Module: Mesa
Branch: master
Commit: bd2ca2bcddaf1d598dfa29a5bee661d7315e573a
URL:
http://cgit.freedesktop.org/mesa/mesa/commit/?id=bd2ca2bcddaf1d598dfa29a5bee661d7315e573a
Author: Rob Clark <robdcl...@gmail.com>
Date: Tue Mar 6 09:53:45 2018 -0500
freedreno/ir3: eliminate unused false-deps
Previously false-dependencies would get flagged as used, even if the
only "use" was a false dep to (for example) prevent a load from being
scheduled after a store.
In addition to being pointless instructions, in some cases they can
cause problems. For example, ldg (and similar instructions) depend on
an immed arg getting CP'd into the instruction, but this doesn't happen
if an instruction is otherwise unused. Which can result in undefined
results (overwriting unintended registers).
Signed-off-by: Rob Clark <robdcl...@gmail.com>
---
src/gallium/drivers/freedreno/ir3/ir3_cp.c | 2 +-
src/gallium/drivers/freedreno/ir3/ir3_depth.c | 40 ++++++++++++++++++++-------
2 files changed, 31 insertions(+), 11 deletions(-)
diff --git a/src/gallium/drivers/freedreno/ir3/ir3_cp.c
b/src/gallium/drivers/freedreno/ir3/ir3_cp.c
index 391e94ca44..67a7714b9c 100644
--- a/src/gallium/drivers/freedreno/ir3/ir3_cp.c
+++ b/src/gallium/drivers/freedreno/ir3/ir3_cp.c
@@ -607,7 +607,7 @@ ir3_cp(struct ir3 *ir, struct ir3_shader_variant *so)
list_for_each_entry (struct ir3_instruction, instr,
&block->instr_list, node) {
struct ir3_instruction *src;
- /* by the way, we don't acount for false-dep's, so the
CP
+ /* by the way, we don't account for false-dep's, so the
CP
* pass should always happen before false-dep's are
inserted
*/
debug_assert(instr->deps_count == 0);
diff --git a/src/gallium/drivers/freedreno/ir3/ir3_depth.c
b/src/gallium/drivers/freedreno/ir3/ir3_depth.c
index 270d53dbed..3ece13928f 100644
--- a/src/gallium/drivers/freedreno/ir3/ir3_depth.c
+++ b/src/gallium/drivers/freedreno/ir3/ir3_depth.c
@@ -133,13 +133,18 @@ ir3_insert_by_depth(struct ir3_instruction *instr, struct
list_head *list)
}
static void
-ir3_instr_depth(struct ir3_instruction *instr, unsigned boost)
+ir3_instr_depth(struct ir3_instruction *instr, unsigned boost, bool falsedep)
{
struct ir3_instruction *src;
/* if we've already visited this instruction, bail now: */
- if (ir3_instr_check_mark(instr))
+ if (falsedep) {
+ /* don't mark falsedep's as used, but process them normally: */
+ if (instr->flags & IR3_INSTR_MARK)
+ return;
+ } else if (ir3_instr_check_mark(instr)) {
return;
+ }
instr->depth = 0;
@@ -147,7 +152,7 @@ ir3_instr_depth(struct ir3_instruction *instr, unsigned
boost)
unsigned sd;
/* visit child to compute it's depth: */
- ir3_instr_depth(src, boost);
+ ir3_instr_depth(src, boost, __is_false_dep(instr, i));
/* for array writes, no need to delay on previous write: */
if (i == 0)
@@ -165,9 +170,10 @@ ir3_instr_depth(struct ir3_instruction *instr, unsigned
boost)
ir3_insert_by_depth(instr, &instr->block->instr_list);
}
-static void
+static bool
remove_unused_by_block(struct ir3_block *block)
{
+ bool progress = false;
list_for_each_entry_safe (struct ir3_instruction, instr,
&block->instr_list, node) {
if (!ir3_instr_check_mark(instr)) {
if (instr->opc == OPC_END)
@@ -178,32 +184,35 @@ remove_unused_by_block(struct ir3_block *block)
instr->flags |= IR3_INSTR_UNUSED;
/* and remove from instruction list: */
list_delinit(&instr->node);
+ progress = true;
}
}
+ return progress;
}
-void
-ir3_depth(struct ir3 *ir)
+static bool
+compute_depth_and_remove_unused(struct ir3 *ir)
{
unsigned i;
+ bool progress = false;
ir3_clear_mark(ir);
for (i = 0; i < ir->noutputs; i++)
if (ir->outputs[i])
- ir3_instr_depth(ir->outputs[i], 0);
+ ir3_instr_depth(ir->outputs[i], 0, false);
list_for_each_entry (struct ir3_block, block, &ir->block_list, node) {
for (i = 0; i < block->keeps_count; i++)
- ir3_instr_depth(block->keeps[i], 0);
+ ir3_instr_depth(block->keeps[i], 0, false);
/* We also need to account for if-condition: */
if (block->condition)
- ir3_instr_depth(block->condition, 6);
+ ir3_instr_depth(block->condition, 6, false);
}
/* mark un-used instructions: */
list_for_each_entry (struct ir3_block, block, &ir->block_list, node) {
- remove_unused_by_block(block);
+ progress |= remove_unused_by_block(block);
}
/* note that we can end up with unused indirects, but we should
@@ -221,4 +230,15 @@ ir3_depth(struct ir3 *ir)
if (in && (in->flags & IR3_INSTR_UNUSED))
ir->inputs[i] = NULL;
}
+
+ return progress;
+}
+
+void
+ir3_depth(struct ir3 *ir)
+{
+ bool progress;
+ do {
+ progress = compute_depth_and_remove_unused(ir);
+ } while (progress);
}
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