[Mesa-dev] [PATCH 3/3] i965/fs: Remove dead_code_eliminate_local().

[Matt Turner]

Subsumed by the new dead_code_eliminate() function. No shader-db
changes.
---
 src/mesa/drivers/dri/i965/brw_fs.cpp | 158 -----------------------------------
 src/mesa/drivers/dri/i965/brw_fs.h   |   1 -
 2 files changed, 159 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index c723bf0..88dfdfc 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -2085,163 +2085,6 @@ fs_visitor::opt_algebraic()
    return progress;
 }
 
-struct dead_code_hash_key
-{
-   int vgrf;
-   int reg_offset;
-};
-
-static bool
-dead_code_hash_compare(const void *a, const void *b)
-{
-   return memcmp(a, b, sizeof(struct dead_code_hash_key)) == 0;
-}
-
-static void
-clear_dead_code_hash(struct hash_table *ht)
-{
-   struct hash_entry *entry;
-
-   hash_table_foreach(ht, entry) {
-      _mesa_hash_table_remove(ht, entry);
-   }
-}
-
-static void
-insert_dead_code_hash(struct hash_table *ht,
-                      int vgrf, int reg_offset, fs_inst *inst)
-{
-   /* We don't bother freeing keys, because they'll be GCed with the ht. */
-   struct dead_code_hash_key *key = ralloc(ht, struct dead_code_hash_key);
-
-   key->vgrf = vgrf;
-   key->reg_offset = reg_offset;
-
-   _mesa_hash_table_insert(ht, _mesa_hash_data(key, sizeof(*key)), key, inst);
-}
-
-static struct hash_entry *
-get_dead_code_hash_entry(struct hash_table *ht, int vgrf, int reg_offset)
-{
-   struct dead_code_hash_key key;
-
-   key.vgrf = vgrf;
-   key.reg_offset = reg_offset;
-
-   return _mesa_hash_table_search(ht, _mesa_hash_data(&key, sizeof(key)), &key);
-}
-
-static void
-remove_dead_code_hash(struct hash_table *ht,
-                      int vgrf, int reg_offset)
-{
-   struct hash_entry *entry = get_dead_code_hash_entry(ht, vgrf, reg_offset);
-   if (!entry)
-      return;
-
-   _mesa_hash_table_remove(ht, entry);
-}
-
-/**
- * Walks basic blocks, removing any regs that are written but not read before
- * being redefined.
- *
- * The dead_code_eliminate() function implements a global dead code
- * elimination, but it only handles the removing the last write to a register
- * if it's never read.  This one can handle intermediate writes, but only
- * within a basic block.
- */
-bool
-fs_visitor::dead_code_eliminate_local()
-{
-   struct hash_table *ht;
-   bool progress = false;
-
-   ht = _mesa_hash_table_create(mem_ctx, dead_code_hash_compare);
-
-   if (ht == NULL) {
-      return false;
-   }
-
-   foreach_list_safe(node, &this->instructions) {
-      fs_inst *inst = (fs_inst *)node;
-
-      /* At a basic block, empty the HT since we don't understand dataflow
-       * here.
-       */
-      if (inst->is_control_flow()) {
-         clear_dead_code_hash(ht);
-         continue;
-      }
-
-      /* Clear the HT of any instructions that got read. */
-      for (int i = 0; i < 3; i++) {
-         fs_reg src = inst->src[i];
-         if (src.file != GRF)
-            continue;
-
-         int read = 1;
-         if (inst->is_send_from_grf())
-            read = virtual_grf_sizes[src.reg] - src.reg_offset;
-
-         for (int reg_offset = src.reg_offset;
-              reg_offset < src.reg_offset + read;
-              reg_offset++) {
-            remove_dead_code_hash(ht, src.reg, reg_offset);
-         }
-      }
-
-      /* Add any update of a GRF to the HT, removing a previous write if it
-       * wasn't read.
-       */
-      if (inst->dst.file == GRF) {
-         if (inst->regs_written > 1) {
-            /* We don't know how to trim channels from an instruction's
-             * writes, so we can't incrementally remove unread channels from
-             * it.  Just remove whatever it overwrites from the table
-             */
-            for (int i = 0; i < inst->regs_written; i++) {
-               remove_dead_code_hash(ht,
-                                     inst->dst.reg,
-                                     inst->dst.reg_offset + i);
-            }
-         } else {
-            struct hash_entry *entry =
-               get_dead_code_hash_entry(ht, inst->dst.reg,
-                                        inst->dst.reg_offset);
-
-            if (entry) {
-               if (inst->is_partial_write()) {
-                  /* For a partial write, we can't remove any previous dead code
-                   * candidate, since we're just modifying their result.
-                   */
-               } else {
-                  /* We're completely updating a channel, and there was a
-                   * previous write to the channel that wasn't read.  Kill it!
-                   */
-                  fs_inst *inst = (fs_inst *)entry->data;
-                  inst->remove();
-                  progress = true;
-               }
-
-               _mesa_hash_table_remove(ht, entry);
-            }
-
-            if (!inst->has_side_effects())
-               insert_dead_code_hash(ht, inst->dst.reg, inst->dst.reg_offset,
-                                     inst);
-         }
-      }
-   }
-
-   _mesa_hash_table_destroy(ht, NULL);
-
-   if (progress)
-      invalidate_live_intervals();
-
-   return progress;
-}
-
 bool
 fs_visitor::compute_to_mrf()
 {
@@ -3194,7 +3037,6 @@ fs_visitor::run()
 	 progress = opt_cse() || progress;
 	 progress = opt_copy_propagate() || progress;
          progress = opt_peephole_predicated_break() || progress;
-	 progress = dead_code_eliminate_local() || progress;
          progress = dead_code_eliminate() || progress;
          progress = opt_peephole_sel() || progress;
          progress = dead_control_flow_eliminate(this) || progress;
diff --git a/src/mesa/drivers/dri/i965/brw_fs.h b/src/mesa/drivers/dri/i965/brw_fs.h
index 3d21ee5..4c12bd7 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.h
+++ b/src/mesa/drivers/dri/i965/brw_fs.h
@@ -374,7 +374,6 @@ public:
    bool register_coalesce();
    bool compute_to_mrf();
    bool dead_code_eliminate();
-   bool dead_code_eliminate_local();
    bool remove_duplicate_mrf_writes();
    bool virtual_grf_interferes(int a, int b);
    void schedule_instructions(instruction_scheduler_mode mode);
-- 
1.8.3.2