[clang] [llvm] [SystemZ] Support i128 as legal type in VRs (PR #74625)

[Ulrich Weigand via cfe-commits]

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@@ -2918,16 +3049,17 @@ static Comparison getCmp(SelectionDAG &DAG, SDValue CmpOp0, SDValue CmpOp1,
                          bool IsSignaling = false) {
   if (CmpOp1.getOpcode() == ISD::Constant) {
     assert(!Chain);
-    uint64_t Constant = cast<ConstantSDNode>(CmpOp1)->getZExtValue();
     unsigned Opcode, CCValid;
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uweigand wrote:

`getZExtValue` will crash when the constant is 128-bit, which can now happen.  Therefore I'm now only evaluating it in code paths where we know the constant cannot be 128-bit.

https://github.com/llvm/llvm-project/pull/74625