While working on a phiopt patch, it was noticed that
SLSR would leave around some unused ssa names. Let's
add simple_dce_from_worklist usage to SLSR to remove
the dead statements. This should give a small improvemnent
for passes afterwards.
Boostrapped and tested on x86_64.
gcc/ChangeLog:
PR tree-optimization/116554
* gimple-ssa-strength-reduction.cc: Include tree-ssa-dce.h.
(replace_mult_candidate): Add sdce_worklist argument, mark
the rhs1/rhs2 for maybe dceing.
(replace_unconditional_candidate): Add sdce_worklist argument,
Update call to replace_mult_candidate.
(replace_conditional_candidate): Add sdce_worklist argument,
update call to replace_mult_candidate.
(replace_uncond_cands_and_profitable_phis): Add sdce_worklist argument,
update call to replace_conditional_candidate,
replace_unconditional_candidate, and
replace_uncond_cands_and_profitable_phis.
(replace_one_candidate): Add sdce_worklist argument, mark
the orig_rhs1/orig_rhs2 for maybe dceing.
(replace_profitable_candidates): Add sdce_worklist argument,
update call to replace_one_candidate and replace_profitable_candidates.
(analyze_candidates_and_replace): Call simple_dce_from_worklist and
update calls to replace_profitable_candidates, and
replace_uncond_cands_and_profitable_phis.
Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>
---
gcc/gimple-ssa-strength-reduction.cc | 59 +++++++++++++++++++---------
1 file changed, 41 insertions(+), 18 deletions(-)
diff --git a/gcc/gimple-ssa-strength-reduction.cc
b/gcc/gimple-ssa-strength-reduction.cc
index 1cb3625c7eb..39cd9339c77 100644
--- a/gcc/gimple-ssa-strength-reduction.cc
+++ b/gcc/gimple-ssa-strength-reduction.cc
@@ -56,6 +56,7 @@ along with GCC; see the file COPYING3. If not see
#include "tree-affine.h"
#include "tree-eh.h"
#include "builtins.h"
+#include "tree-ssa-dce.h"
/* Information about a strength reduction candidate. Each statement
in the candidate table represents an expression of one of the
@@ -2126,7 +2127,8 @@ cand_already_replaced (slsr_cand_t c)
replace_conditional_candidate. */
static void
-replace_mult_candidate (slsr_cand_t c, tree basis_name, offset_int bump)
+replace_mult_candidate (slsr_cand_t c, tree basis_name, offset_int bump,
+ auto_bitmap &sdce_worklist)
{
tree target_type = TREE_TYPE (gimple_assign_lhs (c->cand_stmt));
enum tree_code cand_code = gimple_assign_rhs_code (c->cand_stmt);
@@ -2193,6 +2195,11 @@ replace_mult_candidate (slsr_cand_t c, tree basis_name,
offset_int bump)
if (cand_code != NEGATE_EXPR) {
rhs1 = gimple_assign_rhs1 (c->cand_stmt);
rhs2 = gimple_assign_rhs2 (c->cand_stmt);
+ /* Mark the 2 original rhs for maybe DCEing. */
+ if (TREE_CODE (rhs1) == SSA_NAME)
+ bitmap_set_bit (sdce_worklist, SSA_NAME_VERSION (rhs1));
+ if (TREE_CODE (rhs2) == SSA_NAME)
+ bitmap_set_bit (sdce_worklist, SSA_NAME_VERSION (rhs2));
}
if (cand_code != NEGATE_EXPR
&& ((operand_equal_p (rhs1, basis_name, 0)
@@ -2237,7 +2244,7 @@ replace_mult_candidate (slsr_cand_t c, tree basis_name,
offset_int bump)
folded value ((i - i') * S) is referred to here as the "bump." */
static void
-replace_unconditional_candidate (slsr_cand_t c)
+replace_unconditional_candidate (slsr_cand_t c, auto_bitmap &sdce_worklist)
{
slsr_cand_t basis;
@@ -2247,7 +2254,8 @@ replace_unconditional_candidate (slsr_cand_t c)
basis = lookup_cand (c->basis);
offset_int bump = cand_increment (c) * wi::to_offset (c->stride);
- replace_mult_candidate (c, gimple_assign_lhs (basis->cand_stmt), bump);
+ replace_mult_candidate (c, gimple_assign_lhs (basis->cand_stmt), bump,
+ sdce_worklist);
}
/* Return the index in the increment vector of the given INCREMENT,
@@ -2507,7 +2515,8 @@ create_phi_basis (slsr_cand_t c, gimple *from_phi, tree
basis_name,
basis. */
static void
-replace_conditional_candidate (slsr_cand_t c)
+replace_conditional_candidate (slsr_cand_t c, auto_bitmap &sdce_worklist)
+
{
tree basis_name, name;
slsr_cand_t basis;
@@ -2527,7 +2536,7 @@ replace_conditional_candidate (slsr_cand_t c)
/* Replace C with an add of the new basis phi and a constant. */
offset_int bump = c->index * wi::to_offset (c->stride);
- replace_mult_candidate (c, name, bump);
+ replace_mult_candidate (c, name, bump, sdce_worklist);
}
/* Recursive helper function for phi_add_costs. SPREAD is a measure of
@@ -2608,7 +2617,8 @@ phi_add_costs (gimple *phi, slsr_cand_t c, int
one_add_cost)
so, replace the candidate and introduce the compensation code. */
static void
-replace_uncond_cands_and_profitable_phis (slsr_cand_t c)
+replace_uncond_cands_and_profitable_phis (slsr_cand_t c,
+ auto_bitmap &sdce_worklist)
{
if (phi_dependent_cand_p (c))
{
@@ -2643,17 +2653,19 @@ replace_uncond_cands_and_profitable_phis (slsr_cand_t c)
}
if (cost <= COST_NEUTRAL)
- replace_conditional_candidate (c);
+ replace_conditional_candidate (c, sdce_worklist);
}
}
else
- replace_unconditional_candidate (c);
+ replace_unconditional_candidate (c, sdce_worklist);
if (c->sibling)
- replace_uncond_cands_and_profitable_phis (lookup_cand (c->sibling));
+ replace_uncond_cands_and_profitable_phis (lookup_cand (c->sibling),
+ sdce_worklist);
if (c->dependent)
- replace_uncond_cands_and_profitable_phis (lookup_cand (c->dependent));
+ replace_uncond_cands_and_profitable_phis (lookup_cand (c->dependent),
+ sdce_worklist);
}
/* Count the number of candidates in the tree rooted at C that have
@@ -3675,7 +3687,8 @@ replace_rhs_if_not_dup (enum tree_code new_code, tree
new_rhs1, tree new_rhs2,
is the rhs1 to use in creating the add/subtract. */
static void
-replace_one_candidate (slsr_cand_t c, unsigned i, tree basis_name)
+replace_one_candidate (slsr_cand_t c, unsigned i, tree basis_name,
+ auto_bitmap &sdce_worklist)
{
gimple *stmt_to_print = NULL;
tree orig_rhs1, orig_rhs2;
@@ -3693,6 +3706,12 @@ replace_one_candidate (slsr_cand_t c, unsigned i, tree
basis_name)
if (!orig_rhs2)
return;
+ /* Mark the 2 original rhs for maybe DCEing. */
+ if (TREE_CODE (orig_rhs1) == SSA_NAME)
+ bitmap_set_bit (sdce_worklist, SSA_NAME_VERSION (orig_rhs1));
+ if (TREE_CODE (orig_rhs2) == SSA_NAME)
+ bitmap_set_bit (sdce_worklist, SSA_NAME_VERSION (orig_rhs2));
+
if (dump_file && (dump_flags & TDF_DETAILS))
{
fputs ("Replacing: ", dump_file);
@@ -3835,7 +3854,7 @@ replace_one_candidate (slsr_cand_t c, unsigned i, tree
basis_name)
an increment if such has been shown to be profitable. */
static void
-replace_profitable_candidates (slsr_cand_t c)
+replace_profitable_candidates (slsr_cand_t c, auto_bitmap &sdce_worklist)
{
if (!cand_already_replaced (c))
{
@@ -3872,23 +3891,23 @@ replace_profitable_candidates (slsr_cand_t c)
/* Replace C with an add of the new basis phi and the
increment. */
- replace_one_candidate (c, i, name);
+ replace_one_candidate (c, i, name, sdce_worklist);
}
}
else
{
slsr_cand_t basis = lookup_cand (c->basis);
tree basis_name = gimple_assign_lhs (basis->cand_stmt);
- replace_one_candidate (c, i, basis_name);
+ replace_one_candidate (c, i, basis_name, sdce_worklist);
}
}
}
if (c->sibling)
- replace_profitable_candidates (lookup_cand (c->sibling));
+ replace_profitable_candidates (lookup_cand (c->sibling), sdce_worklist);
if (c->dependent)
- replace_profitable_candidates (lookup_cand (c->dependent));
+ replace_profitable_candidates (lookup_cand (c->dependent), sdce_worklist);
}
/* Analyze costs of related candidates in the candidate vector,
@@ -3899,6 +3918,7 @@ analyze_candidates_and_replace (void)
{
unsigned i;
slsr_cand_t c;
+ auto_bitmap simple_dce_worklist;
/* Each candidate that has a null basis and a non-null
dependent is the root of a tree of related statements.
@@ -3932,7 +3952,8 @@ analyze_candidates_and_replace (void)
compensation code it requires is offset by the strength
reduction savings. */
else if (TREE_CODE (c->stride) == INTEGER_CST)
- replace_uncond_cands_and_profitable_phis (first_dep);
+ replace_uncond_cands_and_profitable_phis (first_dep,
+ simple_dce_worklist);
/* When the stride is an SSA name, it may still be profitable
to replace some or all of the dependent candidates, depending
@@ -3969,7 +3990,7 @@ analyze_candidates_and_replace (void)
dump_incr_vec ();
/* Perform the replacements. */
- replace_profitable_candidates (first_dep);
+ replace_profitable_candidates (first_dep, simple_dce_worklist);
free (incr_vec);
}
}
@@ -3977,6 +3998,8 @@ analyze_candidates_and_replace (void)
/* For conditional candidates, we may have uncommitted insertions
on edges to clean up. */
gsi_commit_edge_inserts ();
+
+ simple_dce_from_worklist (simple_dce_worklist);
}
namespace {
--
2.43.0
