d: Fix internal compiler error: Segmentation fault at gimple-expr.cc:88

Because complex types are deprecated in the language, the new way to
expose native complex types is by defining an enum with a basetype of a
library-defined struct that is implicitly treated as-if it is native.
As casts are not implicitly added by the front-end when downcasting from
enum to its underlying type, we must insert an explicit cast during the
code generation pass.

	PR d/106623

gcc/d/ChangeLog:

	* d-codegen.cc (underlying_complex_expr): New function.
	(d_build_call): Handle passing native complex objects as the
	library-defined equivalent.
	* d-tree.h (underlying_complex_expr): Declare.
	* expr.cc (ExprVisitor::visit (DotVarExp *)): Call
	underlying_complex_expr instead of build_vconvert.

gcc/testsuite/ChangeLog:

	* gdc.dg/torture/pr106623.d: New test.

4 files changed, 64 insertions, 1 deletions

diff --git a/gcc/d/d-codegen.cc b/gcc/d/d-codegen.cc
index d02da1f..aa6bc9e 100644
--- a/gcc/d/d-codegen.cc
+++ b/gcc/d/d-codegen.cc
@@ -1588,6 +1588,32 @@ complex_expr (tree type, tree re, tree im)
 			  type, re, im);
 }
 
+/* Build a two-field record TYPE representing the complex expression EXPR.  */
+
+tree
+underlying_complex_expr (tree type, tree expr)
+{
+  gcc_assert (list_length (TYPE_FIELDS (type)) == 2);
+
+  expr = d_save_expr (expr);
+
+  /* Build a constructor from the real and imaginary parts.  */
+  if (COMPLEX_FLOAT_TYPE_P (TREE_TYPE (expr)) &&
+      (!INDIRECT_REF_P (expr)
+       || !CONVERT_EXPR_CODE_P (TREE_CODE (TREE_OPERAND (expr, 0)))))
+    {
+      vec <constructor_elt, va_gc> *ve = NULL;
+      CONSTRUCTOR_APPEND_ELT (ve, TYPE_FIELDS (type),
+                    real_part (expr));
+      CONSTRUCTOR_APPEND_ELT (ve, TREE_CHAIN (TYPE_FIELDS (type)),
+                    imaginary_part (expr));
+      return build_constructor (type, ve);
+    }
+
+  /* Replace type in the reinterpret cast with a cast to the record type.  */
+  return build_vconvert (type, expr);
+}
+
 /* Cast EXP (which should be a pointer) to TYPE* and then indirect.
    The back-end requires this cast in many cases.  */
 
@@ -2214,6 +2240,14 @@ d_build_call (TypeFunction *tf, tree callable, tree object,
 			      build_address (targ));
 	    }
 
+	  /* Complex types are exposed as special types with an underlying
+	     struct representation, if we are passing the native type to a
+	     function that accepts the library-defined version, then ensure
+	     it is properly reinterpreted as the underlying struct type.  */
+	  if (COMPLEX_FLOAT_TYPE_P (TREE_TYPE (targ))
+	      && arg->type->isTypeStruct ())
+	    targ = underlying_complex_expr (build_ctype (arg->type), targ);
+
 	  /* Type `noreturn` is a terminator, as no other arguments can possibly
 	     be evaluated after it.  */
 	  if (TREE_TYPE (targ) == noreturn_type_node)
diff --git a/gcc/d/d-tree.h b/gcc/d/d-tree.h
index c3e95e4..809a242 100644
--- a/gcc/d/d-tree.h
+++ b/gcc/d/d-tree.h
@@ -576,6 +576,7 @@ extern tree size_mult_expr (tree, tree);
 extern tree real_part (tree);
 extern tree imaginary_part (tree);
 extern tree complex_expr (tree, tree, tree);
+extern tree underlying_complex_expr (tree, tree);
 extern tree indirect_ref (tree, tree);
 extern tree build_deref (tree);
 extern tree build_pointer_index (tree, tree);
diff --git a/gcc/d/expr.cc b/gcc/d/expr.cc
index 40c2689..140df7e 100644
--- a/gcc/d/expr.cc
+++ b/gcc/d/expr.cc
@@ -1892,7 +1892,7 @@ public:
 	       underlying is really a complex type.  */
 	    if (e->e1->type->ty == TY::Tenum
 		&& e->e1->type->isTypeEnum ()->sym->isSpecial ())
-	      object = build_vconvert (build_ctype (tb), object);
+	      object = underlying_complex_expr (build_ctype (tb), object);
 
 	    this->result_ = component_ref (object, get_symbol_decl (vd));
 	  }
diff --git a/gcc/testsuite/gdc.dg/torture/pr106623.d b/gcc/testsuite/gdc.dg/torture/pr106623.d
new file mode 100644
index 0000000..d782b23
--- /dev/null
+++ b/gcc/testsuite/gdc.dg/torture/pr106623.d
@@ -0,0 +1,28 @@
+// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106623
+// { dg-do compile }
+private struct _Complex(T) { T re; T im; }
+enum __c_complex_double : _Complex!double;
+
+pragma(inline, true)
+ulong hashOf()(scope const double val)
+{
+    return *cast(ulong*)&val;
+}
+
+pragma(inline, true)
+ulong hashOf()(scope const _Complex!double val, ulong seed = 0)
+{
+    return hashOf(val.re) + hashOf(val.im);
+}
+
+pragma(inline, true)
+ulong hashOf()(__c_complex_double val, ulong seed = 0)
+{
+    return hashOf(cast(_Complex!double) val, seed);
+}
+
+ulong test106623()
+{
+    __c_complex_double val;
+    return hashOf(val);
+}