Handle BUILD_VECTOR with all zero elements.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@27056 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelLowering.h b/lib/Target/X86/X86ISelLowering.h
index bc4a746..854f76d 100644
--- a/lib/Target/X86/X86ISelLowering.h
+++ b/lib/Target/X86/X86ISelLowering.h
@@ -208,6 +208,9 @@
    /// the specified isShuffleMask VECTOR_SHUFFLE mask with PSHUF* and SHUFP*
    /// instructions.
    unsigned getShuffleSHUFImmediate(SDNode *N);
+
+   /// isZeroVector - Return true if all elements of BUILD_VECTOR are 0 or +0.0.
+   bool isZeroVector(SDNode *N);
  }
 
   //===----------------------------------------------------------------------===//