Chris Fallin
eaf8647fdf
BitVec: remove zero words to avoid expanding when unnecessary.
2021-08-12 14:40:18 -07:00
Chris Fallin
82b7e6ba7b
Review feedback: bitvec: struct-like enum variants, and factor out one-item cache.
2021-08-12 14:33:35 -07:00
Chris Fallin
7652b4b109
Review feedback.
2021-08-12 14:27:20 -07:00
Chris Fallin
2f856435f4
Review feedback.
2021-08-12 14:08:10 -07:00
Chris Fallin
b76b7747d0
Fix comment in postorder.rs.
2021-08-12 14:00:20 -07:00
Chris Fallin
1f30958b5a
Improve domtree as per @Amanieu's feedback.
2021-08-12 12:13:56 -07:00
Chris Fallin
3e1e0f39b6
Convert all log::debug to log::trace.
2021-08-12 12:05:19 -07:00
Chris Fallin
38323e0c27
Some more design-doc and TODO updates from @julian-seward1's feedback.
2021-08-12 11:39:38 -07:00
Chris Fallin
0c795842fd
Add some more detail about spill bundles to design doc.
2021-08-12 11:26:45 -07:00
Chris Fallin
a591535fe9
Use "vector" or "sequence" in lieu of "list" in DESIGN.md, except when referring to linked lists.
...
From feedback from @julian-seward1. I had used "list" in a more generic
sense, meaning ordered sequence of elements, while in a Rust context it
can sometimes be confused with "linked list" specifically. These
alternative terms are more precise.
2021-08-12 11:23:47 -07:00
Chris Fallin
84285c26fb
Rename OperandPolicy to OperandConstraint as per feedback from @julian-seward1.
2021-08-12 11:17:52 -07:00
Chris Fallin
c9e8a87cea
Update TODO with new items from private feedback from @julian-seward1.
2021-08-12 11:17:37 -07:00
Chris Fallin
4c193a9499
Fix heuristic-cost function overflow with high loop depth (found by @Amanieu).
2021-07-28 12:37:32 -07:00
Chris Fallin
66d6821c7b
Fix perf issue with many safepoints.
...
In wasmtime's `gc::many_live_refs` unit-test, approximately ~1K vregs
are live over ~1K safepoints (actually, each vreg is live over half the
safepoints on average, in a LIFO sort of arrangement).
This causes a huge slowdown with the current heuristics. Basically, each
vreg had a `Conflict` requirement because it had both stack uses
(safepoints) and register uses (the actual def and normal use). The
action in this case when processing the vreg's bundle is to split off
the first use -- a conservative-but-correct approach that will always
eventually split bundles far enough to get non-conflicting-requirement
pieces.
However, because each vreg had N stack uses followed by one register
use, this meant that each had to be split N times (!) -- so we had
O(n^2) splits and O(n^2) bundles by the end of the allocation.
This instead implements another simple heuristic that is much better:
when the requirements are conflicting, scan forward and find the exact
point at which the requirements become conflicting, such that the prefix
(first half prior to the split) still has no conflict, and split there.
This turns the above test-case into an O(n)-bundle / O(n)-split
situation.
2021-06-22 14:06:59 -07:00
Chris Fallin
f27abc9c48
Remove infinite-loop check: it is not a high enough bound in some pathological cases (e.g., gc::many_live_refs test in wasmtime), and it has served its purpose in testing. We can rely on more detailed assertions, e.g. that splits actually shrink bundles and that bundles evict only lower-priority bundles, instead.
2021-06-22 12:06:12 -07:00
Chris Fallin
245c212289
Revert "Add fixed-non-allocatable operand support."
...
This feature needs more thought; for now we will of course continue to
support pinned vregs, but perhaps we can do better for
"pass-through-and-forget" operands that are given non-allocatable
registers.
This reverts commit 736f636c36
2021-06-20 23:03:44 -07:00
Chris Fallin
21fb233809
reduce nesting level in DESIGN.md to make pandoc-to-pdf happy
2021-06-19 13:41:26 -07:00
Chris Fallin
a58d36fd94
TODO update: make note on idea for large-input support
2021-06-19 13:20:11 -07:00
Chris Fallin
22eed0a6ae
Make bitvec public; it is used by regalloc.rs shim too.
2021-06-19 12:47:02 -07:00
Chris Fallin
736f636c36
Add fixed-non-allocatable operand support.
2021-06-19 12:17:18 -07:00
Chris Fallin
50eb6fc42f
Keep internal modules private, but re-export under fuzzing feature flag
2021-06-19 12:08:37 -07:00
Chris Fallin
caf7274efd
Remove unused pred_pos
2021-06-19 11:48:54 -07:00
Chris Fallin
36975b8b6f
Add doc-comment note on Edit that stack-to-stack moves are never generated.
2021-06-19 11:34:05 -07:00
Chris Fallin
b36a563d69
Cleanup: split allocator implemntation into 11 files of more reasonable size.
2021-06-18 16:51:41 -07:00
Chris Fallin
6944bc4735
Fix typo (thanks @bjorn3).
...
Co-authored-by: bjorn3 <bjorn3@users.noreply.github.com >
2021-06-18 15:24:11 -07:00
Chris Fallin
6ec6207717
Add design document.
2021-06-18 13:59:12 -07:00
Chris Fallin
a686d5a513
Always recompute prio when recomputing bundle properties; otherwise is zero on new bundles and causes spill weight to be zeroed
2021-06-11 13:21:50 -07:00
Chris Fallin
ea814225a2
Update TODO list
2021-06-10 23:34:18 -07:00
Chris Fallin
1bd1248cb5
Avoid stack-to-stack moves by allocating an extra spillslot and re-using the scratch reg instead.
2021-06-10 22:36:02 -07:00
Chris Fallin
09b2dd4e73
TODO list update
2021-06-10 17:34:04 -07:00
Chris Fallin
fcbf384d74
Use hashset to avoid linear scan in conflict-bundle-set deduplication
2021-06-09 23:53:54 -07:00
Chris Fallin
4ba7b2f57e
Improve redundant-move elimination: don't skip the case where we don't hvae vreg metadata within a BB. Instead, keep the checker happy by feeding more metadata to it on every move.
2021-06-09 23:29:48 -07:00
Chris Fallin
2851ac80c7
Working redundant-move elimination
2021-06-09 23:03:16 -07:00
Chris Fallin
f898b8dcbd
Some fuzzbug fixes
2021-06-09 20:58:54 -07:00
Chris Fallin
e33790d8e7
do not remove redundant move if we don't have local (within-basic-block) vreg tags, as this might throw off the checker
2021-06-08 01:30:29 -07:00
Chris Fallin
0f270e5bcc
WIP.
2021-06-08 01:14:10 -07:00
Chris Fallin
940bc40fae
Redundant move eliminator.
2021-06-08 00:08:28 -07:00
Chris Fallin
c6bcd3c941
WIP: redundant-move elimination.
2021-06-07 21:15:32 -07:00
Chris Fallin
2be7bdbc22
Split-at-first-conflict: first conflict is first of (start of our range), (start of conflict range), not just the latter; otherwise we have a too-early split sometimes
2021-06-07 12:27:58 -07:00
Chris Fallin
0eaa0fde06
Fix to checker: analyze all blocks, even if out-state of entry block is empty
2021-06-05 14:47:55 -07:00
Chris Fallin
30f42a8717
Fix fuzzbug: properly detect too-many-live-regs condition on fuzzing input. Must be careful in how we probe the BTree when we have multiple "equal" (overlapping) keys.
2021-06-03 23:48:33 -07:00
Chris Fallin
5560499b80
Adaptive commitment-map scanning: re-probe from root if we skip too many entries in linear BTree scan
2021-06-03 18:17:28 -07:00
Chris Fallin
00e4240c93
merge bundles much faster by just concatenating range-lists and unstable-sorting, rather than a merge-sort-like traversal. Rust stdlib sort is very optimized. clang.wasm 9.1s -> 6.8s now.
2021-06-03 17:34:19 -07:00
Chris Fallin
6a0739b62a
Implement spill-bundle: move all empty ranges, and empty leading/trailing pieces surrounding split points, to a single spill bundle, in an attempt to avoid excessive movement
2021-06-03 00:18:27 -07:00
Chris Fallin
dc2b0d1913
Add a perf idea to TODO list
2021-06-01 23:13:08 -07:00
Chris Fallin
2fe276ca04
BTreeMap probe fix (fuzzbug): BTree does not interact nicely with LiveRangeKey definition of equality; need to probe with one-less-than start to get proper range
2021-06-01 23:10:34 -07:00
Chris Fallin
a2a770ec50
Fuzzbug fix
2021-06-01 18:57:07 -07:00
Chris Fallin
2614eac21e
fuzzbug fix: restore clean error exit required by regalloc.rs fuzzer on too-many-live-regs error
2021-06-01 16:31:33 -07:00
Chris Fallin
e49727dc75
Fuzzbug fix: fix some weirdness with BTree iteration inner loop
2021-06-01 15:32:12 -07:00
Chris Fallin
44ca1893c3
Fuzzbug fix: properly check for conflicting reqs before merging bundles (cached values are not computed yet)
2021-06-01 14:52:59 -07:00
