[OpenWrt-Devel] Broken GCC 4.9 (and 5.2) on ARM - asking for review/test

Dirk Neukirchen dirkneukirchen at web.de
Thu Aug 20 05:40:12 EDT 2015

GCC 4.9 was marked BROKEN with r46089. Recently GCC 5.2 was added (marked as broken too)

commit msg: " toolchain: mark gcc 4.9 as broken, it miscompiles some code especially on ARM"

Looking through some GCC 5 serious regressions I found:


I cannot replicate the ARM issue because of missing details and I dont have ARM hw where it occurs (arch: malta seems fine)
 - but there was an open ticket from a dev on github regarding the boot problem, which might be a symptom of code miscompile


According to his tests GCC4.9 and GCC5.2 now work with this 2 changes:

adding -fno-ipa-sra to Kernel/CPU CFLAGS

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