diff options
| -rw-r--r-- | src/compiler/glsl/opt_algebraic.cpp | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/src/compiler/glsl/opt_algebraic.cpp b/src/compiler/glsl/opt_algebraic.cpp index ff4be269578..3147d25aea8 100644 --- a/src/compiler/glsl/opt_algebraic.cpp +++ b/src/compiler/glsl/opt_algebraic.cpp @@ -507,6 +507,18 @@ ir_algebraic_visitor::handle_expression(ir_expression *ir) if (is_vec_zero(op_const[1])) return ir->operands[0]; + /* Replace (x + (-x)) with constant 0 */ + for (int i = 0; i < 2; i++) { + if (op_expr[i]) { + if (op_expr[i]->operation == ir_unop_neg) { + ir_rvalue *other = ir->operands[(i + 1) % 2]; + if (other && op_expr[i]->operands[0]->equals(other)) { + return ir_constant::zero(ir, ir->type); + } + } + } + } + /* Reassociate addition of constants so that we can do constant * folding. */ |