Preserve load alignment and dereferenceable metadata during some transformations

Reviewed By: hfinkel

Differential Revision: http://reviews.llvm.org/D13953

llvm-svn: 251809

2 files changed, 12 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
index b6080f29faa..0bd5fa9f877 100644
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -1430,6 +1430,15 @@ void llvm::combineMetadata(Instruction *K, const Instruction *J,
       case LLVMContext::MD_invariant_group:
         // Preserve !invariant.group in K.
         break;
+      case LLVMContext::MD_align:
+        K->setMetadata(Kind, 
+          MDNode::getMostGenericAlignmentOrDereferenceable(JMD, KMD));
+        break;
+      case LLVMContext::MD_dereferenceable:
+      case LLVMContext::MD_dereferenceable_or_null:
+        K->setMetadata(Kind, 
+          MDNode::getMostGenericAlignmentOrDereferenceable(JMD, KMD));
+        break;
     }
   }
   // Set !invariant.group from J if J has it. If both instructions have it
diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
index e44a04aaba6..f9d5d2d4d36 100644
--- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -1097,7 +1097,9 @@ static bool HoistThenElseCodeToIf(BranchInst *BI,
     unsigned KnownIDs[] = {
         LLVMContext::MD_tbaa,    LLVMContext::MD_range,
         LLVMContext::MD_fpmath,  LLVMContext::MD_invariant_load,
-        LLVMContext::MD_nonnull, LLVMContext::MD_invariant_group};
+        LLVMContext::MD_nonnull, LLVMContext::MD_invariant_group,
+        LLVMContext::MD_align,   LLVMContext::MD_dereferenceable,
+        LLVMContext::MD_dereferenceable_or_null};
     combineMetadata(I1, I2, KnownIDs);
     I2->eraseFromParent();
     Changed = true;