We can still use the optimized division methods which make use of
multiplication with overflow.
Signed-off-by: Ilia Mirkin <imir...@alum.mit.edu>
---
src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
b/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
index fabac662e7f..56a50320816 100644
--- a/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
+++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
@@ -1188,6 +1188,21 @@ ConstantFolding::opnd(Instruction *i, ImmediateValue
&imm0, int s)
delete_Instruction(prog, i);
}
+ } else if (s == 1) {
+ // In this case, we still want the optimized lowering that we get
+ // from having division by an immediate.
+ //
+ // a % b == a - (a/b) * b
+ bld.setPosition(i, false);
+ Value *div = bld.mkOp2v(OP_DIV, i->sType, bld.getSSA(),
+ i->getSrc(0), i->getSrc(1));
+ newi = bld.mkOp2(OP_ADD, i->sType, i->getDef(0), i->getSrc(0),
+ bld.mkOp2v(OP_MUL, i->sType, bld.getSSA(), div,
i->getSrc(1)));
+ // TODO: Check that target supports this. In this case, we know that
+ // all backends do.
+ newi->src(1).mod = Modifier(NV50_IR_MOD_NEG);
+
+ delete_Instruction(prog, i);
}
break;
--
2.13.6
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