X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Ftv%2Ftv.c;h=69133cb51f71c9e20aa472fb816de6beaeec5f6e;hb=2a8124bbe0acbc7398d8fc1998c80afa39e77213;hp=cd4e53e0507f50271be609ca3c91d2d143356d91;hpb=f2d236f4fac425604e8552790432332ff216c065;p=libfirm

diff --git a/ir/tv/tv.c b/ir/tv/tv.c
index cd4e53e05..69133cb51 100644
--- a/ir/tv/tv.c
+++ b/ir/tv/tv.c
@@ -94,16 +94,29 @@ enum float_to_int_mode {
 
 #define fail_verify(a) _fail_verify((a), __FILE__, __LINE__)
 
-/****************************************************************************
- *   private variables
- ****************************************************************************/
-static struct set *tarvals = NULL;   /* container for tarval structs */
-static struct set *values = NULL;    /* container for values */
+/** A set containing all existing tarvals. */
+static struct set *tarvals = NULL;
+/** A set containing all existing values. */
+static struct set *values = NULL;
+
+/** The integer overflow mode. */
 static tarval_int_overflow_mode_t int_overflow_mode = TV_OVERFLOW_WRAP;
 
 /** if this is set non-zero, the constant folding for floating point is OFF */
 static int no_float = 0;
 
+/** IEEE-754r half precision */
+static const ieee_descriptor_t half_desc     = {  5,  10, 0, NORMAL };
+/** IEEE-754 single precision */
+static const ieee_descriptor_t single_desc   = {  8,  23, 0, NORMAL };
+/** IEEE-754 double precision */
+static const ieee_descriptor_t double_desc   = { 11,  52, 0, NORMAL };
+/** Intel x87 extended precision */
+static const ieee_descriptor_t extended_desc = { 15,  63, 1, NORMAL };
+
+/** IEEE-754r quad precision */
+static const ieee_descriptor_t quad_desc     = { 15, 112, 0, NORMAL };
+
 /****************************************************************************
  *   private functions
  ****************************************************************************/
@@ -134,8 +147,6 @@ INLINE static void tarval_verify(tarval *tv)
 
 	if (!FIND_TARVAL(tv)) fail_verify(tv);
 	if (tv->length > 0 && !FIND_VALUE(tv->value, tv->length)) fail_verify(tv);
-
-	return;
 }
 #endif /* NDEBUG */
 
@@ -165,17 +176,17 @@ static int cmp_tv(const void *p1, const void *p2, size_t n) {
 
 	assert(tv1->kind == k_tarval);
 	assert(tv2->kind == k_tarval);
-	if(tv1->mode < tv2->mode)
+	if (tv1->mode < tv2->mode)
 		return -1;
-	if(tv1->mode > tv2->mode)
+	if (tv1->mode > tv2->mode)
 		return 1;
-	if(tv1->length < tv2->length)
+	if (tv1->length < tv2->length)
 		return -1;
-	if(tv1->length > tv2->length)
+	if (tv1->length > tv2->length)
 		return 1;
-	if(tv1->value < tv2->value)
+	if (tv1->value < tv2->value)
 		return -1;
-	if(tv1->value > tv2->value)
+	if (tv1->value > tv2->value)
 		return 1;
 
 	return 0;
@@ -279,12 +290,31 @@ static tarval *get_tarval_overflow(const void *value, int length, ir_mode *mode)
 /*
  *   public variables declared in tv.h
  */
-static tarval reserved_tv[4];
+static tarval reserved_tv[6];
 
-tarval *tarval_bad       = &reserved_tv[0];
-tarval *tarval_undefined = &reserved_tv[1];
-tarval *tarval_b_false   = &reserved_tv[2];
-tarval *tarval_b_true    = &reserved_tv[3];
+tarval *tarval_b_false     = &reserved_tv[0];
+tarval *tarval_b_true      = &reserved_tv[1];
+tarval *tarval_bad         = &reserved_tv[2];
+tarval *tarval_undefined   = &reserved_tv[3];
+tarval *tarval_reachable   = &reserved_tv[4];
+tarval *tarval_unreachable = &reserved_tv[5];
+
+/**
+ * get the float descriptor for given mode.
+ */
+static const ieee_descriptor_t *get_descriptor(const ir_mode *mode) {
+	switch (get_mode_size_bits(mode)) {
+	case 16:  return &half_desc;
+	case 32:  return &single_desc;
+	case 64:  return &double_desc;
+	case 80:
+	case 96:  return &extended_desc;
+	case 128: return &quad_desc;
+	default:
+		panic("Unsupported mode in get_descriptor()");
+		return NULL;
+	}
+}
 
 /*
  *   public functions declared in tv.h
@@ -295,6 +325,8 @@ tarval *tarval_b_true    = &reserved_tv[3];
  */
 tarval *new_tarval_from_str(const char *str, size_t len, ir_mode *mode)
 {
+	const ieee_descriptor_t *desc;
+
 	assert(str);
 	assert(len);
 	assert(mode);
@@ -308,27 +340,17 @@ tarval *new_tarval_from_str(const char *str, size_t len, ir_mode *mode)
 
 	case irms_internal_boolean:
 		/* match [tT][rR][uU][eE]|[fF][aA][lL][sS][eE] */
-		if (strcasecmp(str, "true")) return tarval_b_true;
-		else if (strcasecmp(str, "false")) return tarval_b_true;
+		if (strcasecmp(str, "true"))
+			return tarval_b_true;
+		else if (strcasecmp(str, "false"))
+			return tarval_b_true;
 		else
 			/* XXX This is C semantics */
 			return atoi(str) ? tarval_b_true : tarval_b_false;
 
 	case irms_float_number:
-		switch (get_mode_size_bits(mode)) {
-		case 32:
-			fc_val_from_str(str, len, 8, 23, NULL);
-			break;
-		case 64:
-			fc_val_from_str(str, len, 11, 52, NULL);
-			break;
-		case 80:
-		case 96:
-			fc_val_from_str(str, len, 15, 64, NULL);
-			break;
-		default:
-			panic("Unsupported mode in new_tarval_from_str()");
-		}
+		desc = get_descriptor(mode);
+		fc_val_from_str(str, len, desc, NULL);
 		return get_tarval(fc_get_buffer(), fc_get_buffer_length(), mode);
 
 	case irms_reference:
@@ -392,22 +414,11 @@ long get_tarval_long(tarval* tv) {
 }
 
 tarval *new_tarval_from_double(long double d, ir_mode *mode) {
-	assert(mode && (get_mode_sort(mode) == irms_float_number));
+	const ieee_descriptor_t *desc;
 
-	switch (get_mode_size_bits(mode)) {
-	case 32:
-		fc_val_from_ieee754(d, 8, 23, NULL);
-		break;
-	case 64:
-		fc_val_from_ieee754(d, 11, 52, NULL);
-		break;
-	case 80:
-	case 96:
-		fc_val_from_ieee754(d, 15, 64, NULL);
-		break;
-	default:
-		panic("Unsupported mode in new_tarval_from_double()");
-	}
+	assert(mode && (get_mode_sort(mode) == irms_float_number));
+	desc = get_descriptor(mode);
+	fc_val_from_ieee754(d, desc, NULL);
 	return get_tarval(fc_get_buffer(), fc_get_buffer_length(), mode);
 }
 
@@ -460,15 +471,24 @@ tarval *(get_tarval_b_true)(void) {
 	return _get_tarval_b_true();
 }
 
+tarval *(get_tarval_reachable)(void) {
+	return _get_tarval_reachable();
+}
+
+tarval *(get_tarval_unreachable)(void) {
+	return _get_tarval_unreachable();
+}
+
 tarval *get_tarval_max(ir_mode *mode) {
-	assert(mode);
+	const ieee_descriptor_t *desc;
 
+	assert(mode);
 	if (get_mode_n_vector_elems(mode) > 1) {
 		/* vector arithmetic not implemented yet */
 		return tarval_bad;
 	}
 
-	switch(get_mode_sort(mode)) {
+	switch (get_mode_sort(mode)) {
 	case irms_control_flow:
 	case irms_memory:
 	case irms_auxiliary:
@@ -479,20 +499,8 @@ tarval *get_tarval_max(ir_mode *mode) {
 		return tarval_b_true;
 
 	case irms_float_number:
-		switch(get_mode_size_bits(mode)) {
-		case 32:
-			fc_get_max(8, 23, NULL);
-			break;
-		case 64:
-			fc_get_max(11, 52, NULL);
-			break;
-		case 80:
-		case 96:
-			fc_get_max(15, 64, NULL);
-			break;
-		default:
-			panic("Unsupported mode in get_tarval_max()");
-		}
+		desc = get_descriptor(mode);
+		fc_get_max(desc, NULL);
 		return get_tarval(fc_get_buffer(), fc_get_buffer_length(), mode);
 
 	case irms_reference:
@@ -504,14 +512,15 @@ tarval *get_tarval_max(ir_mode *mode) {
 }
 
 tarval *get_tarval_min(ir_mode *mode) {
-	assert(mode);
+	const ieee_descriptor_t *desc;
 
+	assert(mode);
 	if (get_mode_n_vector_elems(mode) > 1) {
 		/* vector arithmetic not implemented yet */
 		return tarval_bad;
 	}
 
-	switch(get_mode_sort(mode)) {
+	switch (get_mode_sort(mode)) {
 	case irms_control_flow:
 	case irms_memory:
 	case irms_auxiliary:
@@ -522,20 +531,8 @@ tarval *get_tarval_min(ir_mode *mode) {
 		return tarval_b_false;
 
 	case irms_float_number:
-		switch(get_mode_size_bits(mode)) {
-		case 32:
-			fc_get_min(8, 23, NULL);
-			break;
-		case 64:
-			fc_get_min(11, 52, NULL);
-			break;
-		case 80:
-		case 96:
-			fc_get_min(15, 64, NULL);
-			break;
-		default:
-			panic("Unsupported mode in get_tarval_min()");
-		}
+		desc = get_descriptor(mode);
+		fc_get_min(desc, NULL);
 		return get_tarval(fc_get_buffer(), fc_get_buffer_length(), mode);
 
 	case irms_reference:
@@ -557,7 +554,7 @@ tarval *get_tarval_null(ir_mode *mode) {
 		return tarval_bad;
 	}
 
-	switch(get_mode_sort(mode)) {
+	switch (get_mode_sort(mode)) {
 	case irms_control_flow:
 	case irms_memory:
 	case irms_auxiliary:
@@ -586,7 +583,7 @@ tarval *get_tarval_one(ir_mode *mode) {
 		return tarval_bad;
 	}
 
-	switch(get_mode_sort(mode)) {
+	switch (get_mode_sort(mode)) {
 	case irms_control_flow:
 	case irms_memory:
 	case irms_auxiliary:
@@ -615,7 +612,7 @@ tarval *get_tarval_all_one(ir_mode *mode) {
 		return tarval_bad;
 	}
 
-	switch(get_mode_sort(mode)) {
+	switch (get_mode_sort(mode)) {
 	case irms_control_flow:
 	case irms_memory:
 	case irms_auxiliary:
@@ -634,6 +631,14 @@ tarval *get_tarval_all_one(ir_mode *mode) {
 	return tarval_bad;
 }
 
+int tarval_is_constant(tarval *tv) {
+	int num_res = sizeof(reserved_tv) / sizeof(reserved_tv[0]);
+
+	/* reserved tarvals are NOT constants. Note that although
+	   tarval_b_true and tarval_b_false are reserved, they are constants of course. */
+	return (tv < &reserved_tv[2] || tv > &reserved_tv[num_res - 1]);
+}
+
 tarval *get_tarval_minus_one(ir_mode *mode) {
 	assert(mode);
 
@@ -642,7 +647,7 @@ tarval *get_tarval_minus_one(ir_mode *mode) {
 		return tarval_bad;
 	}
 
-	switch(get_mode_sort(mode)) {
+	switch (get_mode_sort(mode)) {
 	case irms_control_flow:
 	case irms_memory:
 	case irms_auxiliary:
@@ -663,28 +668,17 @@ tarval *get_tarval_minus_one(ir_mode *mode) {
 }
 
 tarval *get_tarval_nan(ir_mode *mode) {
-	assert(mode);
+	const ieee_descriptor_t *desc;
 
+	assert(mode);
 	if (get_mode_n_vector_elems(mode) > 1) {
 		/* vector arithmetic not implemented yet */
 		return tarval_bad;
 	}
 
 	if (get_mode_sort(mode) == irms_float_number) {
-		switch(get_mode_size_bits(mode)) {
-		case 32:
-			fc_get_qnan(8, 23, NULL);
-			break;
-		case 64:
-			fc_get_qnan(11, 52, NULL);
-			break;
-		case 80:
-		case 96:
-			fc_get_qnan(15, 64, NULL);
-			break;
-		default:
-			panic("Unsupported mode in get_tarval_nan()");
-		}
+		desc = get_descriptor(mode);
+		fc_get_qnan(desc, NULL);
 		return get_tarval(fc_get_buffer(), fc_get_buffer_length(), mode);
 	} else {
 		assert(0 && "tarval is not floating point");
@@ -694,27 +688,14 @@ tarval *get_tarval_nan(ir_mode *mode) {
 
 tarval *get_tarval_plus_inf(ir_mode *mode) {
 	assert(mode);
-
 	if (get_mode_n_vector_elems(mode) > 1) {
 		/* vector arithmetic not implemented yet */
 		return tarval_bad;
 	}
 
 	if (get_mode_sort(mode) == irms_float_number) {
-		switch(get_mode_size_bits(mode)) {
-		case 32:
-			fc_get_plusinf(8, 23, NULL);
-			break;
-		case 64:
-			fc_get_plusinf(11, 52, NULL);
-			break;
-		case 80:
-		case 96:
-			fc_get_plusinf(15, 64, NULL);
-			break;
-		default:
-			panic("Unsupported mode in get_tarval_plus_inf()");
-		}
+		const ieee_descriptor_t *desc = get_descriptor(mode);
+		fc_get_plusinf(desc, NULL);
 		return get_tarval(fc_get_buffer(), fc_get_buffer_length(), mode);
 	} else {
 		assert(0 && "tarval is not floating point");
@@ -731,20 +712,8 @@ tarval *get_tarval_minus_inf(ir_mode *mode) {
 	}
 
 	if (get_mode_sort(mode) == irms_float_number) {
-		switch(get_mode_size_bits(mode)) {
-		case 32:
-			fc_get_minusinf(8, 23, NULL);
-			break;
-		case 64:
-			fc_get_minusinf(11, 52, NULL);
-			break;
-		case 80:
-		case 96:
-			fc_get_minusinf(15, 64, NULL);
-			break;
-		default:
-			panic("Unsupported mode in get_tarval_minus_inf()");
-		}
+		const ieee_descriptor_t *desc = get_descriptor(mode);
+		fc_get_minusinf(desc, NULL);
 		return get_tarval(fc_get_buffer(), fc_get_buffer_length(), mode);
 	} else {
 		assert(0 && "tarval is not floating point");
@@ -881,13 +850,15 @@ pn_Cmp tarval_cmp(tarval *a, tarval *b) {
  * convert to other mode
  */
 tarval *tarval_convert_to(tarval *src, ir_mode *dst_mode) {
-	char *buffer;
-	fp_value *res;
+	char                    *buffer;
+	fp_value                *res;
+	const ieee_descriptor_t *desc;
 
 	assert(src);
 	assert(dst_mode);
 
-	if (src->mode == dst_mode) return src;
+	if (src->mode == dst_mode)
+		return src;
 
 	if (get_mode_n_vector_elems(src->mode) > 1) {
 		/* vector arithmetic not implemented yet */
@@ -904,20 +875,8 @@ tarval *tarval_convert_to(tarval *src, ir_mode *dst_mode) {
 	case irms_float_number:
 		switch (get_mode_sort(dst_mode)) {
 		case irms_float_number:
-			switch (get_mode_size_bits(dst_mode)) {
-			case 32:
-				fc_cast(src->value, 8, 23, NULL);
-				break;
-			case 64:
-				fc_cast(src->value, 11, 52, NULL);
-				break;
-			case 80:
-			case 96:
-				fc_cast(src->value, 15, 64, NULL);
-				break;
-			default:
-				panic("Unsupported mode in tarval_convert_to()");
-			}
+			desc = get_descriptor(dst_mode);
+			fc_cast(src->value, desc, NULL);
 			return get_tarval(fc_get_buffer(), fc_get_buffer_length(), dst_mode);
 
 		case irms_int_number:
@@ -969,20 +928,8 @@ tarval *tarval_convert_to(tarval *src, ir_mode *dst_mode) {
 			snprintf(buffer, 100, "%s",
 				sc_print(src->value, get_mode_size_bits(src->mode), SC_DEC, mode_is_signed(src->mode)));
 			buffer[100 - 1] = '\0';
-			switch (get_mode_size_bits(dst_mode)) {
-			case 32:
-				fc_val_from_str(buffer, 0, 8, 23, NULL);
-				break;
-			case 64:
-				fc_val_from_str(buffer, 0, 11, 52, NULL);
-				break;
-			case 80:
-			case 96:
-				fc_val_from_str(buffer, 0, 15, 64, NULL);
-				break;
-			default:
-				panic("Unsupported mode in tarval_convert_to()");
-			}
+			desc = get_descriptor(dst_mode);
+			fc_val_from_str(buffer, 0, desc, NULL);
 			return get_tarval(fc_get_buffer(), fc_get_buffer_length(), dst_mode);
 
 		default:
@@ -1082,14 +1029,22 @@ tarval *tarval_add(tarval *a, tarval *b) {
 
 	assert(a);
 	assert(b);
-	assert(a->mode == b->mode);
 
 	if (get_mode_n_vector_elems(a->mode) > 1 || get_mode_n_vector_elems(b->mode) > 1) {
 		/* vector arithmetic not implemented yet */
 		return tarval_bad;
 	}
 
+	if (mode_is_reference(a->mode) && a->mode != b->mode) {
+		b = tarval_convert_to(b, a->mode);
+	} else if (mode_is_reference(b->mode) && b->mode != a->mode) {
+		a = tarval_convert_to(a, b->mode);
+	}
+
+	assert(a->mode == b->mode);
+
 	switch (get_mode_sort(a->mode)) {
+	case irms_reference:
 	case irms_int_number:
 		/* modes of a,b are equal, so result has mode of a as this might be the character */
 		buffer = alloca(sc_get_buffer_length());
@@ -1111,18 +1066,27 @@ tarval *tarval_add(tarval *a, tarval *b) {
 /*
  * subtraction
  */
-tarval *tarval_sub(tarval *a, tarval *b) {
-	char *buffer;
+tarval *tarval_sub(tarval *a, tarval *b, ir_mode *dst_mode) {
+	char    *buffer;
 
 	assert(a);
 	assert(b);
-	assert(a->mode == b->mode);
 
 	if (get_mode_n_vector_elems(a->mode) > 1 || get_mode_n_vector_elems(b->mode) > 1) {
 		/* vector arithmetic not implemented yet */
 		return tarval_bad;
 	}
+
+	if (dst_mode != NULL) {
+		if (a->mode != dst_mode)
+			a = tarval_convert_to(a, dst_mode);
+		if (b->mode != dst_mode)
+			b = tarval_convert_to(b, dst_mode);
+	}
+	assert(a->mode == b->mode);
+
 	switch (get_mode_sort(a->mode)) {
+	case irms_reference:
 	case irms_int_number:
 		/* modes of a,b are equal, so result has mode of a as this might be the character */
 		buffer = alloca(sc_get_buffer_length());
@@ -1314,7 +1278,7 @@ tarval *tarval_and(tarval *a, tarval *b) {
 
 	/* works even for vector modes */
 
-	switch(get_mode_sort(a->mode)) {
+	switch (get_mode_sort(a->mode)) {
 	case irms_internal_boolean:
 		return (a == tarval_b_false) ? a : b;
 
@@ -1331,7 +1295,7 @@ tarval *tarval_and(tarval *a, tarval *b) {
 /*
  * bitwise or
  */
-tarval *tarval_or (tarval *a, tarval *b) {
+tarval *tarval_or(tarval *a, tarval *b) {
 	assert(a);
 	assert(b);
 	assert(a->mode == b->mode);
@@ -1564,7 +1528,15 @@ int tarval_snprintf(char *buf, size_t len, tarval *tv) {
 	case irms_control_flow:
 	case irms_memory:
 	case irms_auxiliary:
-		return snprintf(buf, len, "<TV_OVERFLOW_BAD>");
+		if (tv == tarval_bad)
+			return snprintf(buf, len, "<TV_BAD>");
+		if (tv == tarval_undefined)
+			return snprintf(buf, len, "<TV_UNDEF>");
+		if (tv == tarval_unreachable)
+			return snprintf(buf, len, "<TV_UNREACHABLE>");
+		if (tv == tarval_reachable)
+			return snprintf(buf, len, "<TV_REACHABLE>");
+		return snprintf(buf, len, "<TV_??""?>");
 	}
 
 	return 0;
@@ -1687,23 +1659,8 @@ int tarval_ieee754_get_exponent(tarval *tv) {
  * precision loss.
  */
 int tarval_ieee754_can_conv_lossless(tarval *tv, ir_mode *mode) {
-	char exp_size, mant_size;
-	switch (get_mode_size_bits(mode)) {
-	case 32:
-		exp_size = 8; mant_size = 23;
-		break;
-	case 64:
-		exp_size = 11; mant_size = 52;
-		break;
-	case 80:
-	case 96:
-		exp_size = 15; mant_size = 64;
-		break;
-	default:
-		panic("Unsupported mode in tarval_ieee754_can_conv_lossless()");
-		return 0;
-	}
-	return fc_can_lossless_conv_to(tv->value, exp_size, mant_size);
+	const ieee_descriptor_t *desc = get_descriptor(mode);
+	return fc_can_lossless_conv_to(tv->value, desc);
 }
 
 /* Set the immediate precision for IEEE-754 results. */
@@ -1716,6 +1673,17 @@ unsigned tarval_ieee754_get_exact(void) {
 	return fc_is_exact();
 }
 
+/* Return the size of the mantissa in bits (including possible
+   implicit bits) for the given mode. */
+unsigned tarval_ieee754_get_mantissa_size(const ir_mode *mode) {
+	const ieee_descriptor_t *desc;
+
+	assert(get_mode_arithmetic(mode) == irma_ieee754);
+	desc = get_descriptor(mode);
+
+	return desc->mantissa_size + desc->explicit_one;
+}
+
 /* check if its the a floating point NaN */
 int tarval_is_NaN(tarval *tv) {
 	if (! mode_is_float(tv->mode))
@@ -1776,38 +1744,48 @@ static const tarval_mode_info hex_output = {
 /*
  * Initialization of the tarval module: called before init_mode()
  */
-void init_tarval_1(long null_value) {
+void init_tarval_1(long null_value, int support_quad_precision) {
+	/* if these assertion fail, tarval_is_constant() will follow ... */
+	assert(tarval_b_false == &reserved_tv[0] && "b_false MUST be the first reserved tarval!");
+	assert(tarval_b_true  == &reserved_tv[1] && "b_true MUST be the second reserved tarval!");
+
 	_null_value = null_value;
 
 	/* initialize the sets holding the tarvals with a comparison function and
 	 * an initial size, which is the expected number of constants */
 	tarvals = new_set(cmp_tv, N_CONSTANTS);
 	values  = new_set(memcmp, N_CONSTANTS);
-	/* init strcalc with precision of 68 to support floating point values with 64
-	 * bit mantissa (needs extra bits for rounding and overflow) */
-	init_strcalc(68);
-	init_fltcalc(0);
+	/* calls init_strcalc() with needed size */
+	init_fltcalc(support_quad_precision ? 112 : 64);
 }
 
 /*
  * Initialization of the tarval module: called after init_mode()
  */
 void init_tarval_2(void) {
-	tarval_bad->kind        = k_tarval;
-	tarval_bad->mode        = mode_BAD;
-	tarval_bad->value       = INT_TO_PTR(resid_tarval_bad);
+	tarval_bad->kind          = k_tarval;
+	tarval_bad->mode          = mode_BAD;
+	tarval_bad->value         = INT_TO_PTR(resid_tarval_bad);
+
+	tarval_undefined->kind    = k_tarval;
+	tarval_undefined->mode    = mode_ANY;
+	tarval_undefined->value   = INT_TO_PTR(resid_tarval_undefined);
 
-	tarval_undefined->kind  = k_tarval;
-	tarval_undefined->mode  = mode_ANY;
-	tarval_undefined->value = INT_TO_PTR(resid_tarval_undefined);
+	tarval_b_true->kind       = k_tarval;
+	tarval_b_true->mode       = mode_b;
+	tarval_b_true->value      = INT_TO_PTR(resid_tarval_b_true);
 
-	tarval_b_true->kind     = k_tarval;
-	tarval_b_true->mode     = mode_b;
-	tarval_b_true->value    = INT_TO_PTR(resid_tarval_b_true);
+	tarval_b_false->kind      = k_tarval;
+	tarval_b_false->mode      = mode_b;
+	tarval_b_false->value     = INT_TO_PTR(resid_tarval_b_false);
 
-	tarval_b_false->kind    = k_tarval;
-	tarval_b_false->mode    = mode_b;
-	tarval_b_false->value   = INT_TO_PTR(resid_tarval_b_false);
+	tarval_unreachable->kind  = k_tarval;
+	tarval_unreachable->mode  = mode_X;
+	tarval_unreachable->value = INT_TO_PTR(resid_tarval_unreachable);
+
+	tarval_reachable->kind    = k_tarval;
+	tarval_reachable->mode    = mode_X;
+	tarval_reachable->value   = INT_TO_PTR(resid_tarval_reachable);
 
 	/*
 	 * assign output modes that are compatible with the
@@ -1832,6 +1810,10 @@ void finish_tarval(void) {
 	del_set(values);  values = NULL;
 }
 
+int (is_tarval)(const void *thing) {
+	return _is_tarval(thing);
+}
+
 /****************************************************************************
  *   end of tv.c
  ****************************************************************************/