Revert "[analyzer] Model strchr/strrchr/memchr/strstr/strpbrk/strchrnul (#207267)"
This reverts commit a34cb573eae65f48f0e51147289e042a86b55d16.
This feature caused some issues (#209905), so the best course of
action is to postpone it to clang-24 and revert from this branch.
The #210154 tried to fix the surfaced issue, and considered to nominate
it for backport in #211832, but ultimately we had to revert it from
main in #211857 - this confirms that probably the best action is to
revert the half-baked feature from the release branch.
This means that #203260 won't be fixed in clang-23, and that's fine.
Reapply "[VPlan] Re-use VPSlotTracker when printing recipes for costs (NFC)." (#209003) (#211763)
This reverts commit 4c7948d06c93e8d233cd4733fd4107f3b68bc7bc. The commit
always constructs slot on first use, to fix compile-time regressions in
release builds.
Original message:
VPRecipeBase::dump() constructs a fresh VPSlotTracker instance on each
call. VPSlotTracker construction requires iterating over all recipes in
the plan, to number all VPValues.
To avoid doing lots of unnecessary work when printing VPlan costs,
construct a shared VPSlotTracker in VPCostContext, re-used by all
prints.
This can speed up debug output for large loops.
PR: https://github.com/llvm/llvm-project/pull/203386
[ConstraintElim] Re-organize tests with decomposition failures (NFC). (#212130)
Add more tests for failed decomposition, consolidate them in
partial-decomposition.ll.
[mlir][arith] Fold trivial integer division and remainder (#212074)
Add value-preserving folds mirroring LLVM's InstructionSimplify for the
integer division and remainder ops:
```
divui/divsi/ceildivui/ceildivsi/floordivsi(0, x) -> 0
divui/divsi/ceildivui/ceildivsi/floordivsi(x, x) -> 1
remui/remsi(0, x) -> 0
remui/remsi(x, x) -> 0
```
The self and zero-dividend cases are valid refinements because division
or remainder by zero is undefined behaviour; no overflow flags are
required. The folds return a scalar or splat constant and bail out on
shaped types with a dynamic shape.
Folding `x / 0` and `x % 0` to poison is left as a TODO: it would make
the arith dialect depend on the ub dialect to materialize `ub.poison`.
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[libc++][chrono] Implement LWG 4274: Allow chrono::hh_mm_ss to be constructed from unsigned durations (#209686)
**_Implementation details_**:
- Use `is_unsigned_v` instead of `numeric_limits<Rep>::is_signed`, which
is used by `chrono::abs`. `numeric_limits<Rep>::is_signed` may return
false when a custom `Rep` does not specialize `numeric_limits`. Relying
on it to detect the unsigned case could therefore be unreliable for such
a type. `is_unsigned_v` instead gives a compile-time path for built-in
unsigned types, while the sign check keeps signed types correct.
- The constructor calls `__abs_d` four times because each member is
initialized separately. This should not affect runtime performance
because the compiler should inline `__abs_d` and eliminate the repeated
calculations. We could use another helper function or helper class to
explicitly compute the absolute duration only once. However, this would
add extra glue code, and the added complexity is not worthwhile I think.
---------
Co-authored-by: A. Jiang <de34 at live.cn>
[libc++][NFC] Inline fstream functions into the class body (#211738)
The `fstream` member functions are all really short, so inlining them
removes quite a bit of boiler plate code.
[flang][OpenMP] Split DEFAULT into DEFAULT(dsa) and DEFAULT(variant)
The 5.0 and 5.1 specs used DEFAULT clause for what is now OTHERWISE.
Separate these two claues to be able to specify their properties
independently.
[clang][CFG] Fix compound assignment evaluation order (#212115)
CompoundAssignOperator (e.g. `+=`, `-=`, `<<=`) is a distinct StmtClass
deriving from BinaryOperator, but it was not handled in the CFGBuilder
dispatch switches. As a result it fell through to the generic default
path (VisitChildren over reverse_children), which emits the LHS before
the RHS in the CFG.
Per C++17 [expr.ass]/1, all assignment operators - simple and compound -
sequence the right operand before the left operand. Route
CompoundAssignOperator through VisitBinaryOperator (and
VisitBinaryOperatorForTemporaries), whose existing isAssignmentOp()
branch already emits the RHS before the LHS, matching simple assignment.
This mirrors the class of evaluation-order defect fixed for lambda
captures in f3b31871e9b8.
rdar://183253943
Assisted-By: claude
[libc++][pstl] Implementation of a parallel std::mismatch() based on __pstl::__parallel_find() (#209291)
This PR adds a parallel version of `std::mismatch` as one of the backend
operations.
It also provides an implementation based on `__pstl::__parallel_find()`
which does the heavy lifting.
`libdispatch` and `std_thread` backends expose this implementation under
their backend tags, while the `serial` backend redirects the calls to
the serial `std::mismatch`.
4 flavours of the function are exposed: 3-legged, 3-legged with
predicate, 4-legged, 4-legged with predicate.
3-legged flavours are implemented in the `default` (`composition`)
backend by redirecting the call to the 4-legged flavours.
Included tests check that:
- Semantics of the iterator-only functions is correct.
- Semantics of the predicated functions is correct.
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[libc][cpp::string] Allocate fewer temp strings in operator= and += (#210895)
This PR generally updates `cpp::string` to avoid incidental allocations.
Specifically, it:
- Updates `opreator=(string_view)` to avoid allocating a temporary
string:
https://github.com/llvm/llvm-project/blob/67ebc4b221c3e94028b33004cd5cd08deee95048/libc/src/__support/CPP/string.h#L106-L108
- Changes `operator+=(const string&)` to accept a `string_view` so that
strings may be appended without allocation.
- Makes the `string(string_view)` constructor explicit. Before, there
were non-obvious allocations because of the implicit conversion.
As a side effect, this PR has to more carefully handle self-assignment
and self-append. This PR updates append and assignment to avoid calling
`realloc` during append / assignment, as this may invalidate input
pointers held by `string_view` if they point to data held by the string.
This also fixes self-assignment, which previously didn't work, eg
`cpp::string s = "abc"; s = s;` would zero out `s`.
[libc++abi][NFC] Remove some XFAILs which never trigger (#211241)
The oldest library we support is from LLVM 12, so we can remove any
XFAILs for libraries built before that.
[analyzer] Fix _Atomic crashes for Z3 symbolic execution (#212050)
This PR fixes _Atomic crashes for Z3 symbolic execution by passing the
types through getAtomicUnqualifiedType and getCanonicalType and skip
casting in fromCast if `FromTy == ToTy && FromBitWidth == ToBitWidth`.
Assisted-by: Codex
[llvm][ADT] Mark llvm::IntrusiveRefCntPtr with the warn_unused attribute (#211795)
IntrusiveRefCntPtr has non-trivial ctor/dtor, thus unused variables
wouldn't trigger a warning by default. However, they should.
https://clang.llvm.org/docs/AttributeReference.html#warn-unused
Let's mark the class with this attribute get warned about them.
This would have helped catching #211518 and #211517.
Supersedes #211647.
Some tests had to be uplifted because some bots used `-Werror` for those tests.
[SimplifyCFG] Don't create new unreachable BB in `turnSwitchRangeIntoICmp` (#212035)
Previously we relied on `createUnreachableSwitchDefault` to remove
incoming edges in phi nodes and update DT. However, it also creates a
new unreachable BB and updates the default destination of the switch
instruction, which is about to be replaced by a branch instruction. This
patch inlines the function and removes logic about the new BB, to make
sure the DT is updated correctly.
This issue cannot be reproduced via
-simplifycfg-require-and-preserve-domtree=1. I just found it by checking
DT in requestResimplify (will be added after fixing all existing
issues). The following test covers this case:
https://github.com/llvm/llvm-project/blob/5bc304c65494702d9d4928ff6cb369e6e6496e53/llvm/test/Transforms/SimplifyCFG/switch-range-to-icmp.ll#L38-L73
