The following fixes the issue that if the reduction stmt (the stmt
defining the backedge value of a loop PHI) is not in the loop
then this isn't a reduction thus we shouldn't continue analysis.
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.
Richard.
2017-07-25 Richard Biener <rguent...@suse.de>
PR tree-optimization/81510
* tree-vect-loop.c (vect_is_simple_reduction): When the
reduction stmt is not inside the loop bail out.
* gcc.dg/torture/pr81510.c: New testcase.
* gcc.dg/torture/pr81510-2.c: Likewise.
Index: gcc/tree-vect-loop.c
===================================================================
--- gcc/tree-vect-loop.c (revision 250493)
+++ gcc/tree-vect-loop.c (working copy)
@@ -2813,27 +2813,29 @@ vect_is_simple_reduction (loop_vec_info
return NULL;
}
+ if (! flow_bb_inside_loop_p (loop, gimple_bb (def_stmt)))
+ return NULL;
+
nloop_uses = 0;
auto_vec<gphi *, 3> lcphis;
- if (flow_bb_inside_loop_p (loop, gimple_bb (def_stmt)))
- FOR_EACH_IMM_USE_FAST (use_p, imm_iter, name)
- {
- gimple *use_stmt = USE_STMT (use_p);
- if (is_gimple_debug (use_stmt))
- continue;
- if (flow_bb_inside_loop_p (loop, gimple_bb (use_stmt)))
- nloop_uses++;
- else
- /* We can have more than one loop-closed PHI. */
- lcphis.safe_push (as_a <gphi *> (use_stmt));
- if (nloop_uses > 1)
- {
- if (dump_enabled_p ())
- dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
- "reduction used in loop.\n");
- return NULL;
- }
- }
+ FOR_EACH_IMM_USE_FAST (use_p, imm_iter, name)
+ {
+ gimple *use_stmt = USE_STMT (use_p);
+ if (is_gimple_debug (use_stmt))
+ continue;
+ if (flow_bb_inside_loop_p (loop, gimple_bb (use_stmt)))
+ nloop_uses++;
+ else
+ /* We can have more than one loop-closed PHI. */
+ lcphis.safe_push (as_a <gphi *> (use_stmt));
+ if (nloop_uses > 1)
+ {
+ if (dump_enabled_p ())
+ dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
+ "reduction used in loop.\n");
+ return NULL;
+ }
+ }
/* If DEF_STMT is a phi node itself, we expect it to have a single argument
defined in the inner loop. */
Index: gcc/testsuite/gcc.dg/torture/pr81510.c
===================================================================
--- gcc/testsuite/gcc.dg/torture/pr81510.c (revision 0)
+++ gcc/testsuite/gcc.dg/torture/pr81510.c (working copy)
@@ -0,0 +1,29 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-w" } */
+
+typedef int d;
+typedef int f;
+typedef long h;
+int a;
+int b;
+int c;
+int e()
+{
+ f *g;
+ h i;
+ for (;;)
+ if (g)
+ for (; b; b++) {
+ g = c;
+ if (a &= c) {
+ d *j = &b;
+ h k;
+ for (; i; i++) {
+ *g ?: (*j = k);
+ g = &a;
+ }
+ for (; i <= 3; i++)
+ ;
+ }
+ }
+}
Index: gcc/testsuite/gcc.dg/torture/pr81510-2.c
===================================================================
--- gcc/testsuite/gcc.dg/torture/pr81510-2.c (nonexistent)
+++ gcc/testsuite/gcc.dg/torture/pr81510-2.c (working copy)
@@ -0,0 +1,19 @@
+/* { dg-do compile } */
+
+typedef int h;
+typedef int k;
+int a;
+int b;
+int c;
+int d;
+int e;
+int f(int g)
+{
+ h *i = &e;
+ k *j;
+ if (d -= b)
+ for (; *j; *j += 1) {
+ g = g || (a = e ? c = (__UINTPTR_TYPE__)j : 0) + *i;
+ i = &d;
+ }
+}
