Fix #4986 : wrong type for return value

Author: thewilsonator

gen/statements.cpp

@@ -37,6 +37,7 @@
 #include "ir/irmodule.h"
 #include "llvm/IR/CFG.h"
 #include "llvm/IR/InlineAsm.h"
+#include "llvm/Support/Casting.h"
 #include <fstream>
 #include <math.h>
 #include <stdio.h>
@@ -307,6 +308,11 @@ class ToIRVisitor : public Visitor {
           irs->DBuilder.EmitStopPoint(fd->endloc);
         }
 
+        if (returnValue->getType() != funcType->getReturnType()) {
+          assert(llvm::cast<llvm::AllocaInst>(returnValue)->getAllocatedType() == funcType->getReturnType());
+          returnValue = DtoLoad(funcType->getReturnType(), returnValue);
+        }
+
         irs->ir->CreateRet(
             useRetValSlot ? DtoLoad(funcType->getReturnType(), funcGen.retValSlot)
                           : returnValue);

tests/codegen/gh4986.d

@@ -0,0 +1,13 @@
+// RUN: %ldc %s -c
+
+struct Test
+{
+    this(ref inout typeof(this) rhs) inout pure {}
+    const(char)[] toString() const pure => null;
+    alias toString this;
+}
+
+const(char)[] test(ref Test t)
+{
+    return t;
+}