[Mesa-dev] [PATCH 1/2] gm107/ir: do not combine CONST loads

[Samuel Pitoiset]

This will allow to use MOV instead of LD. The main advantage is
that MOV doesn't require a read dependency barrier while LD does,
and so this will both reduce barriers pressure and the number of
stall counts needed to read data from constant memory.

This is currently only for user uniform accesses. I should do
something similar when loading from the driver constant buffer
but it seems like a bit tricky to handle for now.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>
---
 src/gallium/drivers/nouveau/codegen/nv50_ir_target_nvc0.cpp | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

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 4c75ea6..1a9a4e4 100644
--- a/src/gallium/drivers/nouveau/codegen/nv50_ir_target_nvc0.cpp
+++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_target_nvc0.cpp
@@ -410,8 +410,13 @@ TargetNVC0::isAccessSupported(DataFile file, DataType ty) const
 {
    if (ty == TYPE_NONE)
       return false;
-   if (file == FILE_MEMORY_CONST && getChipset() >= 0xe0) // wrong encoding ?
-      return typeSizeof(ty) <= 8;
+   if (file == FILE_MEMORY_CONST) {
+      if (getChipset() >= NVISA_GM107_CHIPSET)
+         return typeSizeof(ty) <= 4;
+      else
+      if (getChipset() >= NVISA_GK104_CHIPSET) // wrong encoding ?
+         return typeSizeof(ty) <= 8;
+   }
    if (ty == TYPE_B96)
       return false;
    return true;
-- 
2.10.1