[SLP] Fix Wsign-compare warning (NFC)

[CoTinker]

llvm-project/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp:4805:57:
warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::size_t’ {aka ‘long unsigned int’} [-Wsign-compare]
[](const auto &P) { return P.value() % 2 != P.index() % 2; }))
~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~

[llvmbot]

@llvm/pr-subscribers-llvm-transforms

@llvm/pr-subscribers-vectorizers

Author: Longsheng Mou (CoTinker)

Changes

llvm-project/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp:4805:57:
warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::size_t’ {aka ‘long unsigned int’} [-Wsign-compare]
[](const auto &P) { return P.value() % 2 != P.index() % 2; }))
~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~

---

Full diff: https://github.com/llvm/llvm-project/pull/131948.diff

1 Files Affected:

• (modified) llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp (+3-1)

diff --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
index 24171f1d9a065..d13d7b75e3913 100644
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -4802,7 +4802,9 @@ BoUpSLP::findReusedOrderedScalars(const BoUpSLP::TreeEntry &TE,
     if (!Entries.front().front()->ReuseShuffleIndices.empty() &&
         TE.getVectorFactor() == 2 && Mask.size() == 2 &&
         any_of(enumerate(Entries.front().front()->ReuseShuffleIndices),
-               [](const auto &P) { return P.value() % 2 != P.index() % 2; }))
+               [](const auto &P) {
+                 return P.value() % 2 != static_cast<int>(P.index()) % 2;
+               }))
       return std::nullopt;
 
     // Perfect match in the graph, will reuse the previously vectorized