(struct loop *, struct loops *, edge);
static void slpeel_update_phis_for_duplicate_loop
(struct loop *, struct loop *, bool after);
-static void slpeel_update_phi_nodes_for_guard (edge, struct loop *, bool, bool);
+static void slpeel_update_phi_nodes_for_guard1
+ (edge, struct loop *, bool, basic_block *, bitmap *);
+static void slpeel_update_phi_nodes_for_guard2
+ (edge, struct loop *, bool, basic_block *);
static edge slpeel_add_loop_guard (basic_block, tree, basic_block, basic_block);
static void allocate_new_names (bitmap);
controls whether LOOP is to be executed. GUARD_EDGE is the edge that
originates from the guard-bb, skips LOOP and reaches the (unique) exit
bb of LOOP. This loop-exit-bb is an empty bb with one successor.
- We denote this bb NEW_MERGE_BB because it had a single predecessor (the
- LOOP header) before the guard code was added, and now it became a merge
+ We denote this bb NEW_MERGE_BB because before the guard code was added
+ it had a single predecessor (the LOOP header), and now it became a merge
point of two paths - the path that ends with the LOOP exit-edge, and
the path that ends with GUARD_EDGE.
+ - NEW_EXIT_BB: New basic block that is added by this function between LOOP
+ and NEW_MERGE_BB. It is used to place loop-closed-ssa-form exit-phis.
- This function creates and updates the relevant phi nodes to account for
- the new incoming edge (GUARD_EDGE) into NEW_MERGE_BB:
- 1. Create phi nodes at NEW_MERGE_BB.
- 2. Update the phi nodes at the successor of NEW_MERGE_BB (denoted
- UPDATE_BB). UPDATE_BB was the exit-bb of LOOP before NEW_MERGE_BB
- was added:
+ ===> The CFG before the guard-code was added:
+ LOOP_header_bb:
+ loop_body
+ if (exit_loop) goto update_bb
+ else goto LOOP_header_bb
+ update_bb:
- ===> The CFG before the guard-code was added:
+ ==> The CFG after the guard-code was added:
+ guard_bb:
+ if (LOOP_guard_condition) goto new_merge_bb
+ else goto LOOP_header_bb
LOOP_header_bb:
- if (exit_loop) goto update_bb : LOOP_header_bb
+ loop_body
+ if (exit_loop_condition) goto new_merge_bb
+ else goto LOOP_header_bb
+ new_merge_bb:
+ goto update_bb
update_bb:
- ==> The CFG after the guard-code was added:
- guard_bb:
- if (LOOP_guard_condition) goto new_merge_bb : LOOP_header_bb
+ ==> The CFG after this function:
+ guard_bb:
+ if (LOOP_guard_condition) goto new_merge_bb
+ else goto LOOP_header_bb
LOOP_header_bb:
- if (exit_loop_condition) goto new_merge_bb : LOOP_header_bb
+ loop_body
+ if (exit_loop_condition) goto new_exit_bb
+ else goto LOOP_header_bb
+ new_exit_bb:
new_merge_bb:
goto update_bb
update_bb:
- - ENTRY_PHIS: If ENTRY_PHIS is TRUE, this indicates that the phis in
- UPDATE_BB are loop entry phis, like the phis in the LOOP header,
- organized in the same order.
- If ENTRY_PHIs is FALSE, this indicates that the phis in UPDATE_BB are
- loop exit phis.
-
- - IS_NEW_LOOP: TRUE if LOOP is a new loop (a duplicated copy of another
- "original" loop). FALSE if LOOP is an original loop (not a newly
- created copy). The SSA_NAME_AUX fields of the defs in the original
- loop are the corresponding new ssa-names used in the new duplicated
- loop copy. IS_NEW_LOOP indicates which of the two args of the phi
- nodes in UPDATE_BB takes the original ssa-name, and which takes the
- new name: If IS_NEW_LOOP is TRUE, the phi-arg that is associated with
- the LOOP-exit-edge takes the new-name, and the phi-arg that is
- associated with GUARD_EDGE takes the original name. If IS_NEW_LOOP is
- FALSE, it's the other way around.
+ This function:
+ 1. creates and updates the relevant phi nodes to account for the new
+ incoming edge (GUARD_EDGE) into NEW_MERGE_BB. This involves:
+ 1.1. Create phi nodes at NEW_MERGE_BB.
+ 1.2. Update the phi nodes at the successor of NEW_MERGE_BB (denoted
+ UPDATE_BB). UPDATE_BB was the exit-bb of LOOP before NEW_MERGE_BB
+ 2. preserves loop-closed-ssa-form by creating the required phi nodes
+ at the exit of LOOP (i.e, in NEW_EXIT_BB).
+
+ There are two flavors to this function:
+
+ slpeel_update_phi_nodes_for_guard1:
+ Here the guard controls whether we enter or skip LOOP, where LOOP is a
+ prolog_loop (loop1 below), and the new phis created in NEW_MERGE_BB are
+ for variables that have phis in the loop header.
+
+ slpeel_update_phi_nodes_for_guard2:
+ Here the guard controls whether we enter or skip LOOP, where LOOP is an
+ epilog_loop (loop2 below), and the new phis created in NEW_MERGE_BB are
+ for variables that have phis in the loop exit.
+
+ I.E., the overall structure is:
+
+ loop1_preheader_bb:
+ guard1 (goto loop1/merg1_bb)
+ loop1
+ loop1_exit_bb:
+ guard2 (goto merge1_bb/merge2_bb)
+ merge1_bb
+ loop2
+ loop2_exit_bb
+ merge2_bb
+ next_bb
+
+ slpeel_update_phi_nodes_for_guard1 takes care of creating phis in
+ loop1_exit_bb and merge1_bb. These are entry phis (phis for the vars
+ that have phis in loop1->header).
+
+ slpeel_update_phi_nodes_for_guard2 takes care of creating phis in
+ loop2_exit_bb and merge2_bb. These are exit phis (phis for the vars
+ that have phis in next_bb). It also adds some of these phis to
+ loop1_exit_bb.
+
+ slpeel_update_phi_nodes_for_guard1 is always called before
+ slpeel_update_phi_nodes_for_guard2. They are both needed in order
+ to create correct data-flow and loop-closed-ssa-form.
+
+ Generally slpeel_update_phi_nodes_for_guard1 creates phis for variables
+ that change between iterations of a loop (and therefore have a phi-node
+ at the loop entry), whereas slpeel_update_phi_nodes_for_guard2 creates
+ phis for variables that are used out of the loop (and therefore have
+ loop-closed exit phis). Some variables may be both updated between
+ iterations and used after the loop. This is why in loop1_exit_bb we
+ may need both entry_phis (created by slpeel_update_phi_nodes_for_guard1)
+ and exit phis (created by slpeel_update_phi_nodes_for_guard2).
+
+ - IS_NEW_LOOP: if IS_NEW_LOOP is true, then LOOP is a newly created copy of
+ an original loop. i.e., we have:
+
+ orig_loop
+ guard_bb (goto LOOP/new_merge)
+ new_loop <-- LOOP
+ new_exit
+ new_merge
+ next_bb
+
+ If IS_NEW_LOOP is false, then LOOP is an original loop, in which case we
+ have:
+
+ new_loop
+ guard_bb (goto LOOP/new_merge)
+ orig_loop <-- LOOP
+ new_exit
+ new_merge
+ next_bb
+
+ The ssa-names defined in the original loop have an SSA_NAME_AUX pointer
+ that records the corresponding new ssa-name used in the new duplicated
+ loop copy.
*/
+/* Function slpeel_update_phi_nodes_for_guard1
+
+ Input:
+ - GUARD_EDGE, LOOP, IS_NEW_LOOP, NEW_EXIT_BB - as explained above.
+ - DEFS - a bitmap of ssa names to mark new names for which we recorded
+ information.
+
+ In the context of the overall structure, we have:
+
+ loop1_preheader_bb:
+ guard1 (goto loop1/merg1_bb)
+LOOP-> loop1
+ loop1_exit_bb:
+ guard2 (goto merge1_bb/merge2_bb)
+ merge1_bb
+ loop2
+ loop2_exit_bb
+ merge2_bb
+ next_bb
+
+ For each name updated between loop iterations (i.e - for each name that has
+ an entry (loop-header) phi in LOOP) we create a new phi in:
+ 1. merge1_bb (to account for the edge from guard1)
+ 2. loop1_exit_bb (an exit-phi to keep LOOP in loop-closed form)
+*/
+
static void
-slpeel_update_phi_nodes_for_guard (edge guard_edge,
- struct loop *loop,
- bool entry_phis,
- bool is_new_loop)
+slpeel_update_phi_nodes_for_guard1 (edge guard_edge, struct loop *loop,
+ bool is_new_loop, basic_block *new_exit_bb,
+ bitmap *defs)
{
- tree orig_phi, new_phi, update_phi;
+ tree orig_phi, new_phi;
+ tree update_phi, update_phi2;
+ tree *new_name_ptr, *new_name_ptr2;
tree guard_arg, loop_arg;
basic_block new_merge_bb = guard_edge->dest;
- edge e = single_succ_edge (new_merge_bb);
+ edge e = EDGE_SUCC (new_merge_bb, 0);
basic_block update_bb = e->dest;
- basic_block orig_bb = (entry_phis ? loop->header : update_bb);
+ basic_block orig_bb = loop->header;
+ edge new_exit_e;
+ tree current_new_name;
+
+ /* Create new bb between loop and new_merge_bb. */
+ *new_exit_bb = split_edge (loop->single_exit);
+ add_bb_to_loop (*new_exit_bb, loop->outer);
+
+ new_exit_e = EDGE_SUCC (*new_exit_bb, 0);
for (orig_phi = phi_nodes (orig_bb), update_phi = phi_nodes (update_bb);
orig_phi && update_phi;
orig_phi = PHI_CHAIN (orig_phi), update_phi = PHI_CHAIN (update_phi))
{
- /* 1. Generate new phi node in NEW_MERGE_BB: */
+ /** 1. Handle new-merge-point phis **/
+
+ /* 1.1. Generate new phi node in NEW_MERGE_BB: */
+ new_phi = create_phi_node (SSA_NAME_VAR (PHI_RESULT (orig_phi)),
+ new_merge_bb);
+
+ /* 1.2. NEW_MERGE_BB has two incoming edges: GUARD_EDGE and the exit-edge
+ of LOOP. Set the two phi args in NEW_PHI for these edges: */
+ loop_arg = PHI_ARG_DEF_FROM_EDGE (orig_phi, EDGE_SUCC (loop->latch, 0));
+ guard_arg = PHI_ARG_DEF_FROM_EDGE (orig_phi, loop_preheader_edge (loop));
+
+ add_phi_arg (new_phi, loop_arg, new_exit_e);
+ add_phi_arg (new_phi, guard_arg, guard_edge);
+
+ /* 1.3. Update phi in successor block. */
+ gcc_assert (PHI_ARG_DEF_FROM_EDGE (update_phi, e) == loop_arg
+ || PHI_ARG_DEF_FROM_EDGE (update_phi, e) == guard_arg);
+ SET_PHI_ARG_DEF (update_phi, e->dest_idx, PHI_RESULT (new_phi));
+ update_phi2 = new_phi;
+
+
+ /** 2. Handle loop-closed-ssa-form phis **/
+
+ /* 2.1. Generate new phi node in NEW_EXIT_BB: */
+ new_phi = create_phi_node (SSA_NAME_VAR (PHI_RESULT (orig_phi)),
+ *new_exit_bb);
+
+ /* 2.2. NEW_EXIT_BB has one incoming edge: the exit-edge of the loop. */
+ add_phi_arg (new_phi, loop_arg, loop->single_exit);
+
+ /* 2.3. Update phi in successor of NEW_EXIT_BB: */
+ gcc_assert (PHI_ARG_DEF_FROM_EDGE (update_phi2, new_exit_e) == loop_arg);
+ SET_PHI_ARG_DEF (update_phi2, new_exit_e->dest_idx, PHI_RESULT (new_phi));
+
+ /* 2.4. Record the newly created name in SSA_NAME_AUX.
+ We want to find a name such that
+ name = *(SSA_NAME_AUX (orig_loop_name))
+ and to set its SSA_NAME_AUX as follows:
+ *(SSA_NAME_AUX (name)) = new_phi_name
+
+ If LOOP is a new loop then loop_arg is already the name we're
+ looking for. If LOOP is the original loop, then loop_arg is
+ the orig_loop_name and the relevant name is recorded in its
+ SSA_NAME_AUX */
+ if (is_new_loop)
+ current_new_name = loop_arg;
+ else
+ {
+ new_name_ptr = SSA_NAME_AUX (loop_arg);
+ gcc_assert (new_name_ptr);
+ current_new_name = *new_name_ptr;
+ }
+#ifdef ENABLE_CHECKING
+ gcc_assert (! SSA_NAME_AUX (current_new_name));
+#endif
+
+ new_name_ptr2 = xmalloc (sizeof (tree));
+ *new_name_ptr2 = PHI_RESULT (new_phi);
+ SSA_NAME_AUX (current_new_name) = new_name_ptr2;
+ bitmap_set_bit (*defs, SSA_NAME_VERSION (current_new_name));
+ }
+
+ set_phi_nodes (new_merge_bb, phi_reverse (phi_nodes (new_merge_bb)));
+}
+
+
+/* Function slpeel_update_phi_nodes_for_guard2
+
+ Input:
+ - GUARD_EDGE, LOOP, IS_NEW_LOOP, NEW_EXIT_BB - as explained above.
+
+ In the context of the overall structure, we have:
+
+ loop1_preheader_bb:
+ guard1 (goto loop1/merg1_bb)
+ loop1
+ loop1_exit_bb:
+ guard2 (goto merge1_bb/merge2_bb)
+ merge1_bb
+LOOP-> loop2
+ loop2_exit_bb
+ merge2_bb
+ next_bb
+
+ For each name used out side the loop (i.e - for each name that has an exit
+ phi in next_bb) we create a new phi in:
+ 1. merge2_bb (to account for the edge from guard_bb)
+ 2. loop2_exit_bb (an exit-phi to keep LOOP in loop-closed form)
+ 3. guard2 bb (an exit phi to keep the preceding loop in loop-closed form),
+ if needed (if it wasn't handled by slpeel_update_phis_nodes_for_phi1).
+*/
+
+static void
+slpeel_update_phi_nodes_for_guard2 (edge guard_edge, struct loop *loop,
+ bool is_new_loop, basic_block *new_exit_bb)
+{
+ tree orig_phi, new_phi;
+ tree update_phi, update_phi2;
+ tree *new_name_ptr, *new_name_ptr2;
+ tree guard_arg, loop_arg;
+ basic_block new_merge_bb = guard_edge->dest;
+ edge e = EDGE_SUCC (new_merge_bb, 0);
+ basic_block update_bb = e->dest;
+ edge new_exit_e;
+ tree orig_def;
+ tree new_name, new_name2;
+ tree arg;
+
+ /* Create new bb between loop and new_merge_bb. */
+ *new_exit_bb = split_edge (loop->single_exit);
+ add_bb_to_loop (*new_exit_bb, loop->outer);
+
+ new_exit_e = EDGE_SUCC (*new_exit_bb, 0);
+
+ for (update_phi = phi_nodes (update_bb); update_phi;
+ update_phi = PHI_CHAIN (update_phi))
+ {
+ orig_phi = update_phi;
+ orig_def = PHI_ARG_DEF_FROM_EDGE (orig_phi, e);
+ new_name_ptr = SSA_NAME_AUX (orig_def);
+ arg = NULL_TREE;
+
+ /** 1. Handle new-merge-point phis **/
+
+ /* 1.1. Generate new phi node in NEW_MERGE_BB: */
new_phi = create_phi_node (SSA_NAME_VAR (PHI_RESULT (orig_phi)),
new_merge_bb);
- /* 2. NEW_MERGE_BB has two incoming edges: GUARD_EDGE and the exit-edge
+ /* 1.2. NEW_MERGE_BB has two incoming edges: GUARD_EDGE and the exit-edge
of LOOP. Set the two phi args in NEW_PHI for these edges: */
- if (entry_phis)
+ new_name = orig_def;
+ new_name2 = NULL_TREE;
+ if (new_name_ptr)
{
- loop_arg = PHI_ARG_DEF_FROM_EDGE (orig_phi,
- loop_latch_edge (loop));
- guard_arg = PHI_ARG_DEF_FROM_EDGE (orig_phi,
- loop_preheader_edge (loop));
+ new_name = *new_name_ptr;
+ new_name_ptr2 = SSA_NAME_AUX (new_name);
+ if (new_name_ptr2)
+ /* Some variables have both loop-entry-phis and loop-exit-phis.
+ Such variables were given yet newer names by phis placed in
+ guard_bb by slpeel_update_phi_nodes_for_guard1. I.e:
+ new_name2 = SSA_NAME_AUX (SSA_NAME_AUX (orig_name)). */
+ new_name2 = *new_name_ptr2;
}
- else /* exit phis */
+
+ if (is_new_loop)
{
- tree orig_def = PHI_ARG_DEF_FROM_EDGE (orig_phi, e);
- tree *new_name_ptr = SSA_NAME_AUX (orig_def);
- tree new_name;
-
- if (new_name_ptr)
- new_name = *new_name_ptr;
- else
- /* Something defined outside of the loop */
- new_name = orig_def;
-
- if (is_new_loop)
- {
- guard_arg = orig_def;
- loop_arg = new_name;
- }
- else
- {
- guard_arg = new_name;
- loop_arg = orig_def;
- }
+ guard_arg = orig_def;
+ loop_arg = new_name;
}
- add_phi_arg (new_phi, loop_arg, loop->single_exit);
+ else
+ {
+ guard_arg = new_name;
+ loop_arg = orig_def;
+ }
+ if (new_name2)
+ guard_arg = new_name2;
+
+ add_phi_arg (new_phi, loop_arg, new_exit_e);
add_phi_arg (new_phi, guard_arg, guard_edge);
- /* 3. Update phi in successor block. */
- gcc_assert (PHI_ARG_DEF_FROM_EDGE (update_phi, e) == loop_arg
- || PHI_ARG_DEF_FROM_EDGE (update_phi, e) == guard_arg);
+ /* 1.3. Update phi in successor block. */
+ gcc_assert (PHI_ARG_DEF_FROM_EDGE (update_phi, e) == orig_def);
SET_PHI_ARG_DEF (update_phi, e->dest_idx, PHI_RESULT (new_phi));
+ update_phi2 = new_phi;
+
+
+ /** 2. Handle loop-closed-ssa-form phis **/
+
+ /* 2.1. Generate new phi node in NEW_EXIT_BB: */
+ new_phi = create_phi_node (SSA_NAME_VAR (PHI_RESULT (orig_phi)),
+ *new_exit_bb);
+
+ /* 2.2. NEW_EXIT_BB has one incoming edge: the exit-edge of the loop. */
+ add_phi_arg (new_phi, loop_arg, loop->single_exit);
+
+ /* 2.3. Update phi in successor of NEW_EXIT_BB: */
+ gcc_assert (PHI_ARG_DEF_FROM_EDGE (update_phi2, new_exit_e) == loop_arg);
+ SET_PHI_ARG_DEF (update_phi2, new_exit_e->dest_idx, PHI_RESULT (new_phi));
+
+
+ /** 3. Handle loop-closed-ssa-form phis for first loop **/
+
+ /* 3.1. Find the relevant names that need an exit-phi in GUARD_BB, i.e.
+ names for which slpeel_update_phi_nodes_for_guard1 had not already
+ created a phi node. This is the case for names that are used out
+ side the loop (and therefore need an exit phi) but are not updated
+ across loop iterations (and therefore don't have a loop-header-phi).
+
+ slpeel_update_phi_nodes_for_guard1 is responssible for creating
+ loop-exit phis in GUARD_BB for names that have a loop-header-phi. When
+ such a phi is created we also record the new name in SSA_NAME_AUX. If
+ this new name exists, then guard_arg was set to this new name
+ (see 1.2 above). Therefore, if guard_arg is not this new name, this is
+ an indication that an exit-phi in GUARD_BB was not yet created, so we
+ take care of it here.
+ */
+ if (guard_arg == new_name2)
+ continue;
+ arg = guard_arg;
+
+ /* 3.2. Generate new phi node in GUARD_BB: */
+ new_phi = create_phi_node (SSA_NAME_VAR (PHI_RESULT (orig_phi)),
+ guard_edge->src);
+
+ /* 3.3. GUARD_BB has one incoming edge: */
+ gcc_assert (EDGE_COUNT (guard_edge->src->preds) == 1);
+ add_phi_arg (new_phi, arg, EDGE_PRED (guard_edge->src, 0));
+
+ /* 3.4. Update phi in successor of GUARD_BB: */
+ gcc_assert (PHI_ARG_DEF_FROM_EDGE (update_phi2, guard_edge)
+ == guard_arg);
+ SET_PHI_ARG_DEF (update_phi2, guard_edge->dest_idx, PHI_RESULT (new_phi));
}
set_phi_nodes (new_merge_bb, phi_reverse (phi_nodes (new_merge_bb)));
edge new_e, enter_e;
tree cond_stmt, then_label, else_label;
- enter_e = single_succ_edge (guard_bb);
+ enter_e = EDGE_SUCC (guard_bb, 0);
enter_e->flags &= ~EDGE_FALLTHRU;
enter_e->flags |= EDGE_FALSE_VALUE;
bsi = bsi_last (guard_bb);
cond_stmt = build3 (COND_EXPR, void_type_node, cond,
then_label, else_label);
bsi_insert_after (&bsi, cond_stmt, BSI_NEW_STMT);
- /* Add new edge to connect entry block to the second loop. */
+ /* Add new edge to connect guard block to the merge/loop-exit block. */
new_e = make_edge (guard_bb, exit_bb, EDGE_TRUE_VALUE);
set_immediate_dominator (CDI_DOMINATORS, exit_bb, dom_bb);
return new_e;
basic_block bb_before_second_loop, bb_after_second_loop;
basic_block bb_before_first_loop;
basic_block bb_between_loops;
+ basic_block new_exit_bb;
edge exit_e = loop->single_exit;
LOC loop_loc;
fold (build2 (LE_EXPR, boolean_type_node, first_niters, integer_zero_node));
skip_e = slpeel_add_loop_guard (bb_before_first_loop, pre_condition,
bb_before_second_loop, bb_before_first_loop);
- slpeel_update_phi_nodes_for_guard (skip_e, first_loop, true /* entry-phis */,
- first_loop == new_loop);
+ slpeel_update_phi_nodes_for_guard1 (skip_e, first_loop,
+ first_loop == new_loop,
+ &new_exit_bb, &definitions);
/* 3. Add the guard that controls whether the second loop is executed.
orig_exit_bb:
*/
- bb_between_loops = split_edge (first_loop->single_exit);
- add_bb_to_loop (bb_between_loops, first_loop->outer);
+ bb_between_loops = new_exit_bb;
bb_after_second_loop = split_edge (second_loop->single_exit);
add_bb_to_loop (bb_after_second_loop, second_loop->outer);
fold (build2 (EQ_EXPR, boolean_type_node, first_niters, niters));
skip_e = slpeel_add_loop_guard (bb_between_loops, pre_condition,
bb_after_second_loop, bb_before_first_loop);
- slpeel_update_phi_nodes_for_guard (skip_e, second_loop, false /* exit-phis */,
- second_loop == new_loop);
-
- /* Flow loop scan does not update loop->single_exit field. */
- first_loop->single_exit = first_loop->single_exit;
- second_loop->single_exit = second_loop->single_exit;
+ slpeel_update_phi_nodes_for_guard2 (skip_e, second_loop,
+ second_loop == new_loop, &new_exit_bb);
/* 4. Make first-loop iterate FIRST_NITERS times, if requested.
*/
destroy_loop_vec_info (loop_vinfo);
loop->aux = NULL;
}
-
- rewrite_into_loop_closed_ssa (NULL); /* FORNOW */
}
projects / platform / upstream / gcc.git / commitdiff