[InstCombine] Preserve llvm.mem.parallel_loop_access metadata when replacing

memcpy with ld/st.

When InstCombine replaces a memcpy with loads+stores it does not copy over the
llvm.mem.parallel_loop_access from the memcpy instruction. This patch fixes
that.

Differential Revision: https://reviews.llvm.org/D23499

llvm-svn: 280617

1 files changed, 6 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index b5e206474e0..15069e62a73 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -192,11 +192,17 @@ Instruction *InstCombiner::SimplifyMemTransfer(MemIntrinsic *MI) {
   L->setAlignment(SrcAlign);
   if (CopyMD)
     L->setMetadata(LLVMContext::MD_tbaa, CopyMD);
+  MDNode *LoopMemParallelMD =
+    MI->getMetadata(LLVMContext::MD_mem_parallel_loop_access);
+  if (LoopMemParallelMD)
+    L->setMetadata(LLVMContext::MD_mem_parallel_loop_access, LoopMemParallelMD);
 
   StoreInst *S = Builder->CreateStore(L, Dest, MI->isVolatile());
   S->setAlignment(DstAlign);
   if (CopyMD)
     S->setMetadata(LLVMContext::MD_tbaa, CopyMD);
+  if (LoopMemParallelMD)
+    S->setMetadata(LLVMContext::MD_mem_parallel_loop_access, LoopMemParallelMD);
 
   // Set the size of the copy to 0, it will be deleted on the next iteration.
   MI->setArgOperand(2, Constant::getNullValue(MemOpLength->getType()));