Index: llvm/trunk/include/llvm/IR/PatternMatch.h
===================================================================
--- llvm/trunk/include/llvm/IR/PatternMatch.h
+++ llvm/trunk/include/llvm/IR/PatternMatch.h
@@ -411,6 +411,18 @@
   return V;
 }
 
+struct is_negated_power2 {
+  bool isValue(const APInt &C) { return (-C).isPowerOf2(); }
+};
+/// Match a integer or vector negated power-of-2.
+/// For vectors, this includes constants with undefined elements.
+inline cst_pred_ty<is_negated_power2> m_NegatedPower2() {
+  return cst_pred_ty<is_negated_power2>();
+}
+inline api_pred_ty<is_negated_power2> m_NegatedPower2(const APInt *&V) {
+  return V;
+}
+
 struct is_power2_or_zero {
   bool isValue(const APInt &C) { return !C || C.isPowerOf2(); }
 };
Index: llvm/trunk/unittests/IR/PatternMatch.cpp
===================================================================
--- llvm/trunk/unittests/IR/PatternMatch.cpp
+++ llvm/trunk/unittests/IR/PatternMatch.cpp
@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/IR/PatternMatch.h"
+#include "llvm/ADT/APSInt.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Analysis/ValueTracking.h"
 #include "llvm/IR/BasicBlock.h"
@@ -470,6 +471,26 @@
   EXPECT_FALSE(m_Unless(m_c_Add(m_Zero(), m_One())).match(X));
 }
 
+TEST_F(PatternMatchTest, Power2) {
+  Value *C128 = IRB.getInt32(128);
+  Value *CNeg128 = ConstantExpr::getNeg(cast<Constant>(C128));
+
+  EXPECT_TRUE(m_Power2().match(C128));
+  EXPECT_FALSE(m_Power2().match(CNeg128));
+
+  EXPECT_FALSE(m_NegatedPower2().match(C128));
+  EXPECT_TRUE(m_NegatedPower2().match(CNeg128));
+
+  Value *CIntMin = IRB.getInt64(APSInt::getSignedMinValue(64).getSExtValue());
+  Value *CNegIntMin = ConstantExpr::getNeg(cast<Constant>(CIntMin));
+
+  EXPECT_TRUE(m_Power2().match(CIntMin));
+  EXPECT_TRUE(m_Power2().match(CNegIntMin));
+
+  EXPECT_TRUE(m_NegatedPower2().match(CIntMin));
+  EXPECT_TRUE(m_NegatedPower2().match(CNegIntMin));
+}
+
 TEST_F(PatternMatchTest, CommutativeDeferredValue) {
   Value *X = IRB.getInt32(1);
   Value *Y = IRB.getInt32(2);