Put virtual operands into loop-closed SSA
When attempting to manually update SSA form after high-level loop
transforms such as loop versioning it is helpful when the loop-closed
SSA form includes virtual operands. While we have the special
rewrite_virtuals_into_loop_closed_ssa function that doesn't
presently scale, invoking update_ssa by itself. So the following
makes the regular loop-closed SSA form also cover virtual operands.
For users of loop_version this allows to use cheaper
TODO_update_ssa_no_phi, skipping dominance frontier compute
(for the whole function) and iterated dominance frontiers for each
copied def.
* tree-ssa-loop-manip.h
(rewrite_virtuals_into_loop_closed_ssa): Remove.
(rewrite_into_loop_closed_ssa_1): Likewise.
* tree-ssa-loop-manip.cc (rewrite_into_loop_closed_ssa_1):
Make static.
(rewrite_into_loop_closed_ssa): Remove loop overload,
always rewrite virtuals into LC SSA.
(check_loop_closed_ssa_bb): Also check virtuals.
* tree-ssa-dce.cc (remove_dead_phis): Preserve virtual
LC PHIs when in LC SSA.
* gimple-loop-jam.cc (fuse_loops): Do not rewrite into
loop-closed SSA here, but ...
(tree_loop_unroll_and_jam): ... here once.
* tree-if-conv.cc (version_loop_for_if_conversion): Use
the cheaper TODO_update_ssa_no_phi.
* tree-loop-distribution.cc (version_loop_by_alias_check):
Likewise.
* tree-ssa-loop-unswitch.cc (tree_unswitch_single_loop):
Likewise.
* tree-vect-loop-manip.cc (vect_loop_versioning): Likewise.
(tree_unswitch_outer_loop): Do not rewrite virtuals into
LC ssa.
* tree-parloops.cc (transform_to_exit_first_loop_alt):
Likewise.
(pass_parallelize_loops::execute): After finishing rewrite
into LC SSA again because we do not maintain it properly.
diff --git a/gcc/gimple-loop-jam.cc b/gcc/gimple-loop-jam.cc
index 9b18b52..8cde6c7 100644
--- a/gcc/gimple-loop-jam.cc
+++ b/gcc/gimple-loop-jam.cc
@@ -363,7 +363,6 @@
delete_loop (next);
next = ln;
}
- rewrite_into_loop_closed_ssa_1 (NULL, 0, SSA_OP_USE, loop);
}
/* Return true if any of the access functions for dataref A
@@ -610,6 +609,7 @@
if (todo)
{
+ rewrite_into_loop_closed_ssa (NULL, 0);
scev_reset ();
free_dominance_info (CDI_DOMINATORS);
}
diff --git a/gcc/tree-if-conv.cc b/gcc/tree-if-conv.cc
index 3c659f6..1c8e1a4 100644
--- a/gcc/tree-if-conv.cc
+++ b/gcc/tree-if-conv.cc
@@ -2934,7 +2934,7 @@
if (preds)
preds->safe_push (g);
gsi_insert_before (&gsi, g, GSI_SAME_STMT);
- update_ssa (TODO_update_ssa);
+ update_ssa (TODO_update_ssa_no_phi);
return new_loop;
}
diff --git a/gcc/tree-loop-distribution.cc b/gcc/tree-loop-distribution.cc
index 18b97fc..ed7f432 100644
--- a/gcc/tree-loop-distribution.cc
+++ b/gcc/tree-loop-distribution.cc
@@ -2751,7 +2751,7 @@
gimple_stmt_iterator cond_gsi = gsi_last_bb (cond_bb);
gsi_insert_seq_before (&cond_gsi, cond_stmts, GSI_SAME_STMT);
}
- update_ssa (TODO_update_ssa);
+ update_ssa (TODO_update_ssa_no_phi);
}
/* Return true if loop versioning is needed to distrubute PARTITIONS.
diff --git a/gcc/tree-parloops.cc b/gcc/tree-parloops.cc
index 2c3ef43..2d3aa78 100644
--- a/gcc/tree-parloops.cc
+++ b/gcc/tree-parloops.cc
@@ -2355,12 +2355,6 @@
tree control = gimple_cond_lhs (cond_stmt);
edge e;
- /* Rewriting virtuals into loop-closed ssa normal form makes this
- transformation simpler. It also ensures that the virtuals are in
- loop-closed ssa normal from after the transformation, which is required by
- create_parallel_loop. */
- rewrite_virtuals_into_loop_closed_ssa (loop);
-
/* Create the new_header block. */
basic_block new_header = split_block_before_cond_jump (exit->src);
edge edge_at_split = single_pred_edge (new_header);
@@ -4223,7 +4217,9 @@
checking_verify_loop_structure ();
- todo |= TODO_update_ssa;
+ update_ssa (TODO_update_ssa);
+ if (in_loop_pipeline)
+ rewrite_into_loop_closed_ssa (NULL, 0);
}
if (!in_loop_pipeline)
diff --git a/gcc/tree-ssa-dce.cc b/gcc/tree-ssa-dce.cc
index 5df6492..bc53358 100644
--- a/gcc/tree-ssa-dce.cc
+++ b/gcc/tree-ssa-dce.cc
@@ -1026,7 +1026,8 @@
{
/* Virtual PHI nodes with one or identical arguments
can be removed. */
- if (degenerate_phi_p (phi))
+ if (!loops_state_satisfies_p (LOOP_CLOSED_SSA)
+ && degenerate_phi_p (phi))
{
tree vdef = gimple_phi_result (phi);
tree vuse = gimple_phi_arg_def (phi, 0);
diff --git a/gcc/tree-ssa-loop-manip.cc b/gcc/tree-ssa-loop-manip.cc
index 5d43563..623d03b 100644
--- a/gcc/tree-ssa-loop-manip.cc
+++ b/gcc/tree-ssa-loop-manip.cc
@@ -625,7 +625,7 @@
UPDATE_FLAG is used in the call to update_ssa. See
TODO_update_ssa* for documentation. */
-void
+static void
rewrite_into_loop_closed_ssa_1 (bitmap changed_bbs, unsigned update_flag,
int use_flags, class loop *loop)
{
@@ -686,24 +686,16 @@
free (use_blocks);
}
-/* Rewrites the non-virtual defs and uses into a loop closed ssa form. If
- CHANGED_BBS is not NULL, we look for uses outside loops only in the basic
+/* Rewrites the defs and uses into a loop closed ssa form.
+ If CHANGED_BBS is not NULL, we look for uses outside loops only in the basic
blocks in this set. UPDATE_FLAG is used in the call to update_ssa. See
TODO_update_ssa* for documentation. */
void
rewrite_into_loop_closed_ssa (bitmap changed_bbs, unsigned update_flag)
{
- rewrite_into_loop_closed_ssa_1 (changed_bbs, update_flag, SSA_OP_USE, NULL);
-}
-
-/* Rewrites virtual defs and uses with def in LOOP into loop closed ssa
- form. */
-
-void
-rewrite_virtuals_into_loop_closed_ssa (class loop *loop)
-{
- rewrite_into_loop_closed_ssa_1 (NULL, 0, SSA_OP_VIRTUAL_USES, loop);
+ rewrite_into_loop_closed_ssa_1 (changed_bbs, update_flag,
+ SSA_OP_ALL_USES, NULL);
}
/* Check invariants of the loop closed ssa form for the def in DEF_BB. */
@@ -736,8 +728,7 @@
{
gphi *phi = bsi.phi ();
- if (!virtual_operand_p (PHI_RESULT (phi)))
- check_loop_closed_ssa_def (bb, PHI_RESULT (phi));
+ check_loop_closed_ssa_def (bb, PHI_RESULT (phi));
}
for (gimple_stmt_iterator bsi = gsi_start_nondebug_bb (bb); !gsi_end_p (bsi);
@@ -747,7 +738,7 @@
tree var;
gimple *stmt = gsi_stmt (bsi);
- FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_DEF)
+ FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_ALL_DEFS)
check_loop_closed_ssa_def (bb, var);
}
}
diff --git a/gcc/tree-ssa-loop-manip.h b/gcc/tree-ssa-loop-manip.h
index 0029319..924cac0 100644
--- a/gcc/tree-ssa-loop-manip.h
+++ b/gcc/tree-ssa-loop-manip.h
@@ -24,10 +24,7 @@
extern void create_iv (tree, tree, tree, class loop *, gimple_stmt_iterator *,
bool, tree *, tree *);
-extern void rewrite_into_loop_closed_ssa_1 (bitmap, unsigned, int,
- class loop *);
extern void rewrite_into_loop_closed_ssa (bitmap, unsigned);
-extern void rewrite_virtuals_into_loop_closed_ssa (class loop *);
extern void verify_loop_closed_ssa (bool, class loop * = NULL);
static inline void
diff --git a/gcc/tree-ssa-loop-unswitch.cc b/gcc/tree-ssa-loop-unswitch.cc
index 3a827f2..7d6781d 100644
--- a/gcc/tree-ssa-loop-unswitch.cc
+++ b/gcc/tree-ssa-loop-unswitch.cc
@@ -980,7 +980,7 @@
free_original_copy_tables ();
/* Update the SSA form after unswitching. */
- update_ssa (TODO_update_ssa);
+ update_ssa (TODO_update_ssa_no_phi);
/* Invoke itself on modified loops. */
bitmap handled_copy = BITMAP_ALLOC (NULL);
@@ -1068,8 +1068,6 @@
auto_vec<gimple *> dbg_to_reset;
while ((guard = find_loop_guard (loop, dbg_to_reset)))
{
- if (! changed)
- rewrite_virtuals_into_loop_closed_ssa (loop);
hoist_guard (loop, guard);
for (gimple *debug_stmt : dbg_to_reset)
{
diff --git a/gcc/tree-vect-loop-manip.cc b/gcc/tree-vect-loop-manip.cc
index e81de45..47c4fe8 100644
--- a/gcc/tree-vect-loop-manip.cc
+++ b/gcc/tree-vect-loop-manip.cc
@@ -3696,7 +3696,7 @@
}
}
- update_ssa (TODO_update_ssa);
+ update_ssa (TODO_update_ssa_no_phi);
}
/* Split the cost model check off to a separate BB. Costing assumes
