[llvm] [SCCP] Remove masking operations (PR #142736)

[Florian Hahn via llvm-commits]

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@@ -232,6 +234,33 @@ static bool replaceSignedInst(SCCPSolver &Solver,
   return true;
 }
 
+/// Try to use \p Inst's value range from \p Solver to simplify it.
+static Value *simplifyInstruction(SCCPSolver &Solver,
+                                  SmallPtrSetImpl<Value *> &InsertedValues,
+                                  Instruction &Inst) {
+  auto GetRange = [&Solver, &InsertedValues](Value *Op) {
+    if (auto *Const = dyn_cast<Constant>(Op))
+      return Const->toConstantRange();
+    if (InsertedValues.contains(Op)) {
+      unsigned Bitwidth = Op->getType()->getScalarSizeInBits();
+      return ConstantRange::getFull(Bitwidth);
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fhahn wrote:

Would be good to document that this is conservative handling for instructions inserted during simplification, i.e. no range info available.

https://github.com/llvm/llvm-project/pull/142736