diff options
Diffstat (limited to 'gcc/doc/loop.texi')
| -rw-r--r-- | gcc/doc/loop.texi | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/gcc/doc/loop.texi b/gcc/doc/loop.texi index fade89d32e8..e486b0c5d10 100644 --- a/gcc/doc/loop.texi +++ b/gcc/doc/loop.texi @@ -64,17 +64,24 @@ function. Each of the loops is represented in a @code{struct loop} structure. Each loop is assigned an index (@code{num} field of the @code{struct loop} structure), and the pointer to the loop is stored in the corresponding field of the @code{larray} vector in the loops -structure. Index of a sub-loop is always greater than the index of its -super-loop. The indices do not have to be continuous, there may be +structure. The indices do not have to be continuous, there may be empty (@code{NULL}) entries in the @code{larray} created by deleting -loops. The index of a loop never changes. +loops. Also, there is no guarantee on the relative order of a loop +and its subloops in the numbering. The index of a loop never changes. The entries of the @code{larray} field should not be accessed directly. The function @code{get_loop} returns the loop description for a loop with the given index. @code{number_of_loops} function returns number of loops in the function. To traverse all loops, use @code{FOR_EACH_LOOP} macro. The @code{flags} argument of the macro is used to determine -the direction of traversal and the set of loops visited. +the direction of traversal and the set of loops visited. Each loop is +guaranteed to be visited exactly once, regardless of the changes to the +loop tree, and the loops may be removed during the traversal. The newly +created loops are never traversed, if they need to be visited, this +must be done separately after their creation. The @code{FOR_EACH_LOOP} +macro allocates temporary variables. If the @code{FOR_EACH_LOOP} loop +were ended using break or goto, they would not be released; +@code{FOR_EACH_LOOP_BREAK} macro must be used instead. Each basic block contains the reference to the innermost loop it belongs to (@code{loop_father}). For this reason, it is only possible to have |