[llvm] [SCCP] Relax two-instruction range checks (PR #158495)

[Yingwei Zheng via llvm-commits]

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@@ -284,6 +286,54 @@ static Value *simplifyInstruction(SCCPSolver &Solver,
     return Sub;
   }
 
+  // Relax range checks.
+  if (auto *ICmp = dyn_cast<ICmpInst>(&Inst)) {
+    Value *X;
+    auto MatchTwoInstructionExactRangeCheck =
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dtcxzyw wrote:

I used to add a common helper in ValueTracking. But I finally decided to duplicate the code because they have different one-use constraints from each other.

https://github.com/llvm/llvm-project/pull/158495