remove duplicate using

Author: tgymnich

llvm/lib/CodeGen/GlobalISel/GISelValueTracking.cpp

@@ -677,7 +677,6 @@ GISelValueTracking::fcmpImpliesClass(CmpInst::Predicate Pred,
                                      const MachineFunction &MF, Register LHS,
                                      FPClassTest RHSClass,
                                      bool LookThroughSrc) {
-  using namespace MIPatternMatch;
   auto LookThrough = [&](Register LHS, Register &Src) {
     return LookThroughSrc && mi_match(LHS, MRI, m_GFabs(m_Reg(Src)));
   };
@@ -693,7 +692,6 @@ GISelValueTracking::fcmpImpliesClass(CmpInst::Predicate Pred,
                                      const MachineFunction &MF, Register LHS,
                                      const APFloat &ConstRHS,
                                      bool LookThroughSrc) {
-  using namespace MIPatternMatch;
   auto LookThrough = [&](Register LHS, Register &Src) {
     return LookThroughSrc && mi_match(LHS, MRI, m_GFabs(m_Reg(Src)));
   };