[PATCH] D31851: [PowerPC] Eliminate compares - add handling for logical operations without the use of condition registers

[Nemanja Ivanovic via Phabricator via llvm-commits]

nemanjai added inline comments.


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Comment at: lib/Target/PowerPC/PPCISelDAGToDAG.cpp:280
     enum SetccInGPROpts { ZExtOrig, ZExtInvert, SExtOrig, SExtInvert };
+    enum LogicalOpsInGPR { KeepInGPR, ExtractToCR };
 
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echristo wrote:
> Part of asking for the enum is wondering why it's necessary. It seems odd to say "getLogicOpInGPR" to want to know whether or not to put something in a GPR.
That's a good point. Perhaps the naming is a poor choice. I could rename it to `performLogicOpInGPR()`.
The idea would be to convey the fact that this simply defers moving the data out of a GPR. What it does is take something like:
`(and (i1 (setcc %a, %b, CC), (setcc %c, %d, CC2)))` and convert it to a sequence that does the comparisons and the logical operation in a GPR.
That of course still leaves the question of whether we want the result of the logical operation itself to stay in a GPR (for further extended operations) or to be moved out to a CR (for use in branches, ISEL, etc.).

So I think maybe renaming the function and/or providing a clearer comment as to what's happening might be the right choice here. What do you think?


Repository:
  rL LLVM

https://reviews.llvm.org/D31851