GlobalISel: add specialized buildCopy function to MachineInstrBuilder.

NFC.

llvm-svn: 276763
diff --git a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
index c581439..9ce7fe4 100644
--- a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
@@ -102,8 +102,8 @@
 
 bool IRTranslator::translateBitCast(const CastInst &CI) {
   if (LLT{*CI.getDestTy()} == LLT{*CI.getSrcTy()}) {
-    MIRBuilder.buildInstr(TargetOpcode::COPY, getOrCreateVReg(CI),
-                          getOrCreateVReg(*CI.getOperand(0)));
+    MIRBuilder.buildCopy(getOrCreateVReg(CI),
+                         getOrCreateVReg(*CI.getOperand(0)));
     return true;
   }
   return translateCast(TargetOpcode::G_BITCAST, CI);