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path: root/llvm/test/Transforms/LoopDistribute/bounds-expansion-bug.ll
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* [SCEV][LSR] Prevent using undefined value in binopsEugene Leviant2019-07-031-6/+10
| | | | | | | | | | | On some occasions ReuseOrCreateCast may convert previously expanded value to undefined. That value may be passed by SCEVExpander as an argument to InsertBinop making IV chain undefined. Differential revision: https://reviews.llvm.org/D63928 llvm-svn: 365009
* Revert "Temporarily Revert "Add basic loop fusion pass.""Eric Christopher2019-04-171-0/+106
| | | | | | | | The reversion apparently deleted the test/Transforms directory. Will be re-reverting again. llvm-svn: 358552
* Temporarily Revert "Add basic loop fusion pass."Eric Christopher2019-04-171-106/+0
| | | | | | | | As it's causing some bot failures (and per request from kbarton). This reverts commit r358543/ab70da07286e618016e78247e4a24fcb84077fda. llvm-svn: 358546
* [LDist] Match behavior between invoking via optimization pipeline or opt ↵Adam Nemet2016-12-211-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | -loop-distribute In r267672, where the loop distribution pragma was introduced, I tried it hard to keep the old behavior for opt: when opt is invoked with -loop-distribute, it should distribute the loop (it's off by default when ran via the optimization pipeline). As MichaelZ has discovered this has the unintended consequence of breaking a very common developer work-flow to reproduce compilations using opt: First you print the pass pipeline of clang with -debug-pass=Arguments and then invoking opt with the returned arguments. clang -debug-pass will include -loop-distribute but the pass is invoked with default=off so nothing happens unless the loop carries the pragma. While through opt (default=on) we will try to distribute all loops. This changes opt's default to off as well to match clang. The tests are modified to explicitly enable the transformation. llvm-svn: 290235
* [LAA] Hold bounds via ValueHandles during SCEV expansionAdam Nemet2015-08-211-0/+106
SCEV expansion can invalidate previously expanded values. For example in SCEVExpander::ReuseOrCreateCast, if we already have the requested cast value but it's not at the desired location, a new cast is inserted and the old cast will be invalidated. Therefore, when expanding the bounds for the pointers, a later entry can invalidate the IR value for an earlier one. The fix is to store a value handle rather than the value itself. The newly added test has a more detailed description of how the bug triggers. This bug can have a negative but potentially highly variable performance impact in Loop Distribution. Because one of the bound values was invalidated and is an undef expression now, InstCombine is free to transform the array overlap check: Start0 <= End1 && Start1 <= End0 into: Start0 <= End1 So depending on the runtime location of the arrays, we would detect a conflict and fall back on the original loop of the versioned loop. Also tested compile time with SPEC2006 LTO bc files. llvm-svn: 245760
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