oss-fuzz: MemorySanitizer: use-of-uninitialized-value in put_8tap_c
reproduce with ./tests/dav1d_fuzzer clusterfuzz-testcase-minimized-dav1d_fuzzer-5697034242228224
clusterfuzz-testcase-minimized-dav1d_fuzzer-5697034242228224
==913==WARNING: MemorySanitizer: use-of-uninitialized-value
#0 0x7f039b716da8 in put_8tap_c (/home/janne/src/dav1d/build-msan-fuzz/tests/../src/libdav1d.so.0+0x19fda8)
#1 0x7f039b707db5 in put_8tap_regular_c (/home/janne/src/dav1d/build-msan-fuzz/tests/../src/libdav1d.so.0+0x190db5)
#2 0x7f039b7431f0 in mc (/home/janne/src/dav1d/build-msan-fuzz/tests/../src/libdav1d.so.0+0x1cc1f0)
#3 0x7f039b73a3c7 in dav1d_recon_b_inter_16bpc (/home/janne/src/dav1d/build-msan-fuzz/tests/../src/libdav1d.so.0+0x1c33c7)
#4 0x7f039b60ca67 in decode_b (/home/janne/src/dav1d/build-msan-fuzz/tests/../src/libdav1d.so.0+0x95a67)
#5 0x7f039b5eabe8 in decode_sb (/home/janne/src/dav1d/build-msan-fuzz/tests/../src/libdav1d.so.0+0x73be8)
#6 0x7f039b5e9c66 in decode_sb (/home/janne/src/dav1d/build-msan-fuzz/tests/../src/libdav1d.so.0+0x72c66)
#7 0x7f039b5e9c66 in decode_sb (/home/janne/src/dav1d/build-msan-fuzz/tests/../src/libdav1d.so.0+0x72c66)
#8 0x7f039b5e8d8c in dav1d_decode_tile_sbrow (/home/janne/src/dav1d/build-msan-fuzz/tests/../src/libdav1d.so.0+0x71d8c)
#9 0x7f039b5f32b0 in dav1d_decode_frame (/home/janne/src/dav1d/build-msan-fuzz/tests/../src/libdav1d.so.0+0x7c2b0)
#10 0x7f039b5f9007 in dav1d_submit_frame (/home/janne/src/dav1d/build-msan-fuzz/tests/../src/libdav1d.so.0+0x82007)
#11 0x7f039b5d6422 in dav1d_parse_obus (/home/janne/src/dav1d/build-msan-fuzz/tests/../src/libdav1d.so.0+0x5f422)
#12 0x7f039b74aabe in dav1d_decode (/home/janne/src/dav1d/build-msan-fuzz/tests/../src/libdav1d.so.0+0x1d3abe)
#13 0x4c67df in LLVMFuzzerTestOneInput (/home/janne/src/dav1d/build-msan-fuzz/tests/dav1d_fuzzer+0x4c67df)
#14 0x42e062 in fuzzer::Fuzzer::ExecuteCallback(unsigned char const*, unsigned long) /var/tmp/portage/sys-libs/compiler-rt-sanitizers-7.0.0/work/compiler-rt-7.0.0.src/lib/fuzzer/FuzzerLoop.cpp:576:15
#15 0x41fbad in fuzzer::RunOneTest(fuzzer::Fuzzer*, char const*, unsigned long) /var/tmp/portage/sys-libs/compiler-rt-sanitizers-7.0.0/work/compiler-rt-7.0.0.src/lib/fuzzer/FuzzerDriver.cpp:280:6
#16 0x424782 in fuzzer::FuzzerDriver(int*, char***, int (*)(unsigned char const*, unsigned long)) /var/tmp/portage/sys-libs/compiler-rt-sanitizers-7.0.0/work/compiler-rt-7.0.0.src/lib/fuzzer/FuzzerDriver.cpp:714:9
#17 0x44d642 in main /var/tmp/portage/sys-libs/compiler-rt-sanitizers-7.0.0/work/compiler-rt-7.0.0.src/lib/fuzzer/FuzzerMain.cpp:20:10
#18 0x7f039a603ae6 in __libc_start_main (/lib64/libc.so.6+0x21ae6)
#19 0x41df69 in _start (/home/janne/src/dav1d/build-msan-fuzz/tests/dav1d_fuzzer+0x41df69)