On Oct 28, 2020, Richard Biener <richard.guent...@gmail.com> wrote:
>> BTW, any reason why we are not (yet?) using something like:
>>
>> #define FOR_EACH_IMM_USE_STMT(STMT, ITER, SSAVAR) \
>> for (auto_end_imm_use_stmt_traverse auto_end \
>> ((((STMT) = first_imm_use_stmt (&(ITER), (SSAVAR))), \
>> &(ITER))); \
>> !end_imm_use_stmt_p (&(ITER)); \
>> (void) ((STMT) = next_imm_use_stmt (&(ITER))))
> Just laziness. Or rather last time I remembered this I tried to do it
> more fancy via range-for but didn't get very far due to the nested
> iteration ...
Use a dtor to automatically remove ITER from IMM_USE list in
FOR_EACH_IMM_USE_STMT.
Regstrapped on x86_64-linux-gnu. Ok to install?
for gcc/ChangeLog
* ssa-iterators.h (end_imm_use_stmt_traverse): Forward
declare.
(auto_end_imm_use_stmt_traverse): New struct.
(FOR_EACH_IMM_USE_STMT): Use it.
---
gcc/ssa-iterators.h | 29 ++++++++++++++++++++++++-----
1 file changed, 24 insertions(+), 5 deletions(-)
diff --git a/gcc/ssa-iterators.h b/gcc/ssa-iterators.h
index 98724da14522d..817997aa952d4 100644
--- a/gcc/ssa-iterators.h
+++ b/gcc/ssa-iterators.h
@@ -77,16 +77,35 @@ struct imm_use_iterator
!end_readonly_imm_use_p (&(ITER)); \
(void) ((DEST) = next_readonly_imm_use (&(ITER))))
-/* Use this iterator to visit each stmt which has a use of SSAVAR. */
+/* Forward declare for use in the class below. */
+static inline void end_imm_use_stmt_traverse (imm_use_iterator *);
+
+/* arrange to automatically call, upon descruction, end_imm_use_stmt_traverse
+ with a given pointer to imm_use_iterator. */
+struct auto_end_imm_use_stmt_traverse
+{
+ imm_use_iterator *imm;
+ auto_end_imm_use_stmt_traverse (imm_use_iterator *imm)
+ : imm (imm) {}
+ ~auto_end_imm_use_stmt_traverse ()
+ { end_imm_use_stmt_traverse (imm); }
+};
+
+/* Use this iterator to visit each stmt which has a use of SSAVAR. The
+ destructor of the auto_end_imm_use_stmt_traverse object deals with removing
+ ITER from SSAVAR's IMM_USE list even when leaving the scope early. */
#define FOR_EACH_IMM_USE_STMT(STMT, ITER, SSAVAR) \
- for ((STMT) = first_imm_use_stmt (&(ITER), (SSAVAR)); \
+ for (struct auto_end_imm_use_stmt_traverse \
+ auto_end_imm_use_stmt_traverse \
+ ((((STMT) = first_imm_use_stmt (&(ITER), (SSAVAR))), \
+ &(ITER))); \
!end_imm_use_stmt_p (&(ITER)); \
(void) ((STMT) = next_imm_use_stmt (&(ITER))))
-/* Use this to terminate the FOR_EACH_IMM_USE_STMT loop early. Failure to
- do so will result in leaving a iterator marker node in the immediate
- use list, and nothing good will come from that. */
+/* These used to be needed to exit FOR_EACH_IMM_USE_STMT early, without leaving
+ ITER behind in the stmt lists. This is now taken care of automatically, but
+ it doesn't hurt to use the macros for documentation purposes. */
#define BREAK_FROM_IMM_USE_STMT(ITER) \
{ \
end_imm_use_stmt_traverse (&(ITER)); \
--
Alexandre Oliva, happy hacker https://FSFLA.org/blogs/lxo/
Free Software Activist GNU Toolchain Engineer
Vim, Vi, Voltei pro Emacs -- GNUlius Caesar
