diff options
| -rw-r--r-- | gcc/config/avr/avr.cc | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/gcc/config/avr/avr.cc b/gcc/config/avr/avr.cc index d5af40f..9fa50ca 100644 --- a/gcc/config/avr/avr.cc +++ b/gcc/config/avr/avr.cc @@ -14425,10 +14425,13 @@ avr_fold_builtin (tree fndecl, int n_args ATTRIBUTE_UNUSED, tree *arg, if (changed) return build_call_expr (fndecl, 3, tmap, tbits, tval); - /* If bits don't change their position we can use vanilla logic - to merge the two arguments. */ + /* If bits don't change their position, we can use vanilla logic + to merge the two arguments... */ - if (avr_map_metric (map, MAP_NONFIXED_0_7) == 0) + if (avr_map_metric (map, MAP_NONFIXED_0_7) == 0 + // ...except when we are copying just one bit. In that + // case, BLD/BST is better than XOR/AND/XOR, see PR90622. + && avr_map_metric (map, MAP_FIXED_0_7) != 1) { int mask_f = avr_map_metric (map, MAP_MASK_PREIMAGE_F); tree tres, tmask = build_int_cst (val_type, mask_f ^ 0xff); |