gcc-5.2 cilk加上卸载到intel gfx硬件

Question

我们可以使用带有gcc-5.2 的cilk plus卸载到图形硬件吗

g++ -std=c++14 -Wall -O3 -march=native -fcilkplus vec_add.cpp -o vec_add
vec_add.cpp:6:0: warning: ignoring #pragma offload target [-Wunknown-pragmas]
 #pragma offload target(gfx) pin(out, in1, in2 : length(n))

编译器对以下测试代码发出上述警告：

#include <iostream>
#include <cilk/cilk.h>
void vec_add(int n, float *out, float *in1, float *in2)
{
#pragma offload target(gfx) pin(out, in1, in2 : length(n))
    cilk_for(int i = 0; i != n; ++i)
    {
        out[i] = in1[i] + in2[i];
    }
}
static int ar_sz = 100000;
int main (int argc, char **argv)
{
    float foo[ar_sz];
    float bar[ar_sz];
    float out[ar_sz];
    for(int i = 0; i != ar_sz; ++i)
    {
        foo[i] = i + ar_sz * 10;
        bar[i] = i;
    }
    vec_add(ar_sz, out, foo, bar);
    for(int i = 0; i != ar_sz; i += 100)
    {
        std::cout << "foo[" << i << "] =" << foo[i] << "t|tbar[" << i << "] =" <<  bar[i] << std::endl;
    }
}

使用编译

FLAGS=-std=c++14 -Wall -O3 -march=native -fcilkplus
all: vec_add fib
vec_add: vec_add.cpp
    g++ $(FLAGS) $< -o $@

Answer 1

"对Cilk Plus的完全支持已添加到GCC编译器中。"这意味着仅完全支持Cilk Plus的语言扩展。Gcc根本无法卸载到英特尔集成显卡。据报道，OpenMP可以卸载至强Phi协处理器和nvidia显卡。

https://gcc.gnu.org/ml/gcc/2016-04/msg00182.html