diff options
| -rw-r--r-- | src/mesa/program/ir_to_mesa.cpp | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/src/mesa/program/ir_to_mesa.cpp b/src/mesa/program/ir_to_mesa.cpp index 1ef609fe15d..f03ea7a95e0 100644 --- a/src/mesa/program/ir_to_mesa.cpp +++ b/src/mesa/program/ir_to_mesa.cpp @@ -1135,7 +1135,13 @@ ir_to_mesa_visitor::visit(ir_expression *ir) switch (ir->operation) { case ir_unop_logic_not: - emit(ir, OPCODE_SEQ, result_dst, op[0], src_reg_for_float(0.0)); + /* Previously 'SEQ dst, src, 0.0' was used for this. However, many + * older GPUs implement SEQ using multiple instructions (i915 uses two + * SGE instructions and a MUL instruction). Since our logic values are + * 0.0 and 1.0, 1-x also implements !x. + */ + op[0].negate = ~op[0].negate; + emit(ir, OPCODE_ADD, result_dst, op[0], src_reg_for_float(1.0)); break; case ir_unop_neg: op[0].negate = ~op[0].negate; |