@@ -876,10 +876,16 @@ DEFTREECODE (LOOP_EXPR, "loop_expr", tcc_statement
of all the cases. */
DEFTREECODE (SWITCH_EXPR, "switch_expr", tcc_statement, 3)
-/* Used to represent a case label. The operands are CASE_LOW and
- CASE_HIGH, respectively. If CASE_LOW is NULL_TREE, the label is a
- 'default' label. If CASE_HIGH is NULL_TREE, the label is a normal case
- label. CASE_LABEL is the corresponding LABEL_DECL. */
+/* Used to represent a case label.
+ Operand 0 is CASE_LOW. It may be NULL_TREE, in which case the label
+ is a 'default' label.
+ Operand 1 is CASE_HIGH. If it is NULL_TREE, the label is a simple
+ (one-value) case label. If it is non-NULL_TREE, the case is a range.
+ Operand 2 is CASE_LABEL, which is is the corresponding LABEL_DECL.
+ Operand 4 is CASE_CHAIN. This operand is only used in tree-cfg.c to
+ speed up the lookup of case labels which use a particular edge in
+ the control flow graph. */
DEFTREECODE (CASE_LABEL_EXPR, "case_label_expr", tcc_statement, 4)
/* Used to represent an inline assembly statement. ASM_STRING returns a
@@ -56,7 +56,7 @@ static const int initial_cfg_capacity = 20;
/* This hash table allows us to efficiently lookup all CASE_LABEL_EXPRs
which use a particular edge. The CASE_LABEL_EXPRs are chained together
- via their TREE_CHAIN field, which we clear after we're done with the
+ via their CASE_CHAIN field, which we clear after we're done with the
hash table to prevent problems with duplication of GIMPLE_SWITCHes.
Access to this list of CASE_LABEL_EXPRs allows us to efficiently