[llvm] [GlobalISel] Exclude scalar to ptr unmerges from unmerge_dead_to_trunc combiner (PR #206707)

[via llvm-commits]

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@@ -2469,8 +2469,8 @@ bool CombinerHelper::matchCombineUnmergeWithDeadLanesToTrunc(
     MachineInstr &MI) const {
   assert(MI.getOpcode() == TargetOpcode::G_UNMERGE_VALUES &&
          "Expected an unmerge");
-  if (MRI.getType(MI.getOperand(0).getReg()).isVector() ||
-      MRI.getType(MI.getOperand(MI.getNumDefs()).getReg()).isVector())
+  if (!MRI.getType(MI.getOperand(0).getReg()).isScalar() ||
+      !MRI.getType(MI.getOperand(MI.getNumDefs()).getReg()).isScalar())
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KRM7 wrote:

Added another test case for this as well

https://github.com/llvm/llvm-project/pull/206707