llvm-project

0074a462 - [LoopInterchange] Hoist isComputableLoopNest() in the control flow (#124247)

[LoopInterchange] Hoist isComputableLoopNest() in the control flow (#124247) The profiling of the LLVM Test-suite reveals that a significant portion, specifically 14,090 out of 139,323, loop nests were identified as non-viable candidates for transformation, leading to the transform exiting from isComputableLoopNest() without any action. More importantly, dependence information was computed for these loop nests before reaching the function isComputableLoopNest(), which does not require DI and relies solely on scalar evolution (SE). To enhance compile-time efficiency, this patch moves the call to isComputableLoopNest() earlier in the control-flow, thereby avoiding unnecessary dependence calculations. The impact of this change is evident on the compile-time-tracker, with the overall geometric mean improvement recorded at 0.11%, while the lencode benchmark gets a more substantial benefit of 0.44%. This improvement can be tracked in the isc-ln-exp-2 branch under my repo.