Go patch committed: Fix struct hash/equality with _ fields

[Ian Lance Taylor]

This patch to the Go frontend fixes the handling of struct hash and
equality when the struct has _ fields.  Those fields should not
participate in the hash and equality functions at all.  Bootstrapped and
ran Go testsuite on x86_64-unknown-linux-gnu.  Committed to mainline.
Will commit to 4.7 branch when it reopens.

Ian


diff -r 3408484e8448 go/expressions.cc
--- a/go/expressions.cc	Wed Sep 19 17:53:19 2012 -0700
+++ b/go/expressions.cc	Wed Sep 19 21:32:53 2012 -0700
@@ -5178,6 +5178,9 @@
        pf != fields->end();
        ++pf, ++field_index)
     {
+      if (Gogo::is_sink_name(pf->field_name()))
+	continue;
+
       if (field_index > 0)
 	{
 	  if (left_temp == NULL)
diff -r 3408484e8448 go/types.cc
--- a/go/types.cc	Wed Sep 19 17:53:19 2012 -0700
+++ b/go/types.cc	Wed Sep 19 21:32:53 2012 -0700
@@ -579,6 +579,9 @@
 	       p != fields->end();
 	       ++p)
 	    {
+	      if (Gogo::is_sink_name(p->field_name()))
+		continue;
+
 	      if (!p->type()->is_comparable())
 		{
 		  if (reason != NULL)
@@ -4294,6 +4297,9 @@
        pf != fields->end();
        ++pf)
     {
+      if (Gogo::is_sink_name(pf->field_name()))
+	return false;
+
       if (!pf->type()->compare_is_identity(gogo))
 	return false;
 
@@ -4767,6 +4773,9 @@
        pf != fields->end();
        ++pf)
     {
+      if (Gogo::is_sink_name(pf->field_name()))
+	continue;
+
       if (first)
 	first = false;
       else
@@ -4858,6 +4867,9 @@
        pf != fields->end();
        ++pf, ++field_index)
     {
+      if (Gogo::is_sink_name(pf->field_name()))
+	continue;
+
       // Compare one field in both P1 and P2.
       Expression* f1 = Expression::make_temporary_reference(p1, bloc);
       f1 = Expression::make_unary(OPERATOR_MULT, f1, bloc);