From 39e740e8a789438e177f171c9a00b7fba5cb7afc Mon Sep 17 00:00:00 2001
From: Ian Lance Taylor <ian@gcc.gnu.org>
Date: Tue, 5 May 2015 20:56:41 +0000
Subject: [PATCH] compiler: Don't make temporaries for constant string
 concatentation.

Fixes golang/go#10642.

From-SVN: r222827
---
 gcc/go/gofrontend/expressions.cc | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/gcc/go/gofrontend/expressions.cc b/gcc/go/gofrontend/expressions.cc
index 40d9aa7726bf..47773304e73d 100644
--- a/gcc/go/gofrontend/expressions.cc
+++ b/gcc/go/gofrontend/expressions.cc
@@ -5194,13 +5194,15 @@ Binary_expression::do_flatten(Gogo* gogo, Named_object*,
   if (this->left_->type()->is_string_type()
       && this->op_ == OPERATOR_PLUS)
     {
-      if (!this->left_->is_variable())
+      if (!this->left_->is_variable()
+	  && !this->left_->is_constant())
         {
           temp = Statement::make_temporary(NULL, this->left_, loc);
           inserter->insert(temp);
           this->left_ = Expression::make_temporary_reference(temp, loc);
         }
-      if (!this->right_->is_variable())
+      if (!this->right_->is_variable()
+	  && !this->right_->is_constant())
         {
           temp =
               Statement::make_temporary(this->left_->type(), this->right_, loc);