[simplifycfg][loop-simplify] Preserve loop metadata in 2 transformations.
insertUniqueBackedgeBlock in lib/Transforms/Utils/LoopSimplify.cpp now
propagates existing llvm.loop metadata to newly the added backedge.
llvm::TryToSimplifyUncondBranchFromEmptyBlock in lib/Transforms/Utils/Local.cpp
now propagates existing llvm.loop metadata to the branch instructions in the
predecessor blocks of the empty block that is removed.
Differential Revision: https://reviews.llvm.org/D26495
llvm-svn: 287341
diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
index 0483c1e..3ad5f58 100644
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -890,6 +890,17 @@
}
}
+ // If the unconditional branch we replaced contains llvm.loop metadata, we
+ // add the metadata to the branch instructions in the predecessors.
+ unsigned LoopMDKind = BB->getContext().getMDKindID("llvm.loop");
+ Instruction *TI = BB->getTerminator();
+ if (TI)
+ if (MDNode *LoopMD = TI->getMetadata(LoopMDKind))
+ for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) {
+ BasicBlock *Pred = *PI;
+ Pred->getTerminator()->setMetadata(LoopMDKind, LoopMD);
+ }
+
// Everything that jumped to BB now goes to Succ.
BB->replaceAllUsesWith(Succ);
if (!Succ->hasName()) Succ->takeName(BB);