https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109519
Bug ID: 109519
Summary: aarch64: wrong code with NEON intrinsics on gcc-10 and
later
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: spop at gcc dot gnu.org
Target Milestone: ---
Steps to reproduce:
$ git clone https://github.com/sebpop/bitshuffle.git -b gcc-10-bug
$ cd bitshuffle/reproduce
$ make
$ ./a.out
The expected output is produced by gcc-7, gcc-9, and clang-15.
16384
4
14
16
33
39
45
51
57
67
102
108
120
126
128
134
138
140
[...]
gcc-9 is the last version of gcc I tested that works.
gcc-10 produces the following output:
./a.out
16384
0
0
0
0
39
45
51
57
gcc-11 and gcc-trunk produce the following output:
./a.out
16384
0
0
0
0
0
0
0
The output is also correct when removing the before-last patch from the git
repo https://github.com/kiyo-masui/bitshuffle/pull/140
This patch exposes the bug in gcc by using NEON intrinsics instead of scalar
computations to translate move_mask instructions from SSE2 to NEON.
