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Speedup update-ssa some more

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The following avoids copying an sbitmap and one traversal by avoiding
to re-allocate old_ssa_names when not necessary.  In addition this
actually checks what the comment before PHI insert iterating promises,
that the old_ssa_names set does not grow.

	* tree-into-ssa.cc (iterating_old_ssa_names): New.
	(add_new_name_mapping): Grow {new,old}_ssa_names separately
	and only when actually needed.  Assert we are not growing
	the old_ssa_names set when iterating over it.
	(update_ssa): Remove old_ssa_names copying and empty_p
	query, note we are iterating over it and expect no set changes.
This commit is contained in:
Richard Biener 2022-07-07 12:59:47 +02:00
parent 9ef714539c
commit 9fc61fc8da
1 changed files with 20 additions and 16 deletions
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36
gcc/tree-into-ssa.cc
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@ -587,6 +587,8 @@ add_to_repl_tbl (tree new_tree, tree old)
bitmap_set_bit (*set, SSA_NAME_VERSION (old));
}
/* Debugging aid to fence old_ssa_names changes when iterating over it. */
static bool iterating_old_ssa_names;
/* Add a new mapping NEW_TREE -> OLD REPL_TBL. Every entry N_i in REPL_TBL
represents the set of names O_1 ... O_j replaced by N_i. This is
@ -602,10 +604,15 @@ add_new_name_mapping (tree new_tree, tree old)
/* We may need to grow NEW_SSA_NAMES and OLD_SSA_NAMES because our
caller may have created new names since the set was created. */
if (SBITMAP_SIZE (new_ssa_names) <= num_ssa_names - 1)
if (SBITMAP_SIZE (new_ssa_names) <= SSA_NAME_VERSION (new_tree))
{
unsigned int new_sz = num_ssa_names + NAME_SETS_GROWTH_FACTOR;
new_ssa_names = sbitmap_resize (new_ssa_names, new_sz, 0);
}
if (SBITMAP_SIZE (old_ssa_names) <= SSA_NAME_VERSION (old))
{
gcc_assert (!iterating_old_ssa_names);
unsigned int new_sz = num_ssa_names + NAME_SETS_GROWTH_FACTOR;
old_ssa_names = sbitmap_resize (old_ssa_names, new_sz, 0);
}
@ -619,8 +626,11 @@ add_new_name_mapping (tree new_tree, tree old)
/* Register NEW_TREE and OLD in NEW_SSA_NAMES and OLD_SSA_NAMES,
respectively. */
if (iterating_old_ssa_names)
gcc_assert (bitmap_bit_p (old_ssa_names, SSA_NAME_VERSION (old)));
else
bitmap_set_bit (old_ssa_names, SSA_NAME_VERSION (old));
bitmap_set_bit (new_ssa_names, SSA_NAME_VERSION (new_tree));
bitmap_set_bit (old_ssa_names, SSA_NAME_VERSION (old));
}
@ -3460,20 +3470,14 @@ update_ssa (unsigned update_flags)
bitmap_initialize (&dfs[bb->index], &bitmap_default_obstack);
compute_dominance_frontiers (dfs);
if (bitmap_first_set_bit (old_ssa_names) >= 0)
{
sbitmap_iterator sbi;
/* insert_update_phi_nodes_for will call add_new_name_mapping
when inserting new PHI nodes, so the set OLD_SSA_NAMES
will grow while we are traversing it (but it will not
gain any new members). Copy OLD_SSA_NAMES to a temporary
for traversal. */
auto_sbitmap tmp (SBITMAP_SIZE (old_ssa_names));
bitmap_copy (tmp, old_ssa_names);
EXECUTE_IF_SET_IN_BITMAP (tmp, 0, i, sbi)
insert_updated_phi_nodes_for (ssa_name (i), dfs, update_flags);
}
/* insert_update_phi_nodes_for will call add_new_name_mapping
when inserting new PHI nodes, but it will not add any
new members to OLD_SSA_NAMES. */
iterating_old_ssa_names = true;
sbitmap_iterator sbi;
EXECUTE_IF_SET_IN_BITMAP (old_ssa_names, 0, i, sbi)
insert_updated_phi_nodes_for (ssa_name (i), dfs, update_flags);
iterating_old_ssa_names = false;
symbols_to_rename.qsort (insert_updated_phi_nodes_compare_uids);
FOR_EACH_VEC_ELT (symbols_to_rename, i, sym)