[llvm] [GISEL] Add G_VSCALE instruction (PR #84542)

[Michael Maitland via llvm-commits]

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@@ -0,0 +1,15 @@
+# RUN: not --crash llc -verify-machineinstrs -run-pass none -o /dev/null %s 2>&1 | FileCheck %s
+
+---
+name:            g_vscale
+body: |
+  bb.0:
+
+  %1:_(s32) = G_CONSTANT 4
+
+  ; CHECK: G_VSCALE operand must be cimm
+  %2:_(s32) = G_VSCALE %1
+
+  ; CHECK: G_VSCALE immediate cannot be zero
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michaelmaitland wrote:

@tschuett I changed `src` to `imm` but it doesn't seem to fix the problem 

https://github.com/llvm/llvm-project/pull/84542