If a selected unit causes a data hazard, the whole block gets cut short.
So, we preview for data hazards _while_ selecting units.
Signed-off-by: Alyssa Rosenzweig <aly...@rosenzweig.io>
---
.../panfrost/midgard/midgard_compile.c | 25 ++++++++++++-------
1 file changed, 16 insertions(+), 9 deletions(-)
diff --git a/src/gallium/drivers/panfrost/midgard/midgard_compile.c
b/src/gallium/drivers/panfrost/midgard/midgard_compile.c
index e37037ac737..f9bd611f789 100644
--- a/src/gallium/drivers/panfrost/midgard/midgard_compile.c
+++ b/src/gallium/drivers/panfrost/midgard/midgard_compile.c
@@ -2060,6 +2060,20 @@ can_run_concurrent_ssa(midgard_instruction *first,
midgard_instruction *second)
return true;
}
+static bool
+midgard_has_hazard(
+ midgard_instruction **segment, unsigned segment_size,
+ midgard_instruction *ains)
+{
+ for (int s = 0; s < segment_size; ++s)
+ if (!can_run_concurrent_ssa(segment[s], ains))
+ return true;
+
+ return false;
+
+
+}
+
/* Schedules, but does not emit, a single basic block. After scheduling, the
* final tag and size of the block are known, which are necessary for branching
* */
@@ -2159,7 +2173,7 @@ schedule_bundle(compiler_context *ctx, midgard_block
*block, midgard_instruction
else
break;
} else {
- if ((units & UNIT_SADD) &&
!(control & UNIT_SADD))
+ if ((units & UNIT_SADD) &&
!(control & UNIT_SADD) && !midgard_has_hazard(segment, segment_size, ains))
unit = UNIT_SADD;
else if (units & UNIT_SMUL)
unit = ((units &
UNIT_VMUL) && !(control & UNIT_VMUL)) ? UNIT_VMUL : UNIT_SMUL;
@@ -2180,14 +2194,7 @@ schedule_bundle(compiler_context *ctx, midgard_block
*block, midgard_instruction
if (last_unit < UNIT_VADD && unit >= UNIT_VADD)
segment_size = 0;
- /* Check for data hazards */
- int has_hazard = false;
-
- for (int s = 0; s < segment_size; ++s)
- if (!can_run_concurrent_ssa(segment[s], ains))
- has_hazard = true;
-
- if (has_hazard)
+ if (midgard_has_hazard(segment, segment_size, ains))
break;
/* We're good to go -- emit the instruction */
--
2.20.1
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