[Mesa-dev] [PATCH 2/5] i965/fs: Add support for copy propagation.
Eric Anholt
eric at anholt.net
Tue May 8 17:59:36 PDT 2012
We could do more by handling abs/negate and non-GRF sources, but this is
a good start.
Total instructions: 208032 -> 207184
60/1246 programs affected (4.8%)
23286 -> 22438 instructions in affected programs (3.6% reduction)
---
src/mesa/drivers/dri/i965/Makefile.sources | 1 +
src/mesa/drivers/dri/i965/brw_fs.cpp | 1 +
src/mesa/drivers/dri/i965/brw_fs.h | 5 +
src/mesa/drivers/dri/i965/brw_fs_cfg.cpp | 1 +
.../drivers/dri/i965/brw_fs_copy_propagation.cpp | 135 ++++++++++++++++++++
5 files changed, 143 insertions(+)
create mode 100644 src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp
diff --git a/src/mesa/drivers/dri/i965/Makefile.sources b/src/mesa/drivers/dri/i965/Makefile.sources
index c564d95..8156f31 100644
--- a/src/mesa/drivers/dri/i965/Makefile.sources
+++ b/src/mesa/drivers/dri/i965/Makefile.sources
@@ -115,6 +115,7 @@ i965_CXX_FILES = \
brw_cubemap_normalize.cpp \
brw_fs.cpp \
brw_fs_cfg.cpp \
+ brw_fs_copy_propagation.cpp \
brw_fs_emit.cpp \
brw_fs_live_variables.cpp \
brw_fs_visitor.cpp \
diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index fd67318..a723cd8 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -1681,6 +1681,7 @@ fs_visitor::run()
progress = propagate_constants() || progress;
progress = opt_algebraic() || progress;
+ progress = opt_copy_propagate() || progress;
progress = register_coalesce() || progress;
progress = compute_to_mrf() || progress;
progress = dead_code_eliminate() || progress;
diff --git a/src/mesa/drivers/dri/i965/brw_fs.h b/src/mesa/drivers/dri/i965/brw_fs.h
index 6b45c4e..8ae855e 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.h
+++ b/src/mesa/drivers/dri/i965/brw_fs.h
@@ -49,6 +49,8 @@ extern "C" {
#include "glsl/glsl_types.h"
#include "glsl/ir.h"
+class fs_bblock;
+
enum register_file {
BAD_FILE,
ARF,
@@ -507,6 +509,9 @@ public:
void calculate_live_intervals();
bool propagate_constants();
bool opt_algebraic();
+ bool opt_copy_propagate();
+ bool opt_copy_propagate_local(void *mem_ctx, fs_bblock *block,
+ exec_list *acp);
bool register_coalesce();
bool compute_to_mrf();
bool dead_code_eliminate();
diff --git a/src/mesa/drivers/dri/i965/brw_fs_cfg.cpp b/src/mesa/drivers/dri/i965/brw_fs_cfg.cpp
index 7c4c481..acc0085 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_cfg.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_cfg.cpp
@@ -25,6 +25,7 @@
*
*/
+#include "brw_fs.h"
#include "brw_fs_cfg.h"
/** @file brw_fs_cfg.cpp
diff --git a/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp b/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp
new file mode 100644
index 0000000..3c9768f
--- /dev/null
+++ b/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp
@@ -0,0 +1,135 @@
+/*
+ * Copyright © 2012 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include "brw_fs.h"
+#include "brw_fs_cfg.h"
+
+struct acp_entry : public exec_node {
+ fs_reg dst;
+ fs_reg src;
+};
+
+/** @file brw_fs_copy_propagation.cpp
+ *
+ * Support for local copy propagation by walking the list of instructions
+ * and maintaining the ACP table of available copies for propagation.
+ *
+ * See Muchnik's Advanced Compiler Design and Implementation, section
+ * 12.5 (p356).
+ */
+
+/* Walks a basic block and does copy propagation on it using the acp
+ * list.
+ */
+bool
+fs_visitor::opt_copy_propagate_local(void *mem_ctx,
+ fs_bblock *block, exec_list *acp)
+{
+ bool progress = false;
+
+ for (fs_inst *inst = block->start;
+ inst != block->end->next;
+ inst = (fs_inst *)inst->next) {
+
+ /* Try propagating into this instruction. */
+ foreach_list(entry_node, acp) {
+ acp_entry *entry = (acp_entry *)entry_node;
+
+ for (int i = 0; i < 3; i++) {
+ if (inst->src[i].file == entry->dst.file &&
+ inst->src[i].reg == entry->dst.reg &&
+ inst->src[i].reg_offset == entry->dst.reg_offset) {
+ inst->src[i].reg = entry->src.reg;
+ inst->src[i].reg_offset = entry->src.reg_offset;
+ progress = true;
+ }
+ }
+ }
+
+ /* kill the destination from the ACP */
+ if (inst->dst.file == GRF) {
+ int start_offset = inst->dst.reg_offset;
+ int end_offset = start_offset + inst->regs_written();
+
+ foreach_list_safe(entry_node, acp) {
+ acp_entry *entry = (acp_entry *)entry_node;
+
+ if (entry->dst.file == GRF &&
+ entry->dst.reg == inst->dst.reg &&
+ entry->dst.reg_offset >= start_offset &&
+ entry->dst.reg_offset < end_offset) {
+ entry->remove();
+ continue;
+ }
+ if (entry->src.file == GRF &&
+ entry->src.reg == inst->dst.reg &&
+ entry->src.reg_offset >= start_offset &&
+ entry->src.reg_offset < end_offset) {
+ entry->remove();
+ }
+ }
+ }
+
+ /* If this instruction is a raw copy, add it to the ACP. */
+ if (inst->opcode == BRW_OPCODE_MOV &&
+ inst->dst.file == GRF &&
+ inst->src[0].file == GRF &&
+ (inst->src[0].reg != inst->dst.reg ||
+ inst->src[0].reg_offset != inst->dst.reg_offset) &&
+ inst->src[0].type == inst->dst.type &&
+ !inst->saturate &&
+ !inst->predicated &&
+ !inst->force_uncompressed &&
+ !inst->force_sechalf &&
+ inst->src[0].smear == -1 &&
+ !inst->src[0].abs &&
+ !inst->src[0].negate) {
+ acp_entry *entry = ralloc(mem_ctx, acp_entry);
+ entry->dst = inst->dst;
+ entry->src = inst->src[0];
+ acp->push_tail(entry);
+ }
+ }
+
+ return progress;
+}
+
+bool
+fs_visitor::opt_copy_propagate()
+{
+ bool progress = false;
+ void *mem_ctx = ralloc_context(this->mem_ctx);
+
+ fs_cfg cfg(this);
+
+ for (int b = 0; b < cfg.num_blocks; b++) {
+ fs_bblock *block = cfg.blocks[b];
+ exec_list acp;
+
+ progress = opt_copy_propagate_local(mem_ctx, block, &acp) || progress;
+ }
+
+ ralloc_free(mem_ctx);
+
+ return progress;
+}
--
1.7.10
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