[Hexagon] Generate valignb for shifting shuffles (instead of vdelta)

llvm-svn: 326627

1 files changed, 35 insertions, 11 deletions

diff --git a/llvm/lib/Target/Hexagon/HexagonISelDAGToDAGHVX.cpp b/llvm/lib/Target/Hexagon/HexagonISelDAGToDAGHVX.cpp
index 553263ee516..9b58e00cbe0 100644
--- a/llvm/lib/Target/Hexagon/HexagonISelDAGToDAGHVX.cpp
+++ b/llvm/lib/Target/Hexagon/HexagonISelDAGToDAGHVX.cpp
@@ -776,6 +776,13 @@ struct ShuffleMask {
     size_t H = Mask.size()/2;
     return ShuffleMask(Mask.take_back(H));
   }
+
+  void print(raw_ostream &OS) const {
+    OS << "MinSrc:" << MinSrc << ", MaxSrc:" << MaxSrc << " {";
+    for (int M : Mask)
+      OS << ' ' << M;
+    OS << " }";
+  }
 };
 } // namespace
 
@@ -1042,19 +1049,36 @@ OpRef HvxSelector::packs(ShuffleMask SM, OpRef Va, OpRef Vb,
   int VecLen = SM.Mask.size();
   MVT Ty = getSingleVT(MVT::i8);
 
-  if (SM.MaxSrc - SM.MinSrc < int(HwLen)) {
-    if (SM.MaxSrc < int(HwLen)) {
-      memcpy(NewMask.data(), SM.Mask.data(), sizeof(int)*VecLen);
-      return Va;
+  auto IsSubvector = [] (ShuffleMask M) {
+    assert(M.MinSrc >= 0 && M.MaxSrc >= 0);
+    for (int I = 0, E = M.Mask.size(); I != E; ++I) {
+      if (M.Mask[I] >= 0 && M.Mask[I]-I != M.MinSrc)
+        return false;
     }
-    if (SM.MinSrc >= int(HwLen)) {
-      for (int I = 0; I != VecLen; ++I) {
-        int M = SM.Mask[I];
-        if (M != -1)
-          M -= HwLen;
-        NewMask[I] = M;
+    return true;
+  };
+
+  if (SM.MaxSrc - SM.MinSrc < int(HwLen)) {
+    if (SM.MinSrc == 0 || SM.MinSrc == int(HwLen) || !IsSubvector(SM)) {
+      if (SM.MaxSrc < int(HwLen)) {
+        memcpy(NewMask.data(), SM.Mask.data(), sizeof(int)*VecLen);
+        return Va;
+      }
+      if (SM.MinSrc >= int(HwLen)) {
+        for (int I = 0; I != VecLen; ++I) {
+          int M = SM.Mask[I];
+          if (M != -1)
+            M -= HwLen;
+          NewMask[I] = M;
+        }
+        return Vb;
       }
-      return Vb;
+    }
+    if (SM.MaxSrc < int(HwLen)) {
+      Vb = Va;
+    } else if (SM.MinSrc > int(HwLen)) {
+      Va = Vb;
+      SM.MinSrc -= HwLen;
     }
     const SDLoc &dl(Results.InpNode);
     SDValue S = DAG.getTargetConstant(SM.MinSrc, dl, MVT::i32);