X86: Decode PALIGN operands so I don't have to do it in my head.

llvm-svn: 173572

2 files changed, 10 insertions, 0 deletions

diff --git a/llvm/lib/Target/X86/Utils/X86ShuffleDecode.cpp b/llvm/lib/Target/X86/Utils/X86ShuffleDecode.cpp
index 8b87c1f9c8a..9694808e641 100644
--- a/llvm/lib/Target/X86/Utils/X86ShuffleDecode.cpp
+++ b/llvm/lib/Target/X86/Utils/X86ShuffleDecode.cpp
@@ -61,6 +61,14 @@ void DecodeMOVLHPSMask(unsigned NElts, SmallVectorImpl<int> &ShuffleMask) {
     ShuffleMask.push_back(NElts+i);
 }
 
+void DecodePALIGNMask(MVT VT, unsigned Imm, SmallVectorImpl<int> &ShuffleMask) {
+  unsigned NumElts = VT.getVectorNumElements();
+  unsigned Offset = Imm * (VT.getVectorElementType().getSizeInBits() / 8);
+
+  for (unsigned i = 0; i != NumElts; ++i)
+    ShuffleMask.push_back((i + Offset) % (NumElts * 2));
+}
+
 /// DecodePSHUFMask - This decodes the shuffle masks for pshufd, and vpermilp*.
 /// VT indicates the type of the vector allowing it to handle different
 /// datatypes and vector widths.
diff --git a/llvm/lib/Target/X86/Utils/X86ShuffleDecode.h b/llvm/lib/Target/X86/Utils/X86ShuffleDecode.h
index 70d8171a815..69ce4432ed1 100644
--- a/llvm/lib/Target/X86/Utils/X86ShuffleDecode.h
+++ b/llvm/lib/Target/X86/Utils/X86ShuffleDecode.h
@@ -35,6 +35,8 @@ void DecodeMOVHLPSMask(unsigned NElts, SmallVectorImpl<int> &ShuffleMask);
 // <0,2> or <0,1,4,5>
 void DecodeMOVLHPSMask(unsigned NElts, SmallVectorImpl<int> &ShuffleMask);
 
+void DecodePALIGNMask(MVT VT, unsigned Imm, SmallVectorImpl<int> &ShuffleMask);
+
 void DecodePSHUFMask(MVT VT, unsigned Imm, SmallVectorImpl<int> &ShuffleMask);
 
 void DecodePSHUFHWMask(MVT VT, unsigned Imm, SmallVectorImpl<int> &ShuffleMask);