Revert "Revert "Strip metadata when speculatively hoisting instructions (r252604)"

Failing clang test is now fixed by the r253458.

llvm-svn: 253459

3 files changed, 16 insertions, 0 deletions

diff --git a/llvm/lib/Analysis/LoopInfo.cpp b/llvm/lib/Analysis/LoopInfo.cpp
index 9ee72361c92..e679b7ad7b8 100644
--- a/llvm/lib/Analysis/LoopInfo.cpp
+++ b/llvm/lib/Analysis/LoopInfo.cpp
@@ -120,6 +120,13 @@ bool Loop::makeLoopInvariant(Instruction *I, bool &Changed,
 
   // Hoist.
   I->moveBefore(InsertPt);
+
+  // There is possibility of hoisting this instruction above some arbitrary
+  // condition. Any metadata defined on it can be control dependent on this
+  // condition. Conservatively strip it here so that we don't give any wrong
+  // information to the optimizer.
+  I->dropUnknownNonDebugMetadata();
+
   Changed = true;
   return true;
 }
diff --git a/llvm/lib/Transforms/Scalar/LICM.cpp b/llvm/lib/Transforms/Scalar/LICM.cpp
index ba39afd4287..6d70cdc3ade 100644
--- a/llvm/lib/Transforms/Scalar/LICM.cpp
+++ b/llvm/lib/Transforms/Scalar/LICM.cpp
@@ -672,6 +672,10 @@ static bool hoist(Instruction &I, BasicBlock *Preheader) {
   // Move the new node to the Preheader, before its terminator.
   I.moveBefore(Preheader->getTerminator());
 
+  // Metadata can be dependent on the condition we are hoisting above.
+  // Conservatively strip all metadata on the instruction.
+  I.dropUnknownNonDebugMetadata();
+
   if (isa<LoadInst>(I)) ++NumMovedLoads;
   else if (isa<CallInst>(I)) ++NumMovedCalls;
   ++NumHoisted;
diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
index e0c598f92e2..ff81e7d5acf 100644
--- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -1618,6 +1618,11 @@ static bool SpeculativelyExecuteBB(BranchInst *BI, BasicBlock *ThenBB,
     SpeculatedStore->setOperand(0, S);
   }
 
+  // Metadata can be dependent on the condition we are hoisting above.
+  // Conservatively strip all metadata on the instruction.
+  for (auto &I: *ThenBB)
+    I.dropUnknownNonDebugMetadata();
+
   // Hoist the instructions.
   BB->getInstList().splice(BI->getIterator(), ThenBB->getInstList(),
                            ThenBB->begin(), std::prev(ThenBB->end()));