diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
index 57d90ef446f38..9e2dda330f548 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -16076,8 +16076,9 @@ bool PPCTargetLowering::decomposeMulByConstant(LLVMContext &Context, EVT VT,
     Imm >>= Shift;
     if (isInt<16>(Imm))
       return false;
-    if (isPowerOf2_64(Imm + 1) || isPowerOf2_64(Imm - 1) ||
-        isPowerOf2_64(1 - Imm) || isPowerOf2_64(-1 - Imm))
+    uint64_t UImm = static_cast<uint64_t>(Imm);
+    if (isPowerOf2_64(UImm + 1) || isPowerOf2_64(UImm - 1) ||
+        isPowerOf2_64(1 - UImm) || isPowerOf2_64(-1 - UImm))
       return true;
   }
   return false;