[Bug target/96835] Constructor in offload template class
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96835
--- Comment #7 from Tobias Weinzierl ---
Adding a default constructor to the vector class still does not allow us to
create the object on the target:
#include
#define mydt double
#pragma omp declare target
struct vector {
vector() {};
vector(mydt x, mydt y);
mydt dot(vector o);
mydt v[2];
};
vector::vector(mydt x, mydt y) {
v[0]=x;
v[1]=y;
}
mydt vector::dot(vector o) { return v[0] * o.v[0] + v[1]*o.v[1]; }
#pragma omp end declare target
int main() {
mydt res;
vector v1(1,1);
vector v2(1,3);
#pragma omp target map(from:res)
{
vector v3;
res = v1.dot(v2);
}
std::cout << res << "\n";
}
However, if we replace the default constructor with a default clause, then we
ca finally create a vector on the GPU, too:
#pragma omp declare target
struct vector {
vector() = default;
[...]
[Bug target/96835] Constructor in offload template class
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96835
--- Comment #6 from Tobias Weinzierl ---
We've found some more stuff. This works:
#include
#define mydt double
#pragma omp declare target
struct vector {
vector(mydt x, mydt y);
mydt dot(vector o);
mydt v[2];
};
vector::vector(mydt x, mydt y) {
v[0]=x;
v[1]=y;
}
mydt vector::dot(vector o) { return v[0] * o.v[0] + v[1]*o.v[1]; }
#pragma omp end declare target
int main() {
mydt res;
vector v1(1,1);
vector v2(1,3);
#pragma omp target map(from:res)
{
res = v1.dot(v2);
}
std::cout << res << "\n";
}
As soon as you instantiate the vector within the target region, it does not
work anymore:
int main() {
mydt res;
#pragma omp target map(from:res)
{
vector v1(1,1);
vector v2(1,3);
res = v1.dot(v2);
}
std::cout << res << "\n";
}
[Bug target/96835] Constructor in offload template class
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96835 --- Comment #5 from Tobias Burnus --- (In reply to Tobias Weinzierl from comment #4) > Created attachment 49339 [details] > Reproducer Compiles here with mainline (11.0.0 20201104) and nvptx offloading (-O0). I wonder whether that was fixed by: OpenMP: Handle cpp_implicit_alias in declare-target discovery (PR96390) r11-3505-g2a10a2c0689db280ee3a94164504b7196b8370f4 Thus, I think the issue of comment 0 (the internal compiler error) is fixed and the automatic 'declare target' works now on mainline. However, the run-time JIT fails here (with and without 'omp declare target) – as in comment 3: libgomp: Link error log ptxas application ptx input, line 255; error : Label expected for argument 0 of instruction 'call' ptxas application ptx input, line 255; error : Function '_ZN6vectorILi4EEC1ERKi' not declared in this scope ^-- this is "vector<4>::vector(int const&)" ^-- and 'C1' means that it is the "complete object constructor" My bet is that this is the nvptx alias issue PR 97106 (see also PR 97102 and, regarding a newer PTX ISA PR96005). Solution: Either resolving the alias in GCC (in mkoffload) or (conditionally) bumping the minimal CUDA version to 10.0 such that .alias is available (PTX ISA >= 6.3).
[Bug target/96835] Constructor in offload template class
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96835 Jonathan Wakely changed: What|Removed |Added Status|WAITING |UNCONFIRMED Ever confirmed|1 |0
[Bug target/96835] Constructor in offload template class
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96835 --- Comment #4 from Tobias Weinzierl --- Created attachment 49339 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=49339=edit Reproducer
[Bug target/96835] Constructor in offload template class
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96835 --- Comment #3 from Tobias Weinzierl --- The full compilation error is + g++-10 -fopenmp -foffload=nvptx-none bug.cpp -o bug ptxas /tmp/cc1XobxJ.o, line 253; error : Illegal operand type to instruction 'ld' ptxas /tmp/cc1XobxJ.o, line 266; error : Label expected for argument 0 of instruction 'call' ptxas /tmp/cc1XobxJ.o, line 266; error : Function '_ZN6vectorILi4EEC1ERKi' not declared in this scope ptxas /tmp/cc1XobxJ.o, line 266; fatal : Call target not recognized ptxas fatal : Ptx assembly aborted due to errors nvptx-as: ptxas returned 255 exit status mkoffload: fatal error: x86_64-linux-gnu-accel-nvptx-none-gcc-10 returned 1 exit status compilation terminated. lto-wrapper: fatal error: /usr/lib/gcc/x86_64-linux-gnu/10//accel/nvptx-none/mkoffload returned 1 exit status compilation terminated. /usr/bin/ld: error: lto-wrapper failed collect2: error: ld returned 1 exit status As long as the constructor is not used within the map region, the code translates fine.
[Bug target/96835] Constructor in offload template class
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96835
--- Comment #2 from Tobias Weinzierl ---
#include
#pragma omp declare target
template
struct vector {
int values_[sz];
vector();
vector(int const& init_val);
int dot(vector o) {
int res = 0;
for (int i = 0; i < sz; ++ i)
res += values_[i] * o.values_[i];
return res;
}
};
template
vector::vector(int const& init_val) {
for (int i = 0; i < sz; ++ i) values_[i] = init_val;
}
template
vector::vector() : vector(0) {
}
#pragma omp end declare target
int main() {
int res;
#pragma omp target map(from:res)
{
vector<4> v1(1);
vector<4> v2(2);
res = v1.dot(v2);
}
printf("%d\n", res);
return 0;
}
[Bug target/96835] Constructor in offload template class
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96835 Jakub Jelinek changed: What|Removed |Added CC||jakub at gcc dot gnu.org Last reconfirmed||2020-08-28 Status|UNCONFIRMED |WAITING Ever confirmed|0 |1 --- Comment #1 from Jakub Jelinek --- Same problems as in PR96833.
