We can safely propagate the conditional mod to an instruction with a different type if the conditional mod does not involve comparing for equality with zero (or probably NaN, but ignore that for now).
This is because -0.0 and +0.0 are both test equal to zero, but their integer representations do not. Cc: 10.5 <mesa-sta...@lists.freedesktop.org> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=89317 --- .../drivers/dri/i965/brw_fs_cmod_propagation.cpp | 8 +++ .../drivers/dri/i965/test_fs_cmod_propagation.cpp | 67 ++++++++++++++++++++++ 2 files changed, 75 insertions(+) diff --git a/src/mesa/drivers/dri/i965/brw_fs_cmod_propagation.cpp b/src/mesa/drivers/dri/i965/brw_fs_cmod_propagation.cpp index c6384ab..a92eef6 100644 --- a/src/mesa/drivers/dri/i965/brw_fs_cmod_propagation.cpp +++ b/src/mesa/drivers/dri/i965/brw_fs_cmod_propagation.cpp @@ -80,6 +80,14 @@ opt_cmod_propagation_local(fs_visitor *v, bblock_t *block) scan_inst->dst.reg_offset != inst->src[0].reg_offset) break; + /* Testing equality with zero is different for ints and floats */ + if (scan_inst->dst.type != inst->dst.type && + (inst->conditional_mod == BRW_CONDITIONAL_Z || + inst->conditional_mod == BRW_CONDITIONAL_NZ || + inst->conditional_mod == BRW_CONDITIONAL_GE || + inst->conditional_mod == BRW_CONDITIONAL_LE)) + break; + /* If the instruction generating inst's source also wrote the * flag, and inst is doing a simple .nz comparison, then inst * is redundant - the appropriate value is already in the flag diff --git a/src/mesa/drivers/dri/i965/test_fs_cmod_propagation.cpp b/src/mesa/drivers/dri/i965/test_fs_cmod_propagation.cpp index fbe4fd9..0287161 100644 --- a/src/mesa/drivers/dri/i965/test_fs_cmod_propagation.cpp +++ b/src/mesa/drivers/dri/i965/test_fs_cmod_propagation.cpp @@ -415,3 +415,70 @@ TEST_F(cmod_propagation_test, movnz) EXPECT_EQ(BRW_OPCODE_CMP, instruction(block0, 0)->opcode); EXPECT_EQ(BRW_CONDITIONAL_GE, instruction(block0, 0)->conditional_mod); } + +TEST_F(cmod_propagation_test, different_types) +{ + fs_reg dest = v->vgrf(glsl_type::int_type); + fs_reg src0 = v->vgrf(glsl_type::int_type); + fs_reg src1 = v->vgrf(glsl_type::int_type); + fs_reg zero(0.0f); + v->emit(BRW_OPCODE_ADD, dest, src0, src1); + v->emit(BRW_OPCODE_CMP, v->reg_null_f, retype(dest, BRW_REGISTER_TYPE_F), + zero) + ->conditional_mod = BRW_CONDITIONAL_G; + + /* = Before = + * + * 0: add(8) dest:D src0:D src1:D + * 1: cmp.g.f0(8) null:F dest:F 0.0f + * + * = After = + * 0: add.g.f0(8) dest:D src0:D src1:D + */ + + v->calculate_cfg(); + bblock_t *block0 = v->cfg->blocks[0]; + + EXPECT_EQ(0, block0->start_ip); + EXPECT_EQ(1, block0->end_ip); + + EXPECT_TRUE(cmod_propagation(v)); + EXPECT_EQ(0, block0->start_ip); + EXPECT_EQ(0, block0->end_ip); + EXPECT_EQ(BRW_OPCODE_ADD, instruction(block0, 0)->opcode); + EXPECT_EQ(BRW_CONDITIONAL_G, instruction(block0, 0)->conditional_mod); +} + +TEST_F(cmod_propagation_test, different_types_cmod_with_zero) +{ + fs_reg dest = v->vgrf(glsl_type::int_type); + fs_reg src0 = v->vgrf(glsl_type::int_type); + fs_reg src1 = v->vgrf(glsl_type::int_type); + fs_reg zero(0.0f); + v->emit(BRW_OPCODE_ADD, dest, src0, src1); + v->emit(BRW_OPCODE_CMP, v->reg_null_f, retype(dest, BRW_REGISTER_TYPE_F), + zero) + ->conditional_mod = BRW_CONDITIONAL_GE; + + /* = Before = + * + * 0: add(8) dest:D src0:D src1:D + * 1: cmp.ge.f0(8) null:F dest:F 0.0f + * + * = After = + * (no changes) + */ + + v->calculate_cfg(); + bblock_t *block0 = v->cfg->blocks[0]; + + EXPECT_EQ(0, block0->start_ip); + EXPECT_EQ(1, block0->end_ip); + + EXPECT_FALSE(cmod_propagation(v)); + EXPECT_EQ(0, block0->start_ip); + EXPECT_EQ(1, block0->end_ip); + EXPECT_EQ(BRW_OPCODE_ADD, instruction(block0, 0)->opcode); + EXPECT_EQ(BRW_OPCODE_CMP, instruction(block0, 1)->opcode); + EXPECT_EQ(BRW_CONDITIONAL_GE, instruction(block0, 1)->conditional_mod); +} -- 2.0.5 _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
