[llvm-ocaml] Assume pointers are at least 2-bit aligned

[alan]

I wanted to make a stacked diff, but I'm still new to Phabricator and messed it up...

llvm/bindings/ocaml/llvm/llvm_ocaml.h

 #define Val_none Val_int(0)
 #define Some_val(v) Field(v, 0)
 #define Tag_some 0
 #define Is_none(v) ((v) == Val_none)
 #define Is_some(v) Is_block(v)
 value caml_alloc_some(value);
 #endif
 
+/* ASSUME: Pointer is at least 2-bit aligned! */
 value to_val(void *ptr);
 
 void *from_val(value v);
 
 void *alloc_temp(value Elements);
 
 #define DiagnosticInfo_val(v) ((LLVMDiagnosticInfoRef)from_val(v))
 #define Context_val(v) ((LLVMContextRef)from_val(v))

llvm/bindings/ocaml/llvm/llvm_ocaml.c

 value caml_alloc_some(value v) {
   CAMLparam1(v);
   value Some = caml_alloc_small(1, 0);
   Field(Some, 0) = v;
   CAMLreturn(Some);
 }
 #endif
 
-value to_val(void *ptr) {
-  if ((((value)ptr) & 1) == 0) {
-    return ((value)ptr) + 1;
-  } else {
-    value v = caml_alloc(1, Abstract_tag);
-    *((void **)Data_abstract_val(v)) = ptr;
-    return v;
-  }
-}
+value to_val(void *ptr) { return ((value)ptr) + 1; }
 
-void *from_val(value v) {
-  if (Is_long(v)) {
-    return (void *)(v - 1);
-  } else {
-    return *((void **)Data_abstract_val(v));
-  }
-}
+void *from_val(value v) { return (void *)(v - 1); }
 
 value llvm_string_of_message(char *Message) {
   value String = caml_copy_string(Message);
   LLVMDisposeMessage(Message);
 
   return String;
 }