[llvm] [AMDGPU] Ensure non-reserved CSR spilled regs are live-in (PR #146427)

[Shilei Tian via llvm-commits]

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+; Just ensure that llc -O1 does not error out
+; RUN: llc -O1 -mtriple=amdgcn-amd-amdhsa -mcpu=gfx908 -verify-machineinstrs %s -o - &>/dev/null
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shiltian wrote:

Not sure if that's gonna work but maybe use the IR right before `amdgpu-isel` as the starting point, and then just run `amdgpu-isel` in the test script.

https://github.com/llvm/llvm-project/pull/146427