[PATCH] D107380: [SystemZ] Implement memcmp with variable length with CLC.

[Jonas Paulsson via Phabricator via llvm-commits]

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Following the same pattern of memset/memcpy, this patch implements a variable length memcmp with a CLC loop followed by an EXRL instruction.

- For a zero length memcompare, the aghi check against -1 should return a CC that is equivalent to "EQ" also for the memcompare IPM result, which seems reasonable..?

- Hope it's ok to add a CC-def on the EXRL_Pseudo instead of an extra opcode like EXRL_Pseudo_CC...

- emitMemMemVarLen() has for now merely been copied from the memcpy patch (with some minor modification).

- ~1300 less library calls on spec.

Now that benchmarking is in progress for the memcpy patch, could this also be evaluated in parallel at this point?


https://reviews.llvm.org/D107380

Files:
  llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
  llvm/lib/Target/SystemZ/SystemZInstrFormats.td
  llvm/lib/Target/SystemZ/SystemZSelectionDAGInfo.cpp
  llvm/test/CodeGen/SystemZ/memcmp-01.ll

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