Properly update AA metadata when performing call slot optimization

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D7482

llvm-svn: 228500

1 files changed, 10 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp b/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp
index 041312b7ac6..006b885bb30 100644
--- a/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp
+++ b/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp
@@ -750,6 +750,16 @@ bool MemCpyOpt::performCallSlotOptzn(Instruction *cpy,
   // its dependence information by changing its parameter.
   MD->removeInstruction(C);
 
+  // Update AA metadata
+  // FIXME: MD_tbaa_struct and MD_mem_parallel_loop_access should also be
+  // handled here, but combineMetadata doesn't support them yet
+  unsigned KnownIDs[] = {
+    LLVMContext::MD_tbaa,
+    LLVMContext::MD_alias_scope,
+    LLVMContext::MD_noalias,
+  };
+  combineMetadata(C, cpy, KnownIDs);
+
   // Remove the memcpy.
   MD->removeInstruction(cpy);
   ++NumMemCpyInstr;