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.
