Go patch committed: Don't initialize zero-sized temporaries

[Ian Lance Taylor]

This patch by Chris Manghane fixes the Go frontend to avoid crashes
when initializing zero-sized temporary values.  This is GCC PR 61204.
Bootstrapped and ran Go testsuite on x86_64-unknown-linux-gnu.
Committed to mainline.

Ian

2015-01-07  Chris Manghane  <cm...@google.com>

PR go/61204
* go-gcc.cc (Gcc_backend::temporary_variable): Don't initialize
zero-sized variable.

Index: go-gcc.cc
===================================================================
--- go-gcc.cc   (revision 219262)
+++ go-gcc.cc   (working copy)
@@ -2536,7 +2536,7 @@ Gcc_backend::temporary_variable(Bfunctio
       BIND_EXPR_VARS(bind_tree) = BLOCK_VARS(block_tree);
     }
 
-  if (init_tree != NULL_TREE)
+  if (this->type_size(btype) != 0 && init_tree != NULL_TREE)
     DECL_INITIAL(var) = fold_convert_loc(location.gcc_location(), type_tree,
                                          init_tree);
 
@@ -2546,6 +2546,13 @@ Gcc_backend::temporary_variable(Bfunctio
   *pstatement = this->make_statement(build1_loc(location.gcc_location(),
                                                 DECL_EXPR,
                                                void_type_node, var));
+
+  // Don't initialize VAR with BINIT, but still evaluate BINIT for
+  // its side effects.
+  if (this->type_size(btype) == 0 && init_tree != NULL_TREE)
+    *pstatement = this->compound_statement(this->expression_statement(binit),
+                                          *pstatement);
+
   return new Bvariable(var);
 }