cb90e6a7c0
[OPENMP50]Codegen for scan directives in parallel for simd regions.
...
Summary:
Added codegen for scan directives in parallel for simd regions.
Emits the code for the directive with inscan reductions.
Original code:
```
#pragma omp parallel for simd reduction(inscan, op : ...)
for() {
<input phase>;
#pragma omp scan (in)exclusive(...)
<scan phase>
}
```
is transformed to something:
```
#pragma omp parallel
{
size num_iters = <num_iters>;
<type> buffer[num_iters];
#pragma omp for simd
for (i: 0..<num_iters>) {
<input phase>;
buffer[i] = red;
}
#pragma omp barrier
for (int k = 0; k != ceil(log2(num_iters)); ++k)
for (size cnt = last_iter; cnt >= pow(2, k); --k)
buffer[i] op= buffer[i-pow(2,k)];
#pragma omp for simd
for (0..<num_iters>) {
red = InclusiveScan ? buffer[i] : buffer[i-1];
<scan phase>;
}
}
```
Reviewers: jdoerfert
Subscribers: yaxunl, guansong, sstefan1, cfe-commits, caomhin
Tags: #clang
Differential Revision: https://reviews.llvm.org/D82115
2020-06-23 08:41:11 -04:00
Saiyedul Islam