[llvm] [GlobalISel] support lowering of G_SHUFFLEVECTOR with pointer args (PR #141959)

[Matt Arsenault via llvm-commits]

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@@ -0,0 +1,22 @@
+# RUN: llc -march=amdgcn -run-pass=legalizer -verify-machineinstrs %s -o -
+
+--- |
+  define i32 @test() {
+    unreachable
+  }
+...
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arsenm wrote:

```suggestion
```

https://github.com/llvm/llvm-project/pull/141959