From f6126e7abfa48e346a652b7d15e367031224a878 Mon Sep 17 00:00:00 2001
From: Alexey Prokhin <alexey.prokhin@yandex.ru>
Date: Fri, 27 Jun 2014 19:19:01 +0400
Subject: [PATCH] Fix DMD Issue 3991 - Void initializers in unions considered
 overlapping

---
 ir/iraggr.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/ir/iraggr.cpp b/ir/iraggr.cpp
index 8a525237f1..360a86c7bf 100644
--- a/ir/iraggr.cpp
+++ b/ir/iraggr.cpp
@@ -87,6 +87,8 @@ llvm::Constant * IrAggr::getDefaultInit()
 //////////////////////////////////////////////////////////////////////////////
 
 static bool isAligned(llvm::Type* type, size_t offset) {
+    if (offset == 0)
+        return true;
     return gDataLayout->getABITypeAlignment(type) % offset == 0;
 }
 
@@ -278,6 +280,8 @@ void IrAggr::addFieldInitializers(
         if (data[i].first) continue;
 
         VarDeclaration* vd = decl->fields[i];
+        if (vd->init && vd->init->isVoidInitializer())
+            continue;
 
         unsigned vd_begin = vd->offset;
         unsigned vd_end = vd_begin + vd->type->size();