The following avoids classifying a double reduction that's not
actually a reduction in the outer loop (because its value isn't
used outside of the outer loop). This avoids us ICEing on the
unexpected stmt/SLP node arrangement.
Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.
PR tree-optimization/116647
* tree-vect-loop.cc (vect_is_simple_reduction): Add missing
check to double reduction detection.
* gcc.dg/torture/pr116647.c: New testcase.
* gcc.dg/vect/no-scevccp-pr86725-2.c: Adjust expected pattern.
* gcc.dg/vect/no-scevccp-pr86725-4.c: Likewise.
---
gcc/testsuite/gcc.dg/torture/pr116647.c | 22 +++++++++++++++++++
.../gcc.dg/vect/no-scevccp-pr86725-2.c | 2 +-
.../gcc.dg/vect/no-scevccp-pr86725-4.c | 2 +-
gcc/tree-vect-loop.cc | 3 ++-
4 files changed, 26 insertions(+), 3 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/torture/pr116647.c
diff --git a/gcc/testsuite/gcc.dg/torture/pr116647.c
b/gcc/testsuite/gcc.dg/torture/pr116647.c
new file mode 100644
index 00000000000..2b5cc348690
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr116647.c
@@ -0,0 +1,22 @@
+/* { dg-do compile } */
+
+int a;
+char b;
+long c, d, e;
+unsigned long f;
+long g() {
+ if (a <= 0)
+ return 1;
+ for (; d; d++) {
+ e = 0;
+ for (; e < a; e++) {
+ unsigned long h = 0;
+ switch (b)
+ case 2:
+ if (e)
+ h = 5;
+ c += h;
+ }
+ }
+ c /= f;
+}
diff --git a/gcc/testsuite/gcc.dg/vect/no-scevccp-pr86725-2.c
b/gcc/testsuite/gcc.dg/vect/no-scevccp-pr86725-2.c
index b208c1a2d61..66185a9483b 100644
--- a/gcc/testsuite/gcc.dg/vect/no-scevccp-pr86725-2.c
+++ b/gcc/testsuite/gcc.dg/vect/no-scevccp-pr86725-2.c
@@ -19,5 +19,5 @@ nr (int xe)
return xe;
}
-/* { dg-final { scan-tree-dump "reduction used in loop" "vect" { target
vect_int } } } */
+/* { dg-final { scan-tree-dump "Unknown def-use cycle pattern" "vect" { target
vect_int } } } */
/* { dg-final { scan-tree-dump-not "OUTER LOOP VECTORIZED" "vect" } } */
diff --git a/gcc/testsuite/gcc.dg/vect/no-scevccp-pr86725-4.c
b/gcc/testsuite/gcc.dg/vect/no-scevccp-pr86725-4.c
index d995c9b30fe..6ada0a10cb3 100644
--- a/gcc/testsuite/gcc.dg/vect/no-scevccp-pr86725-4.c
+++ b/gcc/testsuite/gcc.dg/vect/no-scevccp-pr86725-4.c
@@ -19,5 +19,5 @@ nr (unsigned int xe, unsigned int qqn)
return xe;
}
-/* { dg-final { scan-tree-dump "reduction used in loop" "vect" { target
vect_int } } } */
+/* { dg-final { scan-tree-dump "Unknown def-use cycle pattern" "vect" { target
vect_int } } } */
/* { dg-final { scan-tree-dump-not "OUTER LOOP VECTORIZED" "vect" } } */
diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index e45adbaccbd..77486183a64 100644
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -4342,7 +4342,8 @@ vect_is_simple_reduction (loop_vec_info loop_info,
stmt_vec_info phi_info,
&& is_a <gphi *> (phi_use_stmt)
&& flow_bb_inside_loop_p (loop->inner, gimple_bb (phi_use_stmt))
&& (op1 == PHI_ARG_DEF_FROM_EDGE (phi_use_stmt,
- loop_latch_edge (loop->inner))))
+ loop_latch_edge (loop->inner)))
+ && lcphis.length () == 1)
{
if (dump_enabled_p ())
report_vect_op (MSG_NOTE, def_stmt,
--
2.43.0
