Add a m_SignBit pattern for convenience.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124656 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/llvm/Support/PatternMatch.h b/include/llvm/Support/PatternMatch.h
index b203c1e..ea065a7 100644
--- a/include/llvm/Support/PatternMatch.h
+++ b/include/llvm/Support/PatternMatch.h
@@ -116,6 +116,21 @@
/// 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 {
diff --git a/lib/Analysis/ValueTracking.cpp b/lib/Analysis/ValueTracking.cpp
index 72b3f03..44c1b53 100644
--- a/lib/Analysis/ValueTracking.cpp
+++ b/lib/Analysis/ValueTracking.cpp
@@ -666,9 +666,7 @@
// (signbit) >>l X is clearly a power of two if the one is not shifted off the
// bottom. If it is shifted off the bottom then the result is undefined.
- ConstantInt *CI;
- if (match(V, m_LShr(m_ConstantInt(CI), m_Value())) &&
- CI->getValue().isSignBit())
+ if (match(V, m_LShr(m_SignBit(), m_Value())))
return true;
// The remaining tests are all recursive, so bail out if we hit the limit.