RFC: PATCH: Remove 26 element limit in XVECEXP

diff --git a/gcc/genextract.c b/gcc/genextract.c
index 09e7cde..2afeec0 100644
--- a/gcc/genextract.c
+++ b/gcc/genextract.c
@@ -108,7 +108,7 @@  gen_insn (rtx insn, int insn_code_number)
   else
     for (i = XVECLEN (insn, 1) - 1; i >= 0; i--)
       {
-	VEC_safe_push (char,heap, acc.pathstr, 'a' + i);
+	VEC_safe_push (char,heap, acc.pathstr, encode_xvecexp (i));
 	walk_rtx (XVECEXP (insn, 1, i), &acc);
 	VEC_pop (char, acc.pathstr);
       }
@@ -222,7 +222,7 @@  static void
 walk_rtx (rtx x, struct accum_extract *acc)
 {
   RTX_CODE code;
-  int i, len, base;
+  int i, len, val;
   const char *fmt;
 
   if (x == 0)
@@ -248,10 +248,13 @@  walk_rtx (rtx x, struct accum_extract *acc)
       VEC_safe_set_locstr (&acc->oplocs, XINT (x, 0),
 			   VEC_char_to_string (acc->pathstr));
 
-      base = (code == MATCH_OPERATOR ? '0' : 'a');
       for (i = XVECLEN (x, 2) - 1; i >= 0; i--)
 	{
-	  VEC_safe_push (char,heap, acc->pathstr, base + i);
+	  if (code == MATCH_OPERATOR)
+	    val = '0' + i;
+	  else
+	    val = encode_xvecexp (i);
+	  VEC_safe_push (char,heap, acc->pathstr, val);
 	  walk_rtx (XVECEXP (x, 2, i), acc);
 	  VEC_pop (char, acc->pathstr);
         }
@@ -267,10 +270,13 @@  walk_rtx (rtx x, struct accum_extract *acc)
       if (code == MATCH_DUP)
 	break;
 
-      base = (code == MATCH_OP_DUP ? '0' : 'a');
       for (i = XVECLEN (x, 1) - 1; i >= 0; i--)
         {
-	  VEC_safe_push (char,heap, acc->pathstr, base + i);
+	  if (code == MATCH_OP_DUP)
+	    val = '0' + i;
+	  else
+	    val = encode_xvecexp (i);
+	  VEC_safe_push (char,heap, acc->pathstr, val);
 	  walk_rtx (XVECEXP (x, 1, i), acc);
 	  VEC_pop (char, acc->pathstr);
         }
@@ -295,7 +301,8 @@  walk_rtx (rtx x, struct accum_extract *acc)
 	  int j;
 	  for (j = XVECLEN (x, i) - 1; j >= 0; j--)
 	    {
-	      VEC_safe_push (char,heap, acc->pathstr, 'a' + j);
+	      VEC_safe_push (char,heap, acc->pathstr,
+			     encode_xvecexp (j));
 	      walk_rtx (XVECEXP (x, i, j), acc);
 	      VEC_pop (char, acc->pathstr);
 	    }
@@ -326,7 +333,7 @@  print_path (const char *path)
 
   for (i = len - 1; i >= 0 ; i--)
     {
-      if (ISLOWER (path[i]))
+      if (is_xvecexp (path[i]))
 	fputs ("XVECEXP (", stdout);
       else if (ISDIGIT (path[i]))
 	fputs ("XEXP (", stdout);
@@ -338,8 +345,8 @@  print_path (const char *path)
 
   for (i = 0; i < len; i++)
     {
-      if (ISLOWER (path[i]))
-	printf (", 0, %d)", path[i] - 'a');
+      if (is_xvecexp (path[i]))
+	printf (", 0, %d)", decode_xvecexp (path[i]));
       else if (ISDIGIT(path[i]))
 	printf (", %d)", path[i] - '0');
       else
diff --git a/gcc/genpreds.c b/gcc/genpreds.c
index fba4372..d5e1ddc 100644
--- a/gcc/genpreds.c
+++ b/gcc/genpreds.c
@@ -433,7 +433,7 @@  write_extract_subexp (const char *path)
      order, then write "op", then the indices in forward order.  */
   for (i = len - 1; i >= 0; i--)
     {
-      if (ISLOWER (path[i]))
+      if (is_xvecexp (path[i]))
 	fputs ("XVECEXP (", stdout);
       else if (ISDIGIT (path[i]))
 	fputs ("XEXP (", stdout);
@@ -445,8 +445,8 @@  write_extract_subexp (const char *path)
 
   for (i = 0; i < len; i++)
     {
-      if (ISLOWER (path[i]))
-	printf (", 0, %d)", path[i] - 'a');
+      if (is_xvecexp (path[i]))
+	printf (", 0, %d)", decode_xvecexp (path[i]));
       else if (ISDIGIT (path[i]))
 	printf (", %d)", path[i] - '0');
       else
diff --git a/gcc/genrecog.c b/gcc/genrecog.c
index 74dd0a7..b65eb4f 100644
--- a/gcc/genrecog.c
+++ b/gcc/genrecog.c
@@ -912,6 +912,7 @@  add_to_sequence (rtx pattern, struct decision_head *last, const char *position,
 	      /* Which insn we're looking at is represented by A-Z. We don't
 	         ever use 'A', however; it is always implied.  */
 
+	      gcc_assert (i < 26);
 	      subpos[depth] = (i > 0 ? 'A' + i : 0);
 	      sub = add_to_sequence (XVECEXP (pattern, 0, i),
 				     last, subpos, insn_type, 0);
@@ -999,10 +1000,17 @@  add_to_sequence (rtx pattern, struct decision_head *last, const char *position,
 
 	if (was_code == MATCH_OPERATOR || was_code == MATCH_PARALLEL)
 	  {
-	    char base = (was_code == MATCH_OPERATOR ? '0' : 'a');
+	    int val;
 	    for (i = 0; i < (size_t) XVECLEN (pattern, 2); i++)
 	      {
-		subpos[depth] = i + base;
+		if (was_code == MATCH_OPERATOR)
+		  {
+		    val = '0' + i;
+		    gcc_assert (ISDIGIT (val));
+		  }
+		else
+		  val = encode_xvecexp (i);
+		subpos[depth] = val;
 		sub = add_to_sequence (XVECEXP (pattern, 2, i),
 				       &sub->success, subpos, insn_type, 0);
 	      }
@@ -1102,7 +1110,7 @@  add_to_sequence (rtx pattern, struct decision_head *last, const char *position,
 	    int j;
 	    for (j = 0; j < XVECLEN (pattern, i); j++)
 	      {
-		subpos[depth] = 'a' + j;
+		subpos[depth] = encode_xvecexp (j);
 		sub = add_to_sequence (XVECEXP (pattern, i, j),
 				       &sub->success, subpos, insn_type, 0);
 	      }
@@ -1776,9 +1784,10 @@  change_state (const char *oldpos, const char *newpos, const char *indent)
 		  indent, newpos[depth] - 'A');
 	  printf ("%sx%d = PATTERN (tem);\n", indent, depth + 1);
 	}
-      else if (ISLOWER (newpos[depth]))
+      else if (is_xvecexp (newpos[depth]))
 	printf ("%sx%d = XVECEXP (x%d, 0, %d);\n",
-		indent, depth + 1, depth, newpos[depth] - 'a');
+		indent, depth + 1, depth,
+		decode_xvecexp (newpos[depth]));
       else
 	printf ("%sx%d = XEXP (x%d, %c);\n",
 		indent, depth + 1, depth, newpos[depth]);
@@ -2528,6 +2537,7 @@  make_insn_sequence (rtx insn, enum routine_type type)
 	}
       XVECLEN (x, 0) = j;
 
+      gcc_assert ((j - 1) < 26);
       c_test_pos[0] = 'A' + j - 1;
       c_test_pos[1] = '\0';
     }
diff --git a/gcc/gensupport.h b/gcc/gensupport.h
index 999c222..59eaec6 100644
--- a/gcc/gensupport.h
+++ b/gcc/gensupport.h
@@ -83,4 +83,25 @@  extern void add_predicate (struct pred_data *);
 
 #define FOR_ALL_PREDICATES(p) for (p = first_predicate; p; p = p->next)
 
+static inline bool
+is_xvecexp (unsigned char v)
+{
+  return v >= 'a';
+}
+
+static inline int
+encode_xvecexp (int v)
+{
+  v += 'a';
+  gcc_assert (v >= 'a' && v <= 255);
+  return v;
+}
+
+static inline int
+decode_xvecexp (int v)
+{
+  v -= 'a';
+  return v;
+}
+
 #endif /* GCC_GENSUPPORT_H */