[llvm] [AArch64] Lower scalable i1 vector add reduction to cntp (PR #99031)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-x86_64-debian-dylib` running on `gribozavr4` while building `llvm` at step 7 "test-build-unified-tree-check-llvm".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/60/builds/3065

Here is the relevant piece of the build log for the reference:
```
Step 7 (test-build-unified-tree-check-llvm) failure: test (failure)
******************** TEST 'LLVM :: CodeGen/AArch64/sve-i1-add-reduce.ll' FAILED ********************
Exit Code: 2

Command Output (stderr):
--
RUN: at line 2: /b/1/llvm-x86_64-debian-dylib/build/bin/llc -mtriple=aarch64-linux-gnu -mattr=+sve < /b/1/llvm-x86_64-debian-dylib/llvm-project/llvm/test/CodeGen/AArch64/sve-i1-add-reduce.ll | /b/1/llvm-x86_64-debian-dylib/build/bin/FileCheck /b/1/llvm-x86_64-debian-dylib/llvm-project/llvm/test/CodeGen/AArch64/sve-i1-add-reduce.ll
+ /b/1/llvm-x86_64-debian-dylib/build/bin/FileCheck /b/1/llvm-x86_64-debian-dylib/llvm-project/llvm/test/CodeGen/AArch64/sve-i1-add-reduce.ll
+ /b/1/llvm-x86_64-debian-dylib/build/bin/llc -mtriple=aarch64-linux-gnu -mattr=+sve
LLVM ERROR: Cannot select: t14: nxv2i64 = AArch64ISD::UADDV_PRED t10, t2
  t10: nxv16i1 = AArch64ISD::PTRUE TargetConstant:i32<31>
    t9: i32 = TargetConstant<31>
  t2: nxv16i1,ch = CopyFromReg t0, Register:nxv16i1 %0
    t1: nxv16i1 = Register %0
In function: uaddv_zexti8_nxv16i1
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.	Program arguments: /b/1/llvm-x86_64-debian-dylib/build/bin/llc -mtriple=aarch64-linux-gnu -mattr=+sve
1.	Running pass 'Function Pass Manager' on module '<stdin>'.
2.	Running pass 'AArch64 Instruction Selection' on function '@uaddv_zexti8_nxv16i1'
 #0 0x00007f05310f96b7 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/b/1/llvm-x86_64-debian-dylib/build/lib/libLLVM.so.19.0git+0xe0e6b7)
 #1 0x00007f05310f717e llvm::sys::RunSignalHandlers() (/b/1/llvm-x86_64-debian-dylib/build/lib/libLLVM.so.19.0git+0xe0c17e)
 #2 0x00007f05310f9d8f SignalHandler(int) Signals.cpp:0:0
 #3 0x00007f05302d5140 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x13140)
 #4 0x00007f052fdfbce1 raise (/lib/x86_64-linux-gnu/libc.so.6+0x38ce1)
 #5 0x00007f052fde5537 abort (/lib/x86_64-linux-gnu/libc.so.6+0x22537)
 #6 0x00007f05310439fa llvm::report_fatal_error(llvm::Twine const&, bool) (/b/1/llvm-x86_64-debian-dylib/build/lib/libLLVM.so.19.0git+0xd589fa)
 #7 0x00007f0531c668cf llvm::SelectionDAGISel::CannotYetSelect(llvm::SDNode*) (/b/1/llvm-x86_64-debian-dylib/build/lib/libLLVM.so.19.0git+0x197b8cf)
 #8 0x00007f0531c65aac llvm::SelectionDAGISel::SelectCodeCommon(llvm::SDNode*, unsigned char const*, unsigned int) (/b/1/llvm-x86_64-debian-dylib/build/lib/libLLVM.so.19.0git+0x197aaac)
 #9 0x00007f053395a61d (anonymous namespace)::AArch64DAGToDAGISel::Select(llvm::SDNode*) AArch64ISelDAGToDAG.cpp:0:0
#10 0x00007f0531c59cff llvm::SelectionDAGISel::DoInstructionSelection() (/b/1/llvm-x86_64-debian-dylib/build/lib/libLLVM.so.19.0git+0x196ecff)
#11 0x00007f0531c58c8c llvm::SelectionDAGISel::CodeGenAndEmitDAG() (/b/1/llvm-x86_64-debian-dylib/build/lib/libLLVM.so.19.0git+0x196dc8c)
#12 0x00007f0531c5674b llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&) (/b/1/llvm-x86_64-debian-dylib/build/lib/libLLVM.so.19.0git+0x196b74b)
#13 0x00007f0531c53a60 llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&) (/b/1/llvm-x86_64-debian-dylib/build/lib/libLLVM.so.19.0git+0x1968a60)
#14 0x00007f0531c51226 llvm::SelectionDAGISelLegacy::runOnMachineFunction(llvm::MachineFunction&) (/b/1/llvm-x86_64-debian-dylib/build/lib/libLLVM.so.19.0git+0x1966226)
#15 0x00007f0531623fb0 llvm::MachineFunctionPass::runOnFunction(llvm::Function&) (/b/1/llvm-x86_64-debian-dylib/build/lib/libLLVM.so.19.0git+0x1338fb0)
#16 0x00007f05312be310 llvm::FPPassManager::runOnFunction(llvm::Function&) (/b/1/llvm-x86_64-debian-dylib/build/lib/libLLVM.so.19.0git+0xfd3310)
#17 0x00007f05312c4d71 llvm::FPPassManager::runOnModule(llvm::Module&) (/b/1/llvm-x86_64-debian-dylib/build/lib/libLLVM.so.19.0git+0xfd9d71)
#18 0x00007f05312be9c1 llvm::legacy::PassManagerImpl::run(llvm::Module&) (/b/1/llvm-x86_64-debian-dylib/build/lib/libLLVM.so.19.0git+0xfd39c1)
#19 0x0000000000412671 compileModule(char**, llvm::LLVMContext&) llc.cpp:0:0
#20 0x000000000040fc4d main (/b/1/llvm-x86_64-debian-dylib/build/bin/llc+0x40fc4d)
#21 0x00007f052fde6d0a __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x23d0a)
#22 0x000000000040ea7a _start (/b/1/llvm-x86_64-debian-dylib/build/bin/llc+0x40ea7a)
FileCheck error: '<stdin>' is empty.
FileCheck command line:  /b/1/llvm-x86_64-debian-dylib/build/bin/FileCheck /b/1/llvm-x86_64-debian-dylib/llvm-project/llvm/test/CodeGen/AArch64/sve-i1-add-reduce.ll

--

********************


```

https://github.com/llvm/llvm-project/pull/99031