[llvm] [SLP]Support for zext i1 %x modeling as select %x, 1, 0 (PR #180635)

[via llvm-commits]

Andarwinux wrote:

```
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0.      Program arguments: clang++ -std=c++20 -O3 X86ISelLowering-ca360a.cpp -c -w
1.      <eof> parser at end of file
2.      Optimizer
3.      Running pass "function<eager-inv>(drop-unnecessary-assumes,float2int,lower-constant-intrinsics,chr,loop(loop-rotate<header-duplication;no-prepare-for-lto>,loop-deletion),loop-distribute,inject-tli-mappings,loop-vectorize<no-interleave-forced-only;no-vectorize-forced-only;>,drop-unnecessary-assumes,infer-alignment,loop-load-elim,instcombine<max-iterations=1;no-verify-fixpoint>,simplifycfg<bonus-inst-threshold=1;forward-switch-cond;switch-range-to-icmp;switch-to-arithmetic;switch-to-lookup;no-keep-loops;hoist-common-insts;no-hoist-loads-stores-with-cond-faulting;sink-common-insts;speculate-blocks;simplify-cond-branch;no-speculate-unpredictables>,slp-vectorizer,vector-combine,instcombine<max-iterations=1;no-verify-fixpoint>,loop-unroll<O3>,transform-warning,sroa<preserve-cfg>,infer-alignment,instcombine<max-iterations=1;no-verify-fixpoint>,loop-mssa(licm<allowspeculation>),alignment-from-assumptions,loop-sink,instsimplify,div-rem-pairs,tailcallelim,simplifycfg<bonus-inst-threshold=1;no-forward-switch-cond;switch-range-to-icmp;switch-to-arithmetic;no-switch-to-lookup;keep-loops;no-hoist-common-insts;hoist-loads-stores-with-cond-faulting;no-sink-common-insts;speculate-blocks;simplify-cond-branch;speculate-unpredictables>)" on module "X86ISelLowering-ca360a.cpp"
4.      Running pass "slp-vectorizer" on function "_ZNK4llvm17X86TargetLowering17LowerBUILD_VECTORENS_7SDValueERNS_12SelectionDAGE"
#0 0x000060c573247f26 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) Signals.cpp:0:0
```
[X86ISelLowering-ca360a.cpp](https://github.com/user-attachments/files/25213843/X86ISelLowering-ca360a.cpp)


https://github.com/llvm/llvm-project/pull/180635