[PATCH] D25221: [PPC][DAGCombine] Convert SETCC to subtract when the result is zero extended

[Kit Barton via llvm-commits]

kbarton accepted this revision.
kbarton added a comment.
This revision is now accepted and ready to land.

Aside from some minor formatting of comments, this LGTM.



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Comment at: lib/Target/PowerPC/PPCISelLowering.cpp:9924
+// comparison is kept in a GPR instead of CR. This function is purely for
+// codegen purposes and has some flags to guide the codegen process.
+static SDValue GenerateEquivalentSub(SDNode *N, int Size, bool Complement,
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doxygen-style comments please


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Comment at: lib/Target/PowerPC/PPCISelLowering.h:973
+    // with integer subtraction when (1) there is a legal way of doing it.
+    // (2) keeping the result of comparison in GPR has some performance benefit.
+    SDValue ConvertSETCCToSubtract(SDNode *N, DAGCombinerInfo &DCI) const;
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Can you please convert to doxygen-style comments?


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Comment at: test/CodeGen/PowerPC/setcc-to-sub.ll:2
+; RUN: llc -verify-machineinstrs -mtriple=powerpc64le-unknown-linux-gnu \
+; RUN: -mcpu=pwr8 < %s | FileCheck %s
+
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Is there any reason this has to be run on pwr8?


https://reviews.llvm.org/D25221