[SCCP] Preserve Name when converting SExt->ZExt.

This makes the output IR more readable since we're doing a one to
one replacement.

Reviewed By: fhahn

Differential Revision: https://reviews.llvm.org/D125280

llvm/lib/Transforms/Scalar/SCCP.cpp

@@ -164,6 +164,7 @@ static bool simplifyInstsInBlock(SCCPSolver &Solver, BasicBlock &BB,
         continue;
       if (IV.getConstantRange().isAllNonNegative()) {
         auto *ZExt = new ZExtInst(ExtOp, Inst.getType(), "", &Inst);
+        ZExt->takeName(&Inst);
         InsertedValues.insert(ZExt);
         Inst.replaceAllUsesWith(ZExt);
         Solver.removeLatticeValueFor(&Inst);