[llvm] [AMDGCN] Allow unscheduling of bundled insns (PR #129769)

[Julian Brown via llvm-commits]

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+; RUN: llc -mtriple=amdgcn -mcpu=gfx90a -verify-machineinstrs -O1 -stop-after=machine-scheduler < %s | FileCheck -check-prefix=DEBUG %s
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jtb20 wrote:

I'm not quite confident I can come up with a fully synthetic example -- it'd need to trigger the unscheduling behaviour to exhibit the bug. Also I didn't have much luck with llvm-reduce (it crashed rather than reducing the test... maybe a separate bug!). So I used old-fashioned "delta" instead, which does give a smaller test, but my attempts to further reduce it manually didn't get very far. How's that?

https://github.com/llvm/llvm-project/pull/129769