[Mesa-dev] [PATCH v4 34/40] intel/compiler: validate region restrictions for half-float conversions
Iago Toral Quiroga
itoral at igalia.com
Tue Feb 12 11:56:01 UTC 2019
---
src/intel/compiler/brw_eu_validate.c | 64 ++++++++++++-
src/intel/compiler/test_eu_validate.cpp | 122 ++++++++++++++++++++++++
2 files changed, 185 insertions(+), 1 deletion(-)
diff --git a/src/intel/compiler/brw_eu_validate.c b/src/intel/compiler/brw_eu_validate.c
index 000a05cb6ac..203641fecb9 100644
--- a/src/intel/compiler/brw_eu_validate.c
+++ b/src/intel/compiler/brw_eu_validate.c
@@ -531,7 +531,69 @@ general_restrictions_based_on_operand_types(const struct gen_device_info *devinf
exec_type_size == 8 && dst_type_size == 4)
dst_type_size = 8;
- if (exec_type_size > dst_type_size) {
+ /* From the BDW+ PRM:
+ *
+ * "There is no direct conversion from HF to DF or DF to HF.
+ * There is no direct conversion from HF to Q/UQ or Q/UQ to HF."
+ */
+ enum brw_reg_type src0_type = brw_inst_src0_type(devinfo, inst);
+ ERROR_IF(brw_inst_opcode(devinfo, inst) == BRW_OPCODE_MOV &&
+ ((dst_type == BRW_REGISTER_TYPE_HF && type_sz(src0_type) == 8) ||
+ (dst_type_size == 8 && src0_type == BRW_REGISTER_TYPE_HF)),
+ "There are no direct conversion between 64-bit types and HF");
+
+ /* From the BDW+ PRM:
+ *
+ * "Conversion between Integer and HF (Half Float) must be
+ * DWord-aligned and strided by a DWord on the destination."
+ *
+ * But this seems to be expanded on CHV and SKL+ by:
+ *
+ * "There is a relaxed alignment rule for word destinations. When
+ * the destination type is word (UW, W, HF), destination data types
+ * can be aligned to either the lowest word or the second lowest
+ * word of the execution channel. This means the destination data
+ * words can be either all in the even word locations or all in the
+ * odd word locations."
+ *
+ * We do not implement the second rule as is though, since empirical testing
+ * shows inconsistencies:
+ * - It suggests that packed 16-bit is not allowed, which is not true.
+ * - It suggests that conversions from Q/DF to W (which need to be 64-bit
+ * aligned on the destination) are not possible, which is not true.
+ * - It suggests that conversions from 16-bit executions types to W need
+ * to be 32-bit aligned, which doesn't seem to be necessary.
+ *
+ * So from this rule we only validate the implication that conversion from
+ * F to HF needs to be DWord aligned too (in BDW this is limited to
+ * conversions from integer types).
+ */
+ bool is_half_float_conversion =
+ brw_inst_opcode(devinfo, inst) == BRW_OPCODE_MOV &&
+ dst_type != src0_type &&
+ (dst_type == BRW_REGISTER_TYPE_HF || src0_type == BRW_REGISTER_TYPE_HF);
+
+ if (is_half_float_conversion) {
+ assert(devinfo->gen >= 8);
+
+ if ((dst_type == BRW_REGISTER_TYPE_HF && brw_reg_type_is_integer(src0_type)) ||
+ (brw_reg_type_is_integer(dst_type) && src0_type == BRW_REGISTER_TYPE_HF)) {
+ ERROR_IF(dst_stride * dst_type_size != 4,
+ "Conversions between integer and half-float must be strided "
+ "by a DWord on the destination");
+
+ unsigned subreg = brw_inst_dst_da1_subreg_nr(devinfo, inst);
+ ERROR_IF(subreg % 4 != 0,
+ "Conversions between integer and half-float must be aligned "
+ "to a DWord on the destination");
+ } else if ((devinfo->is_cherryview || devinfo->gen >= 9) &&
+ dst_type == BRW_REGISTER_TYPE_HF) {
+ ERROR_IF(dst_stride != 2,
+ "Conversions to HF must have either all words in even word "
+ "locations or all words in odd word locations");
+ }
+
+ } else if (exec_type_size > dst_type_size) {
if (!(dst_type_is_byte && inst_is_raw_move(devinfo, inst))) {
ERROR_IF(dst_stride * dst_type_size != exec_type_size,
"Destination stride must be equal to the ratio of the sizes "
diff --git a/src/intel/compiler/test_eu_validate.cpp b/src/intel/compiler/test_eu_validate.cpp
index 73300b23122..1557b6d2452 100644
--- a/src/intel/compiler/test_eu_validate.cpp
+++ b/src/intel/compiler/test_eu_validate.cpp
@@ -848,6 +848,128 @@ TEST_P(validation_test, byte_destination_relaxed_alignment)
}
}
+TEST_P(validation_test, half_float_conversion)
+{
+ static const struct {
+ enum brw_reg_type dst_type;
+ enum brw_reg_type src_type;
+ unsigned dst_stride;
+ unsigned dst_subnr;
+ bool expected_result;
+ } inst[] = {
+#define INST(dst_type, src_type, dst_stride, dst_subnr, expected_result) \
+ { \
+ BRW_REGISTER_TYPE_##dst_type, \
+ BRW_REGISTER_TYPE_##src_type, \
+ BRW_HORIZONTAL_STRIDE_##dst_stride, \
+ dst_subnr, \
+ expected_result, \
+ }
+
+ /* MOV to half-float destination (F source handled later) */
+ INST(HF, B, 1, 0, false),
+ INST(HF, W, 1, 0, false),
+ INST(HF, HF, 1, 0, true),
+ INST(HF, HF, 1, 2, true),
+ INST(HF, D, 1, 0, false),
+ INST(HF, Q, 1, 0, false),
+ INST(HF, DF, 1, 0, false),
+ INST(HF, B, 2, 0, true),
+ INST(HF, B, 2, 2, false),
+ INST(HF, W, 2, 0, true),
+ INST(HF, W, 2, 2, false),
+ INST(HF, HF, 2, 0, true),
+ INST(HF, HF, 2, 2, true),
+ INST(HF, D, 2, 0, true),
+ INST(HF, D, 2, 2, false),
+ INST(HF, Q, 2, 0, false),
+ INST(HF, DF, 2, 0, false),
+ INST(HF, B, 4, 0, false),
+ INST(HF, W, 4, 0, false),
+ INST(HF, HF, 4, 0, true),
+ INST(HF, HF, 4, 2, true),
+ INST(HF, D, 4, 0, false),
+ INST(HF, Q, 4, 0, false),
+ INST(HF, DF, 4, 0, false),
+
+ /* MOV from half-float source */
+ INST( B, HF, 1, 0, false),
+ INST( W, HF, 1, 0, false),
+ INST( D, HF, 1, 0, true),
+ INST( D, HF, 1, 4, true),
+ INST( F, HF, 1, 0, true),
+ INST( F, HF, 1, 4, true),
+ INST( Q, HF, 1, 0, false),
+ INST(DF, HF, 1, 0, false),
+ INST( B, HF, 2, 0, false),
+ INST( W, HF, 2, 0, true),
+ INST( W, HF, 2, 2, false),
+ INST( D, HF, 2, 0, false),
+ INST( F, HF, 2, 0, true),
+ INST( F, HF, 2, 2, true),
+ INST( B, HF, 4, 0, true),
+ INST( B, HF, 4, 1, false),
+ INST( W, HF, 4, 0, false),
+
+#undef INST
+ };
+
+ if (devinfo.gen < 8)
+ return;
+
+ for (unsigned i = 0; i < sizeof(inst) / sizeof(inst[0]); i++) {
+ if (!devinfo.has_64bit_types &&
+ (type_sz(inst[i].src_type) == 8 || type_sz(inst[i].dst_type) == 8)) {
+ continue;
+ }
+
+ brw_MOV(p, retype(g0, inst[i].dst_type), retype(g0, inst[i].src_type));
+
+ brw_inst_set_exec_size(&devinfo, last_inst, BRW_EXECUTE_4);
+
+ brw_inst_set_dst_hstride(&devinfo, last_inst, inst[i].dst_stride);
+ brw_inst_set_dst_da1_subreg_nr(&devinfo, last_inst, inst[i].dst_subnr);
+
+ if (inst[i].src_type == BRW_REGISTER_TYPE_B) {
+ brw_inst_set_src0_vstride(&devinfo, last_inst, BRW_VERTICAL_STRIDE_4);
+ brw_inst_set_src0_width(&devinfo, last_inst, BRW_WIDTH_2);
+ brw_inst_set_src0_hstride(&devinfo, last_inst, BRW_HORIZONTAL_STRIDE_2);
+ } else {
+ brw_inst_set_src0_vstride(&devinfo, last_inst, BRW_VERTICAL_STRIDE_4);
+ brw_inst_set_src0_width(&devinfo, last_inst, BRW_WIDTH_4);
+ brw_inst_set_src0_hstride(&devinfo, last_inst, BRW_HORIZONTAL_STRIDE_1);
+ }
+
+ EXPECT_EQ(inst[i].expected_result, validate(p));
+
+ clear_instructions(p);
+ }
+
+ /* Conversion from F to HF has Dword destination alignment restriction
+ * on CHV and SKL+ only
+ */
+ brw_MOV(p, retype(g0, BRW_REGISTER_TYPE_HF),
+ retype(g0, BRW_REGISTER_TYPE_F));
+
+ brw_inst_set_dst_hstride(&devinfo, last_inst, BRW_HORIZONTAL_STRIDE_1);
+
+ if (devinfo.gen >= 9 || devinfo.is_cherryview) {
+ EXPECT_FALSE(validate(p));
+ } else {
+ assert(devinfo.gen == 8);
+ EXPECT_TRUE(validate(p));
+ }
+ clear_instructions(p);
+
+ brw_MOV(p, retype(g0, BRW_REGISTER_TYPE_HF),
+ retype(g0, BRW_REGISTER_TYPE_F));
+
+ brw_inst_set_dst_hstride(&devinfo, last_inst, BRW_HORIZONTAL_STRIDE_2);
+
+ EXPECT_TRUE(validate(p));
+ clear_instructions(p);
+}
+
TEST_P(validation_test, vector_immediate_destination_alignment)
{
static const struct {
--
2.17.1
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