| /* { dg-do compile } */ |
| /* { dg-options "-O2 -ftree-loop-distribution -fdump-tree-ldist-all" } */ |
| |
| int loop1 (int k) |
| { |
| unsigned int i; |
| int a[1000], b[1000], c[1000], d[1000]; |
| |
| for (i = 2; i < (1000-1); i ++) { |
| a[i] = k * i; /* S1 */ |
| b[i] = a[i-2] + k; /* S2 */ |
| c[i] = b[i-1] + a[i+1]; /* S3 */ |
| d[i] = c[i-1] + k + i; /* S4 */ |
| } |
| /* Dependences: |
| S1->S2 (flow, level 1) |
| S2->S3 (flow, level 1) |
| S3->S1 (anti, level 1) |
| S3->S4 (flow, level 1) |
| |
| There are two partitions: {S1, S2, S3} and {S4}. |
| |
| {S1, S2, S3} have to be in the same partition because: |
| - S1 (i) has to be executed before S2 (i+2), as S1 produces a[i] that is then consumed 2 iterations later by S2. |
| - S2 (i) has to be executed before S3 (i+1), as S2 produces b[i] that is then consumed one iteration later by S3, |
| - S3 (i) has to be executed before S1 (i+1), as a[i+1] has to execute before the update to a[i], |
| |
| {S4} is the consumer partition: it consumes the values from array "c" produced in S3. |
| |
| The cost model should fuse all the tasks together as the cost of |
| fetching data from caches is too high. |
| */ |
| |
| return a[1000-2] + b[1000-1] + c[1000-2] + d[1000-2]; |
| } |
| |
| /* { dg-final { scan-tree-dump-times "distributed: split to 2 loops" 0 "ldist" { xfail *-*-* } } } */ |
