[llvm] IR/Verifier: Do not allow kernel to kernel calls. (PR #144445)

[Matt Arsenault via llvm-commits]

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@@ -0,0 +1,9 @@
+; RUN: not llvm-as %s -disable-output 2>&1 | FileCheck %s
+
+define amdgpu_kernel void @kernel(ptr addrspace(1) %out, i32 %n) {
+entry:
+; CHECK: calling convention does not permit calls
+; CHECK-NEXT: call void @kernel(ptr addrspace(1) %out, i32 %n)
+  call void @kernel(ptr addrspace(1) %out, i32 %n)
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arsenm wrote:

I think we should deal with this in codegen. From an IR perspective, nothing is structurally wrong. Codegen should still be able to set up a call to the kernel as-if it were a callable function

https://github.com/llvm/llvm-project/pull/144445