[PATCH] D63281: [TargetLowering] Add SimplifyMultipleUseDemandedBits

Simon Pilgrim via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Sat Jun 15 04:01:53 PDT 2019


RKSimon marked an inline comment as done.
RKSimon added inline comments.


================
Comment at: lib/CodeGen/SelectionDAG/TargetLowering.cpp:664
   if (!Op.getNode()->hasOneUse() && !AssumeSingleUse) {
     if (Depth != 0) {
       // If not at the root, Just compute the Known bits to
----------------
nikic wrote:
> Why are there explicit SimplifyMultipleUseDemandedBits() calls for individual opcodes, rather than a general call in the !hasOneUse branch here? This is what we do in InstCombine.
Because we need to regenerate a single op - afaict we'd have to refactor the entire SimplifyDemandedBits / TargetLoweringOpt  system to enable us to replace individual args of a single node.


Repository:
  rL LLVM

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  https://reviews.llvm.org/D63281/new/

https://reviews.llvm.org/D63281





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