Removes IF/ENDIF and IF/ELSE/ENDIF with no intervening instructions.
total instructions in shared programs: 1360393 - 1360387 (-0.00%)
instructions in affected programs: 157 - 151 (-3.82%)
(no change in vertex shaders)
Reviewed-by: Paul Berry stereotype...@gmail.com
Reviewed-by: Eric Anholt e...@anholt.net
---
src/mesa/drivers/dri/i965/Makefile.sources | 1 +
.../drivers/dri/i965/brw_dead_control_flow.cpp | 83 ++
src/mesa/drivers/dri/i965/brw_dead_control_flow.h | 26 +++
src/mesa/drivers/dri/i965/brw_fs.cpp | 2 +
src/mesa/drivers/dri/i965/brw_vec4.cpp | 2 +
5 files changed, 114 insertions(+)
create mode 100644 src/mesa/drivers/dri/i965/brw_dead_control_flow.cpp
create mode 100644 src/mesa/drivers/dri/i965/brw_dead_control_flow.h
diff --git a/src/mesa/drivers/dri/i965/Makefile.sources
b/src/mesa/drivers/dri/i965/Makefile.sources
index 5724458..ac1363c 100644
--- a/src/mesa/drivers/dri/i965/Makefile.sources
+++ b/src/mesa/drivers/dri/i965/Makefile.sources
@@ -44,6 +44,7 @@ i965_FILES = \
brw_context.c \
brw_cubemap_normalize.cpp \
brw_curbe.c \
+ brw_dead_control_flow.cpp \
brw_device_info.c \
brw_disasm.c \
brw_draw.c \
diff --git a/src/mesa/drivers/dri/i965/brw_dead_control_flow.cpp
b/src/mesa/drivers/dri/i965/brw_dead_control_flow.cpp
new file mode 100644
index 000..8bdf094
--- /dev/null
+++ b/src/mesa/drivers/dri/i965/brw_dead_control_flow.cpp
@@ -0,0 +1,83 @@
+/*
+ * Copyright © 2013 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.
+ */
+
+/** @file brw_dead_control_flow.cpp
+ *
+ * This file implements the dead control flow elimination optimization pass.
+ */
+
+#include brw_shader.h
+#include brw_cfg.h
+
+/* Look for and eliminate dead control flow:
+ *
+ * - if/endif
+ * - if/else/endif
+ */
+bool
+dead_control_flow_eliminate(backend_visitor *v)
+{
+ bool progress = false;
+
+ cfg_t cfg(v);
+
+ for (int b = 0; b cfg.num_blocks; b++) {
+ bblock_t *block = cfg.blocks[b];
+ bool found = false;
+
+ /* ENDIF instructions, by definition, can only be found at the ends of
+ * basic blocks.
+ */
+ backend_instruction *endif_inst = block-end;
+ if (endif_inst-opcode != BRW_OPCODE_ENDIF)
+ continue;
+
+ backend_instruction *if_inst = NULL, *else_inst = NULL;
+ backend_instruction *prev_inst = (backend_instruction *)
endif_inst-prev;
+ if (prev_inst-opcode == BRW_OPCODE_IF) {
+ if_inst = prev_inst;
+ found = true;
+ } else if (prev_inst-opcode == BRW_OPCODE_ELSE) {
+ else_inst = prev_inst;
+
+ prev_inst = (backend_instruction *) prev_inst-prev;
+ if (prev_inst-opcode == BRW_OPCODE_IF) {
+if_inst = prev_inst;
+found = true;
+ }
+ }
+
+ if (found) {
+ if_inst-remove();
+ if (else_inst)
+else_inst-remove();
+ endif_inst-remove();
+ progress = true;
+ }
+ }
+
+ if (progress)
+ v-invalidate_live_intervals();
+
+ return progress;
+}
diff --git a/src/mesa/drivers/dri/i965/brw_dead_control_flow.h
b/src/mesa/drivers/dri/i965/brw_dead_control_flow.h
new file mode 100644
index 000..57a4dab
--- /dev/null
+++ b/src/mesa/drivers/dri/i965/brw_dead_control_flow.h
@@ -0,0 +1,26 @@
+/*
+ * Copyright © 2013 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
