gm107/ir: emit RED instead of ATOM when no dst

This is similar to NVC0 and GK110 emitters where we emit
reduction operations instead of atomic operations when the
destination is not used.

Found after writing some tests which check if performance counters
return the expected value. In that case, gred_count returned 0
on gm107 while at least gk106 returned the correct value.

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

diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_emit_gm107.cpp b/src/gallium/drivers/nouveau/codegen/nv50_ir_emit_gm107.cpp
index 5ed2ad4ba93a3ebad6b6c76c6bf25665edb772ba..5bd0fa0a07509808b7c8dae8c07fe4fbf433bffe 100644 (file)
--- a/src/gallium/drivers/nouveau/codegen/nv50_ir_emit_gm107.cpp
+++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_emit_gm107.cpp
@@ -180,6 +180,7 @@ private:
    void emitIPA();
    void emitATOM();
    void emitATOMS();
+   void emitRED();
    void emitCCTL();
 
    void emitPIXLD();
@@ -2495,6 +2496,29 @@ CodeEmitterGM107::emitATOMS()
    emitGPR  (0x00, insn->def(0));
 }
 
+void
+CodeEmitterGM107::emitRED()
+{
+   unsigned dType;
+
+   switch (insn->dType) {
+   case TYPE_U32: dType = 0; break;
+   case TYPE_S32: dType = 1; break;
+   case TYPE_U64: dType = 2; break;
+   case TYPE_F32: dType = 3; break;
+   case TYPE_B128: dType = 4; break;
+   case TYPE_S64: dType = 5; break;
+   default: assert(!"unexpected dType"); dType = 0; break;
+   }
+
+   emitInsn (0xebf80000);
+   emitField(0x30, 1, insn->src(0).getIndirect(0)->getSize() == 8);
+   emitField(0x17, 3, insn->subOp);
+   emitField(0x14, 3, dType);
+   emitADDR (0x08, 0x1c, 20, 0, insn->src(0));
+   emitGPR  (0x00, insn->src(1));
+}
+
 void
 CodeEmitterGM107::emitCCTL()
 {
@@ -3237,7 +3261,10 @@ CodeEmitterGM107::emitInstruction(Instruction *i)
       if (insn->src(0).getFile() == FILE_MEMORY_SHARED)
          emitATOMS();
       else
-         emitATOM();
+         if (!insn->defExists(0) && insn->subOp < NV50_IR_SUBOP_ATOM_CAS)
+            emitRED();
+         else
+            emitATOM();
       break;
    case OP_CCTL:
       emitCCTL();