ValueMapper: Only check for cycles if operands change
This is a minor optimization to only check for unresolved operands
inside `mapDistinctNode()` if the operands have actually changed. This
shouldn't really cause any change in behaviour. I didn't actually see a
slowdown in a profile, I was just poking around nearby and saw the
opportunity.
llvm-svn: 243866
diff --git a/llvm/lib/Transforms/Utils/ValueMapper.cpp b/llvm/lib/Transforms/Utils/ValueMapper.cpp
index 2de1928..8daf546 100644
--- a/llvm/lib/Transforms/Utils/ValueMapper.cpp
+++ b/llvm/lib/Transforms/Utils/ValueMapper.cpp
@@ -227,13 +227,14 @@
assert(Node->isDistinct() && "Expected distinct node");
MDNode *NewMD = MDNode::replaceWithDistinct(Node->clone());
- remap(Node, NewMD, Cycles, VM, Flags, TypeMapper, Materializer);
- // Track any cycles beneath this node.
- for (Metadata *Op : NewMD->operands())
- if (auto *Node = dyn_cast_or_null<MDNode>(Op))
- if (!Node->isResolved())
- Cycles.push_back(Node);
+ // Remap the operands. If any change, track those that could be involved in
+ // uniquing cycles.
+ if (remap(Node, NewMD, Cycles, VM, Flags, TypeMapper, Materializer))
+ for (Metadata *Op : NewMD->operands())
+ if (auto *Node = dyn_cast_or_null<MDNode>(Op))
+ if (!Node->isResolved())
+ Cycles.push_back(Node);
return NewMD;
}