https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110946
--- Comment #5 from Dave Rodgman <dave.rodgman at arm dot com> --- (In reply to Richard Biener from comment #3) > Note you shouldn't use -Os if you care about performance. GCC is quite > reasonable with code size increases at -O2 (as compared to other compilers). > Instead I suggest you use -flto with -O2 to decrease the size of the final > executable/library and give GCC better knowledge on unit growth. Understood, but I think it depends on the magnitude of the perf difference. I'd expect a smallish perf drop, say 10%, from -Os to be reasonable, but I'd consider a 3x perf difference to be a compiler issue.(In reply to Alexander Monakov from comment #2) > So basically missed inlining at -Os, even memcpy wrappers are not inlined. > > Can you provide a reproducible testcase? > > Note that inline functions in mbedtls/library/alignment.h all miss the > 'static' qualifier, which affects inlining decisions, and looks like a > mistake anyway (if they are really meant to be non-static inlines, shouldn't > there be a comment?) > > Does making them 'static inline' rectify the problem? The easiest way to reproduce is to use the benchmark tool: make programs/test/benchmark CC=gcc CFLAGS="-Os" programs/test/benchmark aes_xts I don't have a compact reproducer, sorry.
