The function slpeel_can_duplicate_loop_p fails to verify we can
copy blocks, instead slpeel_tree_duplicate_loop_to_edge_cfg does
but that's too late. The following fixes this, also simplifying
error reporting which is somewhat pointless if we ICE immediately.
Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.
PR tree-optimization/108970
* tree-vect-loop-manip.cc (slpeel_can_duplicate_loop_p):
Check we can copy the BBs.
(slpeel_tree_duplicate_loop_to_edge_cfg): Avoid redundant
check.
(vect_do_peeling): Streamline error handling.
* gcc.dg/pr108970.c: New testcase.
---
gcc/testsuite/gcc.dg/pr108970.c | 19 ++++++++++++++
gcc/tree-vect-loop-manip.cc | 44 +++++++++------------------------
2 files changed, 31 insertions(+), 32 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/pr108970.c
new file mode 100644
@@ -0,0 +1,19 @@
+/* { dg-do compile } */
+/* { dg-options "-O1 -ftree-loop-vectorize -fno-tree-dce -fno-tree-scev-cprop" } */
+
+int m;
+
+__attribute__ ((noinline, returns_twice)) void
+empty (void)
+{
+}
+
+void
+foo (void)
+{
+ while (m < 1)
+ {
+ empty ();
+ ++m;
+ }
+}
@@ -1080,12 +1080,6 @@ slpeel_tree_duplicate_loop_to_edge_cfg (class loop *loop,
/* Allow duplication of outer loops. */
if (scalar_loop->inner)
duplicate_outer_loop = true;
- /* Check whether duplication is possible. */
- if (!can_copy_bbs_p (pbbs, scalar_loop->num_nodes))
- {
- free (bbs);
- return NULL;
- }
/* Generate new loop structure. */
new_loop = duplicate_loop (scalar_loop, loop_outer (scalar_loop));
@@ -1329,7 +1323,11 @@ slpeel_can_duplicate_loop_p (const class loop *loop, const_edge e)
|| (e != exit_e && e != entry_e))
return false;
- return true;
+ basic_block *bbs = XNEWVEC (basic_block, loop->num_nodes);
+ get_loop_body_with_size (loop, bbs, loop->num_nodes);
+ bool ret = can_copy_bbs_p (bbs, loop->num_nodes);
+ free (bbs);
+ return ret;
}
/* Function vect_get_loop_location.
@@ -2864,7 +2862,6 @@ vect_do_peeling (loop_vec_info loop_vinfo, tree niters, tree nitersm1,
}
}
- dump_user_location_t loop_loc = find_loop_location (loop);
if (vect_epilogues)
/* Make sure to set the epilogue's epilogue scalar loop, such that we can
use the original scalar loop as remaining epilogue if necessary. */
@@ -2874,20 +2871,11 @@ vect_do_peeling (loop_vec_info loop_vinfo, tree niters, tree nitersm1,
if (prolog_peeling)
{
e = loop_preheader_edge (loop);
- if (!slpeel_can_duplicate_loop_p (loop, e))
- {
- dump_printf_loc (MSG_MISSED_OPTIMIZATION, loop_loc,
- "loop can't be duplicated to preheader edge.\n");
- gcc_unreachable ();
- }
+ gcc_checking_assert (slpeel_can_duplicate_loop_p (loop, e));
+
/* Peel prolog and put it on preheader edge of loop. */
prolog = slpeel_tree_duplicate_loop_to_edge_cfg (loop, scalar_loop, e);
- if (!prolog)
- {
- dump_printf_loc (MSG_MISSED_OPTIMIZATION, loop_loc,
- "slpeel_tree_duplicate_loop_to_edge_cfg failed.\n");
- gcc_unreachable ();
- }
+ gcc_assert (prolog);
prolog->force_vectorize = false;
slpeel_update_phi_nodes_for_loops (loop_vinfo, prolog, loop, true);
first_loop = prolog;
@@ -2949,12 +2937,8 @@ vect_do_peeling (loop_vec_info loop_vinfo, tree niters, tree nitersm1,
if (epilog_peeling)
{
e = single_exit (loop);
- if (!slpeel_can_duplicate_loop_p (loop, e))
- {
- dump_printf_loc (MSG_MISSED_OPTIMIZATION, loop_loc,
- "loop can't be duplicated to exit edge.\n");
- gcc_unreachable ();
- }
+ gcc_checking_assert (slpeel_can_duplicate_loop_p (loop, e));
+
/* Peel epilog and put it on exit edge of loop. If we are vectorizing
said epilog then we should use a copy of the main loop as a starting
point. This loop may have already had some preliminary transformations
@@ -2964,12 +2948,8 @@ vect_do_peeling (loop_vec_info loop_vinfo, tree niters, tree nitersm1,
vectorizing. */
epilog = vect_epilogues ? get_loop_copy (loop) : scalar_loop;
epilog = slpeel_tree_duplicate_loop_to_edge_cfg (loop, epilog, e);
- if (!epilog)
- {
- dump_printf_loc (MSG_MISSED_OPTIMIZATION, loop_loc,
- "slpeel_tree_duplicate_loop_to_edge_cfg failed.\n");
- gcc_unreachable ();
- }
+ gcc_assert (epilog);
+
epilog->force_vectorize = false;
slpeel_update_phi_nodes_for_loops (loop_vinfo, loop, epilog, false);