This was left out of the original patch (#142392) to simplify the
initial implementation. However, after refactoring the SVE
prologue/epilogue code in #162253, it's not much of an extension to
support this case.

The main change here is when restoring the SP from the FP for the SVE
restores, we may need an additional frame offset to move from the start
of the ZPR callee-saves to the start of the PPR callee-saves.

This patch also fixes a previously latent bug where we'd add the
`RealignmentPadding` when allocating the PPR locals, then again for the
ZPR locals. This was unnecessary as the stack only needs to be realigned
after all SVE allocations.

In https://github.com/llvm/llvm-project/pull/165720 we started using a
DWARF API (`llvm::dwarf::getTag`) from `BinaryFormat`. This patch makes
dwarfdump link against the necessary LLVM component.

This fixes following linker error that started occurring on some of the
bots:
```
[7758/8172] Linking CXX executable bin/llvm-dwarfdump
FAILED: bin/llvm-dwarfdump
: && /usr/bin/c++ -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wno-missing-field-initializers -pedantic -Wno-long-long -Wimplicit-fallthrough -Wno-uninitialized -Wno-nonnull -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-array-bounds -Wno-stringop-overread -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wno-misleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG -Wl,-rpath-link,/home/botworker/bbot/amdgpu-offload-ubuntu-22-cmake-build-only/build/./lib  -Wl,--gc-sections tools/llvm-dwarfdump/CMakeFiles/llvm-dwarfdump.dir/SectionSizes.cpp.o tools/llvm-dwarfdump/CMakeFiles/llvm-dwarfdump.dir/Statistics.cpp.o tools/llvm-dwarfdump/CMakeFiles/llvm-dwarfdump.dir/llvm-dwarfdump.cpp.o -o bin/llvm-dwarfdump  -Wl,-rpath,"\$ORIGIN/../lib:/home/botworker/bbot/amdgpu-offload-ubuntu-22-cmake-build-only/build/lib:"  lib/libLLVMAMDGPUDesc.so.22.0git  lib/libLLVMSPIRVDesc.so.22.0git  lib/libLLVMX86Desc.so.22.0git  lib/libLLVMAMDGPUInfo.so.22.0git  lib/libLLVMSPIRVInfo.so.22.0git  lib/libLLVMX86Info.so.22.0git  lib/libLLVMDebugInfoDWARF.so.22.0git  lib/libLLVMObject.so.22.0git  lib/libLLVMMC.so.22.0git  lib/libLLVMDebugInfoDWARFLowLevel.so.22.0git  lib/libLLVMTargetParser.so.22.0git  lib/libLLVMSupport.so.22.0git  -Wl,-rpath-link,/home/botworker/bbot/amdgpu-offload-ubuntu-22-cmake-build-only/build/lib && :
/usr/bin/ld: tools/llvm-dwarfdump/CMakeFiles/llvm-dwarfdump.dir/llvm-dwarfdump.cpp.o: undefined reference to symbol '_ZN4llvm5dwarf6getTagENS_9StringRefE'
/usr/bin/ld: /home/botworker/bbot/amdgpu-offload-ubuntu-22-cmake-build-only/build/./lib/libLLVMBinaryFormat.so.22.0git: error adding symbols: DSO missing from command line
collect2: error: ld returned 1 exit status

```

In simplifycfg/cvp/sccp, we eliminate dead edges of switches according
to the knownbits/range info of conditions. However, these approximations
may not meet the real-world needs when the domain of condition values is
sparse. For example, if the condition can only be either -3 or 3, we
cannot prove that the condition never evaluates to 1 (knownbits:
???????1, range: [-3, 4)).
This patch adds a helper function `collectPossibleValues` to enumerate
all the possible values of V. To fix the motivating issue,
`eliminateDeadSwitchCases` will use the result to remove dead edges.

Note: In
https://discourse.llvm.org/t/missed-optimization-due-to-overflow-check/88700
I proposed a new value lattice kind to represent such values. But I find
it hard to apply because the transition becomes much complicated.

Compile-time impact looks neutral:
https://llvm-compile-time-tracker.com/compare.php?from=32d6b2139a6c8f79e074e8c6cfe0cc9e79c4c0c8&to=e47c26e3f1bf9eb062684dda4fafce58438e994b&stat=instructions:u
This patch removes many dead error-handling codes:
https://github.com/dtcxzyw/llvm-opt-benchmark/pull/3012
Closes https://github.com/llvm/llvm-project/issues/165179.

AMDGCN flavoured SPIR-V has slightly different defaults from what the BE
adopts: it assumes all extensions are enabled, and expects nonsemantic
debug info to be generated. Furthermore, it is necessary to encode in
the resulting SPIR-V binary that what was generated was AMDGCN
flavoured, which we do by setting the Generator Version to `UINT16_MAX`
(which matches what we expect to see at reverse translation). We will
register this generator version at
<https://github.com/KhronosGroup/SPIRV-Headers>. This is a preliminary
patch out of a series of patches that are needed for adopting the BE for
AMDGCN flavoured SPIR-V generation.

This change aims to avoid inserting a freeze instruction between the
load and bitcast when scalarizing extend-extract. This is particularly
useful in combination with
https://github.com/llvm/llvm-project/pull/164682, which can then
potentially further scalarize, provided there is no freeze.

alive2 proof: https://alive2.llvm.org/ce/z/W-GD88

To follow-up on a post-commit review.

Also add a corresponding intrinsic property that can be used to mark
intrinsics that do not introduce poison, for example simple arithmetic
intrinsics that propagate poison just like a simple arithmetic
instruction.

As a smoke test this patch adds the new property to
llvm.amdgcn.fmul.legacy.