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path: root/lib/CodeGen/MachineBlockFrequencyInfo.cpp
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* Revert "Introduce a string_ostream string builder facilty"Alp Toker2014-06-26
| | | | | | Temporarily back out commits r211749, r211752 and r211754. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211814 91177308-0d34-0410-b5e6-96231b3b80d8
* Introduce a string_ostream string builder faciltyAlp Toker2014-06-26
| | | | | | | | | | | | | | | | | | | | string_ostream is a safe and efficient string builder that combines opaque stack storage with a built-in ostream interface. small_string_ostream<bytes> additionally permits an explicit stack storage size other than the default 128 bytes to be provided. Beyond that, storage is transferred to the heap. This convenient class can be used in most places an std::string+raw_string_ostream pair or SmallString<>+raw_svector_ostream pair would previously have been used, in order to guarantee consistent access without byte truncation. The patch also converts much of LLVM to use the new facility. These changes include several probable bug fixes for truncated output, a programming error that's no longer possible with the new interface. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211749 91177308-0d34-0410-b5e6-96231b3b80d8
* [Modules] Remove potential ODR violations by sinking the DEBUG_TYPEChandler Carruth2014-04-22
| | | | | | | | | | | | define below all header includes in the lib/CodeGen/... tree. While the current modules implementation doesn't check for this kind of ODR violation yet, it is likely to grow support for it in the future. It also removes one layer of macro pollution across all the included headers. Other sub-trees will follow. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206837 91177308-0d34-0410-b5e6-96231b3b80d8
* Reapply "blockfreq: Rewrite BlockFrequencyInfoImpl"Duncan P. N. Exon Smith2014-04-21
| | | | | | | | | This reverts commit r206707, reapplying r206704. The preceding commit to CalcSpillWeights should have sorted out the failing buildbots. <rdar://problem/14292693> git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206766 91177308-0d34-0410-b5e6-96231b3b80d8
* Revert "blockfreq: Rewrite BlockFrequencyInfoImpl"Duncan P. N. Exon Smith2014-04-19
| | | | | | This reverts commit r206704, as expected. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206707 91177308-0d34-0410-b5e6-96231b3b80d8
* Reapply "blockfreq: Rewrite BlockFrequencyInfoImpl"Duncan P. N. Exon Smith2014-04-19
| | | | | | | | | | | | | | | | | | | | | This reverts commit r206677, reapplying my BlockFrequencyInfo rewrite. I've done a careful audit, added some asserts, and fixed a couple of bugs (unfortunately, they were in unlikely code paths). There's a small chance that this will appease the failing bots [1][2]. (If so, great!) If not, I have a follow-up commit ready that will temporarily add -debug-only=block-freq to the two failing tests, allowing me to compare the code path between what the failing bots and what my machines (and the rest of the bots) are doing. Once I've triggered those builds, I'll revert both commits so the bots go green again. [1]: http://bb.pgr.jp/builders/ninja-x64-msvc-RA-centos6/builds/1816 [2]: http://llvm-amd64.freebsd.your.org/b/builders/clang-i386-freebsd/builds/18445 <rdar://problem/14292693> git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206704 91177308-0d34-0410-b5e6-96231b3b80d8
* Revert "blockfreq: Rewrite BlockFrequencyInfoImpl" (#2)Duncan P. N. Exon Smith2014-04-19
| | | | | | | | | | | This reverts commit r206666, as planned. Still stumped on why the bots are failing. Sanitizer bots haven't turned anything up. If anyone can help me debug either of the failures (referenced in r206666) I'll owe them a beer. (In the meantime, I'll be auditing my patch for undefined behaviour.) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206677 91177308-0d34-0410-b5e6-96231b3b80d8
* Reapply "blockfreq: Rewrite BlockFrequencyInfoImpl" (#2)Duncan P. N. Exon Smith2014-04-18
| | | | | | | | | | | | | | | | | | | This reverts commit r206628, reapplying r206622 (and r206626). Two tests are failing only on buildbots [1][2]: i.e., I can't reproduce on Darwin, and Chandler can't reproduce on Linux. Asan and valgrind don't tell us anything, but we're hoping the msan bot will catch it. So, I'm applying this again to get more feedback from the bots. I'll leave it in long enough to trigger builds in at least the sanitizer buildbots (it was failing for reasons unrelated to my commit last time it was in), and hopefully a few others.... and then I expect to revert a third time. [1]: http://bb.pgr.jp/builders/ninja-x64-msvc-RA-centos6/builds/1816 [2]: http://llvm-amd64.freebsd.your.org/b/builders/clang-i386-freebsd/builds/18445 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206666 91177308-0d34-0410-b5e6-96231b3b80d8
* Revert "blockfreq: Rewrite BlockFrequencyInfoImpl" (#2)Duncan P. N. Exon Smith2014-04-18
| | | | | | | | | This reverts commit r206622 and the MSVC fixup in r206626. Apparently the remotely failing tests are still failing, despite my attempt to fix the nondeterminism in r206621. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206628 91177308-0d34-0410-b5e6-96231b3b80d8
* Reapply "blockfreq: Rewrite BlockFrequencyInfoImpl"Duncan P. N. Exon Smith2014-04-18
| | | | | | | | | | | | | | This reverts commit r206556, effectively reapplying commit r206548 and its fixups in r206549 and r206550. In an intervening commit I've added target triples to the tests that were failing remotely [1] (but passing locally). I'm hoping the mystery is solved? I'll revert this again if the tests are still failing remotely. [1]: http://bb.pgr.jp/builders/ninja-x64-msvc-RA-centos6/builds/1816 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206622 91177308-0d34-0410-b5e6-96231b3b80d8
* Revert "blockfreq: Rewrite BlockFrequencyInfoImpl"Duncan P. N. Exon Smith2014-04-18
| | | | | | | | | | | This reverts commits r206548, r206549 and r206549. There are some unit tests failing that aren't failing locally [1], so reverting until I have time to investigate. [1]: http://bb.pgr.jp/builders/ninja-x64-msvc-RA-centos6/builds/1816 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206556 91177308-0d34-0410-b5e6-96231b3b80d8
* blockfreq: Rewrite BlockFrequencyInfoImplDuncan P. N. Exon Smith2014-04-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Rewrite the shared implementation of BlockFrequencyInfo and MachineBlockFrequencyInfo entirely. The old implementation had a fundamental flaw: precision losses from nested loops (or very wide branches) compounded past loop exits (and convergence points). The @nested_loops testcase at the end of test/Analysis/BlockFrequencyAnalysis/basic.ll is motivating. This function has three nested loops, with branch weights in the loop headers of 1:4000 (exit:continue). The old analysis gives non-sensical results: Printing analysis 'Block Frequency Analysis' for function 'nested_loops': ---- Block Freqs ---- entry = 1.0 for.cond1.preheader = 1.00103 for.cond4.preheader = 5.5222 for.body6 = 18095.19995 for.inc8 = 4.52264 for.inc11 = 0.00109 for.end13 = 0.0 The new analysis gives correct results: Printing analysis 'Block Frequency Analysis' for function 'nested_loops': block-frequency-info: nested_loops - entry: float = 1.0, int = 8 - for.cond1.preheader: float = 4001.0, int = 32007 - for.cond4.preheader: float = 16008001.0, int = 128064007 - for.body6: float = 64048012001.0, int = 512384096007 - for.inc8: float = 16008001.0, int = 128064007 - for.inc11: float = 4001.0, int = 32007 - for.end13: float = 1.0, int = 8 Most importantly, the frequency leaving each loop matches the frequency entering it. The new algorithm leverages BlockMass and PositiveFloat to maintain precision, separates "probability mass distribution" from "loop scaling", and uses dithering to eliminate probability mass loss. I have unit tests for these types out of tree, but it was decided in the review to make the classes private to BlockFrequencyInfoImpl, and try to shrink them (or remove them entirely) in follow-up commits. The new algorithm should generally have a complexity advantage over the old. The previous algorithm was quadratic in the worst case. The new algorithm is still worst-case quadratic in the presence of irreducible control flow, but it's linear without it. The key difference between the old algorithm and the new is that control flow within a loop is evaluated separately from control flow outside, limiting propagation of precision problems and allowing loop scale to be calculated independently of mass distribution. Loops are visited bottom-up, their loop scales are calculated, and they are replaced by pseudo-nodes. Mass is then distributed through the function, which is now a DAG. Finally, loops are revisited top-down to multiply through the loop scales and the masses distributed to pseudo nodes. There are some remaining flaws. - Irreducible control flow isn't modelled correctly. LoopInfo and MachineLoopInfo ignore irreducible edges, so this algorithm will fail to scale accordingly. There's a note in the class documentation about how to get closer. See also the comments in test/Analysis/BlockFrequencyInfo/irreducible.ll. - Loop scale is limited to 4096 per loop (2^12) to avoid exhausting the 64-bit integer precision used downstream. - The "bias" calculation proposed on llvmdev is *not* incorporated here. This will be added in a follow-up commit, once comments from this review have been handled. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206548 91177308-0d34-0410-b5e6-96231b3b80d8
* blockfreq: Rename BlockFrequencyImpl to BlockFrequencyInfoImplDuncan P. N. Exon Smith2014-04-11
| | | | | | | | | | | | This is a shared implementation class for BlockFrequencyInfo and MachineBlockFrequencyInfo, not for BlockFrequency, a related (but distinct) class. No functionality change. <rdar://problem/14292693> git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206083 91177308-0d34-0410-b5e6-96231b3b80d8
* blockfreq: Implement Pass::releaseMemory()Duncan P. N. Exon Smith2014-03-25
| | | | | | | | | | Implement Pass::releaseMemory() in BlockFrequencyInfo and MachineBlockFrequencyInfo. Just delete the private implementation when not in use. Switch to a std::unique_ptr to make the logic more clear. <rdar://problem/14292693> git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204741 91177308-0d34-0410-b5e6-96231b3b80d8
* blockfreq: Use const in MachineBlockFrequencyInfoDuncan P. N. Exon Smith2014-03-25
| | | | | | <rdar://problem/14292693> git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204740 91177308-0d34-0410-b5e6-96231b3b80d8
* [block-freq] Rename getEntryFrequency() -> getEntryFreq() to match ↵Michael Gottesman2013-12-14
| | | | | | getBlockFreq() in all *BlockFrequencyInfo*. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@197304 91177308-0d34-0410-b5e6-96231b3b80d8
* [block-freq] Update BlockFrequencyInfo/MachineBlockFrequencyInfo to use the ↵Michael Gottesman2013-12-14
| | | | | | new print methods. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@197289 91177308-0d34-0410-b5e6-96231b3b80d8
* [block-freq] Add the equivalent methods to MachineBlockFrequencyInfo and ↵Michael Gottesman2013-12-14
| | | | | | BlockFrequencyInfo that were added to BlockFrequencyImpl in r197285 and r197284. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@197287 91177308-0d34-0410-b5e6-96231b3b80d8
* Fixed various whitespace/spelling/80+ issues.Michael Gottesman2013-12-03
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196310 91177308-0d34-0410-b5e6-96231b3b80d8
* Added MachineBlockFrequencyInfo::view for displaying the block frequency ↵Michael Gottesman2013-12-03
| | | | | | | | | | | | propagation graph via graphviz. This is useful for debugging issues in the BlockFrequency implementation since one can easily visualize where probability mass and other errors occur in the propagation. This is the MI version of r194654. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196183 91177308-0d34-0410-b5e6-96231b3b80d8
* BlockFrequency: Bump up the entry frequency a bit.Benjamin Kramer2013-06-25
| | | | | | | This is a band-aid to fix the most severe regressions we're seeing from basing spill decisions on block frequencies, until we have a better solution. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184835 91177308-0d34-0410-b5e6-96231b3b80d8
* Use the new script to sort the includes of every file under lib.Chandler Carruth2012-12-03
| | | | | | | | | | | | | | | | | Sooooo many of these had incorrect or strange main module includes. I have manually inspected all of these, and fixed the main module include to be the nearest plausible thing I could find. If you own or care about any of these source files, I encourage you to take some time and check that these edits were sensible. I can't have broken anything (I strictly added headers, and reordered them, never removed), but they may not be the headers you'd really like to identify as containing the API being implemented. Many forward declarations and missing includes were added to a header files to allow them to parse cleanly when included first. The main module rule does in fact have its merits. =] git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169131 91177308-0d34-0410-b5e6-96231b3b80d8
* Add some constantness to BranchProbabilityInfo and BlockFrequnencyInfo.Jakub Staszak2011-12-20
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146986 91177308-0d34-0410-b5e6-96231b3b80d8
* Add more constantness in BlockFrequencyInfo.Jakub Staszak2011-08-03
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136816 91177308-0d34-0410-b5e6-96231b3b80d8
* Use BlockFrequency instead of uint32_t in BlockFrequencyInfo.Jakub Staszak2011-07-27
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136278 91177308-0d34-0410-b5e6-96231b3b80d8
* Rename BlockFrequency to BlockFrequencyInfo and MachineBlockFrequency toJakub Staszak2011-07-25
MachineBlockFrequencyInfo. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135937 91177308-0d34-0410-b5e6-96231b3b80d8