[DwarfDebug] Don't merge DebugLocEntries if their pieces overlap

Summary:
Later in DWARF emission we check that DebugLocEntries have
non-overlapping pieces, so we should create any such entries
by merging here.

Fixes PR26163.

Reviewers: aprantl
Differential Revision: http://reviews.llvm.org/D16249

llvm-svn: 257979

1 files changed, 2 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 6a1596232be..ae62b6b19a4 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -813,7 +813,8 @@ bool DebugLocEntry::MergeValues(const DebugLocEntry &Next) {
   if (Begin == Next.Begin) {
     auto *Expr = cast_or_null<DIExpression>(Values[0].Expression);
     auto *NextExpr = cast_or_null<DIExpression>(Next.Values[0].Expression);
-    if (Expr->isBitPiece() && NextExpr->isBitPiece()) {
+    if (Expr->isBitPiece() && NextExpr->isBitPiece() &&
+        !piecesOverlap(Expr, NextExpr)) {
       addValues(Next.Values);
       End = Next.End;
       return true;