diff options
| -rw-r--r-- | gcc/avoid-store-forwarding.cc | 18 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.target/aarch64/avoid-store-forwarding-be.c | 23 |
2 files changed, 28 insertions, 13 deletions
diff --git a/gcc/avoid-store-forwarding.cc b/gcc/avoid-store-forwarding.cc index 37e0953..785efd2 100644 --- a/gcc/avoid-store-forwarding.cc +++ b/gcc/avoid-store-forwarding.cc @@ -119,17 +119,6 @@ generate_bit_insert_sequence (store_fwd_info *store_info, rtx dest) unsigned HOST_WIDE_INT bitsize = store_size * BITS_PER_UNIT; unsigned HOST_WIDE_INT start = store_info->offset * BITS_PER_UNIT; - /* Adjust START for machines with BITS_BIG_ENDIAN != BYTES_BIG_ENDIAN. - Given that the bytes will be reversed in this case, we need to - calculate the starting position from the end of the destination - register. */ - if (BITS_BIG_ENDIAN != BYTES_BIG_ENDIAN) - { - unsigned HOST_WIDE_INT load_mode_bitsize - = (GET_MODE_BITSIZE (GET_MODE (dest))).to_constant (); - start = load_mode_bitsize - bitsize - start; - } - rtx mov_reg = store_info->mov_reg; store_bit_field (dest, bitsize, start, 0, 0, GET_MODE (mov_reg), mov_reg, false, false); @@ -248,11 +237,14 @@ process_store_forwarding (vec<store_fwd_info> &stores, rtx_insn *load_insn, { it->mov_reg = gen_reg_rtx (GET_MODE (it->store_mem)); rtx_insn *insns = NULL; - const bool has_zero_offset = it->offset == 0; + const bool has_base_offset + = known_eq (poly_uint64 (it->offset), + subreg_size_lowpart_offset (MEM_SIZE (it->store_mem), + load_size)); /* If we're eliminating the load then find the store with zero offset and use it as the base register to avoid a bit insert if possible. */ - if (load_elim && has_zero_offset) + if (load_elim && has_base_offset) { start_sequence (); diff --git a/gcc/testsuite/gcc.target/aarch64/avoid-store-forwarding-be.c b/gcc/testsuite/gcc.target/aarch64/avoid-store-forwarding-be.c new file mode 100644 index 0000000..2e8946b --- /dev/null +++ b/gcc/testsuite/gcc.target/aarch64/avoid-store-forwarding-be.c @@ -0,0 +1,23 @@ +/* { dg-do run } */ +/* { dg-require-effective-target aarch64_big_endian } */ +/* { dg-options "-O2 -favoid-store-forwarding" } */ + +typedef union { + char arr[2]; + short value; +} DataUnion; + +short __attribute__ ((noinline)) +ssll (DataUnion *data, char x, char y) +{ + data->arr[0] = x; + data->arr[1] = y; + return data->value; +} + +int main () { + DataUnion data = {}; + short value = ssll (&data, 0, 1); + if (value != 1) + __builtin_abort (); +}
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