smithWatermanBackTrack is being shared between AVX2 and AVX-512

[philipc]

When compiling with gcc 11.2.0, smithWatermanBackTrack isn't actually inlined, and this results in both the AVX2 and AVX-512 implementations calling the same copy of it. This is bad because each copy needs to be specialized to use either AVX2 instructions or AVX-512 instructions. Here's the relevant bits from objdump -d build/native/libgkl_smithwaterman.so:

0000000000001610 <_Z19runSWOnePairBT_avx2iiiiPhS_ssaPciPjPi>:
    193c:       e8 8f f7 ff ff          call   10d0 <_Z22smithWatermanBackTrackP10dnaSeqPairiiiiPii@plt>

0000000000002a80 <_Z21runSWOnePairBT_avx512iiiiPhS_ssaPciPjPi>:
    2dec:       e8 df e2 ff ff          call   10d0 <_Z22smithWatermanBackTrackP10dnaSeqPairiiiiPii@plt>

I think it should at least be changed to static inline, and possibly renamed to CONCAT(smithWatermanBackTrack_,SIMD_ENGINE).

[Kmannth]

@philipc Thanks for this note. We build on gcc version 7.3.1 we see distinct functions for AVX2 and AVX512 as expected. Perhaps this is related to the GCC 11.2.0 stack.

From a gcc 7.3.1 I see today:

0000000000000da0 <_Z19runSWOnePairBT_avx2iiiiPhS_ssaPciPjPi>:
e54: 0f 86 ee 10 00 00 jbe 1f48 <_Z19runSWOnePairBT_avx2iiiiPhS_ssaPciPjPi+0x11a8>
...
0000000000002070 <_Z21runSWOnePairBT_avx512iiiiPhS_ssaPciPjPi>:
2124: 0f 86 5e 11 00 00 jbe 3288 <_Z21runSWOnePairBT_avx512iiiiPhS_ssaPciPjPi+0x1218>

[Kmannth]

Feel free to submit a patch.