[Clang][OpenMP] Add parsing/sema for dims modifier in num_teams and thread_limit (#206412)
Add parsing and sema support for `dims` modifier (OpenMP 6.1) in `num_teams` and
`thread_limit` clauses. Example:
```cpp
constexpr int N = 2;
#pragma omp teams num_teams(dims(3): x, y, z) thread_limit(dims(N): a, b)
{ ... }
```
[MC] Pack scheduling class entry counts (#202649)
Generated scheduling classes currently use at most 20 write-resource
entries and 35 write-latency entries, while read-advance counts reach
504. Narrow the two write counts to `uint8_t`, order the three table
indices before the three counts, and emit target-specific compile-time
bounds assertions in generated subtarget source.
This reduces `sizeof(MCSchedClassDesc)` from 14 to 12 bytes in release
builds and from 20 to 16 bytes with debug fields. Fully stripped arm64
`llvm-mca` decreases by 544,896 bytes (1.49%), and the stripped
all-tools multicall binary decreases by 528,376 bytes (0.368%).
Work towards #202616
AI tool disclosure: Co-authored with OpenAI Codex.
[Coroutines] Use destroy slot for CoroElide resume fallthrough
Fixes https://github.com/llvm/llvm-project/issues/188230
A switch coroutine with a CoroElide noalloc variant uses the frame destroy slot as a runtime discriminator: heap-allocated frames store the destroy clone, while allocation-elided frames store the cleanup clone. Its resume clone can reach a fallthrough coro.end after the final suspend.
The coroutine body can invoke a continuation before reaching that coro.end. A suspend_never continuation can complete and free its frame before control returns. When the callee frame was elided into that caller allocation, loading the destroy slot at coro.end reads freed storage, which AddressSanitizer reports as a use-after-free.
Load and cache the destroy function in the switch-resume entry block before executing the resume body, then tail-call the cached value at fallthrough coro.end. The cache retains the frame slot as the allocation discriminator without dereferencing an elided frame after the continuation returns.
Add a C++ CodeGen regression for the original suspend_never final-suspend shape and update CoroSplit tests to require the entry load.
Assisted-By: Codex GPT 5.5
[AMDGPU] Run early-cse<memssa> at the end of the full-LTO pipeline (#208461)
The regular (non-LTO) and ThinLTO function simplification pipelines run
an
EarlyCSE-with-MemorySSA pass near the start of the function pass
sequence, but
the full-LTO postlink pipeline does not. Without it, a redundant
load/store
round-trip can survive all the way to codegen; the later GVN/DSE in the
LTO
pipeline do not catch this particular pattern.
Rather than touch the target-independent LTO pipeline, register
early-cse<memssa> through the AMDGPU FullLinkTimeOptimizationLast
extension
point, so it runs at the end of the full-LTO middle-end (before codegen)
only
for AMDGPU.
Assisted-by: Claude Opus
[libc] Omit -fpie from the full build (#208343)
We shouldn't unconditionally set -fpie, users should be able to control
this with CMAKE_POSITION_INDEPENDENT_CODE.
[libc][math] Implement half precision lgamma function (#192834)
The implementation uses three distinct paths based on $|x|$:
- Small ($|x| < 0.66$): Fits a degree-12 Chebyshev for $h(t) =
\frac{\text{lgamma}(t) + \log(t)}{t}$, recovering $\text{lgamma}(t) = t
\cdot h - \log(t)$.
- Medium ($|x| \in [0.66, 3.37]$): Fits a degree-20 Chebyshev for $g(t)
= \frac{\text{lgamma}(t)}{(t-1)(t-2)}$
- Stirling ($|x| > 3.37$): Uses $(x-0.5) \cdot \log(x) - x +
\frac{\log(2\pi)}{2}$ plus 1/2/4/8-term Bernoulli corrections by
sub-range.
Special cases: NaN, +/-Inf -> +Inf, +/-0 pole, negative integer pole,
lgamma(1) = lgamma(2) = 0 exactly, overflow for large positive x.
Exhaustive tests pass in all 4 rounding modes.
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[Github] Install `llvm-tools` in libc container (#210414)
Currently, the libc container doesn't contain `llvm-tools`. we need to
use them in #200196 because we are not able to use `llvm-lit` without
building clang from source
[InstCombine] Fix 0.0 / x -> 0 folds when the divisor may be zero (#202482)
SimplifyDemandedUseFPClass folded 0/x to a signed zero, guarded only on
the divisor being non-NaN. But when x==0, the result is is NaN, not 0!
Require the divisor to be never (logical) zero, unless a NaN result
isn't demanded.
[IR][NFC] Avoid unneccessary move of analysis results (#210540)
While benchmarking CycleAnalysis, I noticed that each analysis result is
constructed on the stack first and then moved to its final place on the
heap. This is unnecessary -- directly construct the analysis result in
its final place. Consequently, analysis results can be immovable.
[DirectX] Fix `--dx-embed-debug` flag dependency (#210513)
This patch moves the definition of `cl::opt<std::string> PdbDebugPath`
from `DXContainerGlobals.cpp` to `DXILWriter/DXILWriterPass.cpp`,
reversing the dependency.
Fixes the layering violation in #204166.
[mlir-c] Expose hard-failure state in 1:N type conversion callback
The 1:N conversion callback returned MlirLogicalResult, which the binding
could only map to success or nullopt (try-another), leaving the C++
failure() state (fail without trying another conversion) unreachable.
Return a MlirTypeConverterConversionStatus enum instead, with Success,
Failure, and Declined states mapped to success(), failure(), and
std::nullopt respectively. Add a test covering the hard-failure path.
[mlir-c] Expose hard-failure state in 1:N type conversion callback
The 1:N conversion callback returned MlirLogicalResult, which the binding
could only map to success or nullopt (try-another), leaving the C++
failure() state (fail without trying another conversion) unreachable.
Return a MlirTypeConverterConversionStatus enum instead, with Success,
Failure, and Declined states mapped to success(), failure(), and
std::nullopt respectively. Add a test covering the hard-failure path.
