i965/fs: Don't make a name for a vector splitting temporary

If the name is just going to get dropped, don't bother making it.  If
the name is made, release it sooner (rather than later).

No change Valgrind massif results for a trimmed apitrace of dota2.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>

src/mesa/drivers/dri/i965/brw_fs_vector_splitting.cpp

@@ -363,12 +363,17 @@ brw_do_vector_splitting(exec_list *instructions)
       entry->mem_ctx = ralloc_parent(entry->var);
 
       for (unsigned int i = 0; i < entry->var->type->vector_elements; i++) {
-	 const char *name = ralloc_asprintf(mem_ctx, "%s_%c",
-					    entry->var->name,
-					    "xyzw"[i]);
+         char *const name = ir_variable::temporaries_allocate_names
+            ? ralloc_asprintf(mem_ctx, "%s_%c",
+                              entry->var->name,
+                              "xyzw"[i])
+            : NULL;
 
 	 entry->components[i] = new(entry->mem_ctx) ir_variable(type, name,
 								ir_var_temporary);
+
+         ralloc_free(name);
+
 	 entry->var->insert_before(entry->components[i]);
       }