aligned_memchr16ff is not

[UnitedMarsupials-zz]

The function assumes, its argument is properly aligned for casting it to __m128i const *. The assumption appears valid on FreeBSD/amd64, but on a 32-bit FreeBSD/i386 it causes core-dumps.

The below patch makes the function forego the SSE-trickery and always use memchr on i386:

+++ src/lepton/recoder.cc
@@ -99,5 +99,5 @@

 static bool aligned_memchr16ff(const unsigned char *local_huff_data) {
-#if 1
+#if !defined(__i386__)
     __m128i buf = _mm_load_si128((__m128i const*)local_huff_data);
     __m128i ff = _mm_set1_epi8(-1);

Are you normally building/testing on 32-bit systems? With this patch I no longer have crashes running the test suit, but 5 of the 40 tests still fail...

[danielrh]

Really appreciate you noticing this... to be fair I've never tried this on a i386 system--but it sounds like if this code fails on x86 there's probably some aliasing assumption being violated here and it's worth checking out to make it more cross compatible! I may not have time to look at this for a few days, but I'll try to compile in 32 bit mode as soon as I can

[UnitedMarsupials-zz]

Thanks for the quick response, Daniel. I just committed FreeBSD port of lepton, which has this -- and many other -- patches in it.
Although all of the self-tests succeed on FreeBSD/amd64, five are failing for me on i386. I'm attaching the test-suite.log.

Note, that none of my machines here have SSE4, so I had to patch lepton to be satisfied with SSE2 and SSSE3.

[danielrh]

Fixed by c5fd505