https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103226
Aldy Hernandez <aldyh at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |rguenth at gcc dot gnu.org
--- Comment #1 from Aldy Hernandez <aldyh at gcc dot gnu.org> ---
I can't opine on the intricacies of the loopch pass, but the decision the path
solver took was correct:
./cc1 a.c -fdump-tree-all-details -quiet -I/tmp -O2 --param threader-debug=all
Then in the *.ch2 dump file I see:
==============================================
path_range_query: compute_ranges for path: 5->12
range_defined_in_block (BB12) for h_8 is int [0, 0]
=========== BB 5 ============
b.0_3 int [0, 0][5, +INF]
<bb 5> [local count: 60236916]:
e = 1;
goto <bb 12>; [100.00%]
=========== BB 12 ============
Imports: h_8
Exports: h_8
b.0_3 int [0, 0][5, +INF]
<bb 12> [local count: 602369155]:
# h_8 = PHI <0(5), h_11(11)>
if (h_8 != 9)
goto <bb 19>; [90.00%]
else
goto <bb 13>; [10.00%]
etc.
The conditional in BB12 resolves to true:
loopch static returned: _Bool [1, 1]
Which I got from a small tweak to the ch source:
diff --git a/gcc/tree-ssa-loop-ch.c b/gcc/tree-ssa-loop-ch.c
index 566cc275317..d5d80e33450 100644
--- a/gcc/tree-ssa-loop-ch.c
+++ b/gcc/tree-ssa-loop-ch.c
@@ -74,7 +74,14 @@ entry_loop_condition_is_static (class loop *l,
path_range_query *query)
int_range<2> r;
query->compute_ranges (e);
query->range_of_stmt (r, last);
- return r == int_range<2> (desired_static_value, desired_static_value);
+ bool ret = (r == int_range<2> (desired_static_value, desired_static_value));
+ if (ret && dump_file)
+ {
+ fprintf (dump_file, "loopch static returned: ");
+ r.dump(dump_file);
+ fprintf (dump_file, "\n");
+ }
+ return ret;
}
