Add a m_Undef pattern for convenience. This is so that code that uses

pattern matching can also pattern match undef, creating a more uniform
style.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124657 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 10 insertions, 0 deletions

diff --git a/include/llvm/Support/PatternMatch.h b/include/llvm/Support/PatternMatch.h
index ea065a769e..cb94fe5f6e 100644
--- a/include/llvm/Support/PatternMatch.h
+++ b/include/llvm/Support/PatternMatch.h
@@ -75,6 +75,16 @@ inline constantint_ty<Val> m_ConstantInt() {
   return constantint_ty<Val>();
 }
 
+struct undef_ty {
+  template<typename ITy>
+  bool match(ITy *V) {
+    return isa<UndefValue>(V);
+  }
+};
+
+/// m_Undef() - Match an arbitrary undef constant.
+inline undef_ty m_Undef() { return undef_ty(); }
+
 struct zero_ty {
   template<typename ITy>
   bool match(ITy *V) {