[X86] When lowering insert_vector_elt/extract_vector_elt of vXi1 with a non-constant index just use either a 128-bit type or the vXi8 type with the correct number of elements.

Despite what the comment said there isn't better codegen for 512-bit vectors. The 128/256/512 bit implementation jus stores to memory and loads an element. There's no advantage to doing that with a larger size. In fact in many cases it causes a stack realignment and generates worse code.

llvm-svn: 321369

1 files changed, 6 insertions, 8 deletions

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 16dc33cca8e..746e9fc13ec 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -14578,11 +14578,10 @@ static SDValue ExtractBitFromMaskVector(SDValue Op, SelectionDAG &DAG,
     unsigned NumElts = VecVT.getVectorNumElements();
     // Extending v8i1/v16i1 to 512-bit get better performance on KNL
     // than extending to 128/256bit.
-    unsigned VecSize = (NumElts <= 4 ? 128 : 512);
-    MVT ExtVT = MVT::getVectorVT(MVT::getIntegerVT(VecSize / NumElts), NumElts);
-    SDValue Ext = DAG.getNode(ISD::SIGN_EXTEND, dl, ExtVT, Vec);
-    SDValue Elt = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl,
-                              ExtVT.getVectorElementType(), Ext, Idx);
+    MVT ExtEltVT = (NumElts <= 8) ? MVT::getIntegerVT(128 / NumElts) : MVT::i8;
+    MVT ExtVecVT = MVT::getVectorVT(ExtEltVT, NumElts);
+    SDValue Ext = DAG.getNode(ISD::SIGN_EXTEND, dl, ExtVecVT, Vec);
+    SDValue Elt = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, ExtEltVT, Ext, Idx);
     return DAG.getNode(ISD::TRUNCATE, dl, EltVT, Elt);
   }
 
@@ -14777,9 +14776,8 @@ static SDValue InsertBitToMaskVector(SDValue Op, SelectionDAG &DAG,
     // Non constant index. Extend source and destination,
     // insert element and then truncate the result.
     unsigned NumElts = VecVT.getVectorNumElements();
-    unsigned VecSize = (NumElts <= 4 ? 128 : 512);
-    MVT ExtVecVT = MVT::getVectorVT(MVT::getIntegerVT(VecSize/NumElts), NumElts);
-    MVT ExtEltVT = ExtVecVT.getVectorElementType();
+    MVT ExtEltVT = (NumElts <= 8) ? MVT::getIntegerVT(128 / NumElts) : MVT::i8;
+    MVT ExtVecVT = MVT::getVectorVT(ExtEltVT, NumElts);
     SDValue ExtOp = DAG.getNode(ISD::INSERT_VECTOR_ELT, dl, ExtVecVT,
       DAG.getNode(ISD::SIGN_EXTEND, dl, ExtVecVT, Vec),
       DAG.getNode(ISD::SIGN_EXTEND, dl, ExtEltVT, Elt), Idx);