[PATCH] D37076: [LICM] Allow sinking when foldable in loop

[Jun Bum Lim via Phabricator via llvm-commits]

junbuml added inline comments.


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Comment at: lib/Transforms/Scalar/LICM.cpp:713
+  }
+  return TTI->getUserCost(&I, UsersInLoop) ==
+         TargetTransformInfo::TCC_Free;
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As r314923 was reverted, we cannot simply use getUserCost for all instructions because it optimistically assume that a GEP will fold into addressing mode regardless of its users.  I don't think we can rely on this optimistic assumption in here.  To handle GEPs properly in this change, we can check  GEP's users here directly, or we can add a function in TTI to see if an instruction is really foldable.


https://reviews.llvm.org/D37076