[lldb][Windows] Invalidate cached register values on thread stop (#192430)
Invalidate cached values in register context data structures on every
thread stop.
NativeRegisterContextRegisterInfo::InvalidateAllRegisters performs no
operation by default. Subclasses may override it to clear cached values
within their register context data structures whenever a thread stops.
This change intends to set up the necessary infrastructure to support
caching of the thread context in NativeRegisterContextWindows_arm64,
which will improve read performance. Currently, the thread context is
retrieved for every read or write operation.
[AArch64] Improve post-inc stores of SIMD/FP values
Add patterns to match post-increment truncating stores from lane 0 of
wide integer vectors (v4i32/v2i64) to narrower types (i8/i16/i32).
This avoids transferring the value through a GPR when storing.
Also remove the pre-legalization early-exit in combineStoreValueFPToInt
as it prevented the optimization from applying in some cases.
[AArch64] Improve post-inc stores of SIMD/FP values
Add patterns to match post-increment truncating stores from lane 0 of
wide integer vectors (v4i32/v2i64) to narrower types (i8/i16/i32).
This avoids transferring the value through a GPR when storing.
Also remove the pre-legalization early-exit in combineStoreValueFPToInt
as it prevented the optimization from applying in some cases.
[LoopPeel] Peel last iteration to enable load widening
In loops that contain multiple consecutive small loads (e.g., 3 bytes
loading i8's), peeling the last iteration makes it safe to read beyond
the accessed region, enabling the use of a wider load (e.g., i32) for
all other N-1 iterations.
Patterns such as:
```
%a = load i8, ptr %p
%b = load i8, ptr %p+1
%c = load i8, ptr %p+2
...
%p.next = getelementptr i8, ptr %p, 3
```
Can be transformed to:
```
%wide = load i32, ptr %p ; Read 4 bytes
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[DAG][GISel] Rename CTTZ_ZERO_UNDEF/CTLZ_ZERO_UNDEF/CTTZ_ELTS_ZERO_UNDEF -> CTTZ_ZERO_POISON/CTLZ_ZERO_POISON/CTTZ_ELTS_ZERO_POISON (#196732)
DAG/GISel are ambiguous about whether zero-input results in
UNDEF/POISON, unlike the rest of LLVM which makes it clear its POISON.
I've tried to clean this up once and for all by ensuring
SelectionDAG::canCreateUndefOrPoison does a includesPoison(Kind) check,
renaming the opcodes (including the VP variants) and updating as many
comments/tests as possible (I may still have missed some...).
[cmake] use target names instead of legacy variables (#185463)
Use the [name of the imported
targets](https://cmake.org/cmake/help/latest/module/CheckSymbolExists.html)
when testing the libraries during cmake configuration. This removes the
need to also set `CMAKE_REQUIRED_INCLUDES` and
`CMAKE_REQUIRED_DEFINITIONS` and reflects more modern CMake usage where
targets are preferred over variables.
This is already the case when checking libcurl in the same file.
[Clang] Transform lambda's constraints when instantiating parameter mapping (#195995)
This way we can remove a few workarounds of lambda expressions where
outer template arguments of concepts have to be preserved through
ImplicitConceptSpecializationDecls.
Fixes #193944
