On Mon, Oct 24, 2022 at 12:43 PM Kewen.Lin <li...@linux.ibm.com> wrote: > > Hi, > > As PR107338 shows, with the use of widening loads, the > container_type can become a wider type, it causes us to > get wrong shift_n since the BIT_FIELD_REF offset actually > becomes bigger on BE. Taking the case in PR107338 as > example, at the beginning the container type is short and > BIT_FIELD_REF offset is 8 and size is 4, with unpacking to > wider type int, the high 16 bits are zero, by viewing it > as type int, its offset actually becomes to 24. So the > shift_n should be 4 (32 - 24 - 4) instead of 20 (32 - 8 > - 4). > > I noticed that if we move shift_n calculation early > before the adjustments for widening loads (container type > change), it's based on all the stuffs of the original > container, the shfit_n calculated there is exactly what > we want, it can be independent of widening. Besides, I > add prec adjustment together with the current adjustments > for widening loads, although prec's subsequent uses don't > require this change for now, since the container type gets > changed, we should keep the corresponding prec consistent. > > Bootstrapped and regtested on x86_64-redhat-linux, > aarch64-linux-gnu, powerpc64-linux-gnu P7 and P8 and > powerpc64le-linux-gnu P9 and P10. > > Is it ok for trunk?
OK. Richard. > BR, > Kewen > ----- > > PR tree-optimization/107338 > > gcc/ChangeLog: > > * tree-vect-patterns.cc (vect_recog_bitfield_ref_pattern): Move > shfit_n calculation before the adjustments for widening loads. > --- > gcc/tree-vect-patterns.cc | 17 +++++++++++------ > 1 file changed, 11 insertions(+), 6 deletions(-) > > diff --git a/gcc/tree-vect-patterns.cc b/gcc/tree-vect-patterns.cc > index 777ba2f5903..01094e8cb86 100644 > --- a/gcc/tree-vect-patterns.cc > +++ b/gcc/tree-vect-patterns.cc > @@ -1925,6 +1925,16 @@ vect_recog_bitfield_ref_pattern (vec_info *vinfo, > stmt_vec_info stmt_info, > tree container_type = TREE_TYPE (container); > tree vectype = get_vectype_for_scalar_type (vinfo, container_type); > > + /* Calculate shift_n before the adjustments for widening loads, otherwise > + the container may change and we have to consider offset change for > + widening loads on big endianness. The shift_n calculated here can be > + independent of widening. */ > + unsigned HOST_WIDE_INT shift_n = bit_field_offset (bf_ref).to_constant (); > + unsigned HOST_WIDE_INT mask_width = bit_field_size (bf_ref).to_constant (); > + unsigned HOST_WIDE_INT prec = tree_to_uhwi (TYPE_SIZE (container_type)); > + if (BYTES_BIG_ENDIAN) > + shift_n = prec - shift_n - mask_width; > + > /* We move the conversion earlier if the loaded type is smaller than the > return type to enable the use of widening loads. */ > if (TYPE_PRECISION (TREE_TYPE (container)) < TYPE_PRECISION (ret_type) > @@ -1935,6 +1945,7 @@ vect_recog_bitfield_ref_pattern (vec_info *vinfo, > stmt_vec_info stmt_info, > NOP_EXPR, container); > container = gimple_get_lhs (pattern_stmt); > container_type = TREE_TYPE (container); > + prec = tree_to_uhwi (TYPE_SIZE (container_type)); > vectype = get_vectype_for_scalar_type (vinfo, container_type); > append_pattern_def_seq (vinfo, stmt_info, pattern_stmt, vectype); > } > @@ -1953,12 +1964,6 @@ vect_recog_bitfield_ref_pattern (vec_info *vinfo, > stmt_vec_info stmt_info, > shift_first = false; > } > > - unsigned HOST_WIDE_INT shift_n = bit_field_offset (bf_ref).to_constant (); > - unsigned HOST_WIDE_INT mask_width = bit_field_size (bf_ref).to_constant (); > - unsigned HOST_WIDE_INT prec = tree_to_uhwi (TYPE_SIZE (container_type)); > - if (BYTES_BIG_ENDIAN) > - shift_n = prec - shift_n - mask_width; > - > /* If we don't have to shift we only generate the mask, so just fix the > code-path to shift_first. */ > if (shift_n == 0) > -- > 2.35.4
