Replace PHI nodes of dropped ivs with debug temps
From: Alexandre Oliva <aoliva@redhat.com>, Jakub Jelinek <jakub@redhat.com>
for gcc/ChangeLog
PR debug/54693
* tree-ssa-loop-ivopts.c (remove_unused_ivs): Emit debug temps
for dropped IV sets.
---
gcc/tree-ssa-loop-ivopts.c | 106 ++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 105 insertions(+), 1 deletions(-)
@@ -6422,7 +6422,111 @@ remove_unused_ivs (struct ivopts_data *data)
&& !info->inv_id
&& !info->iv->have_use_for
&& !info->preserve_biv)
- bitmap_set_bit (toremove, SSA_NAME_VERSION (info->iv->ssa_name));
+ {
+ bitmap_set_bit (toremove, SSA_NAME_VERSION (info->iv->ssa_name));
+
+ tree def = info->iv->ssa_name;
+
+ if (MAY_HAVE_DEBUG_STMTS && SSA_NAME_DEF_STMT (def))
+ {
+ imm_use_iterator imm_iter;
+ use_operand_p use_p;
+ gimple stmt;
+ int count = 0;
+
+ FOR_EACH_IMM_USE_STMT (stmt, imm_iter, def)
+ {
+ if (!gimple_debug_bind_p (stmt))
+ continue;
+
+ /* We just want to determine whether to do nothing
+ (count == 0), to substitute the computed
+ expression into a single use of the SSA DEF by
+ itself (count == 1), or to use a debug temp
+ because the SSA DEF is used multiple times or as
+ part of a larger expression (count > 1). */
+ count++;
+ if (gimple_debug_bind_get_value (stmt) != def)
+ count++;
+
+ if (count > 1)
+ BREAK_FROM_IMM_USE_STMT (imm_iter);
+ }
+
+ if (!count)
+ continue;
+
+ struct iv_use dummy_use;
+ struct iv_cand *best_cand = NULL, *cand;
+ unsigned i, best_pref = 0, cand_pref;
+
+ memset (&dummy_use, 0, sizeof (dummy_use));
+ dummy_use.iv = info->iv;
+ for (i = 0; i < n_iv_uses (data) && i < 64; i++)
+ {
+ cand = iv_use (data, i)->selected;
+ if (cand == best_cand)
+ continue;
+ cand_pref = operand_equal_p (cand->iv->step,
+ info->iv->step, 0)
+ ? 4 : 0;
+ cand_pref
+ += TYPE_MODE (TREE_TYPE (cand->iv->base))
+ == TYPE_MODE (TREE_TYPE (info->iv->base))
+ ? 2 : 0;
+ cand_pref
+ += TREE_CODE (cand->iv->base) == INTEGER_CST
+ ? 1 : 0;
+ if (best_cand == NULL || best_pref < cand_pref)
+ {
+ best_cand = cand;
+ best_pref = cand_pref;
+ }
+ }
+
+ if (!best_cand)
+ continue;
+
+ tree comp = get_computation_at (data->current_loop,
+ &dummy_use, best_cand,
+ SSA_NAME_DEF_STMT (def));
+ if (!comp)
+ continue;
+
+ if (count > 1)
+ {
+ tree vexpr = make_node (DEBUG_EXPR_DECL);
+ DECL_ARTIFICIAL (vexpr) = 1;
+ TREE_TYPE (vexpr) = TREE_TYPE (comp);
+ if (SSA_NAME_VAR (def))
+ DECL_MODE (vexpr) = DECL_MODE (SSA_NAME_VAR (def));
+ else
+ DECL_MODE (vexpr) = TYPE_MODE (TREE_TYPE (vexpr));
+ gimple def_temp = gimple_build_debug_bind (vexpr, comp, NULL);
+ gimple_stmt_iterator gsi;
+
+ if (gimple_code (SSA_NAME_DEF_STMT (def)) == GIMPLE_PHI)
+ gsi = gsi_after_labels (gimple_bb
+ (SSA_NAME_DEF_STMT (def)));
+ else
+ gsi = gsi_for_stmt (SSA_NAME_DEF_STMT (def));
+
+ gsi_insert_before (&gsi, def_temp, GSI_SAME_STMT);
+ comp = vexpr;
+ }
+
+ FOR_EACH_IMM_USE_STMT (stmt, imm_iter, def)
+ {
+ if (!gimple_debug_bind_p (stmt))
+ continue;
+
+ FOR_EACH_IMM_USE_ON_STMT (use_p, imm_iter)
+ SET_USE (use_p, comp);
+
+ update_stmt (stmt);
+ }
+ }
+ }
}
release_defs_bitset (toremove);