Codegen cleanup.
Codegen cleanup.

* Renamed codegen_* helpers to cg_* for terseness.
* Factored out common cg_binop pattern.
lglucin/Halide,ayanazmat/Halide,aam/Halide,mcanthony/Halide,psuriana/Halide,dougkwan/Halide,fengzhyuan/Halide,aam/Halide,kgnk/Halide,myrtleTree33/Halide,kenkuang1213/Halide,aam/Halide,adasworks/Halide,jiawen/Halide,mcanthony/Halide,mcanthony/Halide,jiawen/Halide,jiawen/Halide,fengzhyuan/Halide,damienfir/Halide,kgnk/Halide,jiawen/Halide,rodrigob/Halide,rodrigob/Halide,kgnk/Halide,dougkwan/Halide,smxlong/Halide,ayanazmat/Halide,delcypher/Halide,adasworks/Halide,tdenniston/Halide,myrtleTree33/Halide,ronen/Halide,delcypher/Halide,dougkwan/Halide,mcanthony/Halide,dougkwan/Halide,tdenniston/Halide,myrtleTree33/Halide,adasworks/Halide,ronen/Halide,psuriana/Halide,dan-tull/Halide,mikeseven/Halide,kenkuang1213/Halide,ayanazmat/Halide,jiawen/Halide,dan-tull/Halide,aam/Halide,gchauras/Halide,psuriana/Halide,fengzhyuan/Halide,mcanthony/Halide,myrtleTree33/Halide,adasworks/Halide,ronen/Halide,smxlong/Halide,fengzhyuan/Halide,delcypher/Halide,lglucin/Halide,aam/Halide,smxlong/Halide,mikeseven/Halide,rodrigob/Halide,fengzhyuan/Halide,ronen/Halide,adasworks/Halide,ronen/Halide,dan-tull/Halide,gchauras/Halide,tdenniston/Halide,damienfir/Halide,mcanthony/Halide,dougkwan/Halide,mikeseven/Halide,mikeseven/Halide,smxlong/Halide,tdenniston/Halide,rodrigob/Halide,lglucin/Halide,fengzhyuan/Halide,gchauras/Halide,ronen/Halide,tdenniston/Halide,kgnk/Halide,kenkuang1213/Halide,tdenniston/Halide,gchauras/Halide,psuriana/Halide,delcypher/Halide,myrtleTree33/Halide,adasworks/Halide,smxlong/Halide,kenkuang1213/Halide,gchauras/Halide,kenkuang1213/Halide,dougkwan/Halide,dan-tull/Halide,mcanthony/Halide,damienfir/Halide,lglucin/Halide,damienfir/Halide,aam/Halide,ronen/Halide,dan-tull/Halide,ayanazmat/Halide,kgnk/Halide,fengzhyuan/Halide,lglucin/Halide,kenkuang1213/Halide,jiawen/Halide,rodrigob/Halide,tdenniston/Halide,mikeseven/Halide,ayanazmat/Halide,adasworks/Halide,psuriana/Halide,psuriana/Halide,damienfir/Halide,myrtleTree33/Halide,mcanthony/Halide,myrtleTree33/Halide,dan-tull/Halide,rodrigob/Halide,kgnk/Halide,kenkuang1213/Halide,myrtleTree33/Halide,damienfir/Halide,delcypher/Halide,ayanazmat/Halide,ronen/Halide,lglucin/Halide,jiawen/Halide,smxlong/Halide,psuriana/Halide,delcypher/Halide,lglucin/Halide,fengzhyuan/Halide,gchauras/Halide,kenkuang1213/Halide,rodrigob/Halide,dan-tull/Halide,damienfir/Halide,ayanazmat/Halide,dougkwan/Halide,rodrigob/Halide,damienfir/Halide,kgnk/Halide,delcypher/Halide,aam/Halide,adasworks/Halide,smxlong/Halide,delcypher/Halide,tdenniston/Halide,kgnk/Halide,smxlong/Halide,dougkwan/Halide,dan-tull/Halide,ayanazmat/Halide