The recent change to vect_synth_mult_by_constant missed to handle
the synth_shift_p case for alg_shift, so we still changed c * 4
to c + c + c + c.
Bootstrap and regtest running on x86_64-unknown-linux-gnu.
PR tree-optimization/121753
* tree-vect-patterns.cc (vect_synth_mult_by_constant): Properly
account for at least one extra op use when synth_shift_p and
an alg_shift use.
---
gcc/tree-vect-patterns.cc | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/gcc/tree-vect-patterns.cc b/gcc/tree-vect-patterns.cc
index 16694d7991c..068ef094204 100644
--- a/gcc/tree-vect-patterns.cc
+++ b/gcc/tree-vect-patterns.cc
@@ -4330,6 +4330,10 @@ vect_synth_mult_by_constant (vec_info *vinfo, tree op,
tree val,
case alg_sub_t2_m:
op_uses++;
break;
+ case alg_shift:
+ if (synth_shift_p)
+ op_uses++;
+ break;
default:
break;
}
--
2.43.0
