[llvm] [IR] Add icmp like matcher (NFC) (PR #192746)

[Yingwei Zheng via llvm-commits]

================
@@ -2314,6 +2314,35 @@ template <typename OpTy> inline auto m_ZExtOrTruncOrSelf(const OpTy &Op) {
   return m_CombineOr(m_ZExt(Op), m_Trunc(Op), Op);
 }
 
+template <typename LHS_t, typename RHS_t> struct IcmpLike_match {
+  CmpPredicate &Pred;
+  LHS_t L;
+  RHS_t R;
+
+  IcmpLike_match(CmpPredicate &P, const LHS_t &Left, const RHS_t &Right)
+      : Pred(P), L(Left), R(Right) {}
+
+  template <typename OpTy> bool match(OpTy *V) const {
+    if (PatternMatch::match(V, m_ICmp(Pred, L, R)))
+      return true;
+    Value *A;
+    // trunc nuw x to i1 is equivalent to icmp ne x, 0
+    if (V->getType()->isIntOrIntVectorTy(1) &&
+        PatternMatch::match(V, m_NUWTrunc(m_Value(A))) && L.match(A) &&
+        R.match(ConstantInt::getNullValue(A->getType()))) {
+      Pred = ICmpInst::ICMP_NE;
+      return true;
+    }
+    return false;
+  }
+};
+
+template <typename LHS, typename RHS>
+inline IcmpLike_match<LHS, RHS> m_IcmpLike(CmpPredicate &Pred, const LHS &L,
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dtcxzyw wrote:

```suggestion
inline IcmpLike_match<LHS, RHS> m_ICmpLike(CmpPredicate &Pred, const LHS &L,
```

https://github.com/llvm/llvm-project/pull/192746