[PATCH] D59006: [x86] improve the default expansion of uaddsat/usubsat

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added inline comments.


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Comment at: llvm/lib/Target/X86/X86ISelLowering.cpp:36147
+    return DAG.getSelect(DL, VT, Cmp, DAG.getAllOnesConstant(DL, VT), Add);
+  }
+
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This only differs from the default expansion by the optimal CondCode to use in the select - ideally we'd have a way for TLI to indicate 'preferred' comparison codes - x86/sse is probably not alone in having limited comparisons (SGT + EQ) and the others  having to be custom handled.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D59006/new/

https://reviews.llvm.org/D59006