[PATCH] D53744: [SimpleLoopUnswitch] Unswitch by experimental.guard intrinsics

[Max Kazantsev via Phabricator via llvm-commits]

mkazantsev added inline comments.


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Comment at: lib/Transforms/Scalar/SimpleLoopUnswitch.cpp:2258-2265
+  // Whether or not we should also collect guards in the loop.
+  bool CollectGuards = false;
+  if (UnswitchGuards) {
+    auto *GuardDecl = L.getHeader()->getParent()->getParent()->getFunction(
+        Intrinsic::getName(Intrinsic::experimental_guard));
+    if (GuardDecl && !GuardDecl->use_empty())
+      CollectGuards = true;
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chandlerc wrote:
> I assume this is trying to avoid the cost of looking for a guard intrinsic? We already walk all the instructions in the loop several times in this routine, so I'm not sure this matters much in practice. I'd just skip this and check the flag below.
Maybe we'll remove it in future, but I see no harm in it.


https://reviews.llvm.org/D53744