1 files changed, 9 insertions, 0 deletions
diff --git a/lib/Transforms/InstCombine/InstCombineCompares.cpp b/lib/Transforms/InstCombine/InstCombineCompares.cpp
index fd2b68a..e9f3458 100644
--- a/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -1277,6 +1277,15 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI,
               return Res;
           }
     }
+
+    // X & -C == -C -> X >  u ~C
+    // X & -C != -C -> X <= u ~C
+    //   iff C is a power of 2
+    if (ICI.isEquality() && RHS == LHSI->getOperand(1) && (-RHSV).isPowerOf2())
+      return new ICmpInst(
+          ICI.getPredicate() == ICmpInst::ICMP_EQ ? ICmpInst::ICMP_UGT
+                                                  : ICmpInst::ICMP_ULE,
+          LHSI->getOperand(0), SubOne(RHS));
     break;
 
   case Instruction::Or: {