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* [lit] Delete empty lines at the end of lit.local.cfg NFCFangrui Song2019-06-171-1/+0
| | | | llvm-svn: 363538
* Revert "Temporarily Revert "Add basic loop fusion pass.""Eric Christopher2019-04-172-0/+207
| | | | | | | | The reversion apparently deleted the test/Transforms directory. Will be re-reverting again. llvm-svn: 358552
* Temporarily Revert "Add basic loop fusion pass."Eric Christopher2019-04-172-207/+0
| | | | | | | | As it's causing some bot failures (and per request from kbarton). This reverts commit r358543/ab70da07286e618016e78247e4a24fcb84077fda. llvm-svn: 358546
* [HotColdSplit] Disable splitting for sanitized functionsVedant Kumar2019-02-261-0/+72
| | | | | | | | | | Splitting can make sanitizer errors harder to understand, as the trapping instruction may not be in the function where the bug was detected. rdar://48142697 llvm-svn: 354931
* [HotColdSplit] Introduce a cost model to control splitting behaviorVedant Kumar2019-01-252-88/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The main goal of the model is to avoid *increasing* function size, as that would eradicate any memory locality benefits from splitting. This happens when: - There are too many inputs or outputs to the cold region. Argument materialization and reloads of outputs have a cost. - The cold region has too many distinct exit blocks, causing a large switch to be formed in the caller. - The code size cost of the split code is less than the cost of a set-up call. A secondary goal is to prevent excessive overall binary size growth. With the cost model in place, I experimented to find a splitting threshold that works well in practice. To make warm & cold code easily separable for analysis purposes, I moved split functions to a "cold" section. I experimented with thresholds between [0, 4] and set the default to the threshold which minimized geomean __text size. Experiment data from building LNT+externals for X86 (N = 639 programs, all sizes in bytes): | Configuration | __text geom size | __cold geom size | TEXT geom size | | **-Os** | 1736.3 | 0, n=0 | 10961.6 | | -Os, thresh=0 | 1740.53 | 124.482, n=134 | 11014 | | -Os, thresh=1 | 1734.79 | 57.8781, n=90 | 10978.6 | | -Os, thresh=2 | ** 1733.85 ** | 65.6604, n=61 | 10977.6 | | -Os, thresh=3 | 1733.85 | 65.3071, n=61 | 10977.6 | | -Os, thresh=4 | 1735.08 | 67.5156, n=54 | 10965.7 | | **-Oz** | 1554.4 | 0, n=0 | 10153 | | -Oz, thresh=2 | ** 1552.2 ** | 65.633, n=61 | 10176 | | **-O3** | 2563.37 | 0, n=0 | 13105.4 | | -O3, thresh=2 | ** 2559.49 ** | 71.1072, n=61 | 13162.4 | Picking thresh=2 reduces the geomean __text section size by 0.14% at -Os, -Oz, and -O3 and causes ~0.2% growth in the TEXT segment. Note that TEXT size is page-aligned, whereas section sizes are byte-aligned. Experiment data from building LNT+externals for ARM64 (N = 558 programs, all sizes in bytes): | Configuration | __text geom size | __cold geom size | TEXT geom size | | **-Os** | 1763.96 | 0, n=0 | 42934.9 | | -Os, thresh=2 | ** 1760.9 ** | 76.6755, n=61 | 42934.9 | Picking thresh=2 reduces the geomean __text section size by 0.17% at -Os and causes no growth in the TEXT segment. Measurements were done with D57082 (r352080) applied. Differential Revision: https://reviews.llvm.org/D57125 llvm-svn: 352228
* [HotColdSplit] Mark inherently cold functions as suchVedant Kumar2019-01-191-0/+31
| | | | | | | | | | If an inherently cold function is found, mark it as cold. For now this means applying the `cold` and `minsize` attributes. As a drive-by, revisit and clean up the criteria for considering a function for splitting. Add tests. llvm-svn: 351623
* [HotColdSplit] Simplify tests by lowering their splitting thresholdsVedant Kumar2019-01-173-1/+165
| | | | | | | | This gets rid of the brittle/mysterious calls to @sink()/@sideeffect() peppered throughout the test cases. They are no longer needed to force splitting to occur. llvm-svn: 351480
* [HotColdSplitting] Use TTI to inform outlining thresholdVedant Kumar2018-11-042-0/+28
Using TargetTransformInfo allows the splitting pass to factor in the code size cost of instructions as it decides whether or not outlining is profitable. This did not regress the overall amount of outlining seen on the handful of internal frameworks I tested. Thanks to Jun Bum Lim for suggesting this! Differential Revision: https://reviews.llvm.org/D53835 llvm-svn: 346108
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