Merge pull request #24 from schweitzpgi/release_50

SROA: This changeset was inspired by c8ef2d5, which fixed a bug in

Author: sscalpone

include/llvm/IR/DebugInfoMetadata.h

@@ -2345,6 +2345,8 @@ class DIVariable : public DINode {
   DITypeRef getType() const { return DITypeRef(getRawType()); }
   uint32_t getAlignInBits() const { return AlignInBits; }
   uint32_t getAlignInBytes() const { return getAlignInBits() / CHAR_BIT; }
+  /// Determines the size of the variable's type.
+  Optional<uint64_t> getSizeInBits() const;
 
   StringRef getFilename() const {
     if (auto *F = getFile())

lib/IR/DebugInfoMetadata.cpp

@@ -626,6 +626,29 @@ DILocalVariable *DILocalVariable::getImpl(LLVMContext &Context, Metadata *Scope,
   DEFINE_GETIMPL_STORE(DILocalVariable, (Line, Arg, Flags, AlignInBits), Ops);
 }
 
+Optional<uint64_t> DIVariable::getSizeInBits() const {
+  // This is used by the Verifier so be mindful of broken types.
+  const Metadata *RawType = getRawType();
+  while (RawType) {
+    // Try to get the size directly.
+    if (auto *T = dyn_cast<DIType>(RawType))
+      if (uint64_t Size = T->getSizeInBits())
+        return Size;
+
+    if (auto *DT = dyn_cast<DIDerivedType>(RawType)) {
+      // Look at the base type.
+      RawType = DT->getRawBaseType();
+      continue;
+    }
+
+    // Missing type or size.
+    break;
+  }
+
+  // Fail gracefully.
+  return None;
+}
+
 DIExpression *DIExpression::getImpl(LLVMContext &Context,
                                     ArrayRef<uint64_t> Elements,
                                     StorageType Storage, bool ShouldCreate) {

lib/Transforms/Scalar/SROA.cpp

@@ -4047,12 +4047,15 @@ bool SROA::splitAlloca(AllocaInst &AI, AllocaSlices &AS) {
   if (DbgDeclareInst *DbgDecl = FindAllocaDbgDeclare(&AI)) {
     auto *Var = DbgDecl->getVariable();
     auto *Expr = DbgDecl->getExpression();
+    auto VarSize = Var->getSizeInBits();
     DIBuilder DIB(*AI.getModule(), /*AllowUnresolved*/ false);
     uint64_t AllocaSize = DL.getTypeSizeInBits(AI.getAllocatedType());
     for (auto Fragment : Fragments) {
       // Create a fragment expression describing the new partition or reuse AI's
       // expression if there is only one partition.
       auto *FragmentExpr = Expr;
+      if (VarSize && (Fragment.Size >= *VarSize))
+        continue;
       if (Fragment.Size < AllocaSize || Expr->isFragment()) {
         // If this alloca is already a scalar replacement of a larger aggregate,
         // Fragment.Offset describes the offset inside the scalar.