[Mesa-dev] [PATCH v2 6/6] nv50/ir: teach insnCanLoad() about SHLADD

[Samuel Pitoiset]

Commutativity is not allowed with SHLADD, but src2 can accept
loads. To allow the load propagation pass to do its job, add a
special case like for SUCLAMP because src1 is always an immediate.

This IMAD to SHLADD optimization helps a bunch of shaders from Tomb
Raider, Victor Vran, UE4 demos (+15% perf with Elemental) and Shadow
Warrior.

GF100/GK104:

total instructions in shared programs :2838045 -> 2834712 (-0.12%)
total gprs used in shared programs    :396684 -> 396386 (-0.08%)
total local used in shared programs   :34416 -> 34416 (0.00%)

                local        gpr       inst      bytes
    helped           0         326        1105        1105
      hurt           0          55           3           3

Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>
---
 src/gallium/drivers/nouveau/codegen/nv50_ir_target_nvc0.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_target_nvc0.cpp b/src/gallium/drivers/nouveau/codegen/nv50_ir_target_nvc0.cpp
index d8fa285..9bc5b8d 100644
--- a/src/gallium/drivers/nouveau/codegen/nv50_ir_target_nvc0.cpp
+++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_target_nvc0.cpp
@@ -334,6 +334,8 @@ TargetNVC0::insnCanLoad(const Instruction *i, int s,
       if (i->src(k).getFile() == FILE_IMMEDIATE) {
          if (k == 2 && i->op == OP_SUCLAMP) // special case
             continue;
+         if (k == 1 && i->op == OP_SHLADD) // special case
+            continue;
          if (i->getSrc(k)->reg.data.u64 != 0)
             return false;
       } else
-- 
2.10.0