[llvm] [DAG] Define computeConstantRange for VSCALE folding (PR #176027)

[Simon Pilgrim via llvm-commits]

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@@ -4534,10 +4524,8 @@ SelectionDAG::computeOverflowForUnsignedMul(SDValue N0, SDValue N1) const {
   if (isNullConstant(N1) || isOneConstant(N1))
     return OFK_Never;
 
-  KnownBits N0Known = computeKnownBits(N0);
-  KnownBits N1Known = computeKnownBits(N1);
-  ConstantRange N0Range = ConstantRange::fromKnownBits(N0Known, false);
-  ConstantRange N1Range = ConstantRange::fromKnownBits(N1Known, false);
+  ConstantRange N0Range = computeConstantRangeIncludingKnownBits(N0, false);
+  ConstantRange N1Range = computeConstantRangeIncludingKnownBits(N1, false);
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RKSimon wrote:

Its unlikely that you'll manage to get a change yet as the computeOverflow helpers aren't used that much yet beyond ADD/SUB CARRY folds, which don't use vectors much.

https://github.com/llvm/llvm-project/pull/176027