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

[Shilei Tian via llvm-commits]

================
@@ -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)
----------------
shiltian wrote:

which is that the callee's CC doesn't match the call site's, and it should be a separate issue.

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