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* [NFCI][LoopUnrollAndJam] Changing LoopUnrollAndJamPass to a functionWhitney Tsang2020-01-094-0/+4
| | | | | | | | | | | | | | | | | | | pass. Summary: This patch changes LoopUnrollAndJamPass to a function pass, and keeps the loops traversal order same as defined in FunctionToLoopPassAdaptor LoopPassManager.h. The next patch will change the loop traversal to outer to inner order, so more loops can be transform. Discussion in llvm-dev mailing list: https://groups.google.com/forum/#!topic/llvm-dev/LF4rUjkVI2g Reviewer: dmgreen, jdoerfert, Meinersbur, kbarton, bmahjour, etiotto Reviewed By: dmgreen Subscribers: hiraditya, zzheng, llvm-commits Tag: LLVM Differential Revision: https://reviews.llvm.org/D72230
* Revert "Temporarily Revert "Add basic loop fusion pass.""Eric Christopher2019-04-1710-0/+2846
| | | | | | | | The reversion apparently deleted the test/Transforms directory. Will be re-reverting again. llvm-svn: 358552
* Temporarily Revert "Add basic loop fusion pass."Eric Christopher2019-04-1710-2846/+0
| | | | | | | | As it's causing some bot failures (and per request from kbarton). This reverts commit r358543/ab70da07286e618016e78247e4a24fcb84077fda. llvm-svn: 358546
* [Unroll/UnrollAndJam/Vectorizer/Distribute] Add followup loop attributes.Michael Kruse2018-12-125-1/+221
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When multiple loop transformation are defined in a loop's metadata, their order of execution is defined by the order of their respective passes in the pass pipeline. For instance, e.g. #pragma clang loop unroll_and_jam(enable) #pragma clang loop distribute(enable) is the same as #pragma clang loop distribute(enable) #pragma clang loop unroll_and_jam(enable) and will try to loop-distribute before Unroll-And-Jam because the LoopDistribute pass is scheduled after UnrollAndJam pass. UnrollAndJamPass only supports one inner loop, i.e. it will necessarily fail after loop distribution. It is not possible to specify another execution order. Also,t the order of passes in the pipeline is subject to change between versions of LLVM, optimization options and which pass manager is used. This patch adds 'followup' attributes to various loop transformation passes. These attributes define which attributes the resulting loop of a transformation should have. For instance, !0 = !{!0, !1, !2} !1 = !{!"llvm.loop.unroll_and_jam.enable"} !2 = !{!"llvm.loop.unroll_and_jam.followup_inner", !3} !3 = !{!"llvm.loop.distribute.enable"} defines a loop ID (!0) to be unrolled-and-jammed (!1) and then the attribute !3 to be added to the jammed inner loop, which contains the instruction to distribute the inner loop. Currently, in both pass managers, pass execution is in a fixed order and UnrollAndJamPass will not execute again after LoopDistribute. We hope to fix this in the future by allowing pass managers to run passes until a fixpoint is reached, use Polly to perform these transformations, or add a loop transformation pass which takes the order issue into account. For mandatory/forced transformations (e.g. by having been declared by #pragma omp simd), the user must be notified when a transformation could not be performed. It is not possible that the responsible pass emits such a warning because the transformation might be 'hidden' in a followup attribute when it is executed, or it is not present in the pipeline at all. For this reason, this patche introduces a WarnMissedTransformations pass, to warn about orphaned transformations. Since this changes the user-visible diagnostic message when a transformation is applied, two test cases in the clang repository need to be updated. To ensure that no other transformation is executed before the intended one, the attribute `llvm.loop.disable_nonforced` can be added which should disable transformation heuristics before the intended transformation is applied. E.g. it would be surprising if a loop is distributed before a #pragma unroll_and_jam is applied. With more supported code transformations (loop fusion, interchange, stripmining, offloading, etc.), transformations can be used as building blocks for more complex transformations (e.g. stripmining+stripmining+interchange -> tiling). Reviewed By: hfinkel, dmgreen Differential Revision: https://reviews.llvm.org/D49281 Differential Revision: https://reviews.llvm.org/D55288 llvm-svn: 348944
* [UnJ] Improve explicit loop count checksDavid Green2018-08-111-0/+144
| | | | | | | | | | | | | Try to improve the computed counts when it has been explicitly set by a pragma or command line option. This moves the code around, so that first call to computeUnrollCount to get a sensible count and override that if explicit unroll and jam counts are specified. Also added some extra debug messages for when unroll and jamming is disabled. Differential Revision: https://reviews.llvm.org/D50075 llvm-svn: 339501
* [UnrollAndJam] New Unroll and Jam passDavid Green2018-07-015-0/+2482
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is a simple implementation of the unroll-and-jam classical loop optimisation. The basic idea is that we take an outer loop of the form: for i.. ForeBlocks(i) for j.. SubLoopBlocks(i, j) AftBlocks(i) Instead of doing normal inner or outer unrolling, we unroll as follows: for i... i+=2 ForeBlocks(i) ForeBlocks(i+1) for j.. SubLoopBlocks(i, j) SubLoopBlocks(i+1, j) AftBlocks(i) AftBlocks(i+1) Remainder Loop So we have unrolled the outer loop, then jammed the two inner loops into one. This can lead to a simpler inner loop if memory accesses can be shared between the now jammed loops. To do this we have to prove that this is all safe, both for the memory accesses (using dependence analysis) and that ForeBlocks(i+1) can move before AftBlocks(i) and SubLoopBlocks(i, j). Differential Revision: https://reviews.llvm.org/D41953 llvm-svn: 336062
* Revert 333358 as it's failing on some builders.David Green2018-05-275-2498/+0
| | | | | | I'm guessing the tests reply on the ARM backend being built. llvm-svn: 333359
* [UnrollAndJam] Add a new Unroll and Jam passDavid Green2018-05-275-0/+2498
This is a simple implementation of the unroll-and-jam classical loop optimisation. The basic idea is that we take an outer loop of the form: for i.. ForeBlocks(i) for j.. SubLoopBlocks(i, j) AftBlocks(i) Instead of doing normal inner or outer unrolling, we unroll as follows: for i... i+=2 ForeBlocks(i) ForeBlocks(i+1) for j.. SubLoopBlocks(i, j) SubLoopBlocks(i+1, j) AftBlocks(i) AftBlocks(i+1) Remainder So we have unrolled the outer loop, then jammed the two inner loops into one. This can lead to a simpler inner loop if memory accesses can be shared between the now-jammed loops. To do this we have to prove that this is all safe, both for the memory accesses (using dependence analysis) and that ForeBlocks(i+1) can move before AftBlocks(i) and SubLoopBlocks(i, j). Differential Revision: https://reviews.llvm.org/D41953 llvm-svn: 333358
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