Booleans are represented as 0/-1 on modern hardware which means we can
just negate them to convert them into a numeric type. Negation has
the benefit that it can be implemented using a source modifier which
can easily be propagated into some other instruction. shader-db
results on HSW:
total instructions in shared programs: 5264246 -> 5264211 (-0.00%)
instructions in affected programs: 1464 -> 1429 (-2.39%)
helped: 15
HURT: 1
No piglit regressions.
---
src/mesa/drivers/dri/i965/brw_fs_nir.cpp | 4 +---
src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp | 7 +------
2 files changed, 2 insertions(+), 9 deletions(-)
diff --git a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
index 4690d00..64ff24c 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
@@ -969,10 +969,8 @@ fs_visitor::nir_emit_alu(const fs_builder &bld,
nir_alu_instr *instr)
break;
case nir_op_b2i:
- bld.AND(result, op[0], fs_reg(1));
- break;
case nir_op_b2f:
- bld.AND(retype(result, BRW_REGISTER_TYPE_UD), op[0],
fs_reg(0x3f800000u));
+ bld.MOV(result, negate(op[0]));
break;
case nir_op_f2b:
diff --git a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
index c9c2661..fd94a70 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
@@ -1733,16 +1733,11 @@ vec4_visitor::visit(ir_expression *ir)
emit(MOV(result_dst, op[0]));
break;
case ir_unop_b2i:
- emit(AND(result_dst, op[0], src_reg(1)));
- break;
case ir_unop_b2f:
if (devinfo->gen <= 5) {
resolve_bool_comparison(ir->operands[0], &op[0]);
}
- op[0].type = BRW_REGISTER_TYPE_D;
- result_dst.type = BRW_REGISTER_TYPE_D;
- emit(AND(result_dst, op[0], src_reg(0x3f800000u)));
- result_dst.type = BRW_REGISTER_TYPE_F;
+ emit(MOV(result_dst, negate(op[0])));
break;
case ir_unop_f2b:
emit(CMP(result_dst, op[0], src_reg(0.0f), BRW_CONDITIONAL_NZ));
--
2.4.3
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