[Mesa-dev] [PATCH 01/12] glsl: Add ir_binop_vector_extract

[Ian Romanick]

From: Ian Romanick <ian.d.romanick at intel.com>

The new opcode is used to get a single field from a vector.  The field
index may not be constant.  This will eventually replace
ir_dereference_array of vectors.  This is similar to the extractelement
instruction in LLVM IR.

http://llvm.org/docs/LangRef.html#extractelement-instruction

v2: Convert tabs to spaces.  Suggested by Eric.

v3: Add array index range checking to ir_binop_vector_extract constant
expression handling.  Suggested by Ken.

Signed-off-by: Ian Romanick <ian.d.romanick at intel.com>
Reviewed-by: Eric Anholt <eric at anholt.net>
---
 src/glsl/ir.cpp                     |  5 +++++
 src/glsl/ir.h                       | 10 +++++++++-
 src/glsl/ir_constant_expression.cpp | 36 +++++++++++++++++++++++++++++++++---
 src/glsl/ir_validate.cpp            |  6 ++++++
 src/mesa/program/ir_to_mesa.cpp     |  1 +
 5 files changed, 54 insertions(+), 4 deletions(-)

diff --git a/src/glsl/ir.cpp b/src/glsl/ir.cpp
index 05b77da..f4596db 100644
--- a/src/glsl/ir.cpp
+++ b/src/glsl/ir.cpp
@@ -399,6 +399,10 @@ ir_expression::ir_expression(int op, ir_rvalue *op0, ir_rvalue *op1)
       this->type = op0->type;
       break;
 
+   case ir_binop_vector_extract:
+      this->type = op0->type->get_scalar_type();
+      break;
+
    default:
       assert(!"not reached: missing automatic type setup for ir_expression");
       this->type = glsl_type::float_type;
@@ -505,6 +509,7 @@ static const char *const operator_strs[] = {
    "pow",
    "packHalf2x16_split",
    "ubo_load",
+   "vector_extract",
    "lrp",
    "vector",
 };
diff --git a/src/glsl/ir.h b/src/glsl/ir.h
index 878a946..ba6a61b 100644
--- a/src/glsl/ir.h
+++ b/src/glsl/ir.h
@@ -1117,9 +1117,17 @@ enum ir_expression_operation {
    ir_binop_ubo_load,
 
    /**
+    * Extract a scalar from a vector
+    *
+    * operand0 is the vector
+    * operand1 is the index of the field to read from operand0
+    */
+   ir_binop_vector_extract,
+
+   /**
     * A sentinel marking the last of the binary operations.
     */
-   ir_last_binop = ir_binop_ubo_load,
+   ir_last_binop = ir_binop_vector_extract,
 
    ir_triop_lrp,
 
diff --git a/src/glsl/ir_constant_expression.cpp b/src/glsl/ir_constant_expression.cpp
index c09e56a..963c88b 100644
--- a/src/glsl/ir_constant_expression.cpp
+++ b/src/glsl/ir_constant_expression.cpp
@@ -391,9 +391,16 @@ ir_expression::constant_expression_value(struct hash_table *variable_context)
    }
 
    if (op[1] != NULL)
-      assert(op[0]->type->base_type == op[1]->type->base_type ||
-	     this->operation == ir_binop_lshift ||
-	     this->operation == ir_binop_rshift);
+      switch (this->operation) {
+      case ir_binop_lshift:
+      case ir_binop_rshift:
+      case ir_binop_vector_extract:
+         break;
+
+      default:
+         assert(op[0]->type->base_type == op[1]->type->base_type);
+         break;
+      }
 
    bool op0_scalar = op[0]->type->is_scalar();
    bool op1_scalar = op[1] != NULL && op[1]->type->is_scalar();
@@ -1230,6 +1237,29 @@ ir_expression::constant_expression_value(struct hash_table *variable_context)
       }
       break;
 
+   case ir_binop_vector_extract: {
+      const int c = MAX2(0, MIN2(op[1]->value.i[0],
+                                 op[0]->type->vector_elements - 1));
+
+      switch (op[0]->type->base_type) {
+      case GLSL_TYPE_UINT:
+         data.u[0] = op[0]->value.u[c];
+         break;
+      case GLSL_TYPE_INT:
+         data.i[0] = op[0]->value.i[c];
+         break;
+      case GLSL_TYPE_FLOAT:
+         data.f[0] = op[0]->value.f[c];
+         break;
+      case GLSL_TYPE_BOOL:
+         data.b[0] = op[0]->value.b[c];
+         break;
+      default:
+         assert(0);
+      }
+      break;
+   }
+
    case ir_binop_bit_xor:
       for (unsigned c = 0, c0 = 0, c1 = 0;
            c < components;
diff --git a/src/glsl/ir_validate.cpp b/src/glsl/ir_validate.cpp
index 699c192..0b9631f2 100644
--- a/src/glsl/ir_validate.cpp
+++ b/src/glsl/ir_validate.cpp
@@ -468,6 +468,12 @@ ir_validate::visit_leave(ir_expression *ir)
       assert(ir->operands[1]->type == glsl_type::uint_type);
       break;
 
+   case ir_binop_vector_extract:
+      assert(ir->operands[0]->type->is_vector());
+      assert(ir->operands[1]->type->is_scalar()
+             && ir->operands[1]->type->is_integer());
+      break;
+
    case ir_triop_lrp:
       assert(ir->operands[0]->type->base_type == GLSL_TYPE_FLOAT);
       assert(ir->operands[0]->type == ir->operands[1]->type);
diff --git a/src/mesa/program/ir_to_mesa.cpp b/src/mesa/program/ir_to_mesa.cpp
index 14cf5ba..7d351c0 100644
--- a/src/mesa/program/ir_to_mesa.cpp
+++ b/src/mesa/program/ir_to_mesa.cpp
@@ -1485,6 +1485,7 @@ ir_to_mesa_visitor::visit(ir_expression *ir)
       emit(ir, OPCODE_LRP, result_dst, op[2], op[1], op[0]);
       break;
 
+   case ir_binop_vector_extract:
    case ir_quadop_vector:
       /* This operation should have already been handled.
        */
-- 
1.8.1.4