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tree-ssa-dom.c (single_incoming_edge_ignoring_loop_edges): New.

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* tree-ssa-dom.c (single_incoming_edge_ignoring_loop_edges): New.
        (get_eq_expr_value): Use it.  Simplify slightly.

From-SVN: r84927
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Jeff Law 2004-07-19 13:01:55 -06:00 • committed by Jeff Law
parent 963ddbd50f
commit 28c008bb89
2 changed files with 46 additions and 17 deletions
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5
gcc/ChangeLog
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@ -1,3 +1,8 @@
2004-07-19 Jeff Law <law@redhat.com>
* tree-ssa-dom.c (single_incoming_edge_ignoring_loop_edges): New.
(get_eq_expr_value): Use it. Simplify slightly.
2004-07-19 Maciej W. Rozycki <macro@linux-mips.org>
* config/mips/mips.md (mulsidi3_32bit_r4000): Fix the clobber list.

58
gcc/tree-ssa-dom.c
View file

@ -268,6 +268,7 @@ static void restore_currdefs_to_original_value (varray_type locals,
unsigned limit);
static void register_definitions_for_stmt (stmt_ann_t, varray_type *);
static void redirect_edges_and_update_ssa_graph (varray_type);
static edge single_incoming_edge_ignoring_loop_edges (basic_block);
/* Local version of fold that doesn't introduce cruft. */
@ -1407,6 +1408,34 @@ record_equivalences_from_phis (struct dom_walk_data *walk_data, basic_block bb)
}
}
/* Ignoring loop backedges, if BB has precisely one incoming edge then
return that edge. Otherwise return NULL. */
static edge
single_incoming_edge_ignoring_loop_edges (basic_block bb)
{
edge retval = NULL;
edge e;
for (e = bb->pred; e; e = e->pred_next)
{
/* A loop back edge can be identified by the destination of
the edge dominating the source of the edge. */
if (dominated_by_p (CDI_DOMINATORS, e->src, e->dest))
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)
return NULL;
/* This is the first non-loop incoming edge we have found. Record
it. */
retval = e;
}
return retval;
}
/* Record any equivalences created by the incoming edge to BB. If BB
has more than one incoming edge, then no equivalence is created. */
@ -1435,21 +1464,20 @@ record_equivalences_from_incoming_edge (struct dom_walk_data *walk_data,
eq_expr_value.src = NULL;
eq_expr_value.dst = NULL;
/* If we have a single predecessor, then extract EDGE_FLAGS from
our single incoming edge. Otherwise clear EDGE_FLAGS and
PARENT_BLOCK_LAST_STMT since they're not needed. */
/* If we have a single predecessor (ignoring loop backedges), then extract
EDGE_FLAGS from the single incoming edge. Otherwise just return as
there is nothing to do. */
if (bb->pred
&& ! bb->pred->pred_next
&& parent_block_last_stmt
&& bb_for_stmt (parent_block_last_stmt) == bb->pred->src)
&& parent_block_last_stmt)
{
edge_flags = bb->pred->flags;
edge e = single_incoming_edge_ignoring_loop_edges (bb);
if (e && bb_for_stmt (parent_block_last_stmt) == e->src)
edge_flags = e->flags;
else
return;
}
else
{
edge_flags = 0;
parent_block_last_stmt = NULL;
}
return;
/* If our parent block ended in a COND_EXPR, add any equivalences
created by the COND_EXPR to the hash table and initialize
@ -1462,9 +1490,7 @@ record_equivalences_from_incoming_edge (struct dom_walk_data *walk_data,
conditional. This assignment is inserted in CONST_AND_COPIES so that
the copy and constant propagator can find more propagation
opportunities. */
if (parent_block_last_stmt
&& bb->pred->pred_next == NULL
&& TREE_CODE (parent_block_last_stmt) == COND_EXPR
if (TREE_CODE (parent_block_last_stmt) == COND_EXPR
&& (edge_flags & (EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
eq_expr_value = get_eq_expr_value (parent_block_last_stmt,
(edge_flags & EDGE_TRUE_VALUE) != 0,
@ -1474,9 +1500,7 @@ record_equivalences_from_incoming_edge (struct dom_walk_data *walk_data,
/* Similarly when the parent block ended in a SWITCH_EXPR.
We can only know the value of the switch's condition if the dominator
parent is also the only predecessor of this block. */
else if (parent_block_last_stmt
&& bb->pred->pred_next == NULL
&& bb->pred->src == parent
else if (bb->pred->src == parent
&& TREE_CODE (parent_block_last_stmt) == SWITCH_EXPR)
{
tree switch_cond = SWITCH_COND (parent_block_last_stmt);