From: Matt Turner <mattst88@gmail.com>
Date: Sat, 30 Nov 2013 06:14:14 +0000 (-0800)
Subject: i965/fs: Remove now useless register_coalesce() pass.
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=9a6b14f6745206eb018c8474feafae4bafdcb8e5;p=mesa.git

i965/fs: Remove now useless register_coalesce() pass.

Reviewed-by: Eric Anholt <eric@anholt.net>
---

diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index 168411cc14d..ad1323ca494 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -2308,152 +2308,6 @@ fs_visitor::register_coalesce_2()
    return progress;
 }
 
-bool
-fs_visitor::register_coalesce()
-{
-   bool progress = false;
-   int if_depth = 0;
-   int loop_depth = 0;
-
-   foreach_list_safe(node, &this->instructions) {
-      fs_inst *inst = (fs_inst *)node;
-
-      /* Make sure that we dominate the instructions we're going to
-       * scan for interfering with our coalescing, or we won't have
-       * scanned enough to see if anything interferes with our
-       * coalescing.  We don't dominate the following instructions if
-       * we're in a loop or an if block.
-       */
-      switch (inst->opcode) {
-      case BRW_OPCODE_DO:
-	 loop_depth++;
-	 break;
-      case BRW_OPCODE_WHILE:
-	 loop_depth--;
-	 break;
-      case BRW_OPCODE_IF:
-	 if_depth++;
-	 break;
-      case BRW_OPCODE_ENDIF:
-	 if_depth--;
-	 break;
-      default:
-	 break;
-      }
-      if (loop_depth || if_depth)
-	 continue;
-
-      if (inst->opcode != BRW_OPCODE_MOV ||
-	  inst->is_partial_write() ||
-	  inst->saturate ||
-	  inst->dst.file != GRF || (inst->src[0].file != GRF &&
-				    inst->src[0].file != UNIFORM)||
-	  inst->dst.type != inst->src[0].type)
-	 continue;
-
-      bool has_source_modifiers = (inst->src[0].abs ||
-                                   inst->src[0].negate ||
-                                   inst->src[0].smear != -1 ||
-                                   inst->src[0].file == UNIFORM);
-
-      /* Found a move of a GRF to a GRF.  Let's see if we can coalesce
-       * them: check for no writes to either one until the exit of the
-       * program.
-       */
-      bool interfered = false;
-
-      for (fs_inst *scan_inst = (fs_inst *)inst->next;
-	   !scan_inst->is_tail_sentinel();
-	   scan_inst = (fs_inst *)scan_inst->next) {
-	 if (scan_inst->dst.file == GRF) {
-	    if (scan_inst->overwrites_reg(inst->dst) ||
-                scan_inst->overwrites_reg(inst->src[0])) {
-	       interfered = true;
-	       break;
-	    }
-	 }
-
-         if (has_source_modifiers) {
-            for (int i = 0; i < 3; i++) {
-               if (scan_inst->src[i].file == GRF &&
-                   scan_inst->src[i].reg == inst->dst.reg &&
-                   scan_inst->src[i].reg_offset == inst->dst.reg_offset &&
-                   inst->dst.type != scan_inst->src[i].type)
-               {
-                 interfered = true;
-                 break;
-               }
-            }
-         }
-
-
-	 /* The gen6 MATH instruction can't handle source modifiers or
-	  * unusual register regions, so avoid coalescing those for
-	  * now.  We should do something more specific.
-	  */
-	 if (has_source_modifiers && !can_do_source_mods(scan_inst)) {
-            interfered = true;
-	    break;
-	 }
-
-	 if (scan_inst->mlen > 0 && scan_inst->base_mrf == -1 &&
-	     scan_inst->src[0].file == GRF &&
-	     scan_inst->src[0].reg == inst->dst.reg) {
-	    interfered = true;
-	    break;
-	 }
-
-	 /* The accumulator result appears to get used for the
-	  * conditional modifier generation.  When negating a UD
-	  * value, there is a 33rd bit generated for the sign in the
-	  * accumulator value, so now you can't check, for example,
-	  * equality with a 32-bit value.  See piglit fs-op-neg-uint.
-	  */
-	 if (scan_inst->conditional_mod &&
-	     inst->src[0].negate &&
-	     inst->src[0].type == BRW_REGISTER_TYPE_UD) {
-	    interfered = true;
-	    break;
-	 }
-      }
-      if (interfered) {
-	 continue;
-      }
-
-      /* Rewrite the later usage to point at the source of the move to
-       * be removed.
-       */
-      for (fs_inst *scan_inst = inst;
-	   !scan_inst->is_tail_sentinel();
-	   scan_inst = (fs_inst *)scan_inst->next) {
-	 for (int i = 0; i < 3; i++) {
-	    if (scan_inst->src[i].file == GRF &&
-		scan_inst->src[i].reg == inst->dst.reg &&
-		scan_inst->src[i].reg_offset == inst->dst.reg_offset) {
-	       fs_reg new_src = inst->src[0];
-               new_src.type = scan_inst->src[i].type;
-               if (scan_inst->src[i].abs) {
-                  new_src.negate = 0;
-                  new_src.abs = 1;
-               }
-	       new_src.negate ^= scan_inst->src[i].negate;
-	       new_src.sechalf = scan_inst->src[i].sechalf;
-	       scan_inst->src[i] = new_src;
-	    }
-	 }
-      }
-
-      inst->remove();
-      progress = true;
-   }
-
-   if (progress)
-      invalidate_live_intervals();
-
-   return progress;
-}
-
-
 bool
 fs_visitor::compute_to_mrf()
 {
@@ -3271,7 +3125,6 @@ fs_visitor::run()
 	 progress = dead_code_eliminate() || progress;
 	 progress = dead_code_eliminate_local() || progress;
          progress = dead_control_flow_eliminate(this) || progress;
-	 progress = register_coalesce() || progress;
 	 progress = register_coalesce_2() || progress;
 	 progress = compute_to_mrf() || progress;
       } while (progress);
diff --git a/src/mesa/drivers/dri/i965/brw_fs.h b/src/mesa/drivers/dri/i965/brw_fs.h
index 7991b870a99..12a7576da76 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.h
+++ b/src/mesa/drivers/dri/i965/brw_fs.h
@@ -314,7 +314,6 @@ public:
    bool try_constant_propagate(fs_inst *inst, acp_entry *entry);
    bool opt_copy_propagate_local(void *mem_ctx, bblock_t *block,
                                  exec_list *acp);
-   bool register_coalesce();
    bool register_coalesce_2();
    bool compute_to_mrf();
    bool dead_code_eliminate();