[PATCH] D23388: [LoopUnroll] By default disable unrolling when optimizing for size.

[Michael Zolotukhin via Phabricator via llvm-commits]

mzolotukhin added a comment.

Hi Davide,

I haven't reevaluated this. At that time, we spotted several compile-time regressions (see the table below), and my goal was simply to change the unrolling behavior back to the original. I didn't try to tune the thresholds in any way, so if anyone has a compelling data, we could definitely revisit the values.

| SingleSource/Benchmarks/Stanford/Perm                            | 37.37% |
| MultiSource/Benchmarks/tramp3d-v4/tramp3d-v4                     | 33.95% |
| SingleSource/Regression/C/bigstack                               | 22.07% |
| MultiSource/Benchmarks/Olden/power/power                         | 13.49% |
| MultiSource/Benchmarks/FreeBench/fourinarow/fourinarow           | 12.68% |
| MultiSource/Benchmarks/Olden/health/health                       | 8.46%  |
| MultiSource/Benchmarks/Olden/bh/bh                               | 7.00%  |
| MultiSource/Benchmarks/mediabench/g721/g721encode/encode         | 5.63%  |
| MultiSource/Benchmarks/nbench/nbench                             | 5.29%  |
| External/SPEC/CINT2006/462_libquantum/462_libquantum             | 5.17%  |
| External/SPEC/CFP2006/447_dealII/447_dealII                      | 4.74%  |
| MultiSource/Benchmarks/MiBench/telecomm-gsm/telecomm-gsm         | 2.38%  |
| MultiSource/Benchmarks/mediabench/gsm/toast/toast                | 2.28%  |
| External/SPEC/CFP2006/433_milc/433_milc                          | 2.08%  |
| MultiSource/Benchmarks/MiBench/consumer-lame/consumer-lame       | 1.62%  |
| MultiSource/Applications/JM/lencod/lencod                        | 1.61%  |
| MultiSource/Benchmarks/MiBench/automotive-susan/automotive-susan | 1.48%  |
| MultiSource/Benchmarks/Olden/bh/bh                               | -1.67% |


Repository:
  rL LLVM

https://reviews.llvm.org/D23388