[PATCH, V2, d] Fix IdentityExp comparison for complex floats

[Johannes Pfau <johannespfau at gmail dot com>]

Next version, addresses the review comments.

Tested at https://github.com/D-Programming-GDC/GDC/pull/768
---
gcc/d/ChangeLog:

2018-11-28  Johannes Pfau  <johannespfau@gmail.com>

	* expr.cc (ExprVisitor::visit(IdentityExp)): Add support for complex types.
	(build_float_identity): New function. 

gcc/testsuite/ChangeLog:

2018-11-28  Johannes Pfau  <johannespfau@gmail.com>

	* gdc.dg/runnable.d: Test IdentityExp for complex types.


 gcc/d/expr.cc                   | 40 ++++++++++++++++++++++++---------
 gcc/testsuite/gdc.dg/runnable.d | 22 ++++++++++++++++++
 2 files changed, 51 insertions(+), 11 deletions(-)

diff --git a/gcc/d/expr.cc b/gcc/d/expr.cc
index 9a1aad42ddc..91cb02f1e9a 100644
--- a/gcc/d/expr.cc
+++ b/gcc/d/expr.cc
@@ -42,6 +42,20 @@ along with GCC; see the file COPYING3.  If not see
 
 #include "d-tree.h"
 
+/* Helper function for floating point identity comparison. Compare
+   only well-defined bits, ignore padding (e.g. for X86 80bit real).  */
+
+static tree build_float_identity (tree_code code, tree t1, tree t2)
+{
+  /* For floating-point values, identity is defined as the bits in the
+     operands being identical.  */
+  tree tmemcmp = builtin_decl_explicit (BUILT_IN_MEMCMP);
+  tree size = size_int (TYPE_PRECISION (TREE_TYPE (t1)) / BITS_PER_UNIT);
+
+  tree result = build_call_expr (tmemcmp, 3, build_address (t1),
+				 build_address (t2), size);
+  return build_boolop (code, result, integer_zero_node);
+}
 
 /* Implements the visitor interface to build the GCC trees of all Expression
    AST classes emitted from the D Front-end.
@@ -275,19 +289,23 @@ public:
 	this->result_ = d_convert (build_ctype (e->type),
 				   build_boolop (code, t1, t2));
       }
-    else if (tb1->isfloating () && tb1->ty != Tvector)
+    else if (tb1->iscomplex () && tb1->ty != Tvector)
       {
-	/* For floating-point values, identity is defined as the bits in the
-	   operands being identical.  */
-	tree t1 = d_save_expr (build_expr (e->e1));
-	tree t2 = d_save_expr (build_expr (e->e2));
-
-	tree tmemcmp = builtin_decl_explicit (BUILT_IN_MEMCMP);
-	tree size = size_int (TYPE_PRECISION (TREE_TYPE (t1)) / BITS_PER_UNIT);
+	tree e1 = d_save_expr (build_expr (e->e1));
+	tree e2 = d_save_expr (build_expr (e->e2));
+	tree req = build_float_identity (code, real_part (e1), real_part (e2));
+	tree ieq = build_float_identity (code, imaginary_part (e1), imaginary_part (e2));
 
-	tree result = build_call_expr (tmemcmp, 3, build_address (t1),
-				       build_address (t2), size);
-	this->result_ = build_boolop (code, result, integer_zero_node);
+	if (code == EQ_EXPR)
+	  this->result_ = build_boolop (TRUTH_ANDIF_EXPR, req, ieq);
+	else
+	  this->result_ = build_boolop (TRUTH_ORIF_EXPR, req, ieq);
+      }
+    else if (tb1->isfloating () && tb1->ty != Tvector)
+      {
+	tree e1 = d_save_expr (build_expr (e->e1));
+	tree e2 = d_save_expr (build_expr (e->e2));
+	this->result_ = build_float_identity (code, e1, e2);
       }
     else if (tb1->ty == Tstruct)
       {
diff --git a/gcc/testsuite/gdc.dg/runnable.d b/gcc/testsuite/gdc.dg/runnable.d
index ec172fae810..65c71e86292 100644
--- a/gcc/testsuite/gdc.dg/runnable.d
+++ b/gcc/testsuite/gdc.dg/runnable.d
@@ -1534,6 +1534,27 @@ void test286()
         assert(0);
 }
 
+/******************************************/
+// https://bugzilla.gdcproject.org/show_bug.cgi?id=309
+
+void test309()
+{
+    creal f1 = +0.0 + 0.0i;
+    creal f2 = +0.0 - 0.0i;
+    creal f3 = -0.0 + 0.0i;
+    creal f4 = +0.0 + 0.0i;
+
+    assert(f1 !is f2);
+    assert(f1 !is f3);
+    assert(f2 !is f3);
+    assert(f1 is f4);
+
+    assert(!(f1 is f2));
+    assert(!(f1 is f3));
+    assert(!(f2 is f3));
+    assert(!(f1 !is f4));
+}
+
 /******************************************/
 
 void main()
@@ -1571,6 +1592,7 @@ void main()
     test273();
     test285();
     test286();
+    test309();
 
     printf("Success!\n");
 }
-- 
2.19.1