[PATCH] D90131: [PowerPC] Add folding patterns for rlwinm + andi_rec.

[ChenZheng via Phabricator via llvm-commits]

shchenz added a comment.

This is more clear than the previous version. Some implementation comments.



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Comment at: llvm/lib/Target/PowerPC/PPCInstrInfo.cpp:3419
+  // Combine RLWINM + ANDI_rec.
+  // We can treat ANDI_rec as RLWINM_rec with the SH = 0.
+  else if (MI.getOpcode() == PPC::ANDI_rec ||
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Nice catch! Then should we reuse legacy logic? If `ANDI_rec` mask is not runofones, we can not fold `RLWINM + ANDI_rec` to a single `RLWINM`? If `ANDI_rec` mask is runofones, can we treat it as special `rlwinm_rec` with sh = 0, and MB, ME can be got from runofones check?


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  https://reviews.llvm.org/D90131/new/

https://reviews.llvm.org/D90131