[PATCH] D127354: Allow bitwidth difference when checking for isOneOrOneSplat.

[Adrian Tong via Phabricator via llvm-commits]

adriantong1024 added inline comments.


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Comment at: llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp:10634
 bool llvm::isOneOrOneSplat(SDValue N, bool AllowUndefs) {
   // TODO: may want to use peekThroughBitcast() here.
+  ConstantSDNode *C = isConstOrConstSplat(N, AllowUndefs, /*AllowTruncation*/ true);
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adriantong1024 wrote:
> craig.topper wrote:
> > Are all of the callers of isOneOrOneSplat ok with this change?
> > 
> > Is this change correct for the caller you’re interested in if the element type of the build_vector is i1?
> Let me go through the callers one by one. There are 8 uses of isOneOrOneSplat in llvm, all in DAGCombiner.cpp.
> 
> so far, I ran through check-llvm and looks good. 
The bitwidth check was added https://reviews.llvm.org/D25374 and I have ran check-llvm-codegen for all available targets and things are fine.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D127354/new/

https://reviews.llvm.org/D127354