> Adding volatile first results in new compiler warnings: The purpose of exercise was not to find a solution, but to simply see how compiler reacts at volatile. Thanks for taking time.
> ccm128.c: In function 'CRYPTO_ccm128_decrypt': > ccm128.c:300:9: warning: passing argument 1 of 'memcpy' discards > 'volatile' qualifier from pointer target type > memcpy(temp.c, inp, 16); > ^ > > And then it also changes the resulting code: > > - ldd [%i4], %i2 > + call memcpy, 0 > ^^^ that's probably the memcpy() that was optimized away before Yes, obviously volatile prevented compiler from optimizing memcpy altogether. Which kind of contradicts the warning. I mean doesn't warning say "I'm going to go ahead and ignore qualifier", but it didn't. Anyway, the hope was that compiler would still inline memcpy, but would be forced to actually write value to temp, that would have to be aligned. Once again, it was really just a wonder... > And yes, with volatile the test no longer crashes even when compiled > with the broken gcc 4.9.1 and -O3. Naturally, because real memcpy is perfectly capable of handling misaligned data in any combination. Thanks again. _______________________________________________ openssl-dev mailing list To unsubscribe: https://mta.openssl.org/mailman/listinfo/openssl-dev
