Merge pull request #3723 from 9rnsr/fix13021

Issue 13021 - Constructing union with floating type and then accessing its field in one expression causes ICE

src/optimize.c

@@ -437,8 +437,10 @@ Expression *Expression_optimize(Expression *e, int result, bool keepLvalue)
             {
                 StructLiteralExp *sle = (StructLiteralExp *)ex;
                 VarDeclaration *vf = e->var->isVarDeclaration();
-                if (vf)
+                if (vf && !vf->overlapped)
                 {
+                    /* Bugzilla 13021: Prevent optimization if vf has overlapped fields.
+                     */
                     ex = sle->getField(e->type, vf->offset);
                     if (ex && ex != EXP_CANT_INTERPRET)
                     {

test/runnable/structlit.d

@@ -1344,6 +1344,44 @@ void test12011()
     static assert(S12011b.e == 1);
 }
 
+/********************************************/
+// 13021
+
+void test13021()
+{
+    static union U1
+    {
+        float a;
+        int b;
+    }
+
+    static union U2
+    {
+        double a;
+        long b;
+    }
+
+    static union U3
+    {
+        real a;
+        struct B { long b1, b2; } // ICE happens only if B.sizeof == real.sizeof
+        B b;
+    }
+
+    static union U4
+    {
+        real a;
+        long[2] b; // ditto
+    }
+
+    auto f = U1(1.0);  auto ok = f.b;
+
+    auto fail1 = U1(1.0).b; // OK <- Internal error: e2ir.c 1162
+    auto fail2 = U2(1.0).b; // OK <- Internal error: e2ir.c 1162
+    auto fail3 = U3(1.0).b; // OK <- Internal error: e2ir.c 1162
+    auto fail4 = U4(1.0).b; // OK <- Internal error: backend/el.c 2904
+}
+
 /********************************************/
 
 int main()
@@ -1388,6 +1426,7 @@ int main()
     test11105();
     test11147();
     test11256();
+    test13021();
 
     printf("Success\n");
     return 0;