If a wide bit-field is inside a union its offset should always be 0.
llvm-svn: 101668
diff --git a/clang/lib/AST/RecordLayoutBuilder.cpp b/clang/lib/AST/RecordLayoutBuilder.cpp
index d1de70a..a674ad7 100644
--- a/clang/lib/AST/RecordLayoutBuilder.cpp
+++ b/clang/lib/AST/RecordLayoutBuilder.cpp
@@ -640,13 +640,16 @@
// We're not going to use any of the unfilled bits in the last byte.
UnfilledBitsInLastByte = 0;
- // The bitfield is allocated starting at the next offset aligned appropriately
- // for T', with length n bits.
- uint64_t FieldOffset = llvm::RoundUpToAlignment(DataSize, TypeAlign);
-
+ uint64_t FieldOffset;
+
if (IsUnion) {
DataSize = std::max(DataSize, FieldSize);
+ FieldOffset = 0;
} else {
+ // The bitfield is allocated starting at the next offset aligned appropriately
+ // for T', with length n bits.
+ FieldOffset = llvm::RoundUpToAlignment(DataSize, TypeAlign);
+
uint64_t NewSizeInBits = FieldOffset + FieldSize;
DataSize = llvm::RoundUpToAlignment(NewSizeInBits, 8);