vc4: Move SF removal to a separate peephole pass.

The DCE pass is going to change significantly to handle control flow,
while we don't really need to change it for the SF handling.  We also need
to add some more SF peephole optimization for SF updates generated by
control flow support.

No change on shader-db.

diff --git a/src/gallium/drivers/vc4/Makefile.sources b/src/gallium/drivers/vc4/Makefile.sources
index 0d1d4f799dc17e8e95f829d2b9e5cc1eeed36adc..612a0a402a00874f9af01c4684ce63527e495998 100644 (file)
--- a/src/gallium/drivers/vc4/Makefile.sources
+++ b/src/gallium/drivers/vc4/Makefile.sources
@@ -26,6 +26,7 @@ C_SOURCES := \
        vc4_opt_constant_folding.c \
        vc4_opt_copy_propagation.c \
        vc4_opt_dead_code.c \
+       vc4_opt_peephole_sf.c \
        vc4_opt_small_immediates.c \
        vc4_opt_vpm.c \
        vc4_program.c \

diff --git a/src/gallium/drivers/vc4/vc4_opt_dead_code.c b/src/gallium/drivers/vc4/vc4_opt_dead_code.c
index ad51ed779ead366ebbf67c25452afdb40b7fd83c..0256159fc691870422152a026c20306a79c23e02 100644 (file)
--- a/src/gallium/drivers/vc4/vc4_opt_dead_code.c
+++ b/src/gallium/drivers/vc4/vc4_opt_dead_code.c
@@ -82,7 +82,6 @@ qir_opt_dead_code(struct vc4_compile *c)
 {
         bool progress = false;
         bool *used = calloc(c->num_temps, sizeof(bool));
-        bool sf_used = false;
 
         list_for_each_entry_safe_rev(struct qinst, inst, &c->instructions,
                                      link) {
@@ -109,22 +108,6 @@ qir_opt_dead_code(struct vc4_compile *c)
                         continue;
                 }
 
-                if (qir_depends_on_flags(inst))
-                        sf_used = true;
-                if (inst->sf) {
-                        if (!sf_used) {
-                                if (debug) {
-                                        fprintf(stderr, "Removing SF on: ");
-                                        qir_dump_inst(c, inst);
-                                        fprintf(stderr, "\n");
-                                }
-
-                                inst->sf = false;
-                                progress = true;
-                        }
-                        sf_used = false;
-                }
-
                 for (int i = 0; i < qir_get_op_nsrc(inst->op); i++) {
                         if (inst->src[i].file == QFILE_TEMP)
                                 used[inst->src[i].index] = true;

diff --git a/src/gallium/drivers/vc4/vc4_opt_peephole_sf.c b/src/gallium/drivers/vc4/vc4_opt_peephole_sf.c
new file mode 100644 (file)
index 0000000..0bc3e67
--- /dev/null
+++ b/src/gallium/drivers/vc4/vc4_opt_peephole_sf.c
@@ -0,0 +1,82 @@
+/*
+ * Copyright © 2016 Broadcom
+ *
+ * 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 vc4_opt_peephole_sf.c
+ *
+ * Quick optimization to eliminate unused SF updates.
+ */
+
+#include "vc4_qir.h"
+#include "util/u_math.h"
+
+static bool debug;
+
+static void
+dump_from(struct vc4_compile *c, struct qinst *inst)
+{
+        if (!debug)
+                return;
+
+        fprintf(stderr, "optimizing: ");
+        qir_dump_inst(c, inst);
+        fprintf(stderr, "\n");
+}
+
+static void
+dump_to(struct vc4_compile *c, struct qinst *inst)
+{
+        if (!debug)
+                return;
+
+        fprintf(stderr, "to: ");
+        qir_dump_inst(c, inst);
+        fprintf(stderr, "\n");
+}
+
+bool
+qir_opt_peephole_sf(struct vc4_compile *c)
+{
+        bool progress = false;
+        bool sf_live = false;
+
+        /* Walk the block from bottom to top, tracking if the SF is used, and
+         * removing unused ones.
+         */
+        list_for_each_entry_rev(struct qinst, inst, &c->instructions, link) {
+                if (inst->sf) {
+                        if (!sf_live) {
+                                dump_from(c, inst);
+                                inst->sf = false;
+                                dump_to(c, inst);
+                                progress = true;
+                        }
+                        sf_live = false;
+                }
+
+                if (qir_depends_on_flags(inst))
+                        sf_live = true;
+        }
+
+        return progress;
+}

diff --git a/src/gallium/drivers/vc4/vc4_qir.c b/src/gallium/drivers/vc4/vc4_qir.c
index 4cdc8a2baae43d2c57d4971305df6f8d0ca26370..b36c0d934cc594c71a22d8a96477c5907fb59a0e 100644 (file)
--- a/src/gallium/drivers/vc4/vc4_qir.c
+++ b/src/gallium/drivers/vc4/vc4_qir.c
@@ -540,6 +540,7 @@ qir_optimize(struct vc4_compile *c)
                 OPTPASS(qir_opt_algebraic);
                 OPTPASS(qir_opt_constant_folding);
                 OPTPASS(qir_opt_copy_propagation);
+                OPTPASS(qir_opt_peephole_sf);
                 OPTPASS(qir_opt_dead_code);
                 OPTPASS(qir_opt_small_immediates);
                 OPTPASS(qir_opt_vpm);

diff --git a/src/gallium/drivers/vc4/vc4_qir.h b/src/gallium/drivers/vc4/vc4_qir.h
index c52d824e34e213ef105bff48110bc7620e74aaa5..8813cb4f1ceee3549ee87c2e1469b7d4d596f388 100644 (file)
--- a/src/gallium/drivers/vc4/vc4_qir.h
+++ b/src/gallium/drivers/vc4/vc4_qir.h
@@ -496,6 +496,7 @@ bool qir_opt_algebraic(struct vc4_compile *c);
 bool qir_opt_constant_folding(struct vc4_compile *c);
 bool qir_opt_copy_propagation(struct vc4_compile *c);
 bool qir_opt_dead_code(struct vc4_compile *c);
+bool qir_opt_peephole_sf(struct vc4_compile *c);
 bool qir_opt_small_immediates(struct vc4_compile *c);
 bool qir_opt_vpm(struct vc4_compile *c);
 void vc4_nir_lower_blend(nir_shader *s, struct vc4_compile *c);