From: Ian Lance Taylor <ian@gcc.gnu.org>
Date: Tue, 12 May 2015 22:13:01 +0000 (+0000)
Subject: compiler: If unary & does not escape, the var does not escape.
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=38109dbe011a7f69dc36c402186f6ffb2b385ac5;p=gcc.git

compiler: If unary & does not escape, the var does not escape.

If we have a unary & that takes the address of a variable, do
not force the variable to escape if the unary & does not
escape.

From-SVN: r223100
---

diff --git a/gcc/go/gofrontend/expressions.cc b/gcc/go/gofrontend/expressions.cc
index e811a8d2a44..05ab42b55da 100644
--- a/gcc/go/gofrontend/expressions.cc
+++ b/gcc/go/gofrontend/expressions.cc
@@ -3668,7 +3668,12 @@ Unary_expression::do_flatten(Gogo* gogo, Named_object*,
 
   if (this->op_ == OPERATOR_AND)
     {
-      if (this->expr_->var_expression() != NULL)
+      // If this->escapes_ is false at this point, then it was set to
+      // false by an explicit call to set_does_not_escape, and the
+      // value does not escape.  If this->escapes_ is true, we may be
+      // able to set it to false if taking the address of a variable
+      // that does not escape.
+      if (this->escapes_ && this->expr_->var_expression() != NULL)
 	{
 	  Named_object* var = this->expr_->var_expression()->named_object();
 	  if (var->is_variable())