New in this version:
Rather than treating `scev_not_known' as an unexpected value in
`expr_invariant_in_loop_p' and have the function crash, handle the
value gracefully by adding check for
`!automatically_generated_chrec_p (expr)'.
Regtested on AArch64 and x86_64, no regressions found.
---------
Given the inability of `expr_invariant_in_loop_p (loop, expr)' to
handle the `scev_not_known' node as the expression, an unknown loop
bound in the inner loop in a nested set of loops led to
`vect_analyze_loop_form' to erroneously consider the outer loop as
suitable for vectorization. This introduces the necessary unknown
loop iteration count check to ensure correct handling of counted loops
with an embedded uncounted loop.
gcc/ChangeLog:
PR tree-optimization/123657
* tree-vect-loop.cc (vect_analyze_loop_form): Add
chrec_dont_know check.
* tree-ssa-loop-ivopts.cc (expr_invariant_in_loop_p):
likewise.
gcc/testsuite/ChangeLog:
* gcc.dg/vect/vect-uncounted-run_4.c (main): New.
---
.../gcc.dg/vect/vect-uncounted-run_4.c | 17 +++++++++++++++++
gcc/tree-ssa-loop-ivopts.cc | 3 ++-
gcc/tree-vect-loop.cc | 3 ++-
3 files changed, 21 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/vect/vect-uncounted-run_4.c
diff --git a/gcc/testsuite/gcc.dg/vect/vect-uncounted-run_4.c
b/gcc/testsuite/gcc.dg/vect/vect-uncounted-run_4.c
new file mode 100644
index 00000000000..f731daf42d9
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/vect-uncounted-run_4.c
@@ -0,0 +1,17 @@
+/* Ensure we don't vectorize outer loops when the inner loop is
uncounted. */
+/* { dg-add-options vect_early_break } */
+/* { dg-require-effective-target vect_early_break_hw } */
+/* { dg-require-effective-target vect_int } */
+/* { dg-additional-options "-O3" } */
+
+int a;
+int main() {
+ for (int b = 0; b < 21; b++) {
+ int c = b;
+ while (c)
+ a = c >>= 1;
+ }
+ if (a != 0) __builtin_abort();
+}
+
+/* { dg-final { scan-tree-dump "missed: not vectorized: inner-loop
count not invariant." "vect" } } */
diff --git a/gcc/tree-ssa-loop-ivopts.cc b/gcc/tree-ssa-loop-ivopts.cc
index 6ecf5bef7b4..bff4077b1a2 100644
--- a/gcc/tree-ssa-loop-ivopts.cc
+++ b/gcc/tree-ssa-loop-ivopts.cc
@@ -1825,7 +1825,8 @@ expr_invariant_in_loop_p (class loop *loop, tree expr)
gcc_assert (loop_depth (loop) > 0);
- if (is_gimple_min_invariant (expr))
+ if (is_gimple_min_invariant (expr)
+ && !automatically_generated_chrec_p (expr))
return true;
if (TREE_CODE (expr) == SSA_NAME)
diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index 03339641750..9d6963a26fe 100644
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -1555,7 +1555,8 @@ vect_analyze_loop_form (class loop *loop, gimple
*loop_vectorized_call,
return opt_result::failure_at (vect_location,
"not vectorized: Bad inner loop.\n");
- if (!expr_invariant_in_loop_p (loop, inner.number_of_iterations))
+ if (inner.number_of_iterations == chrec_dont_know
+ || !expr_invariant_in_loop_p (loop, inner.number_of_iterations))
return opt_result::failure_at (vect_location,
"not vectorized: inner-loop count not"
" invariant.\n");
--
2.43.0
