Revert r199628: "[AArch64 NEON] Fix a bug caused by undef lane when generating VEXT."

This test fails the newly added regression tests.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199631 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 15 insertions, 21 deletions

diff --git a/lib/Target/AArch64/AArch64ISelLowering.cpp b/lib/Target/AArch64/AArch64ISelLowering.cpp
index 27277c47f3..e98fbe1d3a 100644
--- a/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ b/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -4654,28 +4654,22 @@ AArch64TargetLowering::LowerVECTOR_SHUFFLE(SDValue Op,
   // it into NEON_VEXTRACT.
   if (V1EltNum == Length) {
     // Check if the shuffle mask is sequential.
-    int SkipUndef = 0;
-    while (ShuffleMask[SkipUndef] == -1) {
-      SkipUndef++;
-    }
-    int CurMask = ShuffleMask[SkipUndef];
-    if (CurMask >= SkipUndef) {
-      bool IsSequential = true;
-      for (int I = SkipUndef; I < Length; ++I) {
-        if (ShuffleMask[I] != -1 && ShuffleMask[I] != CurMask) {
-          IsSequential = false;
-          break;
-        }
-        CurMask++;
-      }
-      if (IsSequential) {
-        assert((EltSize % 8 == 0) && "Bitsize of vector element is incorrect");
-        unsigned VecSize = EltSize * V1EltNum;
-        unsigned Index = (EltSize / 8) * (ShuffleMask[SkipUndef] - SkipUndef);
-        if (VecSize == 64 || VecSize == 128)
-          return DAG.getNode(AArch64ISD::NEON_VEXTRACT, dl, VT, V1, V2,
-                             DAG.getConstant(Index, MVT::i64));
+    bool IsSequential = true;
+    int CurMask = ShuffleMask[0];
+    for (int I = 0; I < Length; ++I) {
+      if (ShuffleMask[I] != CurMask) {
+        IsSequential = false;
+        break;
       }
+      CurMask++;
+    }
+    if (IsSequential) {
+      assert((EltSize % 8 == 0) && "Bitsize of vector element is incorrect");
+      unsigned VecSize = EltSize * V1EltNum;
+      unsigned Index = (EltSize/8) * ShuffleMask[0];
+      if (VecSize == 64 || VecSize == 128)
+        return DAG.getNode(AArch64ISD::NEON_VEXTRACT, dl, VT, V1, V2,
+                           DAG.getConstant(Index, MVT::i64));
     }
   }