[PATCH] D29037: Constant fold switch inst when looking for trivial conditions to unswitch on.

[Eli Friedman via Phabricator via llvm-commits]

efriedma added inline comments.


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Comment at: lib/Transforms/Scalar/LoopUnswitch.cpp:922
+        const DataLayout &DL = I->getModule()->getDataLayout();
+        if (Constant *Fold = ConstantFoldInstruction(I, DL))
+          Cond = Fold;
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Is this likely to actually do anything in practice...? Most passes (including LoopUnswitch itself) will constant-fold newly generated code.


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Comment at: lib/Transforms/Scalar/LoopUnswitch.cpp:928
+      // At this point, the switched value is a constant.
+      assert(isa<Constant>(Cond) && "Switched value must be a constant");
+      bool FoundDest = false;
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Checking for a Constant isn't good enough here: you need a ConstantInt.


https://reviews.llvm.org/D29037