[PATCH] D157700: [GlobalIsSel] Allow using PatFrags with multiple defs as the root of a combine rule

[Jay Foad via Phabricator via llvm-commits]

foad added inline comments.


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Comment at: llvm/include/llvm/Target/GlobalISel/Combine.td:163
 // Fold (fcanonicalize (fcanonicalize x)) -> (fcanonicalize x).
+def idempotent_prop_frags : GICombinePatFrag<
+  (outs root:$dst, $src), (ins),
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This may be a silly question since I am not too familiar with PatFrags, and have no idea how they are implemented:

Why does a PatFrag like this have two defs, instead of one use and one def?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D157700/new/

https://reviews.llvm.org/D157700