amd64: Transform x87 minus

ir/be/amd64/amd64_spec.pl

@@ -224,6 +224,15 @@ my $x87const = {
 	mode      => $mode_x87,
 };
 
+my $x87unop = {
+	irn_flags => [ "rematerializable" ],
+	in_reqs   => [ "x87" ],
+	out_reqs  => [ "x87" ],
+	ins       => [ "value" ],
+	fixed     => "amd64_op_mode_t op_mode = AMD64_OP_X87;\n",
+	mode      => $mode_x87,
+};
+
 %nodes = (
 push_am => {
 	op_flags  => [ "uses_memory" ],
@@ -738,4 +747,9 @@ fld => {
 	emit      => "fld%FM %AM",
 },
 
+fchs => {
+	template => $x87unop,
+	emit     => "fchs",
+},
+
 );

ir/be/amd64/amd64_transform.c

@@ -1331,6 +1331,13 @@ static ir_node *gen_Minus(ir_node *const node)
 	ir_mode *mode = get_irn_mode(node);
 
 	if (mode_is_float(mode)) {
+		if (mode == x86_mode_E) {
+			dbg_info *dbgi   = get_irn_dbg_info(node);
+			ir_node  *block  = be_transform_node(get_nodes_block(node));
+			ir_node  *op     = get_Minus_op(node);
+			ir_node  *new_op = be_transform_node(op);
+			return new_bd_amd64_fchs(dbgi, block, new_op);
+		}
 		return gen_float_neg(node);
 	} else {
 		return gen_unop(node, n_Minus_op, &new_bd_amd64_neg, pn_amd64_neg_res);