Handle canonical form of e.g.
vector_shuffle v1, v1, <0, 4, 1, 5, 2, 6, 3, 7>
This is turned into
vector_shuffle v1, <undef>, <0, 0, 1, 1, 2, 2, 3, 3>
by dag combiner.
It would match a {p}unpckl on x86.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@27437 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelLowering.h b/lib/Target/X86/X86ISelLowering.h
index 9722d6f..ddb2d30 100644
--- a/lib/Target/X86/X86ISelLowering.h
+++ b/lib/Target/X86/X86ISelLowering.h
@@ -220,6 +220,11 @@
/// specifies a shuffle of elements that is suitable for input to UNPCKH.
bool isUNPCKHMask(SDNode *N);
+ /// isUNPCKL_v_undef_Mask - Special case of isUNPCKLMask for canonical form
+ /// of vector_shuffle v, v, <0, 4, 1, 5>, i.e. vector_shuffle v, undef,
+ /// <0, 0, 1, 1>
+ bool isUNPCKL_v_undef_Mask(SDNode *N);
+
/// isSplatMask - Return true if the specified VECTOR_SHUFFLE operand
/// specifies a splat of a single element.
bool isSplatMask(SDNode *N);