The saturate propagation pass recognizes that the second instruction
below does not interfere with an attempt to propagate the saturate
modifier from instruction 3 to 1.
1: add(8) dst0 src0 src1
2: mov.sat(8) dst1 dst0
3: mov.sat(8) dst2 dst0
Unfortunately, we did not consider the case of instruction 2 having a
source modifier on dst0. Take for instance:
1: add(8) dst0 src0 src1
2: mov.sat(8) dst1 -dst0
3: mov.sat(8) dst2 dst0
Consider such an instruction to interfere. Increase instruction counts
in Anomaly 2, which could be a bug fix depending on the values the first
instruction produces.
Cc: <mesa-sta...@lists.freedesktop.org>
---
.../dri/i965/brw_fs_saturate_propagation.cpp | 12 ++++--
.../dri/i965/test_fs_saturate_propagation.cpp | 44 ++++++++++++++++++++++
2 files changed, 52 insertions(+), 4 deletions(-)
diff --git a/src/mesa/drivers/dri/i965/brw_fs_saturate_propagation.cpp
b/src/mesa/drivers/dri/i965/brw_fs_saturate_propagation.cpp
index bc51661..e406c28 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_saturate_propagation.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_saturate_propagation.cpp
@@ -81,12 +81,16 @@ opt_saturate_propagation_local(fs_visitor *v, bblock_t
*block)
break;
}
for (int i = 0; i < scan_inst->sources; i++) {
- if ((scan_inst->opcode != BRW_OPCODE_MOV || !scan_inst->saturate)
&&
- scan_inst->src[i].file == GRF &&
+ if (scan_inst->src[i].file == GRF &&
scan_inst->src[i].reg == inst->src[0].reg &&
scan_inst->src[i].reg_offset == inst->src[0].reg_offset) {
- interfered = true;
- break;
+ if (scan_inst->opcode != BRW_OPCODE_MOV ||
+ !scan_inst->saturate ||
+ scan_inst->src[0].abs ||
+ scan_inst->src[0].negate) {
+ interfered = true;
+ break;
+ }
}
}
diff --git a/src/mesa/drivers/dri/i965/test_fs_saturate_propagation.cpp
b/src/mesa/drivers/dri/i965/test_fs_saturate_propagation.cpp
index f897bdd..6f762bc 100644
--- a/src/mesa/drivers/dri/i965/test_fs_saturate_propagation.cpp
+++ b/src/mesa/drivers/dri/i965/test_fs_saturate_propagation.cpp
@@ -393,3 +393,47 @@ TEST_F(saturate_propagation_test, intervening_dest_write)
EXPECT_EQ(BRW_OPCODE_MOV, instruction(block0, 2)->opcode);
EXPECT_TRUE(instruction(block0, 2)->saturate);
}
+
+TEST_F(saturate_propagation_test, mul_neg_mov_sat_mov_sat)
+{
+ fs_reg dst0 = v->vgrf(glsl_type::float_type);
+ fs_reg dst1 = v->vgrf(glsl_type::float_type);
+ fs_reg dst2 = v->vgrf(glsl_type::float_type);
+ fs_reg src0 = v->vgrf(glsl_type::float_type);
+ fs_reg src1 = v->vgrf(glsl_type::float_type);
+ v->emit(BRW_OPCODE_MUL, dst0, src0, src1);
+ dst0.negate = true;
+ v->emit(BRW_OPCODE_MOV, dst1, dst0)
+ ->saturate = true;
+ dst0.negate = false;
+ v->emit(BRW_OPCODE_MOV, dst2, dst0)
+ ->saturate = true;
+
+ /* = Before =
+ *
+ * 0: mul(8) dst0 src0 src1
+ * 1: mov.sat(8) dst1 -dst0
+ * 2: mov.sat(8) dst2 dst0
+ *
+ * = After =
+ * (no changes)
+ */
+
+ v->calculate_cfg();
+ bblock_t *block0 = v->cfg->blocks[0];
+
+ EXPECT_EQ(0, block0->start_ip);
+ EXPECT_EQ(2, block0->end_ip);
+
+ EXPECT_FALSE(saturate_propagation(v));
+ EXPECT_EQ(0, block0->start_ip);
+ EXPECT_EQ(2, block0->end_ip);
+ EXPECT_EQ(BRW_OPCODE_MUL, instruction(block0, 0)->opcode);
+ EXPECT_FALSE(instruction(block0, 0)->saturate);
+ EXPECT_FALSE(instruction(block0, 0)->src[1].negate);
+ EXPECT_EQ(BRW_OPCODE_MOV, instruction(block0, 1)->opcode);
+ EXPECT_TRUE(instruction(block0, 1)->saturate);
+ EXPECT_TRUE(instruction(block0, 1)->src[0].negate);
+ EXPECT_EQ(BRW_OPCODE_MOV, instruction(block0, 2)->opcode);
+ EXPECT_TRUE(instruction(block0, 2)->saturate);
+}
--
2.0.5
_______________________________________________
mesa-dev mailing list
mesa-dev@lists.freedesktop.org
http://lists.freedesktop.org/mailman/listinfo/mesa-dev
