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-rw-r--r--src/mesa/drivers/dri/i965/brw_vec4.cpp99
-rw-r--r--src/mesa/drivers/dri/i965/brw_vec4.h2
-rw-r--r--src/mesa/drivers/dri/i965/test_vec4_register_coalesce.cpp21
3 files changed, 113 insertions, 9 deletions
diff --git a/src/mesa/drivers/dri/i965/brw_vec4.cpp b/src/mesa/drivers/dri/i965/brw_vec4.cpp
index 436ba97e147..7ab37e7ca9f 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4.cpp
@@ -600,6 +600,85 @@ vec4_visitor::move_push_constants_to_pull_constants()
pack_uniform_registers();
}
+bool
+vec4_instruction::can_reswizzle_dst(int dst_writemask,
+ int swizzle,
+ int swizzle_mask)
+{
+ /* If this instruction sets anything not referenced by swizzle, then we'd
+ * totally break it when we reswizzle.
+ */
+ if (dst.writemask & ~swizzle_mask)
+ return false;
+
+ switch (opcode) {
+ case BRW_OPCODE_DP4:
+ case BRW_OPCODE_DP3:
+ case BRW_OPCODE_DP2:
+ return true;
+ default:
+ /* Check if there happens to be no reswizzling required. */
+ for (int c = 0; c < 4; c++) {
+ int bit = 1 << BRW_GET_SWZ(swizzle, c);
+ /* Skip components of the swizzle not used by the dst. */
+ if (!(dst_writemask & (1 << c)))
+ continue;
+
+ /* We don't do the reswizzling yet, so just sanity check that we
+ * don't have to.
+ */
+ if (bit != (1 << c))
+ return false;
+ }
+ return true;
+ }
+}
+
+/**
+ * For any channels in the swizzle's source that were populated by this
+ * instruction, rewrite the instruction to put the appropriate result directly
+ * in those channels.
+ *
+ * e.g. for swizzle=yywx, MUL a.xy b c -> MUL a.yy_x b.yy z.yy_x
+ */
+void
+vec4_instruction::reswizzle_dst(int dst_writemask, int swizzle)
+{
+ int new_writemask = 0;
+
+ switch (opcode) {
+ case BRW_OPCODE_DP4:
+ case BRW_OPCODE_DP3:
+ case BRW_OPCODE_DP2:
+ for (int c = 0; c < 4; c++) {
+ int bit = 1 << BRW_GET_SWZ(swizzle, c);
+ /* Skip components of the swizzle not used by the dst. */
+ if (!(dst_writemask & (1 << c)))
+ continue;
+ /* If we were populating this component, then populate the
+ * corresponding channel of the new dst.
+ */
+ if (dst.writemask & bit)
+ new_writemask |= (1 << c);
+ }
+ dst.writemask = new_writemask;
+ break;
+ default:
+ for (int c = 0; c < 4; c++) {
+ int bit = 1 << BRW_GET_SWZ(swizzle, c);
+ /* Skip components of the swizzle not used by the dst. */
+ if (!(dst_writemask & (1 << c)))
+ continue;
+
+ /* We don't do the reswizzling yet, so just sanity check that we
+ * don't have to.
+ */
+ assert(bit == (1 << c));
+ }
+ break;
+ }
+}
+
/*
* Tries to reduce extra MOV instructions by taking GRFs that get just
* written and then MOVed into an MRF and making the original write of
@@ -641,26 +720,20 @@ vec4_visitor::opt_compute_to_mrf()
*/
bool chans_needed[4] = {false, false, false, false};
int chans_remaining = 0;
+ int swizzle_mask = 0;
for (int i = 0; i < 4; i++) {
int chan = BRW_GET_SWZ(inst->src[0].swizzle, i);
if (!(inst->dst.writemask & (1 << i)))
continue;
- /* We don't handle compute-to-MRF across a swizzle. We would
- * need to be able to rewrite instructions above to output
- * results to different channels.
- */
- if (chan != i)
- chans_remaining = 5;
+ swizzle_mask |= (1 << chan);
if (!chans_needed[chan]) {
chans_needed[chan] = true;
chans_remaining++;
}
}
- if (chans_remaining > 4)
- continue;
/* Now walk up the instruction stream trying to see if we can
* rewrite everything writing to the GRF into the MRF instead.
@@ -689,6 +762,13 @@ vec4_visitor::opt_compute_to_mrf()
}
}
+ /* If we can't handle the swizzle, bail. */
+ if (!scan_inst->can_reswizzle_dst(inst->dst.writemask,
+ inst->src[0].swizzle,
+ swizzle_mask)) {
+ break;
+ }
+
/* Mark which channels we found unconditional writes for. */
if (!scan_inst->predicate) {
for (int i = 0; i < 4; i++) {
@@ -759,10 +839,11 @@ vec4_visitor::opt_compute_to_mrf()
if (scan_inst->dst.file == GRF &&
scan_inst->dst.reg == inst->src[0].reg &&
scan_inst->dst.reg_offset == inst->src[0].reg_offset) {
+ scan_inst->reswizzle_dst(inst->dst.writemask,
+ inst->src[0].swizzle);
scan_inst->dst.file = MRF;
scan_inst->dst.reg = mrf;
scan_inst->dst.reg_offset = 0;
- scan_inst->dst.writemask &= inst->dst.writemask;
scan_inst->saturate |= inst->saturate;
}
scan_inst = (vec4_instruction *)scan_inst->next;
diff --git a/src/mesa/drivers/dri/i965/brw_vec4.h b/src/mesa/drivers/dri/i965/brw_vec4.h
index d7c1cce075d..6da44d4080a 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4.h
+++ b/src/mesa/drivers/dri/i965/brw_vec4.h
@@ -194,6 +194,8 @@ public:
bool is_tex();
bool is_math();
+ bool can_reswizzle_dst(int dst_writemask, int swizzle, int swizzle_mask);
+ void reswizzle_dst(int dst_writemask, int swizzle);
};
/**
diff --git a/src/mesa/drivers/dri/i965/test_vec4_register_coalesce.cpp b/src/mesa/drivers/dri/i965/test_vec4_register_coalesce.cpp
index c79b0fd1831..fa9c155655f 100644
--- a/src/mesa/drivers/dri/i965/test_vec4_register_coalesce.cpp
+++ b/src/mesa/drivers/dri/i965/test_vec4_register_coalesce.cpp
@@ -122,3 +122,24 @@ TEST_F(register_coalesce_test, test_multiple_use)
EXPECT_NE(mul->dst.file, MRF);
}
+
+TEST_F(register_coalesce_test, test_dp4_mrf)
+{
+ src_reg some_src_1 = src_reg(v, glsl_type::vec4_type);
+ src_reg some_src_2 = src_reg(v, glsl_type::vec4_type);
+ dst_reg init;
+
+ dst_reg m0 = dst_reg(MRF, 0);
+ m0.writemask = WRITEMASK_Y;
+ m0.type = BRW_REGISTER_TYPE_F;
+
+ dst_reg temp = dst_reg(v, glsl_type::float_type);
+
+ vec4_instruction *dp4 = v->emit(v->DP4(temp, some_src_1, some_src_2));
+ v->emit(v->MOV(m0, src_reg(temp)));
+
+ register_coalesce(v);
+
+ EXPECT_EQ(dp4->dst.file, MRF);
+ EXPECT_EQ(dp4->dst.writemask, WRITEMASK_Y);
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-29 14:13:00 +0000