This adds a relevancy check before trying to set the vector def of
a backedge in an unvectorized PHI.
2021-04-06 Richard Biener <rguenther@suse.de>
PR tree-optimization/99880
* tree-vect-loop.c (maybe_set_vectorized_backedge_value): Only
set vectorized defs of relevant PHIs.
* gcc.dg/torture/pr99880.c: New testcase.
--- /dev/null
+/* { dg-do compile } */
+/* { dg-additional-options "-ftree-vectorize" } */
+
+unsigned a;
+int b, c, d, e;
+void f() {
+ b = 5;
+ for (; b <= 51; b++)
+ ;
+ unsigned int g = -8;
+ while (g) {
+ g += 5;
+ int h = 10;
+ do {
+ h -= a = 1;
+ for (; a; a++)
+ ;
+ c *= c >= d >= b;
+ } while (h);
+ c -= e;
+ }
+}
if (gphi *phi = dyn_cast <gphi *> (USE_STMT (use_p)))
if (gimple_bb (phi)->loop_father->header == gimple_bb (phi)
&& (phi_info = loop_vinfo->lookup_stmt (phi))
+ && STMT_VINFO_RELEVANT_P (phi_info)
&& VECTORIZABLE_CYCLE_DEF (STMT_VINFO_DEF_TYPE (phi_info))
&& STMT_VINFO_REDUC_TYPE (phi_info) != FOLD_LEFT_REDUCTION
&& STMT_VINFO_REDUC_TYPE (phi_info) != EXTRACT_LAST_REDUCTION)