[X86] Add an assert to ensure that a routine is only used with 128-bit vectors. Reduce SmallVector size accordingly.

llvm-svn: 273117

1 files changed, 4 insertions, 2 deletions

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index e428afd68c6..da9c13e0274 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -8687,6 +8687,8 @@ static SDValue lowerVectorShuffleAsPermuteAndUnpack(const SDLoc &DL, MVT VT,
                                                     SelectionDAG &DAG) {
   assert(!VT.isFloatingPoint() &&
          "This routine only supports integer vectors.");
+  assert(VT.is128BitVector() &&
+         "This routine only works on 128-bit vectors.");
   assert(!isSingleInputShuffleMask(Mask) &&
          "This routine should only be used when blending two inputs.");
   assert(Mask.size() >= 2 && "Single element masks are invalid.");
@@ -8701,8 +8703,8 @@ static SDValue lowerVectorShuffleAsPermuteAndUnpack(const SDLoc &DL, MVT VT,
   bool UnpackLo = NumLoInputs >= NumHiInputs;
 
   auto TryUnpack = [&](MVT UnpackVT, int Scale) {
-    SmallVector<int, 32> V1Mask(Mask.size(), -1);
-    SmallVector<int, 32> V2Mask(Mask.size(), -1);
+    SmallVector<int, 16> V1Mask(Mask.size(), -1);
+    SmallVector<int, 16> V2Mask(Mask.size(), -1);
 
     for (int i = 0; i < Size; ++i) {
       if (Mask[i] < 0)