[Bug tree-optimization/70923] [7 regression] gcc.dg/vect/pr60092.c etc. FAIL

[glisse at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70923

--- Comment #3 from Marc Glisse <glisse at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #1)
> We have vect_recog_mult_pattern that should have triggered here but that
> only tries replacement with LSHIFT_EXPR rather than also a simple plus
> for 2 * x.

I guess that would be something like

--- tree-vect-patterns.c        (revision 236808)
+++ tree-vect-patterns.c        (working copy)
@@ -2226,7 +2226,13 @@ vect_recog_mult_pattern (vec<gimple *> *
   power2_neg_val = wi::exact_log2 (wi::neg (oprnd1));

   /* Handle constant operands that are postive or negative powers of 2.  */
-  if (power2_val != -1)
+  if (power2_val == 1)
+    {
+      pattern_stmt
+       = gimple_build_assign (vect_recog_temp_ssa_var (itype, NULL),
+                              PLUS_EXPR, oprnd0, oprnd0);
+    }
+  else if (power2_val != -1)
     {
       shift = build_int_cst (itype, power2_val);
       pattern_stmt

and something similar for the case *-2, it may be nicer to put this new ==1
case inside the !=-1 case (especially for power2_neg_val). But I don't think I
can easily test that, no sparc in the compile farm.