[Mesa-dev] [PATCH] radeon/llvm: add a pattern for min/max

[Vincent Lejeune]

---
 lib/Target/AMDGPU/AMDGPUISelLowering.cpp | 58 ++++++++++++++++++++++++++++++++
 lib/Target/AMDGPU/AMDGPUISelLowering.h   |  1 +
 lib/Target/AMDGPU/R600ISelLowering.cpp   |  6 ++++
 lib/Target/AMDGPU/SIISelLowering.cpp     |  6 ++++
 4 files changed, 71 insertions(+)

diff --git a/lib/Target/AMDGPU/AMDGPUISelLowering.cpp b/lib/Target/AMDGPU/AMDGPUISelLowering.cpp
index 5bde9db..41e8f44 100644
--- a/lib/Target/AMDGPU/AMDGPUISelLowering.cpp
+++ b/lib/Target/AMDGPU/AMDGPUISelLowering.cpp
@@ -172,7 +172,65 @@ SDValue AMDGPUTargetLowering::LowerIntrinsicLRP(SDValue Op,
       OneSubAC);
 }
 
+/// Generate Min/Max pattern
+SDValue AMDGPUTargetLowering::LowerMinMax(SDValue Op,
+    SelectionDAG &DAG) const {
+  DebugLoc DL = Op.getDebugLoc();
+  EVT VT = Op.getValueType();
+
+  SDValue LHS = Op.getOperand(0);
+  SDValue RHS = Op.getOperand(1);
+  SDValue True = Op.getOperand(2);
+  SDValue False = Op.getOperand(3);
+  SDValue CC = Op.getOperand(4);
+
+  if (VT != MVT::f32 ||
+      !((LHS == True && RHS == False) || (LHS == False && RHS == True))) {
+    return SDValue();
+  }
 
+  ISD::CondCode CCOpcode = cast<CondCodeSDNode>(CC)->get();
+  switch (CCOpcode) {
+  case ISD::SETOEQ:
+  case ISD::SETONE:
+  case ISD::SETUNE:
+  case ISD::SETNE:
+  case ISD::SETUEQ:
+  case ISD::SETEQ:
+  case ISD::SETFALSE:
+  case ISD::SETFALSE2:
+  case ISD::SETTRUE:
+  case ISD::SETTRUE2:
+  case ISD::SETUO:
+  case ISD::SETO:
+    assert(0 && "Operation should already be optimised !");
+  case ISD::SETULE:
+  case ISD::SETULT:
+  case ISD::SETOLE:
+  case ISD::SETOLT:
+  case ISD::SETLE:
+  case ISD::SETLT: {
+    if (LHS == True)
+      return DAG.getNode(AMDGPUISD::FMIN, DL, VT, LHS, RHS);
+    else
+      return DAG.getNode(AMDGPUISD::FMAX, DL, VT, LHS, RHS);
+  }
+  case ISD::SETGT:
+  case ISD::SETGE:
+  case ISD::SETUGE:
+  case ISD::SETOGE:
+  case ISD::SETUGT:
+  case ISD::SETOGT: {
+    if (LHS == True)
+      return DAG.getNode(AMDGPUISD::FMAX, DL, VT, LHS, RHS);
+    else
+      return DAG.getNode(AMDGPUISD::FMIN, DL, VT, LHS, RHS);
+  }
+  case ISD::SETCC_INVALID:
+    assert(0 && "Invalid setcc condcode !");
+  }
+  return Op;
+}
 
 SDValue AMDGPUTargetLowering::LowerUDIVREM(SDValue Op,
     SelectionDAG &DAG) const
diff --git a/lib/Target/AMDGPU/AMDGPUISelLowering.h b/lib/Target/AMDGPU/AMDGPUISelLowering.h
index 60de190..3b60ae1 100644
--- a/lib/Target/AMDGPU/AMDGPUISelLowering.h
+++ b/lib/Target/AMDGPU/AMDGPUISelLowering.h
@@ -56,6 +56,7 @@ public:
   virtual SDValue LowerOperation(SDValue Op, SelectionDAG &DAG) const;
   SDValue LowerIntrinsicIABS(SDValue Op, SelectionDAG &DAG) const;
   SDValue LowerIntrinsicLRP(SDValue Op, SelectionDAG &DAG) const;
+  SDValue LowerMinMax(SDValue Op, SelectionDAG &DAG) const;
   virtual const char* getTargetNodeName(unsigned Opcode) const;
 
 // Functions defined in AMDILISelLowering.cpp
diff --git a/lib/Target/AMDGPU/R600ISelLowering.cpp b/lib/Target/AMDGPU/R600ISelLowering.cpp
index 6f1c1d7..dff29f6 100644
--- a/lib/Target/AMDGPU/R600ISelLowering.cpp
+++ b/lib/Target/AMDGPU/R600ISelLowering.cpp
@@ -764,6 +764,12 @@ SDValue R600TargetLowering::LowerSELECT_CC(SDValue Op, SelectionDAG &DAG) const
     }
   }
 
+  // Possible Min/Max pattern
+  SDValue MinMax = LowerMinMax(Op, DAG);
+  if (MinMax.getNode()) {
+    return MinMax;
+  }
+
   // If we make it this for it means we have no native instructions to handle
   // this SELECT_CC, so we must lower it.
   SDValue HWTrue, HWFalse;
diff --git a/lib/Target/AMDGPU/SIISelLowering.cpp b/lib/Target/AMDGPU/SIISelLowering.cpp
index 45f180f..2eb1fcc 100644
--- a/lib/Target/AMDGPU/SIISelLowering.cpp
+++ b/lib/Target/AMDGPU/SIISelLowering.cpp
@@ -383,6 +383,12 @@ SDValue SITargetLowering::LowerSELECT_CC(SDValue Op, SelectionDAG &DAG) const
   EVT VT = Op.getValueType();
   DebugLoc DL = Op.getDebugLoc();
 
+  // Possible Min/Max pattern
+  SDValue MinMax = LowerMinMax(Op, DAG);
+  if (MinMax.getNode()) {
+    return MinMax;
+  }
+
   SDValue Cond = DAG.getNode(ISD::SETCC, DL, MVT::i1, LHS, RHS, CC);
   return DAG.getNode(ISD::SELECT, DL, VT, Cond, True, False);
 }
-- 
1.8.0.1