http://llvm.org https://git.amat.us/llvm/atom/test/Transforms/LoopIdiom?h=release_32 2012-11-02T08:40:24Z 2012-11-02T08:40:24Z Chandler Carruth chandlerc@gmail.com 2012-11-02T08:40:24Z urn:sha1:52df6c2eec06861d9e933bae5b055f0b4e52f74f strided loops again. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167287 91177308-0d34-0410-b5e6-96231b3b80d8 2012-11-02T08:33:25Z Chandler Carruth chandlerc@gmail.com 2012-11-02T08:33:25Z urn:sha1:a864748284f4bab974ffb13b840a611c1f9bc7ac The new analysis is not yet ready for prime time. It has a *critical* flawed assumption, and some troubling shortages of testing. Until it's been hammered into better shape, let's stick with the working code. This should be easy to revert itself when the analysis is ready. Fixes PR14241, a miscompile of any memcpy-able loop which uses a pointer as the induction mechanism. If you have been seeing miscompiles in this revision range, you really want to test with this backed out. The results of this miscompile are a bit subtle as they can lead to downstream passes concluding things are impossible which are in fact possible. Thanks to David Blaikie for the majority of the reduction of this miscompile. I'll be checking in the test case in a non-revert commit. Revesions reverted here: r167045: LoopIdiom: Fix a serious missed optimization: we only turned top-level loops into memmove. r166877: LoopIdiom: Add checks to avoid turning memmove into an infinite loop. r166875: LoopIdiom: Recognize memmove loops. r166874: LoopIdiom: Replace custom dependence analysis with DependenceAnalysis. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167286 91177308-0d34-0410-b5e6-96231b3b80d8 2012-10-31T10:01:29Z Benjamin Kramer benny.kra@googlemail.com 2012-10-31T10:01:29Z urn:sha1:4ad3d981b91ac1293b8f2be29e6452d5206107b8 I'm not entirely happy with this solution, but I don't see a smarter way currently. Fixes PR14214. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167112 91177308-0d34-0410-b5e6-96231b3b80d8 2012-10-31T09:20:38Z Benjamin Kramer benny.kra@googlemail.com 2012-10-31T09:20:38Z urn:sha1:061938b90b1addc3c3269bdbfeae1029f0c05a43 This makes the code match the comments. Resolves a crash in loop idiom (PR14219). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167110 91177308-0d34-0410-b5e6-96231b3b80d8 2012-10-30T19:49:39Z Benjamin Kramer benny.kra@googlemail.com 2012-10-30T19:49:39Z urn:sha1:415f869cf30a272072c0533a2dea85496a210309 Thanks to Preston Briggs for catching this! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167045 91177308-0d34-0410-b5e6-96231b3b80d8 2012-10-27T15:18:28Z Benjamin Kramer benny.kra@googlemail.com 2012-10-27T15:18:28Z urn:sha1:badffcf8fddf3978acf9843a43e66766e9e830c6 I don't think this is possible with the current implementation but that may change eventually. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166877 91177308-0d34-0410-b5e6-96231b3b80d8 2012-10-27T14:25:51Z Benjamin Kramer benny.kra@googlemail.com 2012-10-27T14:25:51Z urn:sha1:d11c5d08a5f4f030d6e357378d0d46d93efd9a59 This turns loops like for (unsigned i = 0; i != n; ++i) p[i] = p[i+1]; into memmove, which has a highly optimized implementation in most libcs. This was really easy with the new DependenceAnalysis :) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166875 91177308-0d34-0410-b5e6-96231b3b80d8 2012-10-27T14:25:44Z Benjamin Kramer benny.kra@googlemail.com 2012-10-27T14:25:44Z urn:sha1:96c8735e28f2f89be37cdd907f680c6c1bf16052 Requires a lot less code and complexity on loop-idiom's side and the more precise analysis can catch more cases, like the one I included as a test case. This also fixes the edge-case miscompilation from PR9481. Compile time performance seems to be slightly worse, but this is mostly due to an extra LCSSA run scheduled by the PassManager and should be fixed there. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166874 91177308-0d34-0410-b5e6-96231b3b80d8 2012-10-21T19:31:16Z Benjamin Kramer benny.kra@googlemail.com 2012-10-21T19:31:16Z urn:sha1:3740e798bc850cd5d40185959801606433b0221f It passes all tests, produces better results than the old code but uses the wrong pass, LoopDependenceAnalysis, which is old and unmaintained. "Why is it still in tree?", you might ask. The answer is obviously: "To confuse developers." Just swapping in the new dependency pass sends the pass manager into an infinte loop, I'll try to figure out why tomorrow. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166399 91177308-0d34-0410-b5e6-96231b3b80d8 2012-10-21T15:03:07Z Benjamin Kramer benny.kra@googlemail.com 2012-10-21T15:03:07Z urn:sha1:5c6e9ae14e012bfe1fdf0e19957922d3c4d85670 Requires a lot less code and complexity on loop-idiom's side and the more precise analysis can catch more cases, like the one I included as a test case. This also fixes the edge-case miscompilation from PR9481. I'm not entirely sure that all cases are handled that the old checks handled but LDA will certainly become smarter in the future. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166390 91177308-0d34-0410-b5e6-96231b3b80d8