diff options
| -rw-r--r-- | gcc/gimple-fold.c | 88 |
1 files changed, 81 insertions, 7 deletions
diff --git a/gcc/gimple-fold.c b/gcc/gimple-fold.c index 5d60bef..905c0a0 100644 --- a/gcc/gimple-fold.c +++ b/gcc/gimple-fold.c @@ -4033,7 +4033,9 @@ clear_padding_flush (clear_padding_struct *buf, bool full) { size_t nonzero_first = wordsize; size_t nonzero_last = 0; - bool all_ones = true; + size_t zero_first = wordsize; + size_t zero_last = 0; + bool all_ones = true, bytes_only = true; if ((unsigned HOST_WIDE_INT) (buf->off + i + wordsize) > (unsigned HOST_WIDE_INT) buf->sz) { @@ -4055,9 +4057,19 @@ clear_padding_flush (clear_padding_struct *buf, bool full) all_ones = false; nonzero_last = j + 1 - i; } + else + { + if (zero_first == wordsize) + zero_first = j - i; + zero_last = j + 1 - i; + } if (buf->buf[j] != 0 && buf->buf[j] != (unsigned char) ~0) - all_ones = false; + { + all_ones = false; + bytes_only = false; + } } + size_t padding_end = i; if (padding_bytes) { if (nonzero_first == 0 @@ -4069,7 +4081,6 @@ clear_padding_flush (clear_padding_struct *buf, bool full) padding_bytes += wordsize; continue; } - size_t padding_end = i; if (all_ones && nonzero_first == 0) { padding_bytes += nonzero_last; @@ -4077,12 +4088,27 @@ clear_padding_flush (clear_padding_struct *buf, bool full) nonzero_first = wordsize; nonzero_last = 0; } - tree atype = build_array_type_nelts (char_type_node, padding_bytes); + else if (bytes_only && nonzero_first == 0) + { + gcc_assert (zero_first && zero_first != wordsize); + padding_bytes += zero_first; + padding_end += zero_first; + } + tree atype, src; + if (padding_bytes == 1) + { + atype = char_type_node; + src = build_zero_cst (char_type_node); + } + else + { + atype = build_array_type_nelts (char_type_node, padding_bytes); + src = build_constructor (atype, NULL); + } tree dst = build2_loc (buf->loc, MEM_REF, atype, buf->base, build_int_cst (buf->alias_type, buf->off + padding_end - padding_bytes)); - tree src = build_constructor (atype, NULL); gimple *g = gimple_build_assign (dst, src); gimple_set_location (g, buf->loc); gsi_insert_before (buf->gsi, g, GSI_SAME_STMT); @@ -4099,6 +4125,45 @@ clear_padding_flush (clear_padding_struct *buf, bool full) padding_bytes = nonzero_last - nonzero_first; continue; } + if (bytes_only) + { + /* If bitfields aren't involved in this word, prefer storing + individual bytes or groups of them over performing a RMW + operation on the whole word. */ + gcc_assert (i + zero_last <= end); + for (size_t j = padding_end; j < i + zero_last; j++) + { + if (buf->buf[j]) + { + size_t k; + for (k = j; k < i + zero_last; k++) + if (buf->buf[k] == 0) + break; + HOST_WIDE_INT off = buf->off + j; + tree atype, src; + if (k - j == 1) + { + atype = char_type_node; + src = build_zero_cst (char_type_node); + } + else + { + atype = build_array_type_nelts (char_type_node, k - j); + src = build_constructor (atype, NULL); + } + tree dst = build2_loc (buf->loc, MEM_REF, atype, + buf->base, + build_int_cst (buf->alias_type, off)); + gimple *g = gimple_build_assign (dst, src); + gimple_set_location (g, buf->loc); + gsi_insert_before (buf->gsi, g, GSI_SAME_STMT); + j = k; + } + } + if (nonzero_last == wordsize) + padding_bytes = nonzero_last - zero_last; + continue; + } for (size_t eltsz = 1; eltsz <= wordsize; eltsz <<= 1) { if (nonzero_last - nonzero_first <= eltsz @@ -4153,12 +4218,21 @@ clear_padding_flush (clear_padding_struct *buf, bool full) { if (padding_bytes) { - tree atype = build_array_type_nelts (char_type_node, padding_bytes); + tree atype, src; + if (padding_bytes == 1) + { + atype = char_type_node; + src = build_zero_cst (char_type_node); + } + else + { + atype = build_array_type_nelts (char_type_node, padding_bytes); + src = build_constructor (atype, NULL); + } tree dst = build2_loc (buf->loc, MEM_REF, atype, buf->base, build_int_cst (buf->alias_type, buf->off + end - padding_bytes)); - tree src = build_constructor (atype, NULL); gimple *g = gimple_build_assign (dst, src); gimple_set_location (g, buf->loc); gsi_insert_before (buf->gsi, g, GSI_SAME_STMT); |