isl_ast_codegen.c: aff_constant_is_negative: use isl_val
isl_ast_codegen.c: aff_constant_is_negative: use isl_val

Signed-off-by: Sven Verdoolaege <e5350bbed4977f5eb8ae1dc6abd9ae59d21ace75@kotnet.org>

BenzoSM/isl,SaberMod/isl-current,Distrotech/isl,nicolasvasilache/isl,tobig/isl,serge-sans-paille/isl,KangDroidSMProject/ISL,jleben/isl,inducer/isl-mirror,abduld/isl,VanirLLVM/toolchain_isl,Distrotech/isl,tobig/isl,jleben/isl,crossbuild/isl,BobSaget-Mod/libisl,simbuerg/isl,inducer/isl-mirror,inducer/isl-mirror,simbuerg/isl,Meinersbur/isl,PollyLabs/isl,SaberMod/isl-current,jleben/isl,VanirLLVM/toolchain_isl,PollyLabs/isl,cfx-next/toolchain_isl-upstream,SaberMod/isl-current,jleben/isl,jleben/isl,nicolasvasilache/isl,abduld/isl,KangDroidSMProject/ISL,cfx-next/toolchain_isl-upstream,UBERTC/isl,Distrotech/isl,Meinersbur/isl,simbuerg/isl,cfx-next/toolchain_isl-upstream,UBERTC/isl,Distrotech/isl,PollyLabs/isl,cfx-next/toolchain_isl-upstream,VanirLLVM/toolchain_isl,inducer/isl-mirror,Distrotech/isl,KangDroidSMProject/ISL,BobSaget-Mod/libisl,BobSaget-Mod/libisl,serge-sans-paille/isl,PollyLabs/isl,crossbuild/isl,Meinersbur/isl,PollyLabs/isl,nicolasvasilache/isl,BenzoSM/isl,cfx-next/toolchain_isl-upstream,evaautomation/isl,nicolasvasilache/isl,evaautomation/isl,BenzoSM/isl,KangDroidSMProject/ISL,SaberMod/isl-current,abduld/isl,BenzoSM/isl,tobig/isl,BenzoSM/isl,UBERTC/isl,nicolasvasilache/isl,VanirLLVM/toolchain_isl,UBERTC/isl,serge-sans-paille/isl,KangDroidSMProject/ISL,BobSaget-Mod/libisl,serge-sans-paille/isl,tobig/isl,crossbuild/isl,Meinersbur/isl,simbuerg/isl,BobSaget-Mod/libisl,simbuerg/isl,evaautomation/isl,VanirLLVM/toolchain_isl,inducer/isl-mirror,evaautomation/isl,serge-sans-paille/isl,abduld/isl,crossbuild/isl