[Mesa-dev] [RFC PATCH 2/5] glsl: add ir_unop_interpolate_at_centroid

[Chris Forbes]

Will be used to implement interpolateAtCentroid() from ARB_gpu_shader5.

Signed-off-by: Chris Forbes <chrisf at ijw.co.nz>
---
 src/glsl/ir.cpp                            | 2 ++
 src/glsl/ir.h                              | 9 ++++++++-
 src/glsl/ir_builder.cpp                    | 6 ++++++
 src/glsl/ir_builder.h                      | 2 ++
 src/glsl/ir_validate.cpp                   | 5 +++++
 src/mesa/program/ir_to_mesa.cpp            | 1 +
 src/mesa/state_tracker/st_glsl_to_tgsi.cpp | 1 +
 7 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/src/glsl/ir.cpp b/src/glsl/ir.cpp
index 1b49736..74d59db 100644
--- a/src/glsl/ir.cpp
+++ b/src/glsl/ir.cpp
@@ -251,6 +251,7 @@ ir_expression::ir_expression(int op, ir_rvalue *op0)
    case ir_unop_dFdx:
    case ir_unop_dFdy:
    case ir_unop_bitfield_reverse:
+   case ir_unop_interpolate_at_centroid:
       this->type = op0->type;
       break;
 
@@ -527,6 +528,7 @@ static const char *const operator_strs[] = {
    "find_msb",
    "find_lsb",
    "noise",
+   "interpolate_at_centroid",
    "+",
    "-",
    "*",
diff --git a/src/glsl/ir.h b/src/glsl/ir.h
index 2f06fb9..7e41008 100644
--- a/src/glsl/ir.h
+++ b/src/glsl/ir.h
@@ -1193,9 +1193,16 @@ enum ir_expression_operation {
    ir_unop_noise,
 
    /**
+    * Interpolate fs input at centroid
+    *
+    * operand0 is the fs input.
+    */
+   ir_unop_interpolate_at_centroid,
+
+   /**
     * A sentinel marking the last of the unary operations.
     */
-   ir_last_unop = ir_unop_noise,
+   ir_last_unop = ir_unop_interpolate_at_centroid,
 
    ir_binop_add,
    ir_binop_sub,
diff --git a/src/glsl/ir_builder.cpp b/src/glsl/ir_builder.cpp
index 6c49734..c532aea 100644
--- a/src/glsl/ir_builder.cpp
+++ b/src/glsl/ir_builder.cpp
@@ -496,6 +496,12 @@ b2f(operand a)
 }
 
 ir_expression *
+interpolate_at_centroid(operand a)
+{
+   return expr(ir_unop_interpolate_at_centroid, a);
+}
+
+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 1f07788..410e8ab 100644
--- a/src/glsl/ir_builder.h
+++ b/src/glsl/ir_builder.h
@@ -184,6 +184,8 @@ ir_expression *i2b(operand a);
 ir_expression *f2b(operand a);
 ir_expression *b2f(operand a);
 
+ir_expression *interpolate_at_centroid(operand a);
+
 ir_expression *fma(operand a, operand b, operand c);
 ir_expression *lrp(operand x, operand y, operand a);
 ir_expression *csel(operand a, operand b, operand c);
diff --git a/src/glsl/ir_validate.cpp b/src/glsl/ir_validate.cpp
index 13e41a0..69dd18f 100644
--- a/src/glsl/ir_validate.cpp
+++ b/src/glsl/ir_validate.cpp
@@ -410,6 +410,11 @@ ir_validate::visit_leave(ir_expression *ir)
       /* XXX what can we assert here? */
       break;
 
+   case ir_unop_interpolate_at_centroid:
+      assert(ir->operands[0]->type == ir->type);
+      assert(ir->operands[0]->type->is_float());
+      break;
+
    case ir_binop_add:
    case ir_binop_sub:
    case ir_binop_mul:
diff --git a/src/mesa/program/ir_to_mesa.cpp b/src/mesa/program/ir_to_mesa.cpp
index c833a12..f75c296 100644
--- a/src/mesa/program/ir_to_mesa.cpp
+++ b/src/mesa/program/ir_to_mesa.cpp
@@ -1501,6 +1501,7 @@ ir_to_mesa_visitor::visit(ir_expression *ir)
    case ir_binop_carry:
    case ir_binop_borrow:
    case ir_binop_imul_high:
+   case ir_unop_interpolate_at_centroid:
       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 0eaf746..418f27d 100644
--- a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
+++ b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
@@ -2007,6 +2007,7 @@ glsl_to_tgsi_visitor::visit(ir_expression *ir)
    case ir_binop_carry:
    case ir_binop_borrow:
    case ir_binop_imul_high:
+   case ir_unop_interpolate_at_centroid:
       /* 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