The type of expression '1<<31' is signed int and this causes cppcheck to
issue the following warning.
src/gf_w32.c:681]: (error) Signed integer overflow for expression
'1<<31'.
Signed-off-by: Brad Hubbard <bhubbard@redhat.com>
in gf_w32_cfmgk_multiply_region_from_single(), follow warning is
reported by gcc:
gf-complete/src/gf_w32.c:410:5: warning: ‘a’ may be used uninitialized
in this function [-Wmaybe-uninitialized]
g = _mm_insert_epi64 (a, g_star, 0);
^
actually, we are using `a` as a dummy parameter for initializing `g` and
`q`. and only the lower lower 64 bits of them are used when doing
calculation. but their lower 64 bits are always initialized using
_mm_insert_epi64(). so this is a false alarm.
but we can silence this warning by moving the statement initializing `a`
up before passing it to _mm_insert_epi64(). this change does not hurt
the performance.
Signed-off-by: Kefu Chai <kchai@redhat.com>
This commits adds support for runtime detection of SIMD instructions. The idea is that you would build once with all supported SIMD functions and the same binaries could run on different machines with varying support for SIMD. At runtime gf-complete will select the right functions based on the processor.
gf_cpu.c has the logic to detect SIMD instructions. On Intel processors this is done through cpuid. For ARM on linux we use getauxv.
The logic in gf_w*.c has been changed to check for runtime SIMD support and fallback to generic code.
Also a new test has been added. It compares the functions selected by gf_init when we enable/disable SIMD support through build flags, with runtime enabling/disabling. The test checks if the results are identical.
There is currently no way to figure out which functions were selected
during gf_init and as a result of SIMD options. This is not even possible
in gdb since most functions are static.
This commit adds a new macro SET_FUNCTION that records the name of the
function selected during init inside the gf_internal structure. This macro
only works when DEBUG_FUNCTIONS is defined during compile. Otherwise the
code works exactly as it did before this change.
The names of selected functions will be used during testing of SIMD
runtime detection.
All calls such as:
gf->multiply.w32 = gf_w16_shift_multiply;
need to be replaced with the following:
SET_FUNCTION(gf,multiply,w32,gf_w16_shift_multiply)
Also added a new flag to tools/gf_methods that will print the names of
functions selected during gf_init.
* (1 << w) are changed into ((uint32_t)1 << w)
* int are changed into uint32_t
gf.c: gf_composite_get_default_poly:
a larger unsigned were assigned to unsigned integers in which case
the type of the assigned variable is changed to be the same as the
value assigned to it.
gf_w16.c: GF_MULTBY_TWO
setting the parameter to a variable instead of passing the expression
resolves the warning for some reason.
Signed-off-by: Loic Dachary <loic@dachary.org>
Since there is no comment indicating fallthrough on purpose added a
break in switch value 3 and 5/before default.
Fix for coverity issue from Ceph project:
CID 1193080 (#1 of 1): Missing break in switch (MISSING_BREAK)
unterminated_case: This case (value 3) is not terminated by a 'break'
statement.
CID 1193081 (#1 of 1): Missing break in switch (MISSING_BREAK)
unterminated_case: This case (value 5) is not terminated by a 'break'
statement.
Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
Brad Hubbard