The weight_vector_type constructor was inadvertently assuming C++17
semantics of the new operator applied on a type with alignment
requirement greater than the largest fundamental alignment.
Unfortunately on earlier C++ dialects the implementation was allowed
to raise an allocation failure when the alignment requirement of the
allocated type was unsupported, in an implementation-defined fashion.
It's expected that a C++ implementation recent enough to implement
P0035R4 would have honored allocation requests for such over-aligned
types even if the C++17 dialect wasn't active, which is likely the
reason why this problem wasn't caught by our CI system.
A more elegant fix would involve wrapping the __SSE2__ block in a
'__cpp_aligned_new >= 201606' preprocessor conditional and continue
taking advantage of the language feature, but that would yield lower
compile-time performance on old compilers not implementing it
(e.g. GCC versions older than 7.0).
Fixes:
af2c320190f3c731 "intel/fs: Implement GRF bank conflict mitigation pass."
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=104226
Reported-by: Józef Kucia <joseph.kucia@gmail.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
struct weight_vector_type {
weight_vector_type() : v(NULL), size(0) {}
- weight_vector_type(unsigned n) :
- v(new vector_type[DIV_ROUND_UP(n, vector_width)]()),
- size(n) {}
+ weight_vector_type(unsigned n) : v(alloc(n)), size(n) {}
weight_vector_type(const weight_vector_type &u) :
- v(new vector_type[DIV_ROUND_UP(u.size, vector_width)]()),
- size(u.size)
+ v(alloc(u.size)), size(u.size)
{
memcpy(v, u.v,
DIV_ROUND_UP(u.size, vector_width) * sizeof(vector_type));
~weight_vector_type()
{
- delete[] v;
+ free(v);
}
weight_vector_type &
vector_type *v;
unsigned size;
+
+ private:
+ static vector_type *
+ alloc(unsigned n)
+ {
+ const unsigned align = MAX2(sizeof(void *), __alignof__(vector_type));
+ const unsigned size = DIV_ROUND_UP(n, vector_width) * sizeof(vector_type);
+ void *p;
+ if (posix_memalign(&p, align, size))
+ return NULL;
+ memset(p, 0, size);
+ return reinterpret_cast<vector_type *>(p);
+ }
};
/**