The following makes sure to take into account prologue peeling
when trying to narrow down the maximum number of iterations
computed for the epilogue of a vectorized epilogue.
Bootstrap & regtest running on x86_64-unknown-linux-gnu.
I did not verify this solves the original aarch64 testcase yet
but it looks like a simpler fix and explains why I don't see
the issue on the 11 branch which does otherwise the same transforms.
Richard.
2022-04-27 Richard Biener <rguent...@suse.de>
PR tree-optimization/105219
* tree-vect-loop.cc (vect_transform_loop): Disable
special code narrowing the vectorized epilogue epilogue
max iterations when peeling for alignment was in effect.
* gcc.dg/vect/pr105219.c: New testcase.
---
gcc/testsuite/gcc.dg/vect/pr105219.c | 29 ++++++++++++++++++++++++++++
gcc/tree-vect-loop.cc | 2 +-
2 files changed, 30 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/gcc.dg/vect/pr105219.c
diff --git a/gcc/testsuite/gcc.dg/vect/pr105219.c
b/gcc/testsuite/gcc.dg/vect/pr105219.c
new file mode 100644
index 00000000000..0cb7ae2f4d6
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/pr105219.c
@@ -0,0 +1,29 @@
+/* { dg-do run } */
+/* { dg-additional-options "-O3" } */
+/* { dg-additional-options "-mtune=intel" { target x86_64-*-* i?86-*-* } } */
+
+#include "tree-vect.h"
+
+int data[128];
+
+void __attribute((noipa))
+foo (int *data, int n)
+{
+ for (int i = 0; i < n; ++i)
+ data[i] = i;
+}
+
+int main()
+{
+ check_vect ();
+ for (int start = 0; start < 16; ++start)
+ for (int n = 1; n < 3*16; ++n)
+ {
+ __builtin_memset (data, 0, sizeof (data));
+ foo (&data[start], n);
+ for (int j = 0; j < n; ++j)
+ if (data[start + j] != j)
+ __builtin_abort ();
+ }
+ return 0;
+}
diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index d7bc34636bd..217abab814b 100644
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -9977,7 +9977,7 @@ vect_transform_loop (loop_vec_info loop_vinfo, gimple
*loop_vectorized_call)
lowest_vf) - 1
: wi::udiv_floor (loop->nb_iterations_upper_bound + bias_for_lowest,
lowest_vf) - 1);
- if (main_vinfo)
+ if (main_vinfo && !main_vinfo->peeling_for_alignment)
{
unsigned int bound;
poly_uint64 main_iters
--
2.34.1
