2 files changed, 17 insertions, 0 deletions
diff --git a/llvm/lib/Target/X86/Utils/X86ShuffleDecode.cpp b/llvm/lib/Target/X86/Utils/X86ShuffleDecode.cpp
index 1a51aa5858e..4fe9a9e949d 100644
--- a/llvm/lib/Target/X86/Utils/X86ShuffleDecode.cpp
+++ b/llvm/lib/Target/X86/Utils/X86ShuffleDecode.cpp
@@ -275,6 +275,19 @@ void DecodeUNPCKLMask(MVT VT, SmallVectorImpl<int> &ShuffleMask) {
   }
 }
 
+/// Decodes a broadcast of a subvector to a larger vector type.
+void DecodeSubVectorBroadcast(MVT DstVT, MVT SrcVT,
+                              SmallVectorImpl<int> &ShuffleMask) {
+  assert(SrcVT.getScalarType() == DstVT.getScalarType() &&
+         "Non matching vector element types");
+  unsigned NumElts = SrcVT.getVectorNumElements();
+  unsigned Scale = DstVT.getSizeInBits() / SrcVT.getSizeInBits();
+
+  for (unsigned i = 0; i != Scale; ++i)
+    for (unsigned j = 0; j != NumElts; ++j)
+      ShuffleMask.push_back(j);
+}
+
 /// \brief Decode a shuffle packed values at 128-bit granularity
 /// (SHUFF32x4/SHUFF64x2/SHUFI32x4/SHUFI64x2)
 /// immediate mask into a shuffle mask.
diff --git a/llvm/lib/Target/X86/Utils/X86ShuffleDecode.h b/llvm/lib/Target/X86/Utils/X86ShuffleDecode.h
index 7caccefc0a8..30b17052b72 100644
--- a/llvm/lib/Target/X86/Utils/X86ShuffleDecode.h
+++ b/llvm/lib/Target/X86/Utils/X86ShuffleDecode.h
@@ -88,6 +88,10 @@ void DecodeUNPCKHMask(MVT VT, SmallVectorImpl<int> &ShuffleMask);
 /// datatypes and vector widths.
 void DecodeUNPCKLMask(MVT VT, SmallVectorImpl<int> &ShuffleMask);
 
+/// Decodes a broadcast of a subvector to a larger vector type.
+void DecodeSubVectorBroadcast(MVT DstVT, MVT SrcVT,
+                              SmallVectorImpl<int> &ShuffleMask);
+
 /// Decode a PSHUFB mask from a raw array of constants such as from
 /// BUILD_VECTOR.
 void DecodePSHUFBMask(ArrayRef<uint64_t> RawMask,