[llvm] Calculate KnownBits from Metadata correctly for vector loads (PR #128908)

[Matt Arsenault via llvm-commits]

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@@ -4004,22 +4004,25 @@ KnownBits SelectionDAG::computeKnownBits(SDValue Op, const APInt &DemandedElts,
         }
       }
     } else if (Op.getResNo() == 0) {
-      KnownBits Known0(!LD->getMemoryVT().isScalableVT()
-                           ? LD->getMemoryVT().getFixedSizeInBits()
-                           : BitWidth);
+      unsigned MemorySize = !LD->getMemoryVT().isScalableVT()
+                                ? LD->getMemoryVT().getFixedSizeInBits()
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arsenm wrote:

This is using the full vector bitwidth. The range is in terms of the scalar element size 

https://github.com/llvm/llvm-project/pull/128908