Change a while loop in op_by_pieces_d::run to a do-while loop to prepare
for offset adjusted operation for the remaining bytes on the last piece
operation of a memory region.
PR middl-end/90773
* expr.c (op_by_pieces_d::get_usable_mode): New member function.
(op_by_pieces_d::run): Cange a while loop to a do-while loop.
---
gcc/expr.c | 76 +++++++++++++++++++++++++++++++++++++-----------------
1 file changed, 53 insertions(+), 23 deletions(-)
diff --git a/gcc/expr.c b/gcc/expr.c
index a0e19465965..07cb64427c9 100644
--- a/gcc/expr.c
+++ b/gcc/expr.c
@@ -1041,6 +1041,9 @@ pieces_addr::maybe_postinc (HOST_WIDE_INT size)
class op_by_pieces_d
{
+ private:
+ scalar_int_mode get_usable_mode (scalar_int_mode mode, unsigned int);
+
protected:
pieces_addr m_to, m_from;
unsigned HOST_WIDE_INT m_len;
@@ -1108,6 +1111,25 @@ op_by_pieces_d::op_by_pieces_d (rtx to, bool to_load,
m_align = align;
}
+/* This function returns the largest usable integer mode for LEN bytes
+ whose size is no bigger than size of MODE. */
+
+scalar_int_mode
+op_by_pieces_d::get_usable_mode (scalar_int_mode mode, unsigned int len)
+{
+ unsigned int size;
+ do
+ {
+ size = GET_MODE_SIZE (mode);
+ if (len >= size && prepare_mode (mode, m_align))
+ break;
+ /* NB: widest_int_mode_for_size checks SIZE > 1. */
+ mode = widest_int_mode_for_size (size);
+ }
+ while (1);
+ return mode;
+}
+
/* This function contains the main loop used for expanding a block
operation. First move what we can in the largest integer mode,
then go to successively smaller modes. For every access, call
@@ -1116,42 +1138,50 @@ op_by_pieces_d::op_by_pieces_d (rtx to, bool to_load,
void
op_by_pieces_d::run ()
{
- while (m_max_size > 1 && m_len > 0)
+ if (m_len == 0)
+ return;
+
+ /* NB: widest_int_mode_for_size checks M_MAX_SIZE > 1. */
+ scalar_int_mode mode = widest_int_mode_for_size (m_max_size);
+ mode = get_usable_mode (mode, m_len);
+
+ do
{
- scalar_int_mode mode = widest_int_mode_for_size (m_max_size);
+ unsigned int size = GET_MODE_SIZE (mode);
+ rtx to1 = NULL_RTX, from1;
- if (prepare_mode (mode, m_align))
+ while (m_len >= size)
{
- unsigned int size = GET_MODE_SIZE (mode);
- rtx to1 = NULL_RTX, from1;
+ if (m_reverse)
+ m_offset -= size;
- while (m_len >= size)
- {
- if (m_reverse)
- m_offset -= size;
+ to1 = m_to.adjust (mode, m_offset);
+ from1 = m_from.adjust (mode, m_offset);
- to1 = m_to.adjust (mode, m_offset);
- from1 = m_from.adjust (mode, m_offset);
+ m_to.maybe_predec (-(HOST_WIDE_INT)size);
+ m_from.maybe_predec (-(HOST_WIDE_INT)size);
- m_to.maybe_predec (-(HOST_WIDE_INT)size);
- m_from.maybe_predec (-(HOST_WIDE_INT)size);
+ generate (to1, from1, mode);
- generate (to1, from1, mode);
+ m_to.maybe_postinc (size);
+ m_from.maybe_postinc (size);
- m_to.maybe_postinc (size);
- m_from.maybe_postinc (size);
+ if (!m_reverse)
+ m_offset += size;
- if (!m_reverse)
- m_offset += size;
+ m_len -= size;
+ }
- m_len -= size;
- }
+ finish_mode (mode);
- finish_mode (mode);
- }
+ if (m_len == 0)
+ return;
- m_max_size = GET_MODE_SIZE (mode);
+ /* NB: widest_int_mode_for_size checks SIZE > 1. */
+ mode = widest_int_mode_for_size (size);
+ mode = get_usable_mode (mode, m_len);
}
+ while (1);
/* The code above should have handled everything. */
gcc_assert (!m_len);
--
2.31.1
