new file mode 100644
@@ -0,0 +1,31 @@
+/* { dg-do compile } */
+/* { dg-options "-O -fgimple -fdump-tree-phiopt1" } */
+
+int __GIMPLE (ssa,startwith("phiopt"))
+foo (int a, int b, int flag)
+{
+ int res;
+
+ __BB(2):
+ if (flag_2(D) != 0)
+ goto __BB6;
+ else
+ goto __BB4;
+
+ __BB(4):
+ if (a_3(D) > b_4(D))
+ goto __BB7;
+ else
+ goto __BB6;
+
+ __BB(6):
+ goto __BB7;
+
+ __BB(7):
+ res_1 = __PHI (__BB4: a_3(D), __BB6: b_4(D));
+ return res_1;
+}
+
+/* We should be able to detect MAX despite the extra edge into
+ the middle BB. */
+/* { dg-final { scan-tree-dump "MAX" "phiopt1" } } */
@@ -220,7 +220,6 @@ tree_ssa_phiopt_worker (bool do_store_elim, bool do_hoist_loads, bool early_p)
/* If either bb1's succ or bb2 or bb2's succ is non NULL. */
if (EDGE_COUNT (bb1->succs) == 0
- || bb2 == NULL
|| EDGE_COUNT (bb2->succs) == 0)
continue;
@@ -276,14 +275,14 @@ tree_ssa_phiopt_worker (bool do_store_elim, bool do_hoist_loads, bool early_p)
|| (e1->flags & EDGE_FALLTHRU) == 0)
continue;
- /* Also make sure that bb1 only have one predecessor and that it
- is bb. */
- if (!single_pred_p (bb1)
- || single_pred (bb1) != bb)
- continue;
-
if (do_store_elim)
{
+ /* Also make sure that bb1 only have one predecessor and that it
+ is bb. */
+ if (!single_pred_p (bb1)
+ || single_pred (bb1) != bb)
+ continue;
+
/* bb1 is the middle block, bb2 the join block, bb the split block,
e1 the fallthrough edge from bb1 to bb2. We can't do the
optimization if the join block has more than two predecessors. */
@@ -328,10 +327,11 @@ tree_ssa_phiopt_worker (bool do_store_elim, bool do_hoist_loads, bool early_p)
node. */
gcc_assert (arg0 != NULL_TREE && arg1 != NULL_TREE);
- gphi *newphi = factor_out_conditional_conversion (e1, e2, phi,
- arg0, arg1,
- cond_stmt);
- if (newphi != NULL)
+ gphi *newphi;
+ if (single_pred_p (bb1)
+ && (newphi = factor_out_conditional_conversion (e1, e2, phi,
+ arg0, arg1,
+ cond_stmt)))
{
phi = newphi;
/* factor_out_conditional_conversion may create a new PHI in
@@ -350,12 +350,14 @@ tree_ssa_phiopt_worker (bool do_store_elim, bool do_hoist_loads, bool early_p)
early_p))
cfgchanged = true;
else if (!early_p
+ && single_pred_p (bb1)
&& cond_removal_in_builtin_zero_pattern (bb, bb1, e1, e2,
phi, arg0, arg1))
cfgchanged = true;
else if (minmax_replacement (bb, bb1, e1, e2, phi, arg0, arg1))
cfgchanged = true;
- else if (spaceship_replacement (bb, bb1, e1, e2, phi, arg0, arg1))
+ else if (single_pred_p (bb1)
+ && spaceship_replacement (bb, bb1, e1, e2, phi, arg0, arg1))
cfgchanged = true;
}
}
@@ -386,7 +388,6 @@ replace_phi_edge_with_variable (basic_block cond_block,
edge e, gphi *phi, tree new_tree)
{
basic_block bb = gimple_bb (phi);
- basic_block block_to_remove;
gimple_stmt_iterator gsi;
tree phi_result = PHI_RESULT (phi);
@@ -422,28 +423,33 @@ replace_phi_edge_with_variable (basic_block cond_block,
SET_USE (PHI_ARG_DEF_PTR (phi, e->dest_idx), new_tree);
/* Remove the empty basic block. */
+ edge edge_to_remove;
if (EDGE_SUCC (cond_block, 0)->dest == bb)
+ edge_to_remove = EDGE_SUCC (cond_block, 1);
+ else
+ edge_to_remove = EDGE_SUCC (cond_block, 0);
+ if (EDGE_COUNT (edge_to_remove->dest->preds) == 1)
{
- EDGE_SUCC (cond_block, 0)->flags |= EDGE_FALLTHRU;
- EDGE_SUCC (cond_block, 0)->flags &= ~(EDGE_TRUE_VALUE | EDGE_FALSE_VALUE);
- EDGE_SUCC (cond_block, 0)->probability = profile_probability::always ();
+ e->flags |= EDGE_FALLTHRU;
+ e->flags &= ~(EDGE_TRUE_VALUE | EDGE_FALSE_VALUE);
+ e->probability = profile_probability::always ();
+ delete_basic_block (edge_to_remove->dest);
- block_to_remove = EDGE_SUCC (cond_block, 1)->dest;
+ /* Eliminate the COND_EXPR at the end of COND_BLOCK. */
+ gsi = gsi_last_bb (cond_block);
+ gsi_remove (&gsi, true);
}
else
{
- EDGE_SUCC (cond_block, 1)->flags |= EDGE_FALLTHRU;
- EDGE_SUCC (cond_block, 1)->flags
- &= ~(EDGE_TRUE_VALUE | EDGE_FALSE_VALUE);
- EDGE_SUCC (cond_block, 1)->probability = profile_probability::always ();
-
- block_to_remove = EDGE_SUCC (cond_block, 0)->dest;
+ /* If there are other edges into the middle block make
+ CFG cleanup deal with the edge removal to avoid
+ updating dominators here in a non-trivial way. */
+ gcond *cond = as_a <gcond *> (last_stmt (cond_block));
+ if (edge_to_remove->flags & EDGE_TRUE_VALUE)
+ gimple_cond_make_false (cond);
+ else
+ gimple_cond_make_true (cond);
}
- delete_basic_block (block_to_remove);
-
- /* Eliminate the COND_EXPR at the end of COND_BLOCK. */
- gsi = gsi_last_bb (cond_block);
- gsi_remove (&gsi, true);
statistics_counter_event (cfun, "Replace PHI with variable", 1);
@@ -959,6 +965,9 @@ match_simplify_replacement (basic_block cond_bb, basic_block middle_bb,
allow it and move it once the transformation is done. */
if (!empty_block_p (middle_bb))
{
+ if (!single_pred_p (middle_bb))
+ return false;
+
stmt_to_move = last_and_only_stmt (middle_bb);
if (!stmt_to_move)
return false;
@@ -1351,7 +1360,10 @@ value_replacement (basic_block cond_bb, basic_block middle_bb,
}
else
{
- statistics_counter_event (cfun, "Replace PHI with variable/value_replacement", 1);
+ if (!single_pred_p (middle_bb))
+ return 0;
+ statistics_counter_event (cfun, "Replace PHI with "
+ "variable/value_replacement", 1);
/* Replace the PHI arguments with arg. */
SET_PHI_ARG_DEF (phi, e0->dest_idx, arg);
@@ -1367,7 +1379,6 @@ value_replacement (basic_block cond_bb, basic_block middle_bb,
}
return 1;
}
-
}
/* Now optimize (x != 0) ? x + y : y to just x + y. */