value-relation: Small tweaks to tables

As I said earlier, all these tables are used solely in value-relation.cc
and never modified, plus because VREL_LAST is small especially the
two-dimensional arrays are vast a lot of .data (or .rodata) space
- 576 bytes each.  The following patch makes those arrays static const
and uses unsigned char instead of relation_kind so that the
two-dimensional arrays shrink to 144 bytes.

2023-01-26  Jakub Jelinek  <jakub@redhat.com>

	* value-relation.cc (kind_string): Add const.
	(rr_negate_table, rr_swap_table, rr_intersect_table,
	rr_union_table, rr_transitive_table): Add static const, change
	element type from relation_kind to unsigned char.
	(relation_negate, relation_swap, relation_intersect, relation_union,
	relation_transitive): Cast rr_*_table element to relation_kind.
	(relation_to_code): Add static const.
	(relation_tests): Assert VREL_LAST is smaller than UCHAR_MAX.

1 files changed, 14 insertions, 12 deletions

diff --git a/gcc/value-relation.cc b/gcc/value-relation.cc
index 6f8a1b7..5ca8a7e 100644
--- a/gcc/value-relation.cc
+++ b/gcc/value-relation.cc
@@ -32,7 +32,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "alloc-pool.h"
 #include "dominance.h"
 
-static const char *kind_string[VREL_LAST] =
+static const char *const kind_string[VREL_LAST] =
 { "varying", "undefined", "<", "<=", ">", ">=", "==", "!=", "pe8", "pe16",
   "pe32", "pe64" };
 
@@ -45,7 +45,7 @@ print_relation (FILE *f, relation_kind rel)
 }
 
 // This table is used to negate the operands.  op1 REL op2 -> !(op1 REL op2).
-relation_kind rr_negate_table[VREL_LAST] = {
+static const unsigned char rr_negate_table[VREL_LAST] = {
   VREL_VARYING, VREL_UNDEFINED, VREL_GE, VREL_GT, VREL_LE, VREL_LT, VREL_NE,
   VREL_EQ };
 
@@ -54,11 +54,11 @@ relation_kind rr_negate_table[VREL_LAST] = {
 relation_kind
 relation_negate (relation_kind r)
 {
-  return rr_negate_table [r];
+  return relation_kind (rr_negate_table [r]);
 }
 
 // This table is used to swap the operands.  op1 REL op2 -> op2 REL op1.
-relation_kind rr_swap_table[VREL_LAST] = {
+static const unsigned char rr_swap_table[VREL_LAST] = {
   VREL_VARYING, VREL_UNDEFINED, VREL_GT, VREL_GE, VREL_LT, VREL_LE, VREL_EQ,
   VREL_NE };
 
@@ -67,12 +67,12 @@ relation_kind rr_swap_table[VREL_LAST] = {
 relation_kind
 relation_swap (relation_kind r)
 {
-  return rr_swap_table [r];
+  return relation_kind (rr_swap_table [r]);
 }
 
 // This table is used to perform an intersection between 2 relations.
 
-relation_kind rr_intersect_table[VREL_LAST][VREL_LAST] = {
+static const unsigned char rr_intersect_table[VREL_LAST][VREL_LAST] = {
 // VREL_VARYING
   { VREL_VARYING, VREL_UNDEFINED, VREL_LT, VREL_LE, VREL_GT, VREL_GE, VREL_EQ,
     VREL_NE },
@@ -104,13 +104,13 @@ relation_kind rr_intersect_table[VREL_LAST][VREL_LAST] = {
 relation_kind
 relation_intersect (relation_kind r1, relation_kind r2)
 {
-  return rr_intersect_table[r1][r2];
+  return relation_kind (rr_intersect_table[r1][r2]);
 }
 
 
 // This table is used to perform a union between 2 relations.
 
-relation_kind rr_union_table[VREL_LAST][VREL_LAST] = {
+static const unsigned char rr_union_table[VREL_LAST][VREL_LAST] = {
 // VREL_VARYING
   { VREL_VARYING, VREL_VARYING, VREL_VARYING, VREL_VARYING, VREL_VARYING,
     VREL_VARYING, VREL_VARYING, VREL_VARYING },
@@ -141,14 +141,14 @@ relation_kind rr_union_table[VREL_LAST][VREL_LAST] = {
 relation_kind
 relation_union (relation_kind r1, relation_kind r2)
 {
-  return rr_union_table[r1][r2];
+  return relation_kind (rr_union_table[r1][r2]);
 }
 
 
 // This table is used to determine transitivity between 2 relations.
 // (A relation0 B) and (B relation1 C) implies  (A result C)
 
-relation_kind rr_transitive_table[VREL_LAST][VREL_LAST] = {
+static const unsigned char rr_transitive_table[VREL_LAST][VREL_LAST] = {
 // VREL_VARYING
   { VREL_VARYING, VREL_VARYING, VREL_VARYING, VREL_VARYING, VREL_VARYING,
     VREL_VARYING, VREL_VARYING, VREL_VARYING },
@@ -180,12 +180,12 @@ relation_kind rr_transitive_table[VREL_LAST][VREL_LAST] = {
 relation_kind
 relation_transitive (relation_kind r1, relation_kind r2)
 {
-  return rr_transitive_table[r1][r2];
+  return relation_kind (rr_transitive_table[r1][r2]);
 }
 
 // This vector maps a relation to the equivalent tree code.
 
-tree_code relation_to_code [VREL_LAST] = {
+static const tree_code relation_to_code [VREL_LAST] = {
   ERROR_MARK, ERROR_MARK, LT_EXPR, LE_EXPR, GT_EXPR, GE_EXPR, EQ_EXPR,
   NE_EXPR };
 
@@ -1727,6 +1727,8 @@ namespace selftest
 void
 relation_tests ()
 {
+  // rr_*_table tables use unsigned char rather than relation_kind.
+  ASSERT_LT (VREL_LAST, UCHAR_MAX);
   // Verify commutativity of relation_intersect and relation_union.
   for (relation_kind r1 = VREL_VARYING; r1 < VREL_PE8;
        r1 = relation_kind (r1 + 1))