diff --git a/dmd2/mtype.c b/dmd2/mtype.c
index 45e596da..4fb13713 100644
--- a/dmd2/mtype.c
+++ b/dmd2/mtype.c
@@ -82,28 +82,24 @@ int REALSIZE = 16;
 int REALPAD = 6;
 int REALALIGNSIZE = 16;
 #elif TARGET_LINUX || TARGET_FREEBSD || TARGET_OPENBSD || TARGET_SOLARIS
-int REALSIZE = 12; // LDC_FIXME: We differ from DMD here, yet target defines are never set?!
+int REALSIZE = 12;
 int REALPAD = 2;
 int REALALIGNSIZE = 4;
-#elif defined(IN_GCC)
+#elif TARGET_WINDOS
+int REALSIZE = 10;
+int REALPAD = 0;
+int REALALIGNSIZE = 2;
+#elif defined(IN_GCC) || defined(IN_LLVM)
 int REALSIZE = 0;
 int REALPAD = 0;
 int REALALIGNSIZE = 0;
 #else
-int REALSIZE = 10;
-int REALPAD = 0;
-int REALALIGNSIZE = 2;
+#error "fix this"
 #endif
 
 int Tsize_t = Tuns32;
 int Tptrdiff_t = Tint32;
 
-#if _WIN32 && !(defined __MINGW32__ || defined _MSC_VER)
-static double zero = 0;
-double Port::nan = NAN;
-double Port::infinity = 1/zero;
-#endif
-
 /***************************** Type *****************************/
 
 ClassDeclaration *Type::typeinfo;
@@ -2901,9 +2897,22 @@ d_uns64 TypeBasic::size(Loc loc)
 
 unsigned TypeBasic::alignsize()
 {
+#if IN_LLVM
     if (ty == Tvoid)
         return 1;
     return GetTypeAlignment(sir, this);
+#endif
+
+    unsigned sz;
+
+    switch (ty)
+    {
+        case Tfloat80:
+        case Timaginary80:
+        case Tcomplex80:
+            sz = REALALIGNSIZE;
+            break;
+
 #if TARGET_LINUX || TARGET_OSX || TARGET_FREEBSD || TARGET_OPENBSD || TARGET_SOLARIS
         case Tint64:
         case Tuns64:
@@ -2923,13 +2932,12 @@ unsigned TypeBasic::alignsize()
             sz = global.params.is64bit ? 8 : 4;
             break;
 #endif
-#if IN_DMD
+
         default:
             sz = size(0);
             break;
     }
     return sz;
-#endif
 }
 
 #if IN_LLVM
diff --git a/driver/main.cpp b/driver/main.cpp
index 3ed1d247..9f3d6ab5 100644
--- a/driver/main.cpp
+++ b/driver/main.cpp
@@ -547,7 +547,7 @@ int main(int argc, char** argv)
         VersionCondition::addPredefinedGlobalIdent("D_LP64");
     }
 
-    if (mRelocModel == llvm::Reloc::PIC_) {
+    if (gTargetMachine->getRelocationModel() == llvm::Reloc::PIC_) {
         VersionCondition::addPredefinedGlobalIdent("D_PIC");
     }
 
diff --git a/driver/target.cpp b/driver/target.cpp
index 416e7230..5c85bea0 100644
--- a/driver/target.cpp
+++ b/driver/target.cpp
@@ -175,6 +175,13 @@ llvm::TargetMachine* createTargetMachine(
         FeaturesStr = Features.getString();
     }
 
+    if (triple.isMacOSX() && relocModel == llvm::Reloc::Default)
+    {
+        // OS X defaults to PIC (and as of 10.7.5/LLVM 3.1-3.3, TLS use leads
+        // to crashes for non-PIC code). LLVM doesn't handle this.
+        relocModel = llvm::Reloc::PIC_;
+    }
+
 #if LDC_LLVM_VER == 300
     llvm::NoFramePointerElim = genDebugInfo;
 
diff --git a/gen/functions.cpp b/gen/functions.cpp
index bee0c17f..bfca527f 100644
--- a/gen/functions.cpp
+++ b/gen/functions.cpp
@@ -968,6 +968,19 @@ void DtoDefineFunction(FuncDeclaration* fd)
     if (fd->isMain())
         gIR->emitMain = true;
 
+    // On x86_64, always set 'uwtable' for System V ABI compatibility.
+    // TODO: Find a better place for this.
+    if (global.params.targetTriple.getArch() == llvm::Triple::x86_64)
+    {
+#if LDC_LLVM_VER >= 303
+        func->addFnAttr(llvm::Attribute::UWTable);
+#elif LDC_LLVM_VER == 302
+        func->addFnAttr(llvm::Attributes::UWTable);
+#else
+        func->addFnAttr(UWTable);
+#endif
+    }
+
     std::string entryname("entry");
 
     llvm::BasicBlock* beginbb = llvm::BasicBlock::Create(gIR->context(), entryname,func);