I never used STM8 but I’m impressed with this achievement of SDCC compiler.
The ST marketing materials put STM8 Dhrystone performance at 0.29 DMIPS / Mhz.
Commercial compilers as Raisonance achieves 0.289 DMIPS / Mhz, Cosmic achieves 0.296 DMIPS / Mhz and IAR achieves 0.347 DMIPS / Mhz. See benchmark comparison here: http://colecovision.eu/stm8/compilers.shtml
SDCC 3.5.0 achieves 0.151 DMIPS / Mhz and SDCC 3.6.0 achieve 0.167 DMIPS / Mhz.
Now the SDCC in the repository (Revision #9652) outperforms them all at 0.355 DMIPS / Mhz.
If you want to use STM8 on Linux, these links could be useful:
Source: Philipp Klaus Krause email in the SDCC mailing list “STM8 Dhrystone performance – new record at 0.355 DMIPS / Mhz using SDCC”.