diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
--- a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -2664,8 +2664,8 @@
   // Inverted form (example):
   // (icmp slt (X | Y), 0) & (icmp sgt (X & Y), -1) -> (icmp slt (X ^ Y), 0)
   bool TrueIfSignedL, TrueIfSignedR;
-  if (InstCombiner::isSignBitCheck(PredL, *LHSC, TrueIfSignedL) &&
-      InstCombiner::isSignBitCheck(PredR, *RHSC, TrueIfSignedR) &&
+  if (isSignBitCheck(PredL, *LHSC, TrueIfSignedL) &&
+      isSignBitCheck(PredR, *RHSC, TrueIfSignedR) &&
       (RHS->hasOneUse() || LHS->hasOneUse())) {
     Value *X, *Y;
     if (IsAnd) {
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
--- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -2981,7 +2981,7 @@
     const APInt *C;
     bool TrueIfSigned;
     if (match(Op1, m_APInt(C)) && Bitcast->hasOneUse() &&
-        InstCombiner::isSignBitCheck(Pred, *C, TrueIfSigned)) {
+        isSignBitCheck(Pred, *C, TrueIfSigned)) {
       if (match(BCSrcOp, m_FPExt(m_Value(X))) ||
           match(BCSrcOp, m_FPTrunc(m_Value(X)))) {
         // (bitcast (fpext/fptrunc X)) to iX) < 0 --> (bitcast X to iY) < 0