Add a m_SignBit pattern for convenience.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124656 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 15 insertions, 0 deletions

diff --git a/include/llvm/Support/PatternMatch.h b/include/llvm/Support/PatternMatch.h
index b203c1ee1a..ea065a769e 100644
--- a/include/llvm/Support/PatternMatch.h
+++ b/include/llvm/Support/PatternMatch.h
@@ -116,6 +116,21 @@ struct all_ones_ty {
 /// m_AllOnes() - Match an integer or vector with all bits set to true.
 inline all_ones_ty m_AllOnes() { return all_ones_ty(); }
 
+struct signbit_ty {
+  template<typename ITy>
+  bool match(ITy *V) {
+    if (const ConstantInt *CI = dyn_cast<ConstantInt>(V))
+      return CI->getValue().isSignBit();
+    if (const ConstantVector *CV = dyn_cast<ConstantVector>(V))
+      if (ConstantInt *CI = cast_or_null<ConstantInt>(CV->getSplatValue()))
+        return CI->getValue().isSignBit();
+    return false;
+  }
+};
+
+/// m_SignBit() - Match an integer or vector with only the sign bit(s) set.
+inline signbit_ty m_SignBit() { return signbit_ty(); }
+
 
 template<typename Class>
 struct bind_ty {