Fix "comparison of unsigned expression >= 0 is always true" warning. NFCI.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@351816 91177308-0d34-0410-b5e6-96231b3b80d8

Author: RKSimon

lib/Target/X86/X86InstrInfo.cpp

@@ -1582,7 +1582,7 @@ MachineInstr *X86InstrInfo::commuteInstructionImpl(MachineInstr &MI, bool NewMI,
     if (DstIdx == SrcIdx && (ZMask & (1 << DstIdx)) == 0 &&
         countPopulation(ZMask) == 2) {
       unsigned AltIdx = findFirstSet((ZMask | (1 << DstIdx)) ^ 15);
-      assert(0 <= AltIdx && AltIdx < 4 && "Illegal insertion index");
+      assert(AltIdx < 4 && "Illegal insertion index");
       unsigned AltImm = (AltIdx << 6) | (AltIdx << 4) | ZMask;
       auto &WorkingMI = cloneIfNew(MI);
       WorkingMI.getOperand(MI.getNumOperands() - 1).setImm(AltImm);