1 files changed, 45 insertions, 14 deletions

diff --git a/llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp b/llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp
index 12c17c3e9eb..9e3ac8b871e 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp
@@ -1012,22 +1012,29 @@ SDValue AMDGPUTargetLowering::LowerINTRINSIC_WO_CHAIN(SDValue Op,
   EVT VT = Op.getValueType();
 
   switch (IntrinsicID) {
-    default: return Op;
-    case AMDGPUIntrinsic::AMDGPU_clamp: // Legacy name.
-      return DAG.getNode(AMDGPUISD::CLAMP, DL, VT,
-                         Op.getOperand(1), Op.getOperand(2), Op.getOperand(3));
+  default: return Op;
+  case AMDGPUIntrinsic::AMDGPU_clamp: {
+    // Deprecated in favor of emitting min/max combo or fmed3.
+    ConstantFPSDNode *CSrc1 = dyn_cast<ConstantFPSDNode>(Op.getOperand(2));
+    ConstantFPSDNode *CSrc2 = dyn_cast<ConstantFPSDNode>(Op.getOperand(3));
+    if (CSrc1 && CSrc2 && CSrc1->isZero() && CSrc2->isExactlyValue(1.0))
+      return DAG.getNode(AMDGPUISD::CLAMP, DL, VT, Op.getOperand(1));
 
-    case AMDGPUIntrinsic::AMDGPU_bfe_i32:
-      return DAG.getNode(AMDGPUISD::BFE_I32, DL, VT,
-                         Op.getOperand(1),
-                         Op.getOperand(2),
-                         Op.getOperand(3));
+    SDValue Max = DAG.getNode(ISD::FMAXNUM, DL, VT, Op.getOperand(1),
+                              Op.getOperand(2));
+    return DAG.getNode(ISD::FMINNUM, DL, VT, Max, Op.getOperand(3));
+  }
+  case AMDGPUIntrinsic::AMDGPU_bfe_i32:
+    return DAG.getNode(AMDGPUISD::BFE_I32, DL, VT,
+                       Op.getOperand(1),
+                       Op.getOperand(2),
+                       Op.getOperand(3));
 
-    case AMDGPUIntrinsic::AMDGPU_bfe_u32:
-      return DAG.getNode(AMDGPUISD::BFE_U32, DL, VT,
-                         Op.getOperand(1),
-                         Op.getOperand(2),
-                         Op.getOperand(3));
+  case AMDGPUIntrinsic::AMDGPU_bfe_u32:
+    return DAG.getNode(AMDGPUISD::BFE_U32, DL, VT,
+                       Op.getOperand(1),
+                       Op.getOperand(2),
+                       Op.getOperand(3));
   }
 }
 
@@ -2445,6 +2452,28 @@ SDValue AMDGPUTargetLowering::performStoreCombine(SDNode *N,
                       SN->getBasePtr(), SN->getMemOperand());
 }
 
+SDValue AMDGPUTargetLowering::performClampCombine(SDNode *N,
+                                                  DAGCombinerInfo &DCI) const {
+  ConstantFPSDNode *CSrc = dyn_cast<ConstantFPSDNode>(N->getOperand(0));
+  if (!CSrc)
+    return SDValue();
+
+  const APFloat &F = CSrc->getValueAPF();
+  APFloat Zero = APFloat::getZero(F.getSemantics());
+  APFloat::cmpResult Cmp0 = F.compare(Zero);
+  if (Cmp0 == APFloat::cmpLessThan ||
+      (Cmp0 == APFloat::cmpUnordered && Subtarget->enableDX10Clamp())) {
+    return DCI.DAG.getConstantFP(Zero, SDLoc(N), N->getValueType(0));
+  }
+
+  APFloat One(F.getSemantics(), "1.0");
+  APFloat::cmpResult Cmp1 = F.compare(One);
+  if (Cmp1 == APFloat::cmpGreaterThan)
+    return DCI.DAG.getConstantFP(One, SDLoc(N), N->getValueType(0));
+
+  return SDValue(CSrc, 0);
+}
+
 /// Split the 64-bit value \p LHS into two 32-bit components, and perform the
 /// binary operation \p Opc to it with the corresponding constant operands.
 SDValue AMDGPUTargetLowering::splitBinaryBitConstantOpImpl(
@@ -3323,6 +3352,8 @@ SDValue AMDGPUTargetLowering::PerformDAGCombine(SDNode *N,
     return performLoadCombine(N, DCI);
   case ISD::STORE:
     return performStoreCombine(N, DCI);
+  case AMDGPUISD::CLAMP:
+    return performClampCombine(N, DCI);
   }
   return SDValue();
 }