[llvm] [WIP][ScalarEvolution] Replace getSCEV call with computeConstantRange (PR #152769)

[Danila Malyutin via llvm-commits]

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@@ -6945,7 +6945,16 @@ const ConstantRange &ScalarEvolution::getRangeRef(
         ConstantRange RangeFromOps(BitWidth, /*isFullSet=*/false);
 
         for (const auto &Op : Phi->operands()) {
-          auto OpRange = getRangeRef(getSCEV(Op), SignHint, Depth + 1);
+          ConstantRange OpRange = RangeFromOps;
+          if (auto *S = getExistingSCEV(Op)) {
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danilaml wrote:

Yeah, this was just an attempt to limit regressions for this approach.

https://github.com/llvm/llvm-project/pull/152769