_iterator si,
&& is_gimple_call (stmt) && gimple_call_noreturn_p (stmt))
need_noreturn_fixup.safe_push (stmt);
}
+ return retval;
}
/* Helper for walk_non_aliased_vuses. Determine if we arrived at
