I optimized the following patterns:

 sext <4 x i1> to <4 x i64>
 sext <4 x i8> to <4 x i64>
 sext <4 x i16> to <4 x i64>
 
I'm running Combine on SIGN_EXTEND_IN_REG and revert SEXT patterns:
 (sext_in_reg (v4i64 anyext (v4i32 x )), ExtraVT) -> (v4i64 sext (v4i32 sext_in_reg (v4i32 x , ExtraVT)))
 
 The sext_in_reg (v4i32 x) may be lowered to shl+sar operations.
 The "sar" does not exist on 64-bit operation, so lowering sext_in_reg (v4i64 x) has no vector solution.

I also added a cost of this operations to the AVX costs table.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175619 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 37 insertions, 0 deletions

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 9ed03cd1ee..a2271663ee 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -1323,6 +1323,7 @@ X86TargetLowering::X86TargetLowering(X86TargetMachine &TM)
   setTargetDAGCombine(ISD::ZERO_EXTEND);
   setTargetDAGCombine(ISD::ANY_EXTEND);
   setTargetDAGCombine(ISD::SIGN_EXTEND);
+  setTargetDAGCombine(ISD::SIGN_EXTEND_INREG);
   setTargetDAGCombine(ISD::TRUNCATE);
   setTargetDAGCombine(ISD::SINT_TO_FP);
   setTargetDAGCombine(ISD::SETCC);
@@ -17076,6 +17077,41 @@ static SDValue PerformVZEXT_MOVLCombine(SDNode *N, SelectionDAG &DAG) {
   return SDValue();
 }
 
+static SDValue PerformSIGN_EXTEND_INREGCombine(SDNode *N, SelectionDAG &DAG, 
+                                               const X86Subtarget *Subtarget) {
+  EVT VT = N->getValueType(0);
+  if (!VT.isVector())
+    return SDValue();
+
+  SDValue N0 = N->getOperand(0);
+  SDValue N1 = N->getOperand(1);
+  EVT ExtraVT = cast<VTSDNode>(N1)->getVT();
+  DebugLoc dl = N->getDebugLoc();
+
+  // The SIGN_EXTEND_INREG to v4i64 is expensive operation on the
+  // both SSE and AVX2 since there is no sign-extended shift right
+  // operation on a vector with 64-bit elements.
+  //(sext_in_reg (v4i64 anyext (v4i32 x )), ExtraVT) ->
+  // (v4i64 sext (v4i32 sext_in_reg (v4i32 x , ExtraVT)))
+  if (VT == MVT::v4i64 && (N0.getOpcode() == ISD::ANY_EXTEND ||
+      N0.getOpcode() == ISD::SIGN_EXTEND)) {
+    SDValue N00 = N0.getOperand(0);
+
+    // EXTLOAD has a better solution on AVX2, 
+    // it may be replaced with X86ISD::VSEXT node.
+    if (N00.getOpcode() == ISD::LOAD && Subtarget->hasInt256())
+      if (!ISD::isNormalLoad(N00.getNode()))
+        return SDValue();
+
+    if (N00.getValueType() == MVT::v4i32 && ExtraVT.getSizeInBits() < 128) {
+        SDValue Tmp = DAG.getNode(ISD::SIGN_EXTEND_INREG, dl, MVT::v4i32, 
+                                  N00, N1);
+      return DAG.getNode(ISD::SIGN_EXTEND, dl, MVT::v4i64, Tmp);
+    }
+  }
+  return SDValue();
+}
+
 static SDValue PerformSExtCombine(SDNode *N, SelectionDAG &DAG,
                                   TargetLowering::DAGCombinerInfo &DCI,
                                   const X86Subtarget *Subtarget) {
@@ -17468,6 +17504,7 @@ SDValue X86TargetLowering::PerformDAGCombine(SDNode *N,
   case ISD::ANY_EXTEND:
   case ISD::ZERO_EXTEND:    return PerformZExtCombine(N, DAG, DCI, Subtarget);
   case ISD::SIGN_EXTEND:    return PerformSExtCombine(N, DAG, DCI, Subtarget);
+  case ISD::SIGN_EXTEND_INREG: return PerformSIGN_EXTEND_INREGCombine(N, DAG, Subtarget);
   case ISD::TRUNCATE:       return PerformTruncateCombine(N, DAG,DCI,Subtarget);
   case ISD::SETCC:          return PerformISDSETCCCombine(N, DAG);
   case X86ISD::SETCC:       return PerformSETCCCombine(N, DAG, DCI, Subtarget);