Allow vector shuffle normalizing to use concat vector even if the sources are commuted in the shuffle mask.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147527 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index f0323e1..67b4e9e 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -2778,12 +2778,13 @@
TLI.getValueType(I.getType()), InVec, InIdx));
}
-// Utility for visitShuffleVector - Returns true if the mask is mask starting
-// from SIndx and increasing to the element length (undefs are allowed).
-static bool SequentialMask(SmallVectorImpl<int> &Mask, unsigned SIndx) {
- unsigned MaskNumElts = Mask.size();
- for (unsigned i = 0; i != MaskNumElts; ++i)
- if ((Mask[i] >= 0) && (Mask[i] != (int)(i + SIndx)))
+// Utility for visitShuffleVector - Return true if every element in Mask,
+// begining // from position Pos and ending in Pos+Size, falls within the
+// specified sequential range [L, L+Pos). or is undef.
+static bool isSequentialInRange(const SmallVectorImpl<int> &Mask,
+ int Pos, int Size, int Low) {
+ for (int i = Pos, e = Pos+Size; i != e; ++i, ++Low)
+ if (Mask[i] >= 0 && Mask[i] != Low)
return false;
return true;
}
@@ -2820,11 +2821,23 @@
// Mask is longer than the source vectors and is a multiple of the source
// vectors. We can use concatenate vector to make the mask and vectors
// lengths match.
- if (SrcNumElts*2 == MaskNumElts && SequentialMask(Mask, 0)) {
- // The shuffle is concatenating two vectors together.
- setValue(&I, DAG.getNode(ISD::CONCAT_VECTORS, getCurDebugLoc(),
- VT, Src1, Src2));
- return;
+ if (SrcNumElts*2 == MaskNumElts) {
+ // First check for Src1 in low and Src2 in high
+ if (isSequentialInRange(Mask, 0, SrcNumElts, 0) &&
+ isSequentialInRange(Mask, SrcNumElts, SrcNumElts, SrcNumElts)) {
+ // The shuffle is concatenating two vectors together.
+ setValue(&I, DAG.getNode(ISD::CONCAT_VECTORS, getCurDebugLoc(),
+ VT, Src1, Src2));
+ return;
+ }
+ // Then check for Src2 in low and Src1 in high
+ if (isSequentialInRange(Mask, 0, SrcNumElts, SrcNumElts) &&
+ isSequentialInRange(Mask, SrcNumElts, SrcNumElts, 0)) {
+ // The shuffle is concatenating two vectors together.
+ setValue(&I, DAG.getNode(ISD::CONCAT_VECTORS, getCurDebugLoc(),
+ VT, Src2, Src1));
+ return;
+ }
}
// Pad both vectors with undefs to make them the same length as the mask.