Changes

[VPlan] Mark overriden function in VPWidenPHIRecipe as virtual.

VPReductionRecipe overrides those implementations. Mark them as virtual
in the VPWidenPHIRecipe to unbreak build in certain configurations.

Revert "[VPlan] Add VPReductionPHIRecipe (NFC)." and follow-ups

This reverts commit 3fed6d443f802c43aade1b5b1b09f5e2f8b3edb1,
bbcbf21ae60c928e07dde6a1c468763b3209d1e6 and
6c3451cd76cbd0cd973d9c2b08b168dcd0bce3c2.

The changes causing build failures with certain configurations, e.g.
https://lab.llvm.org/buildbot/#/builders/67/builds/3365/steps/6/logs/stdio

    lib/libLLVMVectorize.a(LoopVectorize.cpp.o): In function `llvm::VPRecipeBuilder::tryToCreateWidenRecipe(llvm::Instruction*, llvm::ArrayRef<llvm::VPValue*>, llvm::VFRange&, std::unique_ptr<llvm::VPlan, std::default_delete<llvm::VPlan> >&) [clone .localalias.8]':
    LoopVectorize.cpp:(.text._ZN4llvm15VPRecipeBuilder22tryToCreateWidenRecipeEPNS_11InstructionENS_8ArrayRefIPNS_7VPValueEEERNS_7VFRangeERSt10unique_ptrINS_5VPlanESt14default_deleteISA_EE+0x63b): undefined reference to `vtable for llvm::VPReductionPHIRecipe'
    collect2: error: ld returned 1 exit status

[hwasan] Fix incorrect candidate matching for stack OOB.

We would find an address with matching tag, only to discover in
ShowCandidate that it's very far away from [stack].

Reviewed By: eugenis

Differential Revision: https://reviews.llvm.org/D105197

[CodeGen][AArch64][SVE] Use ld1r[bhsd] for vector splat from memory

This avoids the use of the vector unit for copying from scalar to
vector. There is an extra ptrue instruction, but a predicate register
with the ptrue pattern populated is likely to be free in the context of
real code.

Tests were generated from a template to cover the axes mentioned at the
top of the test file.

Co-authored-by: Francesco Petrogalli <francesco.petrogalli@arm.com>

Differential Revision: https://reviews.llvm.org/D103170

[LV] Prevent vectorization with unsupported element types.

This patch adds a TTI function, isElementTypeLegalForScalableVector, to query
whether it is possible to vectorize a given element type. This is called by
isLegalToVectorizeInstTypesForScalable to reject scalable vectorization if
any of the instruction types in the loop are unsupported, e.g:

  int foo(__int128_t* ptr, int N)
    #pragma clang loop vectorize_width(4, scalable)
    for (int i=0; i<N; ++i)
      ptr[i] = ptr[i] + 42;

This example currently crashes if we attempt to vectorize since i128 is not a
supported type for scalable vectorization.

Reviewed By: sdesmalen, david-arm

Differential Revision: https://reviews.llvm.org/D102253

[runtimes] Move enable_32bit to the DSL

This is necessary for from-scratch configurations to support the 32-bit
mode of the test suite.

Differential Revision: https://reviews.llvm.org/D105435

Revert "[profile][test] Improve coverage-linkage.cpp"

This reverts commit 36ba86fe8a29cdf3251b786db7f342efde666cb2.
Fails on some bots, see comments on
https://reviews.llvm.org/rG36ba86fe8a29cdf3251b786db7f342efde666cb2

[CostModel][X86] i8/i16 sitofp/uitofp are sext/zext to i32 for sitofp

Provide a generic fallback that extends sub-i32 scalars before using the existing sitofp instructions.

These numbers can be tweaked for specific sse levels, but we should get the default handling in place first.

We get the extension for free for non-vector loads.

Recommit "[VPlan] Add VPReductionPHIRecipe (NFC)." and follow-ups.

This reverts commit 706bbfb35bd31051e46ac77aab3e9b2dbc3abe78.

The committed version moves the definition of VPReductionPHIRecipe out
of an ifdef only intended for ::print helpers. This should resolve the
build failures that caused the revert

[libc++] NFC: Move the status docs to their own subdirectory

This cleans up the libcxx/doc directory quite a bit and will avoid the
proliferation of status files in that directory as new standards are voted.