[Mesa-dev] [PATCH] i965: Emit better code for ir_unop_sign.

[Matt Turner]

total instructions in shared programs: 1519751 -> 1519442 (-0.02%)
instructions in affected programs:     10154 -> 9845 (-3.04%)
---
 src/mesa/drivers/dri/i965/brw_fs_visitor.cpp   | 23 +++++++++++++++--------
 src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp | 23 ++++++++++++++++-------
 2 files changed, 31 insertions(+), 15 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
index 9eb9a9d..a0e803b 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
@@ -382,18 +382,25 @@ fs_visitor::visit(ir_expression *ir)
       emit(MOV(this->result, op[0]));
       break;
    case ir_unop_sign:
-      temp = fs_reg(this, ir->type);
+      if (ir->type->is_float()) {
+         emit(CMP(reg_null_f, op[0], fs_reg(0.0f), BRW_CONDITIONAL_NZ));
 
-      emit(MOV(this->result, fs_reg(0.0f)));
+         op[0].type = BRW_REGISTER_TYPE_UD;
+         this->result.type = BRW_REGISTER_TYPE_UD;
+         emit(AND(this->result, op[0], fs_reg(0x80000000u)));
 
-      emit(CMP(reg_null_f, op[0], fs_reg(0.0f), BRW_CONDITIONAL_G));
-      inst = emit(MOV(this->result, fs_reg(1.0f)));
-      inst->predicate = BRW_PREDICATE_NORMAL;
+         inst = emit(OR(this->result, this->result, fs_reg(0x3f800000u)));
+         inst->predicate = BRW_PREDICATE_NORMAL;
 
-      emit(CMP(reg_null_f, op[0], fs_reg(0.0f), BRW_CONDITIONAL_L));
-      inst = emit(MOV(this->result, fs_reg(-1.0f)));
-      inst->predicate = BRW_PREDICATE_NORMAL;
+         this->result.type = BRW_REGISTER_TYPE_F;
+      } else {
+         emit(CMP(reg_null_d, op[0], fs_reg(0), BRW_CONDITIONAL_G));
 
+         emit(ASR(this->result, op[0], fs_reg(31)));
+
+         inst = emit(OR(this->result, this->result, fs_reg(1)));
+         inst->predicate = BRW_PREDICATE_NORMAL;
+      }
       break;
    case ir_unop_rcp:
       emit_math(SHADER_OPCODE_RCP, this->result, op[0]);
diff --git a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
index a13eafb..986663b 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
@@ -1259,16 +1259,25 @@ vec4_visitor::visit(ir_expression *ir)
       break;
 
    case ir_unop_sign:
-      emit(MOV(result_dst, src_reg(0.0f)));
+      if (ir->type->is_float()) {
+         emit(CMP(dst_null_f(), op[0], src_reg(0.0f), BRW_CONDITIONAL_NZ));
 
-      emit(CMP(dst_null_d(), op[0], src_reg(0.0f), BRW_CONDITIONAL_G));
-      inst = emit(MOV(result_dst, src_reg(1.0f)));
-      inst->predicate = BRW_PREDICATE_NORMAL;
+         op[0].type = BRW_REGISTER_TYPE_UD;
+         result_dst.type = BRW_REGISTER_TYPE_UD;
+         emit(AND(result_dst, op[0], src_reg(0x80000000u)));
 
-      emit(CMP(dst_null_d(), op[0], src_reg(0.0f), BRW_CONDITIONAL_L));
-      inst = emit(MOV(result_dst, src_reg(-1.0f)));
-      inst->predicate = BRW_PREDICATE_NORMAL;
+         inst = emit(OR(result_dst, src_reg(result_dst), src_reg(0x3f800000u)));
+         inst->predicate = BRW_PREDICATE_NORMAL;
+
+         this->result.type = BRW_REGISTER_TYPE_F;
+      } else {
+         emit(CMP(dst_null_d(), op[0], src_reg(0), BRW_CONDITIONAL_G));
+
+         emit(ASR(result_dst, op[0], src_reg(31)));
 
+         inst = emit(OR(result_dst, src_reg(result_dst), src_reg(1)));
+         inst->predicate = BRW_PREDICATE_NORMAL;
+      }
       break;
 
    case ir_unop_rcp:
-- 
1.8.3.2