Go patch committed: Make Slice_construction_expression::do_flatten idempotent

[Ian Lance Taylor]

Because of the way the Go frontend handles call expressions with
multiple results, it's possible for expressions to be flattened more
than once.  In the case of Slice_construction_expression, allocating
the slice storage multiple times caused a compiler crash as one of the
Temporary_statement's wound up not getting a backend expression.  This
patch fixes the problem.

The test case for this is https://golang.org/cl/34020.

Bootstrapped and ran Go testsuite on x86_64-pc-linux-gnu.  Committed
to mainline.

Ian

Index: gcc/go/gofrontend/MERGE
===================================================================
--- gcc/go/gofrontend/MERGE     (revision 243424)
+++ gcc/go/gofrontend/MERGE     (working copy)
@@ -1,4 +1,4 @@
-08d221726e3f50cb197a931ba385fac67f66a028
+7a941ba323660ec7034cd92d4eab466024a3c72c
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.
Index: gcc/go/gofrontend/expressions.cc
===================================================================
--- gcc/go/gofrontend/expressions.cc    (revision 243321)
+++ gcc/go/gofrontend/expressions.cc    (working copy)
@@ -12951,8 +12951,8 @@ Slice_construction_expression::do_flatte
   // Base class flattening first
   this->Array_construction_expression::do_flatten(gogo, no, inserter);
 
-  // Create an stack-allocated storage temp if storage won't escape
-  if (!this->storage_escapes_)
+  // Create a stack-allocated storage temp if storage won't escape
+  if (!this->storage_escapes_ && this->slice_storage_ == NULL)
     {
       Location loc = this->location();
       this->array_val_ = create_array_val();