Linus Torvalds wrote:
>
> On Sun, 14 Aug 2005, Oleg Nesterov wrote:
> >
> > Without this patch evaluate_iterator() evaluates
> > stmt->iterator_pre_condition twice.
>
> If you do this, please (a) verify that linearize.c still does the right
> thing for for-loops, and (b) remove the special cases that see if
> "pre_condition == post_condition".
I think that only linearize.c should be changed, but linearize.c is
beyond my understanding completely.
pseudo_t linearize_statement:
....
1986 case STMT_ITERATOR: {
....
2001 if (pre_condition == post_condition) {
2002 loop_top = alloc_basic_block(ep, stmt->pos);
2003 set_activeblock(ep, loop_top);
2004 }
2005
2006 if (pre_condition)
2007 linearize_cond_branch(ep, pre_condition,
loop_body, loop_end);
Looking at parse_{for,while,do}_statement i think that
(pre_condition != NULL) ALWAYS_EQUAL_TO (pre_condition ==
post_condition)
except may be "for (;;)", when both conditions == NULL. No?
I am sending the patch, but I doubt it is correct. However, ./test-linearize
shows the same output before and after patch with this code:
int cond(void), func();
static void t1(void)
{
for (;;) func();
}
static void t2(void)
{
for (; cond(); ) func();
}
Oleg.
--- git-snapshot-20050814/parse.c~2_forpost 2005-08-15 21:44:43.000000000
+0400
+++ git-snapshot-20050814/parse.c 2005-08-15 22:30:45.000000000 +0400
@@ -1200,7 +1200,7 @@ static struct token *parse_for_statement
stmt->iterator_pre_statement = make_statement(e1);
stmt->iterator_pre_condition = e2;
stmt->iterator_post_statement = make_statement(e3);
- stmt->iterator_post_condition = e2;
+ stmt->iterator_post_condition = NULL;
stmt->iterator_statement = iterator;
end_iterator(stmt);
@@ -1217,7 +1217,7 @@ static struct token *parse_while_stateme
token = statement(token, &iterator);
stmt->iterator_pre_condition = expr;
- stmt->iterator_post_condition = expr;
+ stmt->iterator_post_condition = NULL;
stmt->iterator_statement = iterator;
end_iterator(stmt);
--- git-snapshot-20050814/linearize.c~2_forpost 2005-08-12 02:14:53.000000000
+0400
+++ git-snapshot-20050814/linearize.c 2005-08-15 23:28:29.000000000 +0400
@@ -1997,14 +1997,12 @@ pseudo_t linearize_statement(struct entr
loop_body = loop_top = alloc_basic_block(ep, stmt->pos);
loop_continue = alloc_basic_block(ep, stmt->pos);
loop_end = alloc_basic_block(ep, stmt->pos);
-
- if (pre_condition == post_condition) {
+
+ if (pre_condition) {
loop_top = alloc_basic_block(ep, stmt->pos);
set_activeblock(ep, loop_top);
- }
-
- if (pre_condition)
linearize_cond_branch(ep, pre_condition, loop_body,
loop_end);
+ }
bind_label(stmt->iterator_continue, loop_continue, stmt->pos);
bind_label(stmt->iterator_break, loop_end, stmt->pos);
@@ -2015,7 +2013,7 @@ pseudo_t linearize_statement(struct entr
set_activeblock(ep, loop_continue);
linearize_statement(ep, post_statement);
- if (!post_condition || pre_condition == post_condition)
+ if (!post_condition)
add_goto(ep, loop_top);
else
linearize_cond_branch(ep, post_condition, loop_top,
loop_end);
-
To unsubscribe from this list: send the line "unsubscribe linux-sparse" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
