Mesa (master): nvc0/ir: do not lower shared+atomics on GM107+

[Samuel Pitoiset]

Module: Mesa
Branch: master
Commit: 839a469166b9c0b9959620eda85a6481f9efa15f
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=839a469166b9c0b9959620eda85a6481f9efa15f

Author: Samuel Pitoiset <samuel.pitoiset at gmail.com>
Date:   Mon Mar  7 18:56:21 2016 +0100

nvc0/ir: do not lower shared+atomics on GM107+

For Maxwell, the ATOMS instruction can be used to perform atomic
operations on shared memory instead of this load/store lowering pass.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>
Reviewed-by: Ilia Mirkin <imirkin at alum.mit.edu>

---

 .../drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp   | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp b/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp
index fb2aec6..ce83618 100644
--- a/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp
+++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp
@@ -1288,11 +1288,12 @@ NVC0LoweringPass::handleATOM(Instruction *atom)
       sv = SV_LBASE;
       break;
    case FILE_MEMORY_SHARED:
-      if (targ->getChipset() >= NVISA_GK104_CHIPSET) {
-         handleSharedATOMNVE4(atom);
-      } else {
+      // For Fermi/Kepler, we have to use ld lock/st unlock to perform atomic
+      // operations on shared memory. For Maxwell, ATOMS is enough.
+      if (targ->getChipset() < NVISA_GK104_CHIPSET)
          handleSharedATOM(atom);
-      }
+      else if (targ->getChipset() < NVISA_GM107_CHIPSET)
+         handleSharedATOMNVE4(atom);
       return true;
    default:
       assert(atom->src(0).getFile() == FILE_MEMORY_GLOBAL);
@@ -1320,9 +1321,11 @@ NVC0LoweringPass::handleATOM(Instruction *atom)
 bool
 NVC0LoweringPass::handleCasExch(Instruction *cas, bool needCctl)
 {
-   if (cas->src(0).getFile() == FILE_MEMORY_SHARED) {
-      // ATOM_CAS and ATOM_EXCH are handled in handleSharedATOM().
-      return false;
+   if (targ->getChipset() < NVISA_GM107_CHIPSET) {
+      if (cas->src(0).getFile() == FILE_MEMORY_SHARED) {
+         // ATOM_CAS and ATOM_EXCH are handled in handleSharedATOM().
+         return false;
+      }
    }
 
    if (cas->subOp != NV50_IR_SUBOP_ATOM_CAS &&