Hi,
the current code for strided loads can't deal with the situation when a
prologue loop (peeling for alignment) is created after analyzing the data
refs. There are multiple issues (non-constant steps in DRs mainly), so
this is a simple stop gap.
Regtesting on x86_64-linux (all langs) in progress. Okay for trunk?
Ciao,
Michael.
--------------------
PR tree-optimization/53185
* tree-vect-data-refs.c (vect_enhance_data_refs_alignment): Disable
peeling when we see strided loads.
testsuite/
* gcc.dg/vect/pr53185.c: New test.
Index: tree-vect-data-refs.c
===================================================================
--- tree-vect-data-refs.c (revision 187287)
+++ tree-vect-data-refs.c (working copy)
@@ -1507,6 +1507,17 @@ vect_enhance_data_refs_alignment (loop_v
&& GROUP_FIRST_ELEMENT (stmt_info) != stmt)
continue;
+ /* FORNOW: Any strided load prevents peeling. The induction
+ variable analysis will fail when the prologue loop is generated,
+ and so we can't generate the new base for the pointer. */
+ if (STMT_VINFO_STRIDE_LOAD_P (stmt_info))
+ {
+ if (vect_print_dump_info (REPORT_DETAILS))
+ fprintf (vect_dump, "strided load prevents peeling");
+ do_peeling = false;
+ break;
+ }
+
/* For invariant accesses there is nothing to enhance. */
if (integer_zerop (DR_STEP (dr)))
continue;
Index: testsuite/gcc.dg/vect/pr53185.c
===================================================================
--- testsuite/gcc.dg/vect/pr53185.c (revision 0)
+++ testsuite/gcc.dg/vect/pr53185.c (revision 0)
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-options "-O3 -ftree-vectorize" } */
+unsigned short a, e;
+int *b, *d;
+int c;
+extern int fn2();
+void fn1 () {
+ void *f;
+ for (;;) {
+ fn2 ();
+ b = f;
+ e = 0;
+ for (; e < a; ++e)
+ b[e] = d[e * c];
+ }
+}
