[llvm] [VPlan] Peek through nested phi incoming values in computeBlendMasks (PR #203164)

[via llvm-commits]

github-actions[bot] wrote:

test-suite diff from d291bcd466edac6b0e21b6f6437462d763e337de...bd598881dc2f511283e3583c4f6648c2ef1f1697: https://github.com/llvm/llvm-project/actions/runs/33355969306/artifacts/9746606341

Statistics: https://github.com/llvm/llvm-project/actions/runs/33355969306/artifacts/9746606790

## riscv64-linux-gnu `-march=rva23u64 -O3`
| ('Program', '')    |   ('size..text', 'base') |   ('size..text', 'head') |   ('size..text', 'diff') |
|:-------------------|-------------------------:|-------------------------:|-------------------------:|
| Geomean difference |                      nan |                      nan |                        0 |
## aarch64-linux-gnu `-march=armv9-a -O3`
| ('Program', '')                             |   ('size..text', 'base') |   ('size..text', 'head') |   ('size..text', 'diff') |
|:--------------------------------------------|-------------------------:|-------------------------:|-------------------------:|
| test-suite...ProxyApps-C++/CLAMR/CLAMR.test |                   647848 |                   648000 |              0.000234623 |
| Geomean difference                          |                      nan |                      nan |              7.28557e-07 |
## x86_64-linux-gnu `-march=x86-64-v3 -O3`
| ('Program', '')                             |   ('size..text', 'base') |   ('size..text', 'head') |   ('size..text', 'diff') |
|:--------------------------------------------|-------------------------:|-------------------------:|-------------------------:|
| test-suite...ProxyApps-C++/CLAMR/CLAMR.test |                   746320 |                   746480 |              0.000214385 |
| Geomean difference                          |                      nan |                      nan |              6.61612e-07 |


https://github.com/llvm/llvm-project/pull/203164