Added an implementation for the signbit builtins

4 files changed, 26 insertions, 0 deletions

diff --git a/libfirm b/libfirm
-Subproject b031096c75829e287eb18942542ebcd4c6daa8a
+Subproject 137232fc4070ecc828cb448b11bad355bcb10f9
diff --git a/src/ast/entity_t.h b/src/ast/entity_t.h
index 206ec09..63b84c0 100644
--- a/src/ast/entity_t.h
+++ b/src/ast/entity_t.h
@@ -71,6 +71,7 @@ typedef enum {
 	BUILTIN_OBJECT_SIZE,
 	BUILTIN_ROTL,
 	BUILTIN_ROTR,
+	BUILTIN_SIGNBIT,
 	BUILTIN_VA_END,
 } builtin_kind_t;
 
diff --git a/src/firm/ast2firm.c b/src/firm/ast2firm.c
index dc2292b..82afb3d 100644
--- a/src/firm/ast2firm.c
+++ b/src/firm/ast2firm.c
@@ -736,6 +736,13 @@ entity_created:
 	return irentity;
 }
 
+/**
+ * Creates a new Conv node if dest_mode differs from the mode of value,
+ * otherwise returns value unchanged.
+ *
+ * @param value       the node representing the value to convert
+ * @param dest_mode   the mode to convert to
+ */
 static ir_node *create_conv(dbg_info *dbgi, ir_node *value, ir_mode *dest_mode)
 {
 	ir_mode *value_mode = get_irn_mode(value);
@@ -1000,6 +1007,21 @@ static ir_node *process_builtin_call(const call_expression_t *call)
 		ir_node      *one      = new_d_Const(dbgi, get_mode_one(res_mode));
 		return new_d_Mux(dbgi, cmp, zero, one);
 	}
+	case BUILTIN_SIGNBIT: {
+		expression_t *arg      = call->arguments->expression;
+		// Might be faster to pop into a 64 bit slot on x86_64
+		ir_node      *val      = create_conv(dbgi, expression_to_value(arg), get_modeF());
+		ir_node      *bits     = new_d_Bitcast(dbgi, val, get_modeIu());
+		ir_node      *mask     = new_d_Const_long(dbgi, get_modeIu(), 1L << 31);
+		ir_node      *flag     = new_d_And(dbgi, bits, mask);
+		ir_node      *cmp      = new_d_Cmp(dbgi, flag, mask, ir_relation_equal);
+
+		type_t       *res_type = function_type->function.return_type;
+		ir_mode      *res_mode = get_ir_mode_storage(res_type);
+		ir_node      *zero     = new_d_Const(dbgi, get_mode_null(res_mode));
+		ir_node      *one      = new_d_Const(dbgi, get_mode_one(res_mode));
+		return new_d_Mux(dbgi, cmp, zero, one);
+	}
 	case BUILTIN_EXPECT: {
 		expression_t *argument = call->arguments->expression;
 		return expression_to_value(argument);
diff --git a/src/parser/builtins.c b/src/parser/builtins.c
index f5ce851..a50d2d8 100644
--- a/src/parser/builtins.c
+++ b/src/parser/builtins.c
@@ -111,6 +111,9 @@ void create_gnu_builtins(void)
 	b(BUILTIN_NAN,         "nanf",           make_function_1_type(type_float, type_char_ptr, DM_CONST));
 	b(BUILTIN_NAN,         "nanl",           make_function_1_type(type_long_double, type_char_ptr, DM_CONST));
 	b(BUILTIN_ISNAN,       "isnan",          make_function_type(type_int, 1, (type_t *[]) { template }, DM_CONST));
+	b(BUILTIN_SIGNBIT,     "signbit",        make_function_1_type(type_int, type_double, DM_CONST));
+	b(BUILTIN_SIGNBIT,     "signbitf",       make_function_1_type(type_int, type_float, DM_CONST));
+	b(BUILTIN_SIGNBIT,     "signbitl",       make_function_1_type(type_int, type_long_double, DM_CONST));
 	b(BUILTIN_VA_END,      "va_end",         make_function_1_type(type_void, type_valist_arg, DM_NONE));
 	b(BUILTIN_EXPECT,      "expect",         make_function_2_type(type_long, type_long, type_long, DM_CONST));
 	b(BUILTIN_OBJECT_SIZE, "object_size",    make_function_2_type(type_size_t, type_void_ptr, type_int, DM_CONST));