diff --git a/lib/Target/ARM/AsmPrinter/ARMAsmPrinter.cpp b/lib/Target/ARM/AsmPrinter/ARMAsmPrinter.cpp
index 78d32243727..c1982f411d5 100644
--- a/lib/Target/ARM/AsmPrinter/ARMAsmPrinter.cpp
+++ b/lib/Target/ARM/AsmPrinter/ARMAsmPrinter.cpp
@@ -644,7 +644,7 @@ ARMAsmPrinter::printBitfieldInvMaskImmOperand(const MachineInstr *MI, int Op) {
   const MachineOperand &MO = MI->getOperand(Op);
   uint32_t v = ~MO.getImm();
   int32_t lsb = ffs (v) - 1;
-  int32_t width = fls (v) - lsb;
+  int32_t width = (32 - CountLeadingZeros_32 (v)) - lsb;
   assert(MO.isImm() && "Not a valid bf_inv_mask_imm value!");
   O << "#" << lsb << ", #" << width;
 }