X-Git-Url: https://git.libre-soc.org/?a=blobdiff_plain;f=src%2Fglsl%2Fopt_dead_code_local.cpp;h=0c5c684a4a9413ae7557df59187ac0cee43139ea;hb=6d1f83ec09164bd805c90785635bbcf861b403e5;hp=88dcdc25176602c4f65efcb5d15db2b132e0c2e3;hpb=61c59234f916406512b3591f46599cc29a5d8e23;p=mesa.git

diff --git a/src/glsl/opt_dead_code_local.cpp b/src/glsl/opt_dead_code_local.cpp
index 88dcdc25176..0c5c684a4a9 100644
--- a/src/glsl/opt_dead_code_local.cpp
+++ b/src/glsl/opt_dead_code_local.cpp
@@ -38,23 +38,27 @@
 #include "ir_optimization.h"
 #include "glsl_types.h"
 
-using std::printf;
-
 static bool debug = false;
 
+namespace {
+
 class assignment_entry : public exec_node
 {
 public:
-   assignment_entry(ir_variable *lhs, ir_instruction *ir)
+   assignment_entry(ir_variable *lhs, ir_assignment *ir)
    {
       assert(lhs);
       assert(ir);
       this->lhs = lhs;
       this->ir = ir;
+      this->unused = ir->write_mask;
    }
 
    ir_variable *lhs;
-   ir_instruction *ir;
+   ir_assignment *ir;
+
+   /* bitmask of xyzw channels written that haven't been used so far. */
+   int unused;
 };
 
 class kill_for_derefs_visitor : public ir_hierarchical_visitor {
@@ -64,19 +68,65 @@ public:
       this->assignments = assignments;
    }
 
-   virtual ir_visitor_status visit(ir_dereference_variable *ir)
+   void use_channels(ir_variable *const var, int used)
    {
-      ir_variable *const var = ir->variable_referenced();
-
-      foreach_iter(exec_list_iterator, iter, *this->assignments) {
-	 assignment_entry *entry = (assignment_entry *)iter.get();
+      foreach_list_safe(n, this->assignments) {
+	 assignment_entry *entry = (assignment_entry *) n;
 
 	 if (entry->lhs == var) {
-	    if (debug)
-	       printf("kill %s\n", entry->lhs->name);
-	    entry->remove();
+	    if (var->type->is_scalar() || var->type->is_vector()) {
+	       if (debug)
+		  printf("used %s (0x%01x - 0x%01x)\n", entry->lhs->name,
+			 entry->unused, used & 0xf);
+	       entry->unused &= ~used;
+	       if (!entry->unused)
+		  entry->remove();
+	    } else {
+	       if (debug)
+		  printf("used %s\n", entry->lhs->name);
+	       entry->remove();
+	    }
 	 }
       }
+   }
+
+   virtual ir_visitor_status visit(ir_dereference_variable *ir)
+   {
+      use_channels(ir->var, ~0);
+
+      return visit_continue;
+   }
+
+   virtual ir_visitor_status visit(ir_swizzle *ir)
+   {
+      ir_dereference_variable *deref = ir->val->as_dereference_variable();
+      if (!deref)
+	 return visit_continue;
+
+      int used = 0;
+      used |= 1 << ir->mask.x;
+      used |= 1 << ir->mask.y;
+      used |= 1 << ir->mask.z;
+      used |= 1 << ir->mask.w;
+
+      use_channels(deref->var, used);
+
+      return visit_continue_with_parent;
+   }
+
+   virtual ir_visitor_status visit(ir_emit_vertex *ir)
+   {
+      /* For the purpose of dead code elimination, emitting a vertex counts as
+       * "reading" all of the currently assigned output variables.
+       */
+      foreach_list_safe(n, this->assignments) {
+         assignment_entry *entry = (assignment_entry *) n;
+         if (entry->lhs->data.mode == ir_var_shader_out) {
+            if (debug)
+               printf("kill %s\n", entry->lhs->name);
+            entry->remove();
+         }
+      }
 
       return visit_continue;
    }
@@ -107,6 +157,7 @@ public:
    ir_hierarchical_visitor *visitor;
 };
 
+} /* unnamed namespace */
 
 /**
  * Adds an entry to the available copy list if it's a plain assignment
@@ -131,39 +182,97 @@ process_assignment(void *ctx, ir_assignment *ir, exec_list *assignments)
    var = ir->lhs->variable_referenced();
    assert(var);
 
-   bool always_assign = true;
-   if (ir->condition) {
-      ir_constant *condition = ir->condition->as_constant();
-      if (!condition || !condition->value.b[0])
-	 always_assign = false;
-   }
-
    /* Now, check if we did a whole-variable assignment. */
-   if (always_assign && (ir->whole_variable_written() != NULL)) {
-      /* We did a whole-variable assignment.  So, any instruction in
-       * the assignment list with the same LHS is dead.
-       */
-      if (debug)
-	 printf("looking for %s to remove\n", var->name);
-      foreach_iter(exec_list_iterator, iter, *assignments) {
-	 assignment_entry *entry = (assignment_entry *)iter.get();
+   if (!ir->condition) {
+      ir_dereference_variable *deref_var = ir->lhs->as_dereference_variable();
 
-	 if (entry->lhs == var) {
-	    if (debug)
-	       printf("removing %s\n", var->name);
-	    entry->ir->remove();
-	    entry->remove();
-	    progress = true;
+      /* If it's a vector type, we can do per-channel elimination of
+       * use of the RHS.
+       */
+      if (deref_var && (deref_var->var->type->is_scalar() ||
+			deref_var->var->type->is_vector())) {
+
+	 if (debug)
+	    printf("looking for %s.0x%01x to remove\n", var->name,
+		   ir->write_mask);
+
+	 foreach_list_safe(n, assignments) {
+	    assignment_entry *entry = (assignment_entry *) n;
+
+	    if (entry->lhs != var)
+	       continue;
+
+	    int remove = entry->unused & ir->write_mask;
+	    if (debug) {
+	       printf("%s 0x%01x - 0x%01x = 0x%01x\n",
+		      var->name,
+		      entry->ir->write_mask,
+		      remove, entry->ir->write_mask & ~remove);
+	    }
+	    if (remove) {
+	       progress = true;
+
+	       if (debug) {
+		  printf("rewriting:\n  ");
+		  entry->ir->print();
+		  printf("\n");
+	       }
+
+	       entry->ir->write_mask &= ~remove;
+	       entry->unused &= ~remove;
+	       if (entry->ir->write_mask == 0) {
+		  /* Delete the dead assignment. */
+		  entry->ir->remove();
+		  entry->remove();
+	       } else {
+		  void *mem_ctx = ralloc_parent(entry->ir);
+		  /* Reswizzle the RHS arguments according to the new
+		   * write_mask.
+		   */
+		  unsigned components[4];
+		  unsigned channels = 0;
+		  unsigned next = 0;
+
+		  for (int i = 0; i < 4; i++) {
+		     if ((entry->ir->write_mask | remove) & (1 << i)) {
+			if (!(remove & (1 << i)))
+			   components[channels++] = next;
+			next++;
+		     }
+		  }
+
+		  entry->ir->rhs = new(mem_ctx) ir_swizzle(entry->ir->rhs,
+							   components,
+							   channels);
+		  if (debug) {
+		     printf("to:\n  ");
+		     entry->ir->print();
+		     printf("\n");
+		  }
+	       }
+	    }
+	 }
+      } else if (ir->whole_variable_written() != NULL) {
+	 /* We did a whole-variable assignment.  So, any instruction in
+	  * the assignment list with the same LHS is dead.
+	  */
+	 if (debug)
+	    printf("looking for %s to remove\n", var->name);
+	 foreach_list_safe(n, assignments) {
+	    assignment_entry *entry = (assignment_entry *) n;
+
+	    if (entry->lhs == var) {
+	       if (debug)
+		  printf("removing %s\n", var->name);
+	       entry->ir->remove();
+	       entry->remove();
+	       progress = true;
+	    }
 	 }
       }
    }
 
-   /* Add this instruction to the assignment list available to be removed.
-    * But not if the assignment has other side effects.
-    */
-   if (ir_has_call(ir))
-      return progress;
-
+   /* Add this instruction to the assignment list available to be removed. */
    assignment_entry *entry = new(ctx) assignment_entry(var, ir);
    assignments->push_tail(entry);
 
@@ -171,10 +280,10 @@ process_assignment(void *ctx, ir_assignment *ir, exec_list *assignments)
       printf("add %s\n", var->name);
 
       printf("current entries\n");
-      foreach_iter(exec_list_iterator, iter, *assignments) {
-	 assignment_entry *entry = (assignment_entry *)iter.get();
+      foreach_list(n, assignments) {
+	 assignment_entry *entry = (assignment_entry *) n;
 
-	 printf("    %s\n", entry->lhs->name);
+	 printf("    %s (0x%01x)\n", entry->lhs->name, entry->unused);
       }
    }