[llvm] [RISCV] Use APInt in isSimpleVIDSequence to account for index overflow (PR #100072)

[Pengcheng Wang via llvm-commits]

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@@ -3408,21 +3412,21 @@ static std::optional<VIDSequence> isSimpleVIDSequence(SDValue Op,
       // Calculate the step since the last non-undef element, and ensure
       // it's consistent across the entire sequence.
       unsigned IdxDiff = Idx - PrevElt->second;
-      int64_t ValDiff = SignExtend64(*Elt - PrevElt->first, EltSizeInBits);
+      APInt ValDiff = *Elt - PrevElt->first;
 
       // A zero-value value difference means that we're somewhere in the middle
       // of a fractional step, e.g. <0,0,0*,0,1,1,1,1>. Wait until we notice a
       // step change before evaluating the sequence.
       if (ValDiff == 0)
         continue;
 
-      int64_t Remainder = ValDiff % IdxDiff;
+      int64_t Remainder = ValDiff.srem(IdxDiff);
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wangpc-pp wrote:

Should we use `APInt` for `Remainder` too?

https://github.com/llvm/llvm-project/pull/100072