diff options
| -rw-r--r-- | src/mesa/drivers/dri/i965/brw_fs_cmod_propagation.cpp | 16 | ||||
| -rw-r--r-- | src/mesa/drivers/dri/i965/test_fs_cmod_propagation.cpp | 41 |
2 files changed, 55 insertions, 2 deletions
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 9592bf26ac6..c8eb3a4f8be 100644 --- a/src/mesa/drivers/dri/i965/brw_fs_cmod_propagation.cpp +++ b/src/mesa/drivers/dri/i965/brw_fs_cmod_propagation.cpp @@ -37,6 +37,15 @@ * we can do the comparison as part of the ADD instruction directly: * * add.ge.f0(8) g70<1>F g69<8,8,1>F 4096F + * + * If there had been a use of the flag register and another CMP using g70 + * + * add.ge.f0(8) g70<1>F g69<8,8,1>F 4096F + * (+f0) sel(8) g71<F> g72<8,8,1>F g73<8,8,1>F + * cmp.ge.f0(8) null g70<8,8,1>F 0F + * + * we can recognize that the CMP is generating the flag value that already + * exists and therefore remove the instruction. */ static bool @@ -57,6 +66,7 @@ opt_cmod_propagation_local(fs_visitor *v, bblock_t *block) !inst->src[1].is_zero()) continue; + bool read_flag = false; foreach_inst_in_block_reverse_starting_from(fs_inst, scan_inst, inst, block) { if (scan_inst->overwrites_reg(inst->src[0])) { @@ -65,7 +75,7 @@ opt_cmod_propagation_local(fs_visitor *v, bblock_t *block) break; if (scan_inst->can_do_cmod() && - (scan_inst->conditional_mod == BRW_CONDITIONAL_NONE || + ((!read_flag && scan_inst->conditional_mod == BRW_CONDITIONAL_NONE) || scan_inst->conditional_mod == inst->conditional_mod)) { scan_inst->conditional_mod = inst->conditional_mod; inst->remove(block); @@ -74,8 +84,10 @@ opt_cmod_propagation_local(fs_visitor *v, bblock_t *block) break; } - if (scan_inst->reads_flag() || scan_inst->writes_flag()) + if (scan_inst->writes_flag()) break; + + read_flag = read_flag || scan_inst->reads_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 3aa05987e4c..95d335d9543 100644 --- a/src/mesa/drivers/dri/i965/test_fs_cmod_propagation.cpp +++ b/src/mesa/drivers/dri/i965/test_fs_cmod_propagation.cpp @@ -309,3 +309,44 @@ TEST_F(cmod_propagation_test, intervening_dest_write) EXPECT_EQ(BRW_OPCODE_CMP, instruction(block0, 2)->opcode); EXPECT_EQ(BRW_CONDITIONAL_GE, instruction(block0, 2)->conditional_mod); } + +TEST_F(cmod_propagation_test, intervening_flag_read_same_value) +{ + fs_reg dest0 = v->vgrf(glsl_type::float_type); + fs_reg dest1 = v->vgrf(glsl_type::float_type); + fs_reg src0 = v->vgrf(glsl_type::float_type); + fs_reg src1 = v->vgrf(glsl_type::float_type); + fs_reg src2 = v->vgrf(glsl_type::float_type); + fs_reg zero(0.0f); + v->emit(BRW_OPCODE_ADD, dest0, src0, src1) + ->conditional_mod = BRW_CONDITIONAL_GE; + v->emit(BRW_OPCODE_SEL, dest1, src2, zero) + ->predicate = BRW_PREDICATE_NORMAL; + v->emit(BRW_OPCODE_CMP, v->reg_null_f, dest0, zero) + ->conditional_mod = BRW_CONDITIONAL_GE; + + /* = Before = + * + * 0: add.ge.f0(8) dest0 src0 src1 + * 1: (+f0) sel(8) dest1 src2 0.0f + * 2: cmp.ge.f0(8) null dest0 0.0f + * + * = After = + * 0: add.ge.f0(8) dest0 src0 src1 + * 1: (+f0) sel(8) dest1 src2 0.0f + */ + + v->calculate_cfg(); + bblock_t *block0 = v->cfg->blocks[0]; + + EXPECT_EQ(0, block0->start_ip); + EXPECT_EQ(2, block0->end_ip); + + EXPECT_TRUE(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_CONDITIONAL_GE, instruction(block0, 0)->conditional_mod); + EXPECT_EQ(BRW_OPCODE_SEL, instruction(block0, 1)->opcode); + EXPECT_EQ(BRW_PREDICATE_NORMAL, instruction(block0, 1)->predicate); +} |