glsl: Add ir_quadop_vector expression

The vector operator collects 2, 3, or 4 scalar components into a
vector.  Doing this has several advantages.  First, it will make
ud-chain tracking for components of vectors much easier.  Second, a
later optimization pass could collect scalars into vectors to allow
generation of SWZ instructions (or similar as operands to other
instructions on R200 and i915).  It also enables an easy way to
generate IR for SWZ instructions in the ARB_vertex_program assembler.

1 files changed, 132 insertions, 0 deletions

diff --git a/src/mesa/program/ir_to_mesa.cpp b/src/mesa/program/ir_to_mesa.cpp
index 1b5337e92e..1cb8183042 100644
--- a/src/mesa/program/ir_to_mesa.cpp
+++ b/src/mesa/program/ir_to_mesa.cpp
@@ -289,6 +289,8 @@ public:
    GLboolean try_emit_mad(ir_expression *ir,
 			  int mul_operand);
 
+   void emit_swz(ir_expression *ir);
+
    bool process_move_condition(ir_rvalue *ir);
 
    void *mem_ctx;
@@ -958,6 +960,123 @@ ir_to_mesa_visitor::reladdr_to_temp(ir_instruction *ir,
 }
 
 void
+ir_to_mesa_visitor::emit_swz(ir_expression *ir)
+{
+   /* Assume that the vector operator is in a form compatible with OPCODE_SWZ.
+    * This means that each of the operands is either an immediate value of -1,
+    * 0, or 1, or is a component from one source register (possibly with
+    * negation).
+    */
+   uint8_t components[4] = { 0 };
+   bool negate[4] = { false };
+   ir_variable *var = NULL;
+
+   for (unsigned i = 0; i < ir->type->vector_elements; i++) {
+      ir_rvalue *op = ir->operands[i];
+
+      assert(op->type->is_scalar());
+
+      while (op != NULL) {
+	 switch (op->ir_type) {
+	 case ir_type_constant: {
+
+	    assert(op->type->is_scalar());
+
+	    const ir_constant *const c = op->as_constant();
+	    if (c->is_one()) {
+	       components[i] = SWIZZLE_ONE;
+	    } else if (c->is_zero()) {
+	       components[i] = SWIZZLE_ZERO;
+	    } else if (c->is_negative_one()) {
+	       components[i] = SWIZZLE_ONE;
+	       negate[i] = true;
+	    } else {
+	       assert(!"SWZ constant must be 0.0 or 1.0.");
+	    }
+
+	    op = NULL;
+	    break;
+	 }
+
+	 case ir_type_dereference_variable: {
+	    ir_dereference_variable *const deref =
+	       (ir_dereference_variable *) op;
+
+	    assert((var == NULL) || (deref->var == var));
+	    components[i] = SWIZZLE_X;
+	    var = deref->var;
+	    op = NULL;
+	    break;
+	 }
+
+	 case ir_type_expression: {
+	    ir_expression *const expr = (ir_expression *) op;
+
+	    assert(expr->operation == ir_unop_neg);
+	    negate[i] = true;
+
+	    op = expr->operands[0];
+	    break;
+	 }
+
+	 case ir_type_swizzle: {
+	    ir_swizzle *const swiz = (ir_swizzle *) op;
+
+	    components[i] = swiz->mask.x;
+	    op = swiz->val;
+	    break;
+	 }
+
+	 default:
+	    assert(!"Should not get here.");
+	    return;
+	 }
+      }
+   }
+
+   assert(var != NULL);
+
+   ir_dereference_variable *const deref =
+      new(mem_ctx) ir_dereference_variable(var);
+
+   this->result.file = PROGRAM_UNDEFINED;
+   deref->accept(this);
+   if (this->result.file == PROGRAM_UNDEFINED) {
+      ir_print_visitor v;
+      printf("Failed to get tree for expression operand:\n");
+      deref->accept(&v);
+      exit(1);
+   }
+
+   ir_to_mesa_src_reg src;
+
+   src = this->result;
+   src.swizzle = MAKE_SWIZZLE4(components[0],
+			       components[1],
+			       components[2],
+			       components[3]);
+   src.negate = ((unsigned(negate[0]) << 0)
+		 | (unsigned(negate[1]) << 1)
+		 | (unsigned(negate[2]) << 2)
+		 | (unsigned(negate[3]) << 3));
+
+   /* Storage for our result.  Ideally for an assignment we'd be using the
+    * actual storage for the result here, instead.
+    */
+   const ir_to_mesa_src_reg result_src = get_temp(ir->type);
+   ir_to_mesa_dst_reg result_dst = ir_to_mesa_dst_reg_from_src(result_src);
+
+   /* Limit writes to the channels that will be used by result_src later.
+    * This does limit this temp's use as a temporary for multi-instruction
+    * sequences.
+    */
+   result_dst.writemask = (1 << ir->type->vector_elements) - 1;
+
+   ir_to_mesa_emit_op1(ir, OPCODE_SWZ, result_dst, src);
+   this->result = result_src;
+}
+
+void
 ir_to_mesa_visitor::visit(ir_expression *ir)
 {
    unsigned int operand;
@@ -974,6 +1093,11 @@ ir_to_mesa_visitor::visit(ir_expression *ir)
 	 return;
    }
 
+   if (ir->operation == ir_quadop_vector) {
+      this->emit_swz(ir);
+      return;
+   }
+
    for (operand = 0; operand < ir->get_num_operands(); operand++) {
       this->result.file = PROGRAM_UNDEFINED;
       ir->operands[operand]->accept(this);
@@ -1231,6 +1355,12 @@ ir_to_mesa_visitor::visit(ir_expression *ir)
    case ir_unop_round_even:
       assert(!"GLSL 1.30 features unsupported");
       break;
+
+   case ir_quadop_vector:
+      /* This operation should have already been handled.
+       */
+      assert(!"Should not get here.");
+      break;
    }
 
    this->result = result_src;
@@ -2676,6 +2806,8 @@ _mesa_ir_link_shader(struct gl_context *ctx, struct gl_shader_program *prog)
 
 	 progress = do_common_optimization(ir, true, options->MaxUnrollIterations) || progress;
 
+	 progress = lower_quadop_vector(ir, true) || progress;
+
 	 if (options->EmitNoIfs)
 	    progress = do_if_to_cond_assign(ir) || progress;