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.
The problem is the check for very_unlikely is just wrong. It should
just be never. So let's remove that.
Also adds a testcase for __builtin_abort instead of __builtin_unreachable
since there are slightly different pathes to get the probilities.
Bootstrapped and tested on x86_64-linux-gnu.
gcc/ChangeLog:
* tree-ssa-loop-ch.cc (should_duplicate_loop_header_p): Remove
check on very_unlikely probability.
gcc/testsuite/ChangeLog:
PR tree-optimization/122734
* gcc.dg/tree-ssa/copy-headers-13.c: New test.
Signed-off-by: Andrew Pinski <[email protected]>
---
.../gcc.dg/tree-ssa/copy-headers-13.c | 25 +++++++++++++++++++
gcc/tree-ssa-loop-ch.cc | 8 +-----
2 files changed, 26 insertions(+), 7 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/copy-headers-13.c
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/copy-headers-13.c
b/gcc/testsuite/gcc.dg/tree-ssa/copy-headers-13.c
new file mode 100644
index 00000000000..cc1b76cccee
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/copy-headers-13.c
@@ -0,0 +1,25 @@
+/* { dg-do compile } */
+/* { dg-options "-O3 -fdump-tree-ch-details -fdump-tree-ldist-details" } */
+
+/* PR tree-optimization/122734 */
+/* We want to duplicate the block after the one containing the condition going
to abort as
+ it is unlikely.
+/* So in the end ldist can generate a memset. */
+
+static inline int size(int *a)
+{
+ int t = *a;
+ if (t < 0) __builtin_abort();
+ return t;
+}
+
+void f(int *l, short *d)
+{
+ for(int i = 0; i < size(l); i++)
+ d[i] = 0;
+}
+
+/* { dg-final { scan-tree-dump-times "Duplicating bb . is a win" 1 "ch2" } } */
+/* { dg-final { scan-tree-dump-times "Will duplicate bb" 2 "ch2" } } */
+/* { dg-final { scan-tree-dump "is now do-while loop" "ch2" } } */
+/* { dg-final { scan-tree-dump "generated memset zero" "ldist" } } */
diff --git a/gcc/tree-ssa-loop-ch.cc b/gcc/tree-ssa-loop-ch.cc
index feecf91cf70..e6e2b330b45 100644
--- a/gcc/tree-ssa-loop-ch.cc
+++ b/gcc/tree-ssa-loop-ch.cc
@@ -474,13 +474,7 @@ should_duplicate_loop_header_p (basic_block header, class
loop *loop,
bool hasone = false;
FOR_EACH_EDGE (e, ei, header->succs)
if (loop_exit_edge_p (loop, e)
- && (probably_never_executed_edge_p (cfun, e)
- /* We want to rule out paths to noreturns but not
- low probabilities resulting from adjustments
- or combining.
- FIXME: once we have better quality tracking,
- make this more robust. */
- || e->probability <= profile_probability::very_unlikely ()))
+ && probably_never_executed_edge_p (cfun, e))
{
hasone = true;
if (dump_file && (dump_flags & TDF_DETAILS))
--
2.43.0
