[Mesa-dev] [RFC PATCH 3/5] glsl: add ir_binop_interpolate_at_offset

[Chris Forbes]

Will be used to implement interpolateAtOffset() and
interpolateAtSample() from ARB_gpu_shader5.

Signed-off-by: Chris Forbes <chrisf at ijw.co.nz>
---
 src/glsl/ir.cpp                            |  2 ++
 src/glsl/ir.h                              | 10 +++++++++-
 src/glsl/ir_builder.cpp                    |  6 ++++++
 src/glsl/ir_builder.h                      |  1 +
 src/glsl/ir_constant_expression.cpp        |  1 +
 src/glsl/ir_validate.cpp                   |  7 +++++++
 src/mesa/program/ir_to_mesa.cpp            |  1 +
 src/mesa/state_tracker/st_glsl_to_tgsi.cpp |  1 +
 8 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/src/glsl/ir.cpp b/src/glsl/ir.cpp
index 74d59db..dcfece9 100644
--- a/src/glsl/ir.cpp
+++ b/src/glsl/ir.cpp
@@ -406,6 +406,7 @@ ir_expression::ir_expression(int op, ir_rvalue *op0, ir_rvalue *op1)
    case ir_binop_rshift:
    case ir_binop_bfm:
    case ir_binop_ldexp:
+   case ir_binop_interpolate_at_offset:
       this->type = op0->type;
       break;
 
@@ -562,6 +563,7 @@ static const char *const operator_strs[] = {
    "ubo_load",
    "ldexp",
    "vector_extract",
+   "interpolate_at_offset",
    "fma",
    "lrp",
    "csel",
diff --git a/src/glsl/ir.h b/src/glsl/ir.h
index 7e41008..5e9103f 100644
--- a/src/glsl/ir.h
+++ b/src/glsl/ir.h
@@ -1321,9 +1321,17 @@ enum ir_expression_operation {
    ir_binop_vector_extract,
 
    /**
+    * Interpolate fs input at offset
+    *
+    * operand0 is the fs input
+    * operand1 is the offset from the pixel center
+    */
+   ir_binop_interpolate_at_offset,
+
+   /**
     * A sentinel marking the last of the binary operations.
     */
-   ir_last_binop = ir_binop_vector_extract,
+   ir_last_binop = ir_binop_interpolate_at_offset,
 
    /**
     * \name Fused floating-point multiply-add, part of ARB_gpu_shader5.
diff --git a/src/glsl/ir_builder.cpp b/src/glsl/ir_builder.cpp
index c532aea..09a32a3 100644
--- a/src/glsl/ir_builder.cpp
+++ b/src/glsl/ir_builder.cpp
@@ -502,6 +502,12 @@ interpolate_at_centroid(operand a)
 }
 
 ir_expression *
+interpolate_at_offset(operand a, operand b)
+{
+   return expr(ir_binop_interpolate_at_offset, a, b);
+}
+
+ir_expression *
 fma(operand a, operand b, operand c)
 {
    return expr(ir_triop_fma, a, b, c);
diff --git a/src/glsl/ir_builder.h b/src/glsl/ir_builder.h
index 410e8ab..c049010 100644
--- a/src/glsl/ir_builder.h
+++ b/src/glsl/ir_builder.h
@@ -185,6 +185,7 @@ ir_expression *f2b(operand a);
 ir_expression *b2f(operand a);
 
 ir_expression *interpolate_at_centroid(operand a);
+ir_expression *interpolate_at_offset(operand a, operand b);
 
 ir_expression *fma(operand a, operand b, operand c);
 ir_expression *lrp(operand x, operand y, operand a);
diff --git a/src/glsl/ir_constant_expression.cpp b/src/glsl/ir_constant_expression.cpp
index 0efd1d5..dfffa1d 100644
--- a/src/glsl/ir_constant_expression.cpp
+++ b/src/glsl/ir_constant_expression.cpp
@@ -415,6 +415,7 @@ ir_expression::constant_expression_value(struct hash_table *variable_context)
       case ir_binop_lshift:
       case ir_binop_rshift:
       case ir_binop_ldexp:
+      case ir_binop_interpolate_at_offset:
       case ir_binop_vector_extract:
       case ir_triop_csel:
       case ir_triop_bitfield_extract:
diff --git a/src/glsl/ir_validate.cpp b/src/glsl/ir_validate.cpp
index 69dd18f..9e39afe 100644
--- a/src/glsl/ir_validate.cpp
+++ b/src/glsl/ir_validate.cpp
@@ -551,6 +551,13 @@ ir_validate::visit_leave(ir_expression *ir)
              && ir->operands[1]->type->is_integer());
       break;
 
+   case ir_binop_interpolate_at_offset:
+      assert(ir->operands[0]->type == ir->type);
+      assert(ir->operands[0]->type->is_float());
+      assert(ir->operands[1]->type->components() == 2);
+      assert(ir->operands[1]->type->is_float());
+      break;
+
    case ir_triop_fma:
       assert(ir->type->base_type == GLSL_TYPE_FLOAT);
       assert(ir->type == ir->operands[0]->type);
diff --git a/src/mesa/program/ir_to_mesa.cpp b/src/mesa/program/ir_to_mesa.cpp
index f75c296..6fd9fb6 100644
--- a/src/mesa/program/ir_to_mesa.cpp
+++ b/src/mesa/program/ir_to_mesa.cpp
@@ -1502,6 +1502,7 @@ ir_to_mesa_visitor::visit(ir_expression *ir)
    case ir_binop_borrow:
    case ir_binop_imul_high:
    case ir_unop_interpolate_at_centroid:
+   case ir_binop_interpolate_at_offset:
       assert(!"not supported");
       break;
 
diff --git a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
index 418f27d..65e2925 100644
--- a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
+++ b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
@@ -2008,6 +2008,7 @@ glsl_to_tgsi_visitor::visit(ir_expression *ir)
    case ir_binop_borrow:
    case ir_binop_imul_high:
    case ir_unop_interpolate_at_centroid:
+   case ir_binop_interpolate_at_offset:
       /* This operation is not supported, or should have already been handled.
        */
       assert(!"Invalid ir opcode in glsl_to_tgsi_visitor::visit()");
-- 
1.8.4.2