[llvm] [RISCV] Enable TTI::shouldDropLSRSolutionIfLessProfitable by default (PR #89927)

[Yingwei Zheng via llvm-commits]

dtcxzyw wrote:

Hi @asb, I found this patch caused some significant performance regression (up to 37.8%) on llvm-test-suite with `rv64gczba_zbb_zbkb_zbs -O3 -flto=thin`. Can you have a look about this?

| Name                                                         | Before (Billion Insts) | After (Billion Insts) | Ratio |
| ------------------------------------------------------------ | ---------------------- | --------------------- | ----- |
| SingleSource/Benchmarks/Polybench/linear-algebra/kernels/doitgen/doitgen | 4.222953611            | 5.820735229           | 1.378 |
| SingleSource/Benchmarks/Polybench/datamining/covariance/covariance | 4.090009899            | 5.593993395           | 1.368 |
| SingleSource/Benchmarks/Polybench/datamining/correlation/correlation | 4.095016076            | 5.599001576           | 1.367 |
| SingleSource/Benchmarks/Polybench/medley/reg_detect/reg_detect | 0.206776896            | 0.267266747           | 1.293 |
| SingleSource/Benchmarks/Shootout/Shootout-ary3               | 10.507102477           | 13.507101469          | 1.286 |
| SingleSource/Benchmarks/Polybench/linear-algebra/kernels/mvt/mvt | 0.576970074            | 0.720934057           | 1.250 |
| SingleSource/Benchmarks/Polybench/linear-algebra/solvers/durbin/durbin | 0.535427699            | 0.663343689           | 1.239 |
| SingleSource/Benchmarks/Polybench/linear-algebra/kernels/trisolv/trisolv | 0.160518143            | 0.192501995           | 1.199 |
| SingleSource/Benchmarks/Polybench/stencils/adi/adi           | 3.382377197            | 4.017469438           | 1.188 |
| MultiSource/Benchmarks/MiBench/automotive-susan/automotive-susan | 0.284736344            | 0.334505345           | 1.175 |
| SingleSource/Benchmarks/Polybench/linear-algebra/kernels/atax/atax | 0.368520477            | 0.43248861            | 1.174 |
| SingleSource/Benchmarks/BenchmarkGame/puzzle                 | 3.092676262            | 3.592676238           | 1.162 |
| SingleSource/Benchmarks/Misc/himenobmtxpa                    | 2.368697352            | 2.746954721           | 1.160 |
| MultiSource/Benchmarks/Rodinia/srad/srad                     | 2.247984884            | 2.600044498           | 1.157 |

For detailed performance data, please refer to https://github.com/dtcxzyw/llvm-ci/issues/1165 and https://github.com/dtcxzyw/llvm-ci/pull/1166.




https://github.com/llvm/llvm-project/pull/89927