Discussion:
[PATCH] nv50/ir: clean up saturated values immediately
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Ilia Mirkin
2017-08-12 17:45:21 UTC
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Since we don't iterate to a fixed point, we can end up in situations
where we have a SAT instruction + a long immediate. This is not legal.
However since it's immediately computable, just run unary straight away
to handle the situation.

Fixes: 24a799ad35a82 ("nv50/ir: fix ConstantFolding with saturation")
Reported-by: Tobias Klausmann <***@mni.thm.de>
Signed-off-by: Ilia Mirkin <***@alum.mit.edu>
---
src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp b/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
index cfc0dfc53cf..6584f3b1152 100644
--- a/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
+++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
@@ -727,7 +727,9 @@ ConstantFolding::expr(Instruction *i,
// Leave PFETCH alone... we just folded its 2 args into 1.
break;
default:
- i->op = i->saturate ? OP_SAT : OP_MOV; /* SAT handled by unary() */
+ i->op = i->saturate ? OP_SAT : OP_MOV;
+ if (i->saturate)
+ unary(i, *i->getSrc(0)->asImm());
break;
}
i->subOp = 0;
@@ -1515,6 +1517,8 @@ ConstantFolding::opnd(Instruction *i, ImmediateValue &imm0, int s)
if (newi->op == OP_MOV && newi->saturate) {
newi->saturate = 0;
newi->op = OP_SAT;
+ if (newi->getSrc(0)->asImm())
+ unary(newi, *newi->getSrc(0)->asImm());
}

if (newi->op != op)
--
2.13.0
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