From dcf005213b9bb6482271bcb04ef2a0032ce1b566 Mon Sep 17 00:00:00 2001
From: Alexey Prokhin <alexey.prokhin@yandex.ru>
Date: Sun, 8 Dec 2013 13:13:43 +0400
Subject: [PATCH] Implement cast to void

---
 gen/llvmhelpers.cpp |  8 --------
 gen/toir.cpp        | 10 +++-------
 2 files changed, 3 insertions(+), 15 deletions(-)

diff --git a/gen/llvmhelpers.cpp b/gen/llvmhelpers.cpp
index 99309520..54df6b63 100644
--- a/gen/llvmhelpers.cpp
+++ b/gen/llvmhelpers.cpp
@@ -576,14 +576,6 @@ DValue* DtoCastInt(Loc& loc, DValue* val, Type* _to)
         return new DImValue(_to, rval);
     }
 
-    // Check for special DMD hack to avoid "has no effect" error.
-    // See expression.c, method AssignExp::semantic(), around line 11499
-    llvm::ConstantInt* isConstInt = isaConstantInt(rval);
-    if (from == Type::tint32 && to == Type::tvoid && isConstInt->isNullValue())
-    {
-        return val;
-    }
-
     size_t fromsz = from->size();
     size_t tosz = to->size();
 
diff --git a/gen/toir.cpp b/gen/toir.cpp
index 537d5495..59db9692 100644
--- a/gen/toir.cpp
+++ b/gen/toir.cpp
@@ -1140,13 +1140,9 @@ DValue* CastExp::toElem(IRState* p)
     // get the value to cast
     DValue* u = e1->toElem(p);
 
-    // a constructor expression is casted to void in order to mark
-    // the value as unused. See expression.d, method AssignExp::semantic(),
-    // around line 11681
-    if (to == Type::tvoid && e1->op == TOKconstruct)
-    {
-        return new DNullValue(Type::tvoid, 0);
-    }
+    // handle cast to void (usually created by frontend to avoid "has no effect" error)
+    if (to == Type::tvoid)
+        return new DImValue(Type::tvoid, llvm::UndefValue::get(voidToI8(DtoType(Type::tvoid))));
 
     // cast it to the 'to' type, if necessary
     DValue* v = u;