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ir_to_mesa: Emit smarter ir_binop_logic_or for vertex programs 

Continue using ADD in the other case because a fragment shader backend
could fuse the ADD with a MUL to generate a MAD for ((x && y) || z).

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>
This commit is contained in:
Ian Romanick 2016-04-13 11:43:23 -07:00
parent f7328f9afd
commit 2483a9a08c
1 changed files with 11 additions and 15 deletions
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26
src/mesa/program/ir_to_mesa.cpp
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@ -1212,24 +1212,20 @@ ir_to_mesa_visitor::visit(ir_expression *ir)
break;
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.
*/
/* 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]);
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));
/* The Boolean arguments are stored as float 0.0 and 1.0. If either
* value is 1.0, the result of the logcal-or should be 1.0. If both
* values are 0.0, the result should be 0.0. This is exactly what
* MAX does.
*/
emit(ir, OPCODE_MAX, result_dst, op[0], op[1]);
}
break;
}