Debug info: Let LowerDbgDeclare perfom the dbg.declare -> dbg.value

lowering only for load/stores to scalar allocas. The resulting values
confuse the backend and don't add anything because we can describe
array-allocas with a dbg.declare intrinsic just fine.

rdar://problem/15464571

llvm-svn: 195052

1 files changed, 5 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
index 82b8da3a107..2768041fb2b 100644
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -1045,7 +1045,11 @@ bool llvm::LowerDbgDeclare(Function &F) {
   for (SmallVectorImpl<DbgDeclareInst *>::iterator I = Dbgs.begin(),
          E = Dbgs.end(); I != E; ++I) {
     DbgDeclareInst *DDI = *I;
-    if (AllocaInst *AI = dyn_cast_or_null<AllocaInst>(DDI->getAddress())) {
+    AllocaInst *AI = dyn_cast_or_null<AllocaInst>(DDI->getAddress());
+    // If this is an alloca for a scalar variable, insert a dbg.value
+    // at each load and store to the alloca and erase the dbg.declare.
+    if (AI && !AI->isArrayAllocation()) {
+
       // We only remove the dbg.declare intrinsic if all uses are
       // converted to dbg.value intrinsics.
       bool RemoveDDI = true;