After r16-6104-gb5c64db0a49d46, we try to duplicate bb's
that contain loop exit that have "never exit" but we check
against the propability of the exit to very_unlikely. If we
have PGO, then a loop exit might be very unlikely to be taken
if we interate the loop more than 2000 times. So we should take
into account if the probability is reliable or not; this basically
says if the probability is based on profile data (or corrected profile data)
or based on heurstics.
This should fix PR 123126 but I don't have a full SPEC setup with PGO
to be able to test it.
Bootstrapped and tested on x86_64-linux-gnu.
gcc/ChangeLog:
* tree-ssa-loop-ch.cc (should_duplicate_loop_header_p): Check
the reliable_p of the edge's probability.
Signed-off-by: Andrew Pinski <[email protected]>
---
gcc/tree-ssa-loop-ch.cc | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/gcc/tree-ssa-loop-ch.cc b/gcc/tree-ssa-loop-ch.cc
index feecf91cf70..293720fbd04 100644
--- a/gcc/tree-ssa-loop-ch.cc
+++ b/gcc/tree-ssa-loop-ch.cc
@@ -480,7 +480,8 @@ should_duplicate_loop_header_p (basic_block header, class
loop *loop,
or combining.
FIXME: once we have better quality tracking,
make this more robust. */
- || e->probability <= profile_probability::very_unlikely ()))
+ || (!e->probability.reliable_p ()
+ && e->probability <= profile_probability::very_unlikely
())))
{
hasone = true;
if (dump_file && (dump_flags & TDF_DETAILS))
--
2.43.0
