[PATCH] D26088: Don't leave unused divs/rems sitting around in BypassSlowDivision.

Artem Belevich via llvm-commits llvm-commits at lists.llvm.org
Fri Oct 28 11:13:50 PDT 2016

tra added inline comments.

Comment at: llvm/lib/Transforms/Utils/BypassSlowDivision.cpp:251
+  // Above we eagerly create divs and rems, as pairs, so that we can efficiently
+  // create divrem machine instructions.  Now erase unused any divs / rems so we
+  // don't leave extra instructions sitting around.
Should it be "erase any unused divs/rems..."?

Comment at: llvm/lib/Transforms/Utils/BypassSlowDivision.cpp:260
+      for (Value *Operand : Phi->operand_values())
+        if (Instruction *I = dyn_cast<Instruction>(Operand))
+          ToErase.push_back(I);
What's supposed to happen with operands that are not instructions?
Destruction of unused subgraph sounds like a common operation, perhaps we already have a function to do it?


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