PGI User Forum

[ink]

i fail to understand where is "Complex loop carried dependence" in the code below. if leave only one of the arrays everything is fine but not if both are present.
===================================
#include <stdlib.h>
#define COUNT 16384

int main(int argc, char **argv){
float *d;
float *d2;

d = (float *)malloc( COUNT * sizeof(float));
d2 = (float *)malloc( COUNT * sizeof(float));

#pragma acc region for
for(int i = 0; i < COUNT; i++) {
float sum = 0.0;
float sum2 = 0.0;
d[i] = sum;
d2[i] = sum2;
}
}
===================================
pgcc -ta=nvidia -Minfo=accel -o t.exe t.c
main:
11, No parallel kernels found, accelerator region ignored
12, Complex loop carried dependence of d prevents parallelization
Loop carried dependence of d2 prevents parallelization
Loop carried backward dependence of d2 prevents vectorization

[mkcolg]

Hi ink,

You need to compile with "-Msafeptr" to assert that your pointers don't overlap.

[ink]

Hi Mat,
thanks for your help. it worked indeed.
all i need now is support for derived types and unsigned int.
thanks again