The following handles the case of the main exit going to a path without
virtual use and handles it similar to the alternate exit handling.
Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.
PR tree-optimization/113659
* tree-vect-loop-manip.cc (slpeel_tree_duplicate_loop_to_edge_cfg):
Handle main exit without virtual use.
* gcc.dg/pr113659.c: New testcase.
---
gcc/testsuite/gcc.dg/pr113659.c | 14 ++++++++++++++
gcc/tree-vect-loop-manip.cc | 20 +++++++++++++++++---
2 files changed, 31 insertions(+), 3 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/pr113659.c
diff --git a/gcc/testsuite/gcc.dg/pr113659.c b/gcc/testsuite/gcc.dg/pr113659.c
new file mode 100644
index 00000000000..dc1091b647d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr113659.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-O3 -fno-tree-sra" } */
+/* { dg-additional-options "-msse4.1" { target { x86_64-*-* i?86-*-* } } } */
+
+struct Foo {
+ int *ptr;
+};
+int Baz(struct Foo first)
+{
+ while (first.ptr)
+ if (*first.ptr++)
+ return 0;
+ __builtin_unreachable ();
+}
diff --git a/gcc/tree-vect-loop-manip.cc b/gcc/tree-vect-loop-manip.cc
index 873a28d7c56..3f974d6d839 100644
--- a/gcc/tree-vect-loop-manip.cc
+++ b/gcc/tree-vect-loop-manip.cc
@@ -1708,9 +1708,23 @@ slpeel_tree_duplicate_loop_to_edge_cfg (class loop
*loop, edge loop_exit,
LC PHI node to feed the merge PHI. */
tree *res;
if (virtual_operand_p (new_arg))
- /* Use the existing virtual LC SSA from exit block. */
- new_arg = gimple_phi_result
- (get_virtual_phi (main_loop_exit_block));
+ {
+ /* Use the existing virtual LC SSA from exit block. */
+ gphi *vphi = get_virtual_phi (main_loop_exit_block);
+ /* ??? When the exit yields to a path without
+ any virtual use we can miss a LC PHI for the
+ live virtual operand. Simply choosing the
+ one live at the start of the loop header isn't
+ correct, but we should get here only with
+ early-exit vectorization which will move all
+ defs after the main exit, so leave a temporarily
+ wrong virtual operand in place. This happens
+ for gcc.dg/pr113659.c. */
+ if (vphi)
+ new_arg = gimple_phi_result (vphi);
+ else
+ new_arg = gimple_phi_result (from_phi);
+ }
else if ((res = new_phi_args.get (new_arg)))
new_arg = *res;
else
--
2.35.3
