Hi Everyone, This is a big FYI...
The test script has been showing a small issue when using a minimally featured cpu: c++ -DNDEBUG -g2 -O2 -msse -msse2 -fPIC -march=native -pipe -c sha.cpp ERROR: failed to generate sha1rnds4 instruction ERROR: failed to generate sha1nexte instruction ERROR: failed to generate sha1msg1 instruction ERROR: failed to generate sha1msg2 instruction ERROR: failed to generate sha256rnds2 instruction ERROR: failed to generate sha256msg1 instruction ERROR: failed to generate sha256msg2 instruction This use case is the distro's, where they build without --march=native and then distribute the library to users with a variety of machines. We used to have code that handled the use case. It was removed at http://github.com/weidai11/cryptopp/commit/fb6a11ff08b9. The code was removed for two reasons. First, it caused a few minor problems, like http://github.com/weidai11/cryptopp/issues/53 due to C++11 constexpr (for example, an IMM needs a CONSTEXPR or template parameter, not a function parameter). Second, GCC Bug https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57202 stated intrinsics would always be available is GCC version 5 and above. With the fb6a11ff08b9 removal and the 57202 bug, I thought the new use cases would be: (1) GCC 5 users and above would get the intrinsics, and (2) GCC 4 and below would get CXX by default. GCC 4.8 and 4.9 users could install an updated compiler from backports, and move from (2) into (1). It would simplify the code and side step the 53 bug. It seemed like a good trade-off simplicity and performance while side stepping bugs. It turns out 57202 did not enable intrinsics all the time. Additionally, it only enables intrinsics for IA32 (and not other platforms like ARM). I advised Wei incorrectly, so I got the OK to remove the code. Arg... I want to start adding the code back incrementally. I'm going to start with SHA since its the immediate painpoint. But we need to do it for AEN-NI, PCLMUL, SSE4, and some SSSE3. And we need to do it with ARM, but ARM's a little trickier because of some assembler goodness. For the ARM assembler issue see https://sourceware.org/ml/binutils/2017-04/msg00171.html. Jeff -- -- You received this message because you are subscribed to the "Crypto++ Users" Google Group. To unsubscribe, send an email to cryptopp-users-unsubscr...@googlegroups.com. More information about Crypto++ and this group is available at http://www.cryptopp.com. --- You received this message because you are subscribed to the Google Groups "Crypto++ Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to cryptopp-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
