isl_pw_aff_set_rational: avoid invalid access on error
isl_pw_aff_set_rational: avoid invalid access on error

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

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