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-rw-r--r--src/mesa/program/ir_to_mesa.cpp25
1 files changed, 21 insertions, 4 deletions
diff --git a/src/mesa/program/ir_to_mesa.cpp b/src/mesa/program/ir_to_mesa.cpp
index f03ea7a95e0..fcd14c89cd7 100644
--- a/src/mesa/program/ir_to_mesa.cpp
+++ b/src/mesa/program/ir_to_mesa.cpp
@@ -1267,11 +1267,28 @@ ir_to_mesa_visitor::visit(ir_expression *ir)
emit(ir, OPCODE_SNE, result_dst, op[0], op[1]);
break;
- case ir_binop_logic_or:
- /* This could be a saturated add and skip the SNE. */
- emit(ir, OPCODE_ADD, result_dst, op[0], op[1]);
- emit(ir, OPCODE_SNE, result_dst, result_src, src_reg_for_float(0.0));
+ case ir_binop_logic_or: {
+ /* After the addition, the value will be an integer on the
+ * range [0,2]. Zero stays zero, and positive values become 1.0.
+ */
+ ir_to_mesa_instruction *add =
+ emit(ir, OPCODE_ADD, result_dst, op[0], op[1]);
+ if (this->prog->Target == GL_FRAGMENT_PROGRAM_ARB) {
+ /* The clamping to [0,1] can be done for free in the fragment
+ * shader with a saturate.
+ */
+ add->saturate = true;
+ } else {
+ /* Negating the result of the addition gives values on the range
+ * [-2, 0]. Zero stays zero, and negative values become 1.0. This
+ * is achieved using SLT.
+ */
+ src_reg slt_src = result_src;
+ slt_src.negate = ~slt_src.negate;
+ emit(ir, OPCODE_SLT, result_dst, slt_src, src_reg_for_float(0.0));
+ }
break;
+ }
case ir_binop_logic_and:
/* the bool args are stored as float 0.0 or 1.0, so "mul" gives us "and". */