[X86][AVX] Add target shuffle decode support for VBROADCAST

Currently we only decode broadcasts from a vector of the same size.

llvm-svn: 275823

1 files changed, 6 insertions, 0 deletions

diff --git a/llvm/lib/Target/X86/Utils/X86ShuffleDecode.cpp b/llvm/lib/Target/X86/Utils/X86ShuffleDecode.cpp
index 4fe9a9e949d..18f71675437 100644
--- a/llvm/lib/Target/X86/Utils/X86ShuffleDecode.cpp
+++ b/llvm/lib/Target/X86/Utils/X86ShuffleDecode.cpp
@@ -275,6 +275,12 @@ void DecodeUNPCKLMask(MVT VT, SmallVectorImpl<int> &ShuffleMask) {
   }
 }
 
+/// Decodes a broadcast of the first element of a vector.
+void DecodeVectorBroadcast(MVT DstVT, SmallVectorImpl<int> &ShuffleMask) {
+  unsigned NumElts = DstVT.getVectorNumElements();
+  ShuffleMask.append(NumElts, 0);
+}
+
 /// Decodes a broadcast of a subvector to a larger vector type.
 void DecodeSubVectorBroadcast(MVT DstVT, MVT SrcVT,
                               SmallVectorImpl<int> &ShuffleMask) {